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Al Nuaimi M, Al Khaaldi A, Trad O, Almulla A, Al Rufaye H, Ghatasheh G, Al Dhaheri F. HHV6-Associated Hydrocephalus in a Pediatric Hematopoietic Stem Cell Transplant Recipient: An Unusual Presentation. J Pediatr Hematol Oncol 2024:00043426-990000000-00427. [PMID: 38832402 DOI: 10.1097/mph.0000000000002892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 04/25/2024] [Indexed: 06/05/2024]
Abstract
Human herpesvirus 6 (HHV-6) is a widely spread DNA virus that is ubiquitous and persistent with primary infection occurring in early childhood, with reactivation of the infection a common phenomenon in severely immunocompromised hosts, including hematopoietic stem cell transplant (HSCT) patients, influencing morbidity and mortality. A wide spectrum of clinical presentations is reported in the literature with HHV-6 reactivation including post-transplant limbic encephalitis (PALE). We report the unusual case of a 6-year-old female 107 days postallogenic HSCT due to transfusion dependent beta thalassemia major who developed acute cerebellitis with secondary supratentorial hydrocephalus that required invasive surgical intervention. In addition to accompanying imaging findings, the patient tested positive for HHV-6 by PCR from both serum and CSF samples and demonstrated dramatic improvement with the institution of steroid therapy in addition to ganciclovir treatment. The availability of rapid diagnostic measures in addition to a multidisciplinary approach is crucial to manage HHV-6 encephalitis and associated complications in HSCT patients.
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Affiliation(s)
- Mohammed Al Nuaimi
- Division of Pediatric Hematology and Oncology, Tawam Oncology Centre
- Department of Pediatrics, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain
| | - Aisha Al Khaaldi
- Department of Pediatrics, Al Qassimi Women and Children Hospital
- Sharjah University Hospital, Sharjah
| | - Omar Trad
- Division of Pediatric Hematology and Oncology, Tawam Oncology Centre
| | - Asia Almulla
- Division of Pediatric Hematology and Oncology, Tawam Oncology Centre
- Sharjah University Hospital, Sharjah
| | - Haydar Al Rufaye
- Division of Pediatric Hematology and Oncology, Tawam Oncology Centre
| | - Ghassan Ghatasheh
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Tawam Hospital
| | - Fatima Al Dhaheri
- Department of Pediatrics, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain
- Pediatric Infectious Diseases Unit, Department of Pediatrics, Sheikh Khalifa Medical City, Abu-Dhabi, United Arab Emirates
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2
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Collin V, Biquand É, Tremblay V, Lavoie ÉG, Blondeau A, Gravel A, Galloy M, Lashgari A, Dessapt J, Côté J, Flamand L, Fradet-Turcotte A. The immediate-early protein 1 of human herpesvirus 6B interacts with NBS1 and inhibits ATM signaling. EMBO Rep 2024; 25:725-744. [PMID: 38177923 PMCID: PMC10897193 DOI: 10.1038/s44319-023-00035-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 12/03/2023] [Accepted: 12/06/2023] [Indexed: 01/06/2024] Open
Abstract
Viral infection often trigger an ATM serine/threonine kinase (ATM)-dependent DNA damage response in host cells that suppresses viral replication. Viruses evolved different strategies to counteract this antiviral surveillance system. Here, we report that human herpesvirus 6B (HHV-6B) infection causes genomic instability by suppressing ATM signaling in host cells. Expression of immediate-early protein 1 (IE1) phenocopies this phenotype and blocks homology-directed double-strand break repair. Mechanistically, IE1 interacts with NBS1, and inhibits ATM signaling through two distinct domains. HHV-6B seems to efficiently inhibit ATM signaling as further depletion of either NBS1 or ATM do not significantly boost viral replication in infected cells. Interestingly, viral integration of HHV-6B into the host's telomeres is not strictly dependent on NBS1, challenging current models where integration occurs through homology-directed repair. Given that spontaneous IE1 expression has been detected in cells of subjects with inherited chromosomally-integrated form of HHV-6B (iciHHV-6B), a condition associated with several health conditions, our results raise the possibility of a link between genomic instability and the development of iciHHV-6-associated diseases.
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Affiliation(s)
- Vanessa Collin
- Division of Infectious Disease and Immunity, Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Quebec City, QC, G1V 4G2, Canada
- Department of Microbiology, Infectious Disease and Immunology, Faculty of Medicine, Université Laval, Quebec City, QC, G1V 0A6, Canada
| | - Élise Biquand
- Oncology Division, Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Quebec City, QC, G1R 2J6, Canada
- Department of Molecular biology, Medical Biochemistry and Pathology, Faculty of Medicine, Université Laval, Québec City, QC, G1V 0A6, Canada
- Université Laval Cancer Research Center, Université Laval, Quebec City, QC, G1R 3S3, Canada
- INSERM, Centre d'Étude des Pathologies Respiratoires (CEPR), UMR 1100, Université de Tours, Tours, France
| | - Vincent Tremblay
- Oncology Division, Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Quebec City, QC, G1R 2J6, Canada
- Department of Molecular biology, Medical Biochemistry and Pathology, Faculty of Medicine, Université Laval, Québec City, QC, G1V 0A6, Canada
- Université Laval Cancer Research Center, Université Laval, Quebec City, QC, G1R 3S3, Canada
| | - Élise G Lavoie
- Oncology Division, Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Quebec City, QC, G1R 2J6, Canada
- Université Laval Cancer Research Center, Université Laval, Quebec City, QC, G1R 3S3, Canada
| | - Andréanne Blondeau
- Oncology Division, Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Quebec City, QC, G1R 2J6, Canada
- Université Laval Cancer Research Center, Université Laval, Quebec City, QC, G1R 3S3, Canada
| | - Annie Gravel
- Division of Infectious Disease and Immunity, Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Quebec City, QC, G1V 4G2, Canada
- Department of Microbiology, Infectious Disease and Immunology, Faculty of Medicine, Université Laval, Quebec City, QC, G1V 0A6, Canada
| | - Maxime Galloy
- Oncology Division, Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Quebec City, QC, G1R 2J6, Canada
- Department of Molecular biology, Medical Biochemistry and Pathology, Faculty of Medicine, Université Laval, Québec City, QC, G1V 0A6, Canada
- Université Laval Cancer Research Center, Université Laval, Quebec City, QC, G1R 3S3, Canada
| | - Anahita Lashgari
- Oncology Division, Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Quebec City, QC, G1R 2J6, Canada
- Department of Molecular biology, Medical Biochemistry and Pathology, Faculty of Medicine, Université Laval, Québec City, QC, G1V 0A6, Canada
- Université Laval Cancer Research Center, Université Laval, Quebec City, QC, G1R 3S3, Canada
| | - Julien Dessapt
- Oncology Division, Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Quebec City, QC, G1R 2J6, Canada
- Department of Molecular biology, Medical Biochemistry and Pathology, Faculty of Medicine, Université Laval, Québec City, QC, G1V 0A6, Canada
- Université Laval Cancer Research Center, Université Laval, Quebec City, QC, G1R 3S3, Canada
| | - Jacques Côté
- Oncology Division, Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Quebec City, QC, G1R 2J6, Canada
- Department of Molecular biology, Medical Biochemistry and Pathology, Faculty of Medicine, Université Laval, Québec City, QC, G1V 0A6, Canada
- Université Laval Cancer Research Center, Université Laval, Quebec City, QC, G1R 3S3, Canada
| | - Louis Flamand
- Division of Infectious Disease and Immunity, Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Quebec City, QC, G1V 4G2, Canada.
- Department of Microbiology, Infectious Disease and Immunology, Faculty of Medicine, Université Laval, Quebec City, QC, G1V 0A6, Canada.
| | - Amélie Fradet-Turcotte
- Oncology Division, Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Quebec City, QC, G1R 2J6, Canada.
- Department of Molecular biology, Medical Biochemistry and Pathology, Faculty of Medicine, Université Laval, Québec City, QC, G1V 0A6, Canada.
- Université Laval Cancer Research Center, Université Laval, Quebec City, QC, G1R 3S3, Canada.
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Zareie AR, Dabral P, Verma SC. G-Quadruplexes in the Regulation of Viral Gene Expressions and Their Impacts on Controlling Infection. Pathogens 2024; 13:60. [PMID: 38251367 PMCID: PMC10819198 DOI: 10.3390/pathogens13010060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 01/05/2024] [Accepted: 01/05/2024] [Indexed: 01/23/2024] Open
Abstract
G-quadruplexes (G4s) are noncanonical nucleic acid structures that play significant roles in regulating various biological processes, including replication, transcription, translation, and recombination. Recent studies have identified G4s in the genomes of several viruses, such as herpes viruses, hepatitis viruses, and human coronaviruses. These structures are implicated in regulating viral transcription, replication, and virion production, influencing viral infectivity and pathogenesis. G4-stabilizing ligands, like TMPyP4, PhenDC3, and BRACO19, show potential antiviral properties by targeting and stabilizing G4 structures, inhibiting essential viral life-cycle processes. This review delves into the existing literature on G4's involvement in viral regulation, emphasizing specific G4-stabilizing ligands. While progress has been made in understanding how these ligands regulate viruses, further research is needed to elucidate the mechanisms through which G4s impact viral processes. More research is necessary to develop G4-stabilizing ligands as novel antiviral agents. The increasing body of literature underscores the importance of G4s in viral biology and the development of innovative therapeutic strategies against viral infections. Despite some ligands' known regulatory effects on viruses, a deeper comprehension of the multifaceted impact of G4s on viral processes is essential. This review advocates for intensified research to unravel the intricate relationship between G4s and viral processes, paving the way for novel antiviral treatments.
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Affiliation(s)
| | | | - Subhash C. Verma
- Department of Microbiology and Immunology, University of Nevada, Reno School of Medicine, 1664 N Virginia Street, Reno, NV 89557, USA; (A.R.Z.); (P.D.)
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4
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Wang H, Tomatis-Souverbielle C, Everhart K, Oyeniran SJ, Leber AL. Detection of human herpesvirus 6 in pediatric CSF samples: causing disease or incidental distraction? Diagn Microbiol Infect Dis 2023; 107:116029. [PMID: 37527599 DOI: 10.1016/j.diagmicrobio.2023.116029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 07/13/2023] [Accepted: 07/15/2023] [Indexed: 08/03/2023]
Abstract
Interpretation of human herpesvirus type 6 (HHV6) detection in the cerebrospinal fluid (CSF) of children can be complex; the virus can cause acute infection, reactivation, or can be inherited chromosomally integrated (iciHHV6). Our objectives were to determine the prevalence of HHV6 including iciHHV6 in CSF and compare the clinical and laboratory characteristics with and without iciHHV6 in our patient population. Overall, the prevalence of HHV6 and iciHHV6 was 2.4% and 0.85%, respectively. Children with iciHHV6 were significantly younger and less likely to present with fever. Septic infants (≤60 days) accounted for 65.2% (15/23) of the iciHHV6 patients. Patients with iciHHV6 had higher viral loads in CSF and whole blood. Twenty-one (91.3%) patients with iciHHV6 and 12 (33.3%) without ici-HHV6 were determined to have an incidental detection of HHV6 not associated with presenting symptoms. Molecular detection of HHV6 in CSF is not always associated with HHV6 infection and may represent iciHHV6 particularly in infants evaluated for sepsis.
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Affiliation(s)
- Huanyu Wang
- Department of Pathology and Laboratory Medicine, Nationwide Children's Hospital, Columbus, OH, USA; Department of Pathology, The Ohio State University, Columbus, OH, USA
| | - Cristina Tomatis-Souverbielle
- Division of Infectious Diseases, Department of Pediatrics, Nationwide Children's Hospital and The Ohio State University, Columbus, OH, USA
| | - Kathy Everhart
- Department of Pathology and Laboratory Medicine, Nationwide Children's Hospital, Columbus, OH, USA
| | - Sophonie J Oyeniran
- Department of Pathology and Laboratory Medicine, Nationwide Children's Hospital, Columbus, OH, USA; Department of Pathology, The Ohio State University, Columbus, OH, USA
| | - Amy L Leber
- Department of Pathology and Laboratory Medicine, Nationwide Children's Hospital, Columbus, OH, USA; Division of Infectious Diseases, Department of Pediatrics, Nationwide Children's Hospital and The Ohio State University, Columbus, OH, USA; Department of Pathology, The Ohio State University, Columbus, OH, USA.
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5
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Noviello M, Lorentino F, Xue E, Racca S, Furnari G, Valtolina V, Campodonico E, Dvir R, Lupo-Stanghellini MT, Giglio F, Piemontese S, Clerici D, Oltolini C, Tassi E, Beretta V, Farina F, Mannina D, Ardemagni A, Vago L, Bernardi M, Corti C, Peccatori J, Clementi M, Ciceri F, Bonini C, Greco R. Human herpesvirus 6-specific T-cell immunity in allogeneic hematopoietic stem cell transplant recipients. Blood Adv 2023; 7:5446-5457. [PMID: 37067947 PMCID: PMC10515312 DOI: 10.1182/bloodadvances.2022009274] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 04/05/2023] [Accepted: 04/07/2023] [Indexed: 04/18/2023] Open
Abstract
Human herpesvirus 6 (HHV-6) can reactivate after allogeneic hematopoietic stem cell transplant (allo-HSCT) and may lead to severe symptoms. HHV-6-specific immune responses after HSCT are largely unexplored. We conducted a prospective observational study on 208 consecutive adult patients who received allo-HSCT to investigate HHV-6 reactivations and specific immune responses. Interferon gamma-producing HHV-6-specific T cells were quantified using enzyme-linked immunospot assay (ELISpot). HHV-6 reactivation occurred in 63% of patients, at a median of 25 days from allo-HSCT. Only 40% of these presented a clinically relevant infection, defined by the presence of classical HHV-6 end-organ diseases (EODs), based on European Conference on Infections in Leukaemia (ECIL) guidelines, and other possible HHV6-related EODs. Using multivariate analysis, we identified risk factors for HHV-6 reactivation: previous allo-HSCT, posttransplant cyclophosphamide (PT-Cy), and time-dependent steroids introduction. The use of PT-Cy and steroids were associated with clinically relevant infections, whereas higher CD3+ cell counts seemed to be protective. Interestingly, circulating HHV-6-specific T cells were significantly higher in patients with reactivated virus. Moreover, HHV-6-specific T-cell responses, quantified at >4 days after the first viremia detection, predicted clinically relevant infections (P < .0001), with higher specificity (93%) and sensitivity (79%) than polyclonal CD3+ cells per μL. Overall survival and transplant-related mortality were not affected by time-dependent HHV-6 reactivation, whereas a significant association was observed between clinically relevant infections and acute graft-versus-host disease. These results shed light on the role of HHV-6 in allo-HSCT and may affect HHV-6 monitoring and treatment.
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Affiliation(s)
- Maddalena Noviello
- Experimental Hematology Unit, Division of Immunology, Transplantation and Infectious Diseases, Milano, Italy
- Cell Therapy Immunomonitoring Laboratory, Division of Immunology, Transplantation and Infectious Diseases, Ospedale San Raffaele Scientific Institute, Milano, Italy
| | - Francesca Lorentino
- Haematology and Bone Marrow Transplant Unit, Ospedale San Raffaele Scientific Institute, Milano, Italy
| | - Elisabetta Xue
- Haematology and Bone Marrow Transplant Unit, Ospedale San Raffaele Scientific Institute, Milano, Italy
| | - Sara Racca
- Laboratory of Microbiology and Virology, Ospedale San Raffaele Scientific Institute, Milan, Italy
| | | | - Veronica Valtolina
- Experimental Hematology Unit, Division of Immunology, Transplantation and Infectious Diseases, Milano, Italy
- Cell Therapy Immunomonitoring Laboratory, Division of Immunology, Transplantation and Infectious Diseases, Ospedale San Raffaele Scientific Institute, Milano, Italy
| | - Edoardo Campodonico
- Haematology and Bone Marrow Transplant Unit, Ospedale San Raffaele Scientific Institute, Milano, Italy
- Università Vita-Salute San Raffaele, Milan, Italy
| | - Roee Dvir
- Laboratory of Microbiology and Virology, Ospedale San Raffaele Scientific Institute, Milan, Italy
| | | | - Fabio Giglio
- Haematology and Bone Marrow Transplant Unit, Ospedale San Raffaele Scientific Institute, Milano, Italy
| | - Simona Piemontese
- Haematology and Bone Marrow Transplant Unit, Ospedale San Raffaele Scientific Institute, Milano, Italy
| | - Daniela Clerici
- Haematology and Bone Marrow Transplant Unit, Ospedale San Raffaele Scientific Institute, Milano, Italy
| | - Chiara Oltolini
- Infectious Disease Unit, Ospedale San Raffaele Scientific Institute, Milan, Italy
| | - Elena Tassi
- Experimental Hematology Unit, Division of Immunology, Transplantation and Infectious Diseases, Milano, Italy
- Cell Therapy Immunomonitoring Laboratory, Division of Immunology, Transplantation and Infectious Diseases, Ospedale San Raffaele Scientific Institute, Milano, Italy
| | - Valeria Beretta
- Experimental Hematology Unit, Division of Immunology, Transplantation and Infectious Diseases, Milano, Italy
- Cell Therapy Immunomonitoring Laboratory, Division of Immunology, Transplantation and Infectious Diseases, Ospedale San Raffaele Scientific Institute, Milano, Italy
| | - Francesca Farina
- Haematology and Bone Marrow Transplant Unit, Ospedale San Raffaele Scientific Institute, Milano, Italy
| | - Daniele Mannina
- Haematology and Bone Marrow Transplant Unit, Ospedale San Raffaele Scientific Institute, Milano, Italy
| | - Anna Ardemagni
- Laboratory of Microbiology and Virology, Ospedale San Raffaele Scientific Institute, Milan, Italy
| | - Luca Vago
- Università Vita-Salute San Raffaele, Milan, Italy
- Unit of Immunogenetics, Leukemia Genomics and Immunobiology, Ospedale San Raffaele Scientific Institute, Milan, Italy
| | - Massimo Bernardi
- Haematology and Bone Marrow Transplant Unit, Ospedale San Raffaele Scientific Institute, Milano, Italy
| | - Consuelo Corti
- Haematology and Bone Marrow Transplant Unit, Ospedale San Raffaele Scientific Institute, Milano, Italy
| | - Jacopo Peccatori
- Haematology and Bone Marrow Transplant Unit, Ospedale San Raffaele Scientific Institute, Milano, Italy
| | - Massimo Clementi
- Laboratory of Microbiology and Virology, Ospedale San Raffaele Scientific Institute, Milan, Italy
- Università Vita-Salute San Raffaele, Milan, Italy
| | - Fabio Ciceri
- Haematology and Bone Marrow Transplant Unit, Ospedale San Raffaele Scientific Institute, Milano, Italy
- Università Vita-Salute San Raffaele, Milan, Italy
| | - Chiara Bonini
- Experimental Hematology Unit, Division of Immunology, Transplantation and Infectious Diseases, Milano, Italy
- Cell Therapy Immunomonitoring Laboratory, Division of Immunology, Transplantation and Infectious Diseases, Ospedale San Raffaele Scientific Institute, Milano, Italy
- Università Vita-Salute San Raffaele, Milan, Italy
| | - Raffaella Greco
- Haematology and Bone Marrow Transplant Unit, Ospedale San Raffaele Scientific Institute, Milano, Italy
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Inherited Chromosomally Integrated Human Herpesvirus 6: Laboratory and Clinical Features. Microorganisms 2023; 11:microorganisms11030548. [PMID: 36985122 PMCID: PMC10052293 DOI: 10.3390/microorganisms11030548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 02/15/2023] [Indexed: 02/25/2023] Open
Abstract
Inherited chromosomally integrated human herpesvirus 6 (iciHHV-6) is a condition in which the complete HHV-6 genome is integrated into the chromosomes of the host germ cell and is vertically transmitted. The aims of this study were to identify iciHHV-6 prevalence in hospitalized patients and clinical features in individuals carrying this integration. HHV-6 PCR on hair follicles was used to confirm iciHHV-6 status when the blood viral load was more than 5 Log10 copies/mL. From January 2012 to June 2022, HHV-6 DNAemia was investigated in 2019 patients. In particular, 49 had a viral load higher than 6 Log10 copies/mL and HHV-6 DNA in hair follicles was positive. A viral load between 5.0 and 5.9 Log10 copies/mL was observed in 10 patients: 6 infants with acute HHV-6 infection and 4 patients with leukopenia and HHV-6 integration. Therefore, the iciHHV-6 prevalence in our population was 2.6% (53/2019). Adult patients with integration presented hematological (24%), autoimmune (11%), autoimmune neurological (19%), not-autoimmune neurological (22%), and other diseases (19%), whereas 5% had no clinically relevant disease. Although in our study population a high percentage of iciHHV-6 adult hospitalized patients presented a specific pathology, it is still unknown whether the integration is responsible for, or contributes to, the disease development.
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Kusakin AV, Goleva OV, Danilov LG, Krylov AV, Tsay VV, Kalinin RS, Tian NS, Eismont YA, Mukomolova AL, Chukhlovin AB, Komissarov AS, Glotov OS. The Telomeric Repeats of HHV-6A Do Not Determine the Chromosome into Which the Virus Is Integrated. Genes (Basel) 2023; 14:521. [PMID: 36833448 PMCID: PMC9957103 DOI: 10.3390/genes14020521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 02/10/2023] [Accepted: 02/13/2023] [Indexed: 02/22/2023] Open
Abstract
Human herpes virus 6A (HHV-6A) is able to integrate into the telomeric and subtelomeric regions of human chromosomes representing chromosomally integrated HHV-6A (ciHHV-6A). The integration starts from the right direct repeat (DRR) region. It has been shown experimentally that perfect telomeric repeats (pTMR) in the DRR region are required for the integration, while the absence of the imperfect telomeric repeats (impTMR) only slightly reduces the frequency of HHV-6 integration cases. The aim of this study was to determine whether telomeric repeats within DRR may define the chromosome into which the HHV-6A integrates. We analysed 66 HHV-6A genomes obtained from public databases. Insertion and deletion patterns of DRR regions were examined. We also compared TMR within the herpes virus DRR and human chromosome sequences retrieved from the Telomere-to-Telomere consortium. Our results show that telomeric repeats in DRR in circulating and ciHHV-6A have an affinity for all human chromosomes studied and thus do not define a chromosome for integration.
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Affiliation(s)
- Aleksey V. Kusakin
- Pediatric Research and Clinical Center for Infectious Diseases, 197022 St. Petersburg, Russia
- SCAMT Institute, ITMO University, 191002 St. Petersburg, Russia
| | - Olga V. Goleva
- Pediatric Research and Clinical Center for Infectious Diseases, 197022 St. Petersburg, Russia
| | - Lavrentii G. Danilov
- Department of Genetics and Biotechnology, Saint-Petersburg State University, Universitetskaya Nab. 7/9, 199034 St. Petersburg, Russia
| | - Andrey V. Krylov
- Pediatric Research and Clinical Center for Infectious Diseases, 197022 St. Petersburg, Russia
| | - Victoria V. Tsay
- Pediatric Research and Clinical Center for Infectious Diseases, 197022 St. Petersburg, Russia
| | - Roman S. Kalinin
- Pediatric Research and Clinical Center for Infectious Diseases, 197022 St. Petersburg, Russia
| | - Natalia S. Tian
- Pediatric Research and Clinical Center for Infectious Diseases, 197022 St. Petersburg, Russia
| | - Yuri A. Eismont
- Pediatric Research and Clinical Center for Infectious Diseases, 197022 St. Petersburg, Russia
| | - Anna L. Mukomolova
- Pediatric Research and Clinical Center for Infectious Diseases, 197022 St. Petersburg, Russia
| | - Alexei B. Chukhlovin
- Pediatric Research and Clinical Center for Infectious Diseases, 197022 St. Petersburg, Russia
- R.M.Gorbacheva Memorial Institute of Oncology, Hematology and Transplantation, Pavlov First Saint Petersburg State Medical University, 197022 St. Petersburg, Russia
| | | | - Oleg S. Glotov
- Pediatric Research and Clinical Center for Infectious Diseases, 197022 St. Petersburg, Russia
- D.O. Ott Research Institute of Obstetrics, Gynaecology, and Reproductology, 199034 St. Petersburg, Russia
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8
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Sandhu A, Kim J, Bell LM, Jyonouchi S, Akhtar LN, Henrickson SE. Persistent HHV-6 DNAemia in a Patient Presenting With Meningoencephalitis. Pediatrics 2022; 150:189904. [PMID: 36330748 DOI: 10.1542/peds.2022-056759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/19/2022] [Indexed: 11/06/2022] Open
Affiliation(s)
| | | | - Louis M Bell
- Division of Infectious Diseases.,Division of General Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | | | | | - Sarah E Henrickson
- Division of Allergy and Immunology.,Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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9
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Hogestyn JM, Salois G, Xie L, Apa C, Youngyunpipatkul J, Pröschel C, Mayer-Pröschel M. Expression of the human herpesvirus 6A latency-associated transcript U94A impairs cytoskeletal functions in human neural cells. Mol Cell Neurosci 2022; 123:103770. [PMID: 36055520 PMCID: PMC10124163 DOI: 10.1016/j.mcn.2022.103770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 08/12/2022] [Accepted: 08/20/2022] [Indexed: 12/30/2022] Open
Abstract
Many neurodegenerative diseases have a multifactorial etiology and variable course of progression that cannot be explained by current models. Neurotropic viruses have long been suggested to play a role in these diseases, although their exact contributions remain unclear. Human herpesvirus 6A (HHV-6A) is one of the most common viruses detected in the adult brain, and has been clinically associated with multiple sclerosis (MS), and, more recently, Alzheimer's disease (AD). HHV-6A is a ubiquitous viral pathogen capable of infecting glia and neurons. Primary infection in childhood is followed by the induction of latency, characterized by expression of the U94A viral transcript in the absence of viral replication. Here we examine the effects of U94A on cells of the central nervous system. We found that U94A expression inhibits the migration and impairs cytoplasmic maturation of human oligodendrocyte precursor cells (OPCs) without affecting their viability, a phenotype that may contribute to the failure of remyelination seen in many patients with MS. A subsequent proteomics analysis of U94A expression OPCs revealed altered expression of genes involved in tubulin associated cytoskeletal regulation. As HHV-6A seems to significantly be associated with early AD pathology, we extended our initially analysis of the impact of U94A on human derived neurons. We found that U94A expression inhibits neurite outgrowth of primary human cortical neurons and impairs synapse maturation. Based on these data we suggest that U94A expression by latent HHV-6A in glial cells and neurons renders them susceptible to dysfunction and degeneration. Therefore, latent viral infections of the brain represent a unique pathological risk factor that may contribute to disease processes.
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Affiliation(s)
- Jessica M Hogestyn
- Department of Biomedical Genetics, 601 Elmwood Avenue, Box 633, University of Rochester, Rochester, NY 14642, USA; Department of Neuroscience, School of Medicine and Dentistry, 601 Elmwood Avenue, Box 633, University of Rochester, Rochester, NY 14642, USA
| | - Garrick Salois
- Department of Biomedical Genetics, 601 Elmwood Avenue, Box 633, University of Rochester, Rochester, NY 14642, USA; Department of Neuroscience, School of Medicine and Dentistry, 601 Elmwood Avenue, Box 633, University of Rochester, Rochester, NY 14642, USA
| | - Li Xie
- Department of Biomedical Genetics, 601 Elmwood Avenue, Box 633, University of Rochester, Rochester, NY 14642, USA
| | - Connor Apa
- Department of Biomedical Genetics, 601 Elmwood Avenue, Box 633, University of Rochester, Rochester, NY 14642, USA; Stem cell and Regenerative Medicine Institute, 601 Elmwood Avenue, Box 633, University of Rochester, Rochester, NY 14642, USA
| | - Justin Youngyunpipatkul
- Department of Biomedical Genetics, 601 Elmwood Avenue, Box 633, University of Rochester, Rochester, NY 14642, USA
| | - Christoph Pröschel
- Department of Biomedical Genetics, 601 Elmwood Avenue, Box 633, University of Rochester, Rochester, NY 14642, USA; Stem cell and Regenerative Medicine Institute, 601 Elmwood Avenue, Box 633, University of Rochester, Rochester, NY 14642, USA
| | - Margot Mayer-Pröschel
- Department of Biomedical Genetics, 601 Elmwood Avenue, Box 633, University of Rochester, Rochester, NY 14642, USA; Department of Neuroscience, School of Medicine and Dentistry, 601 Elmwood Avenue, Box 633, University of Rochester, Rochester, NY 14642, USA,.
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10
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Impact of Host Telomere Length on HHV-6 Integration. Viruses 2022; 14:v14091864. [PMID: 36146670 PMCID: PMC9505050 DOI: 10.3390/v14091864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/15/2022] [Accepted: 08/21/2022] [Indexed: 12/04/2022] Open
Abstract
Human herpesvirus 6A and 6B are two closely related viruses that infect almost all humans. In contrast to most herpesviruses, HHV-6A/B can integrate their genomes into the telomeres during the infection process. Both viruses can also integrate in germ cells and subsequently be inherited in children. How HHV-6A/B integrate into host telomeres and the consequences of this remain a subject of active research. Here, we developed a method to measure telomere length by quantitative fluorescence in situ hybridization, confocal microscopy, and computational processing. This method was validated using a panel of HeLa cells having short or long telomeres. These cell lines were infected with HHV-6A, revealing that the virus could efficiently integrate into telomeres independent of their length. Furthermore, we assessed the telomere lengths after HHV-6A integration and found that the virus-containing telomeres display a variety of lengths, suggesting that either telomere length is restored after integration or telomeres are not shortened by integration. Our results highlight new aspects of HHV-6A/B biology and the role of telomere length on virus integration.
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11
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Izquierdo L, Canivet CM, De Martin E, Antonini TM, Roque-Afonso AM, Coilly A, Deback C. Investigation of Inherited Chromosomally Integrated Human Herpesvirus-6A+ and -6B+ in a Patient with Ulipristal Acetate-Induced Fulminant Hepatic Failure. Viruses 2021; 14:v14010062. [PMID: 35062266 PMCID: PMC8778448 DOI: 10.3390/v14010062] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 12/23/2021] [Accepted: 12/27/2021] [Indexed: 01/01/2023] Open
Abstract
Inherited chromosomally integrated (ici) human herpes virus 6 (HHV-6) is estimated to occur in 0.6–2.7% of people worldwide. HHV-6 comprises two distinct species: HHV-6A and HHV-6B. Both HHV-6A and HHV-6B integration have been reported. Several drugs are capable of activating iciHHV-6 in tissues, the consequences of which are poorly understood. We report herein a case of a woman with iciHHV-6A+ and iciHHV-6B+, who developed ulipristal acetate (a selective progesterone receptor modulator)-induced fulminant hepatic failure that required liver transplantation. We confirmed the presence of ~one copy per cell of both HHV-6A and HHV-6B DNA in her hair follicles using multiplex HHV-6A/B real-time PCR and demonstrated the Mendelian inheritance of both iciHHV-6A and iciHHV-6B in her family members over three generations. Because of the rarity of this presentation, we discuss herein the possible links between reactivated HHV-6 from iciHHV-6A and/or iciHHV-6B and adverse drug reactions, suggesting that iciHHV-6 could be screened before the introduction of any hepatotoxic drugs to exclude HHV-6 active disease or combined idiosyncratic drug-induced liver injury in these patients.
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Affiliation(s)
- Laure Izquierdo
- Laboratoire de Virologie, Institut National de la Santé et de la Recherche Médicale Unité 1193 AP-HP, Hôpitaux Universitaires Paris Saclay, Hôpital Paul-Brousse, 94800 Villejuif, France; (L.I.); (A.-M.R.-A.)
| | - Clémence M. Canivet
- Laboratoire HIFIH, UPRES EA3859, SFR 4208, Service d’Hépato-Gastroentérologie et Oncologie Digestive, Centre Hospitalier Universitaire d’Angers, Université d’Angers, 49000 Angers, France;
| | - Eleonora De Martin
- Centre Hépato-Biliaire, AP-HP, Institut National de la Santé et de la Recherche Médicale Unité 1193, Hôpitaux Universitaires Paris Saclay, Hôpital Paul-Brousse, 94800 Villejuif, France; (E.D.M.); (T.M.A.); (A.C.)
| | - Teresa M. Antonini
- Centre Hépato-Biliaire, AP-HP, Institut National de la Santé et de la Recherche Médicale Unité 1193, Hôpitaux Universitaires Paris Saclay, Hôpital Paul-Brousse, 94800 Villejuif, France; (E.D.M.); (T.M.A.); (A.C.)
| | - Anne-Marie Roque-Afonso
- Laboratoire de Virologie, Institut National de la Santé et de la Recherche Médicale Unité 1193 AP-HP, Hôpitaux Universitaires Paris Saclay, Hôpital Paul-Brousse, 94800 Villejuif, France; (L.I.); (A.-M.R.-A.)
| | - Audrey Coilly
- Centre Hépato-Biliaire, AP-HP, Institut National de la Santé et de la Recherche Médicale Unité 1193, Hôpitaux Universitaires Paris Saclay, Hôpital Paul-Brousse, 94800 Villejuif, France; (E.D.M.); (T.M.A.); (A.C.)
| | - Claire Deback
- Laboratoire de Virologie, AP-HP, Hôpitaux Universitaires Paris Saclay, Hôpital Paul-Brousse, 94800 Villejuif, France
- Inserm U996, Inflammation, Microbiome and Immunosurveillance, Université Paris-Saclay, 92140 Clamart, France
- Correspondence: ; Tel.: +33-141-28-80-00
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12
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Wang X, Patel SA, Haddadin M, Cerny J. Post-allogeneic hematopoietic stem cell transplantation viral reactivations and viremias: a focused review on human herpesvirus-6, BK virus and adenovirus. Ther Adv Infect Dis 2021; 8:20499361211018027. [PMID: 34104434 PMCID: PMC8155777 DOI: 10.1177/20499361211018027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 04/27/2021] [Indexed: 12/30/2022] Open
Abstract
Human cytomegalovirus and Epstein-Barr virus have been recognized as potential drivers of morbidity and mortality of patients undergoing allogeneic stem cell transplantation for years. Specific protocols for monitoring, prophylaxis and pre-emptive therapy are in place in many transplant settings. In this review, we focus on the next three most frequent viruses, human herpesvirus-6, BK virus and adenovirus, causing reactivation and/or viremia after allogeneic transplant, which are increasingly detected in patients in the post-transplant period owing to emerging techniques of molecular biology, recipients' characteristics, treatment modalities used for conditioning and factors related donors or stem cell source. Given the less frequent detection of an illness related to these viruses, there are often no specific protocols in place for the management of affected patients. While some patients develop significant morbidity (generally older), others may not need therapy at all (generally younger or children). Furthermore, some of the antiviral therapies used are potentially toxic. With the addition of increased risk of secondary infections, risk of graft failure or increased risk of graft-versus-host disease as well as the relationship with other post-transplant complications, the outcomes of patients with these viremias remain unsatisfactory and even long-term survivors experience increased morbidity.
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Affiliation(s)
- Xin Wang
- Department of Medicine, UMass Memorial Medical Center, Worcester, MA, USA
| | - Shyam A Patel
- Division of Hematology-Oncology, Department of Medicine, UMass Memorial Medical Center, Worcester, MA, USA
| | - Michael Haddadin
- Division of Hematology-Oncology, Department of Medicine, UMass Memorial Medical Center, Worcester, MA, USA
| | - Jan Cerny
- Division of Hematology and Oncology, Department of Medicine, UMass Memorial Medical Center, 55 Lake Avenue North, Worcester, MA, 01655, USA
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13
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Wood ML, Veal CD, Neumann R, Suárez NM, Nichols J, Parker AJ, Martin D, Romaine SPR, Codd V, Samani NJ, Voors AA, Tomaszewski M, Flamand L, Davison AJ, Royle NJ. Variation in human herpesvirus 6B telomeric integration, excision, and transmission between tissues and individuals. eLife 2021; 10:70452. [PMID: 34545807 PMCID: PMC8492063 DOI: 10.7554/elife.70452] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 09/20/2021] [Indexed: 12/12/2022] Open
Abstract
Human herpesviruses 6A and 6B (HHV-6A/6B) are ubiquitous pathogens that persist lifelong in latent form and can cause severe conditions upon reactivation. They are spread by community-acquired infection of free virus (acqHHV6A/6B) and by germline transmission of inherited chromosomally integrated HHV-6A/6B (iciHHV-6A/6B) in telomeres. We exploited a hypervariable region of the HHV-6B genome to investigate the relationship between acquired and inherited virus and revealed predominantly maternal transmission of acqHHV-6B in families. Remarkably, we demonstrate that some copies of acqHHV-6B in saliva from healthy adults gained a telomere, indicative of integration and latency, and that the frequency of viral genome excision from telomeres in iciHHV-6B carriers is surprisingly high and varies between tissues. In addition, newly formed short telomeres generated by partial viral genome release are frequently lengthened, particularly in telomerase-expressing pluripotent cells. Consequently, iciHHV-6B carriers are mosaic for different iciHHV-6B structures, including circular extra-chromosomal forms that have the potential to reactivate. Finally, we show transmission of an HHV-6B strain from an iciHHV-6B mother to her non-iciHHV-6B son. Altogether, we demonstrate that iciHHV-6B can readily transition between telomere-integrated and free virus forms.
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Affiliation(s)
- Michael L Wood
- Department of Genetics and Genome Biology, University of LeicesterLeicesterUnited Kingdom
| | - Colin D Veal
- Department of Genetics and Genome Biology, University of LeicesterLeicesterUnited Kingdom
| | - Rita Neumann
- Department of Genetics and Genome Biology, University of LeicesterLeicesterUnited Kingdom
| | - Nicolás M Suárez
- MRC-University of Glasgow Centre for Virus ResearchGlasgowUnited Kingdom
| | - Jenna Nichols
- MRC-University of Glasgow Centre for Virus ResearchGlasgowUnited Kingdom
| | - Andrei J Parker
- Department of Genetics and Genome Biology, University of LeicesterLeicesterUnited Kingdom
| | - Diana Martin
- Department of Genetics and Genome Biology, University of LeicesterLeicesterUnited Kingdom
| | - Simon PR Romaine
- Department of Cardiovascular Sciences, University of LeicesterLeicesterUnited Kingdom,NIHR Leicester Biomedical Research Centre, Glenfield HospitalLeicesterUnited Kingdom
| | - Veryan Codd
- Department of Cardiovascular Sciences, University of LeicesterLeicesterUnited Kingdom
| | - Nilesh J Samani
- Department of Cardiovascular Sciences, University of LeicesterLeicesterUnited Kingdom
| | - Adriaan A Voors
- University of Groningen, Department of Cardiology, University Medical Center GroningenGroningenNetherlands
| | - Maciej Tomaszewski
- Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of ManchesterManchesterUnited Kingdom
| | - Louis Flamand
- Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université Laval, Quebec CityQuébecCanada
| | - Andrew J Davison
- MRC-University of Glasgow Centre for Virus ResearchGlasgowUnited Kingdom
| | - Nicola J Royle
- Department of Genetics and Genome Biology, University of LeicesterLeicesterUnited Kingdom
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14
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Abstract
Next-generation sequencing technologies allowed sequencing of thousands of genomes. However, there are genomic regions that remain difficult to characterize, including telomeres, centromeres, and other low-complexity regions, as well as transposable elements and endogenous viruses. Human herpesvirus 6A and 6B (HHV-6A and HHV-6B) are closely related viruses that infect most humans and can integrate their genomes into the telomeres of infected cells. Integration also occurs in germ cells, meaning that the virus can be inherited and result in individuals harboring the virus in every cell of their body. The integrated virus can reactivate and cause disease in humans. While it is well established that the virus resides in the telomere region, the integration locus is poorly defined due to the low sequence complexity (TTAGGG)n of telomeres that cannot be easily resolved through sequencing. We therefore employed genome imaging of the integrated HHV-6A and HHV-6B genomes using whole-genome optical site mapping technology. Using this technology, we identified which chromosome arm harbors the virus genome and obtained a high-resolution map of the integration loci of multiple patients. Surprisingly, this revealed long telomere sequences at the virus-subtelomere junction that were previously missed using PCR-based approaches. Contrary to what was previously thought, our technique revealed that the telomere lengths of chromosomes harboring the integrated virus genome were comparable to the other chromosomes. Taken together, our data shed light on the genetic structure of the HHV-6A and HHV-6B integration locus, demonstrating the utility of optical mapping for the analysis of genomic regions that are difficult to sequence.
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15
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Weschke DP, Leisenring WM, Lawler RL, Stevens-Ayers T, Huang ML, Jerome KR, Zerr DM, Hansen JA, Boeckh M, Hill JA. Inflammatory Cytokine Profile in Individuals with Inherited Chromosomally Integrated Human Herpesvirus 6. Biol Blood Marrow Transplant 2019; 26:254-261. [PMID: 31678540 DOI: 10.1016/j.bbmt.2019.10.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 10/21/2019] [Accepted: 10/27/2019] [Indexed: 12/16/2022]
Abstract
Acute graft-versus-host-disease (aGVHD) is a major complication following hematopoietic cell transplantations (HCTs). We have shown that HCT recipients in whom either the donor or patient had inherited chromosomally integrated human herpesvirus 6 (iciHHV-6) have a higher incidence of developing more severe aGVHD. Previous studies established that increased proinflammatory cytokines are associated with increased risk for aGVHD and nonrelapse mortality post-HCT. We hypothesized that HCT recipients with donor or recipient iciHHV-6 (iciHHV-6pos HCT cases) will have higher cytokine levels compared with HCT recipients without iciHHV-6 (iciHHV-6neg HCT controls). We identified 64 iciHHV-6pos HCT cases with plasma from days 7, 14, and/or 21 post-HCT and before aGVHD onset in patients who developed aGVHD. We identified 64 iciHHV-6neg HCT controls matched for aGVHD risk factors. We also identified 28 donors with iciHHV-6 and 56 matched donors without iciHHV-6. We measured plasma cytokine concentrations for IL-6, suppression of tumorigenicity 2, T cell immunoglobulin and mucin-domain containing 3, TNFα, soluble TNF receptor 1 (TNFRp55), and C-reactive protein (CRP). We used Mann-Whitney tests and repeated-measures models to compare cytokine levels. iciHHV-6pos HCT cases had higher CRP levels on day 7 and day 21 and higher TNFRp55 levels on day 14 and day 21 compared with iciHHV-6neg HCT controls. These findings were recapitulated in a repeated-measures model. The differences were most evident among patients who subsequently developed aGVHD grades 2 to 4. Additionally, iciHHV-6pos HCT cases had earlier-onset aGVHD (median, 20 versus 27 days post-HCT; P = .02). There were no differences in cytokine levels among healthy donors with or without iciHHV-6. This study demonstrates that HCT recipients with iciHHV-6 have higher proinflammatory cytokines that may be associated with increased risk for aGVHD.
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Affiliation(s)
- Daniel P Weschke
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Wendy M Leisenring
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Richard L Lawler
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Terry Stevens-Ayers
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Meei-Li Huang
- Department of Laboratory Medicine, University of Washington, Seattle, Washington
| | - Keith R Jerome
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington; Department of Laboratory Medicine, University of Washington, Seattle, Washington
| | - Danielle M Zerr
- Department of Pediatrics, University of Washington, Seattle, Washington
| | - John A Hansen
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington; Department of Medicine, University of Washington, Seattle, Washington
| | - Michael Boeckh
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington; Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington; Department of Medicine, University of Washington, Seattle, Washington
| | - Joshua A Hill
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington; Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington; Department of Medicine, University of Washington, Seattle, Washington.
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16
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Pellett Madan R, Hand J. Human herpesvirus 6, 7, and 8 in solid organ transplantation: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice. Clin Transplant 2019; 33:e13518. [PMID: 30844089 DOI: 10.1111/ctr.13518] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Accepted: 02/26/2019] [Indexed: 12/17/2022]
Abstract
These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of HHV-6A, HHV-6B, HHV-7, and HHV-8 in the pre- and post-transplant period. The majority of HHV-6 (A and B) and HHV-7 infections in transplant recipients are asymptomatic; symptomatic disease is reported infrequently across organs. Routine screening for HHV-6 and 7 DNAemia is not recommended in asymptomatic patients, nor is prophylaxis or preemptive therapy. Detection of viral nucleic acid by quantitative PCR in blood or CSF is the preferred method for diagnosis of HHV-6 and HHV-7 infection. The possibility of chromosomally integrated HHV-6 DNA should be considered in individuals with persistently high viral loads. Antiviral therapy should be initiated for HHV-6 encephalitis and should be considered for other manifestations of disease. HHV-8 causes Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman disease and is also associated with hemophagocytic syndrome and bone marrow failure. HHV-8 screening and monitoring may be indicated to prevent disease. Treatment of HHV-8 related disease centers on reduction of immunosuppression and conversion to sirolimus, while chemotherapy may be needed for unresponsive disease. The role of antiviral therapy for HHV-8 infection has not yet been defined.
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Affiliation(s)
- Rebecca Pellett Madan
- Department of Pediatrics, New York University Langone School of Medicine, New York City, New York
| | - Jonathan Hand
- Department of Infectious Diseases, Ochsner Clinical School, Ochsner Medical Center, The University of Queensland School of Medicine, New Orleans, Louisiana
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17
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Greninger AL, Roychoudhury P, Makhsous N, Hanson D, Chase J, Krueger G, Xie H, Huang ML, Saunders L, Ablashi D, Koelle DM, Cook L, Jerome KR. Copy Number Heterogeneity, Large Origin Tandem Repeats, and Interspecies Recombination in Human Herpesvirus 6A (HHV-6A) and HHV-6B Reference Strains. J Virol 2018; 92:e00135-18. [PMID: 29491155 PMCID: PMC5923074 DOI: 10.1128/jvi.00135-18] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 02/21/2018] [Indexed: 12/17/2022] Open
Abstract
Quantitative PCR is a diagnostic pillar for clinical virology testing, and reference materials are necessary for accurate, comparable quantitation between clinical laboratories. Accurate quantitation of human herpesvirus 6A/B (HHV-6A/B) is important for detection of viral reactivation and inherited chromosomally integrated HHV-6A/B in immunocompromised patients. Reference materials in clinical virology commonly consist of laboratory-adapted viral strains that may be affected by the culture process. We performed next-generation sequencing to make relative copy number measurements at single nucleotide resolution of eight candidate HHV-6A and seven HHV-6B reference strains and DNA materials from the HHV-6 Foundation and Advanced Biotechnologies Inc. Eleven of 17 (65%) HHV-6A/B candidate reference materials showed multiple copies of the origin of replication upstream of the U41 gene by next-generation sequencing. These large tandem repeats arose independently in culture-adapted HHV-6A and HHV-6B strains, measuring 1,254 bp and 983 bp, respectively. The average copy number measured was between 5 and 10 times the number of copies of the rest of the genome. We also report the first interspecies recombinant HHV-6A/B strain with a HHV-6A backbone and a >5.5-kb region from HHV-6B, from U41 to U43, that covered the origin tandem repeat. Specific HHV-6A reference strains demonstrated duplication of regions at U1/U2, U87, and U89, as well as deletion in the U12-to-U24 region and the U94/U95 genes. HHV-6A/B strains derived from cord blood mononuclear cells from different laboratories on different continents with fewer passages revealed no copy number differences throughout the viral genome. These data indicate that large origin tandem duplications are an adaptation of both HHV-6A and HHV-6B in culture and show interspecies recombination is possible within the Betaherpesvirinae.IMPORTANCE Anything in science that needs to be quantitated requires a standard unit of measurement. This includes viruses, for which quantitation increasingly determines definitions of pathology and guidelines for treatment. However, the act of making standard or reference material in virology can alter its very accuracy through genomic duplications, insertions, and rearrangements. We used deep sequencing to examine candidate reference strains for HHV-6, a ubiquitous human virus that can reactivate in the immunocompromised population and is integrated into the human genome in every cell of the body for 1% of people worldwide. We found large tandem repeats in the origin of replication for both HHV-6A and HHV-6B that are selected for in culture. We also found the first interspecies recombinant between HHV-6A and HHV-6B, a phenomenon that is well known in alphaherpesviruses but to date has not been seen in betaherpesviruses. These data critically inform HHV-6A/B biology and the standard selection process.
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Affiliation(s)
- Alexander L Greninger
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, USA
- Fred Hutchinson Cancer Research Institute, Seattle, Washington, USA
| | - Pavitra Roychoudhury
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, USA
- Fred Hutchinson Cancer Research Institute, Seattle, Washington, USA
| | - Negar Makhsous
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, USA
| | - Derek Hanson
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Jill Chase
- HHV-6 Foundation, Santa Barbara, California, USA
| | - Gerhard Krueger
- Department of Pathology and Laboratory Medicine, University of Houston, Houston, Texas, USA
| | - Hong Xie
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, USA
| | - Meei-Li Huang
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, USA
| | - Lindsay Saunders
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, USA
| | | | - David M Koelle
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, USA
- Fred Hutchinson Cancer Research Institute, Seattle, Washington, USA
- Department of Medicine, University of Washington, Seattle, Washington, USA
- Department of Global Health, University of Washington, Seattle, Washington, USA
| | - Linda Cook
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, USA
| | - Keith R Jerome
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, USA
- Fred Hutchinson Cancer Research Institute, Seattle, Washington, USA
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18
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Abstract
Urine culture and microscopy techniques are used to profile the bacterial species present in urinary tract infections. To gain insight into the urinary flora, we analyzed clinical laboratory features and the microbial metagenome of 121 clean-catch urine samples. 16S rDNA gene signatures were successfully obtained for 116 participants, while metagenome sequencing data was successfully generated for samples from 49 participants. Although 16S rDNA sequencing was more sensitive, metagenome sequencing allowed for a more comprehensive and unbiased representation of the microbial flora, including eukarya and viral pathogens, and of bacterial virulence factors. Urine samples positive by metagenome sequencing contained a plethora of bacterial (median 41 genera/sample), eukarya (median 2 species/sample) and viral sequences (median 3 viruses/sample). Genomic analyses suggested cases of infection with potential pathogens that are often missed during routine urine culture due to species specific growth requirements. While conventional microbiological methods are inadequate to identify a large diversity of microbial species that are present in urine, genomic approaches appear to more comprehensively and quantitatively describe the urinary microbiome.
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19
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Markolović M, Ćupić M. The prevalence of herpesvirus infections in children and young adults transplant recipients - kidney and hematopoetic stem cells. MEDICINSKI PODMLADAK 2018. [DOI: 10.5937/mp69-16747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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20
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Inherited Chromosomally Integrated Human Herpesvirus 6 Genomes Are Ancient, Intact, and Potentially Able To Reactivate from Telomeres. J Virol 2017; 91:JVI.01137-17. [PMID: 28835501 PMCID: PMC5660504 DOI: 10.1128/jvi.01137-17] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 08/15/2017] [Indexed: 01/31/2023] Open
Abstract
The genomes of human herpesvirus 6A (HHV-6A) and HHV-6B have the capacity to integrate into telomeres, the essential capping structures of chromosomes that play roles in cancer and ageing. About 1% of people worldwide are carriers of chromosomally integrated HHV-6 (ciHHV-6), which is inherited as a genetic trait. Understanding the consequences of integration for the evolution of the viral genome, for the telomere, and for the risk of disease associated with carrier status is hampered by a lack of knowledge about ciHHV-6 genomes. Here, we report an analysis of 28 ciHHV-6 genomes and show that they are significantly divergent from the few modern nonintegrated HHV-6 strains for which complete sequences are currently available. In addition, ciHHV-6B genomes in Europeans are more closely related to each other than to ciHHV-6B genomes from China and Pakistan, suggesting regional variation of the trait. Remarkably, at least one group of European ciHHV-6B carriers has inherited the same ciHHV-6B genome, integrated in the same telomere allele, from a common ancestor estimated to have existed 24,500 ± 10,600 years ago. Despite the antiquity of some, and possibly most, germ line HHV-6 integrations, the majority of ciHHV-6B (95%) and ciHHV-6A (72%) genomes contain a full set of intact viral genes and therefore appear to have the capacity for viral gene expression and full reactivation. IMPORTANCE Inheritance of HHV-6A or HHV-6B integrated into a telomere occurs at a low frequency in most populations studied to date, but its characteristics are poorly understood. However, stratification of ciHHV-6 carriers in modern populations due to common ancestry is an important consideration for genome-wide association studies that aim to identify disease risks for these people. Here, we present full sequence analysis of 28 ciHHV-6 genomes and show that ciHHV-6B in many carriers with European ancestry most likely originated from ancient integration events in a small number of ancestors. We propose that ancient ancestral origins for ciHHV-6A and ciHHV-6B are also likely in other populations. Moreover, despite their antiquity, all of the ciHHV-6 genomes appear to retain the capacity to express viral genes, and most are predicted to be capable of full viral reactivation. These discoveries represent potentially important considerations in immunocompromised patients, in particular in organ transplantation and in stem cell therapy.
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21
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Abstract
Human roseoloviruses include three different species, human herpesviruses 6A, 6B, and 7 (HHV-6A, HHV-6B, HHV-7), genetically related to human cytomegalovirus. They exhibit a wide cell tropism in vivo and, like other herpesviruses, induce a lifelong latent infection in humans. In about 1% of the general population, HHV-6 DNA is covalently integrated into the subtelomeric region of cell chromosomes (ciHHV-6). Many active infections, corresponding to primary infections, reactivations, or exogenous reinfections, are asymptomatic. They also may cause serious diseases, particularly in immunocompromised individuals, including hematopoietic stem-cell transplant (HSCT) and solid-organ transplant recipients, and acquired immunodeficiency syndrome (AIDS) patients. This opportunistic pathogenic role is formally established for HHV-6 infection and less clear for HHV-7. It mainly concerns the central-nervous system, bone marrow, lungs, gastrointestinal tract, skin, and liver. As the best example, HHV-6 causes both exanthema subitum, a benign disease associated with primary infection, and severe encephalitis associated with virus reactivations in HSCT recipients. Diagnosis using serologic and direct antigen-detection methods currently exhibits limitations. The most prominent technique is the quantification of viral DNA in blood, other body fluids, and organs by means of real-time polymerase-chain reaction (PCR). The antiviral compounds ganciclovir, foscarnet, and cidofovir are effective against active infections, but there is currently no consensus regarding the indications of treatment or specifics of drug administration. Numerous questions about HHV-6A, HHV-6B, HHV-7 are still pending, concerning in particular clinical impact and therapeutic options in immunocompromised patients.
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Stabilization of Telomere G-Quadruplexes Interferes with Human Herpesvirus 6A Chromosomal Integration. J Virol 2017; 91:JVI.00402-17. [PMID: 28468887 DOI: 10.1128/jvi.00402-17] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 04/29/2017] [Indexed: 11/20/2022] Open
Abstract
Human herpesviruses 6A and 6B (HHV-6A/B) can integrate their genomes into the telomeres of human chromosomes using a mechanism that remains poorly understood. To achieve a better understanding of the HHV-6A/B integration mechanism, we made use of BRACO-19, a compound that stabilizes G-quadruplex secondary structures and prevents telomere elongation by the telomerase complex. First, we analyzed the folding of telomeric sequences into G-quadruplex structures and their binding to BRACO-19 using G-quadruplex-specific antibodies and surface plasmon resonance. Circular dichroism studies indicate that BRACO-19 modifies the conformation and greatly stabilizes the G-quadruplexes formed in G-rich telomeric DNA. Subsequently we assessed the effects of BRACO-19 on the HHV-6A initial phase of infection. Our results indicate that BRACO-19 does not affect entry of HHV-6A DNA into cells. We next investigated if stabilization of G-quadruplexes by BRACO-19 affected HHV-6A's ability to integrate its genome into host chromosomes. Incubation of telomerase-expressing cells with BRACO-19, such as HeLa and MCF-7, caused a significant reduction in the HHV-6A integration frequency (P < 0.002); in contrast, BRACO-19 had no effect on HHV-6 integration frequency in U2OS cells that lack telomerase activity and elongate their telomeres through alternative lengthening mechanisms. Our data suggest that the fluidity of telomeres is important for efficient chromosomal integration of HHV-6A and that interference with telomerase activity negatively affects the generation of cellular clones containing integrated HHV-6A.IMPORTANCE HHV-6A/B can integrate their genomes into the telomeres of infected cells. Telomeres consist of repeated hexanucleotides (TTAGGG) of various lengths (up to several kilobases) and end with a single-stranded 3' extension. To avoid recognition and induce a DNA damage response, the single-stranded overhang folds back on itself and forms a telomeric loop (T-loop) or adopts a tertiary structure, referred to as a G-quadruplex. In the current study, we have examined the effects of a G-quadruplex binding and stabilizing agent, BRACO-19, on HHV-6A chromosomal integration. By stabilizing G-quadruplex structures, BRACO-19 affects the ability of the telomerase complex to elongate telomeres. Our results indicate that BRACO-19 reduces the number of clones harboring integrated HHV-6A. This study is the first of its kind and suggests that telomerase activity is essential to restore a functional telomere of adequate length following HHV-6A integration.
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Cell Culture Systems To Study Human Herpesvirus 6A/B Chromosomal Integration. J Virol 2017; 91:JVI.00437-17. [PMID: 28468878 DOI: 10.1128/jvi.00437-17] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 04/22/2017] [Indexed: 01/01/2023] Open
Abstract
Human herpesviruses 6A/B (HHV-6A/B) can integrate their viral genomes in the telomeres of human chromosomes. The viral and cellular factors contributing to HHV-6A/B integration remain largely unknown, mostly due to the lack of efficient and reproducible cell culture models to study HHV-6A/B integration. In this study, we characterized the HHV-6A/B integration efficiencies in several human cell lines using two different approaches. First, after a short-term infection (5 h), cells were processed for single-cell cloning and analyzed for chromosomally integrated HHV-6A/B (ciHHV-6A/B). Second, cells were infected with HHV-6A/B and allowed to grow in bulk for 4 weeks or longer and then analyzed for the presence of ciHHV-6. Using quantitative PCR (qPCR), droplet digital PCR, and fluorescent in situ hybridization, we could demonstrate that HHV-6A/B integrated in most human cell lines tested, including telomerase-positive (HeLa, MCF-7, HCT-116, and HEK293T) and telomerase-negative cell lines (U2OS and GM847). Our results also indicate that inhibition of DNA replication, using phosphonoacetic acid, did not affect HHV-6A/B integration. Certain clones harboring ciHHV-6A/B spontaneously express viral genes and proteins. Treatment of cells with phorbol ester or histone deacetylase inhibitors triggered the expression of many viral genes, including U39, U90, and U100, without the production of infectious virus, suggesting that the tested stimuli were not sufficient to trigger full reactivation. In summary, both integration models yielded comparable results and should enable the identification of viral and cellular factors contributing to HHV-6A/B integration and the screening of drugs influencing viral gene expression, as well as the release of infectious HHV-6A/B from the integrated state.IMPORTANCE The analysis and understanding of HHV-6A/B genome integration into host DNA is currently limited due to the lack of reproducible and efficient viral integration systems. In the present study, we describe two quantitative cell culture viral integration systems. These systems can be used to define cellular and viral factors that play a role in HHV-6A/B integration. Furthermore, these systems will allow us to decipher the conditions resulting in virus gene expression and excision of the integrated viral genome resulting in reactivation.
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Detection of Human Herpesvirus 6B (HHV-6B) Reactivation in Hematopoietic Cell Transplant Recipients with Inherited Chromosomally Integrated HHV-6A by Droplet Digital PCR. J Clin Microbiol 2016; 54:1223-7. [PMID: 26888901 DOI: 10.1128/jcm.03275-15] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 01/25/2016] [Indexed: 12/17/2022] Open
Abstract
The presence of inherited chromosomally integrated human herpesvirus 6 (ciHHV-6) in hematopoietic cell transplant (HCT) donors or recipients confounds molecular testing for HHV-6 reactivation, which occurs in 30 to 50% of transplants. Here we describe a multiplex droplet digital PCR clinical diagnostic assay that concurrently distinguishes between HHV-6 species (A or B) and identifies inherited ciHHV-6. By applying this assay to recipient post-HCT plasma and serum samples, we demonstrated reactivation of HHV-6B in 25% (4/16 recipients) of HCT recipients with donor- or recipient-derived inherited ciHHV-6A, underscoring the need for diagnostic testing for HHV-6 infection even in the presence of ciHHV-6.
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25
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Agut H, Bonnafous P, Gautheret-Dejean A. Laboratory and clinical aspects of human herpesvirus 6 infections. Clin Microbiol Rev 2015; 28:313-35. [PMID: 25762531 PMCID: PMC4402955 DOI: 10.1128/cmr.00122-14] [Citation(s) in RCA: 177] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Human herpesvirus 6 (HHV-6) is a widespread betaherpesvirus which is genetically related to human cytomegalovirus (HCMV) and now encompasses two different species: HHV-6A and HHV-6B. HHV-6 exhibits a wide cell tropism in vivo and, like other herpesviruses, induces a lifelong latent infection in humans. As a noticeable difference with respect to other human herpesviruses, genomic HHV-6 DNA is covalently integrated into the subtelomeric region of cell chromosomes (ciHHV-6) in about 1% of the general population. Although it is infrequent, this may be a confounding factor for the diagnosis of active viral infection. The diagnosis of HHV-6 infection is performed by both serologic and direct methods. The most prominent technique is the quantification of viral DNA in blood, other body fluids, and organs by means of real-time PCR. Many active HHV-6 infections, corresponding to primary infections, reactivations, or exogenous reinfections, are asymptomatic. However, the virus may be the cause of serious diseases, particularly in immunocompromised individuals. As emblematic examples of HHV-6 pathogenicity, exanthema subitum, a benign disease of infancy, is associated with primary infection, whereas further virus reactivations can induce severe encephalitis cases, particularly in hematopoietic stem cell transplant recipients. Generally speaking, the formal demonstration of the causative role of HHV-6 in many acute and chronic human diseases is difficult due to the ubiquitous nature of the virus, chronicity of infection, existence of two distinct species, and limitations of current investigational tools. The antiviral compounds ganciclovir, foscarnet, and cidofovir are effective against active HHV-6 infections, but the indications for treatment, as well as the conditions of drug administration, are not formally approved to date. There are still numerous pending questions about HHV-6 which should stimulate future research works on the pathophysiology, diagnosis, and therapy of this remarkable human virus.
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Affiliation(s)
- Henri Agut
- Sorbonne Universités, UPMC, CIMI-Paris UMRS CR7, PVI Team, Paris, France INSERM, CIMI-Paris U1135, PVI Team, Paris, France AP-HP, Hôpitaux Universitaires Pitié Salpêtrière-Charles Foix, Service de Virologie, Paris, France
| | - Pascale Bonnafous
- Sorbonne Universités, UPMC, CIMI-Paris UMRS CR7, PVI Team, Paris, France INSERM, CIMI-Paris U1135, PVI Team, Paris, France
| | - Agnès Gautheret-Dejean
- Sorbonne Universités, UPMC, CIMI-Paris UMRS CR7, PVI Team, Paris, France INSERM, CIMI-Paris U1135, PVI Team, Paris, France AP-HP, Hôpitaux Universitaires Pitié Salpêtrière-Charles Foix, Service de Virologie, Paris, France Université René Descartes, Faculté de Pharmacie, Laboratoire de Microbiologie UPRES EA 4065, Paris, France
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26
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Abstract
Endogenous retrovirus (ERV) genomes integrated into the chromosomal DNA of the host were first detected in chickens and mice as Mendelian determinants of Gag and Env proteins and of the release of infectious virus particles. The presence of ERV was confirmed by DNA hybridization. With complete host genomes available for analysis, we can now see the great extent of viral invasion into the genomes of numerous vertebrate species, including humans. ERVs are found at many loci in host DNA and also in the genomes of large DNA viruses, such as herpesviruses and poxviruses. The evolution of xenotropism and cross-species infection is discussed in the light of the dynamic relationship between exogenous and endogenous retroviruses.
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Affiliation(s)
- Robin A Weiss
- Division of Infection and Immunity, Wohl Virion Centre, University College London, , Cruciform Building, Gower Street, London WC1 6BT, UK
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27
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Breuer S, Rauch M, Matthes-Martin S, Lion T. Molecular diagnosis and management of viral infections in hematopoietic stem cell transplant recipients. Mol Diagn Ther 2012; 16:63-77. [PMID: 22497528 DOI: 10.1007/bf03256431] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Viral infections after allogeneic hematopoietic stem cell transplantation (HSCT) are important complications associated with high morbidity and mortality. In this setting, reactivations of persisting latent viral pathogens from donor and/or recipient cells play a central role whereas the sterile environment of transplant units renders new infections less likely. The viruses currently regarded as most relevant in the HSCT setting include particularly the herpes virus family--specifically cytomegalovirus (CMV), Epstein-Barr virus (EBV), and human herpesvirus 6 (HHV-6)--as well as human adenoviruses (AdVs) and the polyoma virus BK (BKV). Timely detection and monitoring of virus copy numbers are prerequisites for successful preemptive treatment approaches. Pre- and post-transplant surveillance by sensitive and quantitative molecular methods has therefore become an essential part of the diagnostic routine. In this review, we discuss diagnostic aspects and the clinical management of the most important viral infections in HSCT recipients, with a focus on pediatric patients.
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Affiliation(s)
- Sabine Breuer
- Department of Pediatric Stem Cell Transplantation, St. Anna Childrens Hospital, Medical University of Vienna, Vienna, Austria
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28
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Abstract
Herpesviruses are members of a diverse family of viruses that colonize all vertebrates from fish to mammals. Although more than one hundred herpesviruses exist, all are nearly identical architecturally, with a genome consisting of a linear double-stranded DNA molecule (100 to 225 kbp) protected by an icosahedral capsid made up of 162 hollow-centered capsomeres, a tegument surrounding the nucleocapsid, and a viral envelope derived from host membranes. Upon infection, the linear viral DNA is delivered to the nucleus, where it circularizes to form the viral episome. Depending on several factors, the viral cycle can proceed either to a productive infection or to a state of latency. In either case, the viral genetic information is maintained as extrachromosomal circular DNA. Interestingly, however, certain oncogenic herpesviruses such as Marek's disease virus and Epstein-Barr virus can be found integrated at low frequencies in the host's chromosomes. These findings have mostly been viewed as anecdotal and considered exceptions rather than properties of herpesviruses. In recent years, the consistent and rather frequent detection (in approximately 1% of the human population) of human herpesvirus 6 (HHV-6) viral DNA integrated into human chromosomes has spurred renewed interest in our understanding of how these viruses infect, replicate, and propagate themselves. In this review, we provide a historical perspective on chromosomal integration by herpesviruses and present the current state of knowledge on integration by HHV-6 with the possible clinical implications associated with viral integration.
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Murine gammaherpesvirus 68 LANA is essential for virus reactivation from splenocytes but not long-term carriage of viral genome. J Virol 2010; 84:7214-24. [PMID: 20444892 DOI: 10.1128/jvi.00133-10] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
ORF73, which encodes the latency-associated nuclear antigen (LANA), is a conserved gamma-2-herpesvirus gene. The murine gammaherpesvirus 68 (MHV68) LANA (mLANA) is critical for efficient virus replication and the establishment of latent infection following intranasal inoculation. To test whether the initial host immune response limits the capacity of mLANA-null virus to traffic to and establish latency in the spleen, we infected type I interferon receptor knockout (IFN-alpha/betaR(-/-)) mice via intranasal inoculation and observed the presence of viral genome-positive splenocytes at day 18 postinfection at approximately 10-fold-lower levels than in the genetically repaired marker rescue-infected mice. However, no mLANA-null virus reactivation from infected IFN-alpha/betaR(-/-) splenocytes was observed. To more thoroughly define a role of mLANA in MHV68 infection, we evaluated the capacity of an mLANA-null virus to establish and maintain infection apart from restriction in the lungs of immunocompetent mice. At day 18 following intraperitoneal infection of C57BL/6 mice, the mLANA-null virus was able to establish a chronic infection in the spleen albeit at a 5-fold-reduced level. However, as in IFN-alpha/betaR(-/-) mice, little or no virus reactivation could be detected from mLANA-null virus-infected splenocytes upon explant. An examination of peritoneal exudate cells (PECs) following intraperitoneal inoculation revealed nearly equivalent frequencies of PECs harboring the mLANA-null virus relative to the marker rescue virus. Furthermore, although significantly compromised, mLANA-null virus reactivation from PECs was detected upon explant. Notably, at later times postinfection, the frequency of mLANA-null genome-positive splenocytes was indistinguishable from that of marker rescue virus-infected animals. Analyses of viral genome-positive splenocytes revealed the absence of viral episomes in mLANA-null infected mice, suggesting that the viral genome is integrated or maintained in a linear state. Thus, these data provide the first evidence that a LANA homolog is directly involved in the formation and/or maintenance of an extrachromosomal viral episome in vivo, which is likely required for the reactivation of MHV68.
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30
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Hall CB, Caserta MT, Schnabel K, Shelley LM, Marino AS, Carnahan JA, Yoo C, Lofthus GK, McDermott MP. Chromosomal integration of human herpesvirus 6 is the major mode of congenital human herpesvirus 6 infection. Pediatrics 2008; 122:513-20. [PMID: 18762520 DOI: 10.1542/peds.2007-2838] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE We examined the frequency and characteristics of chromosomally integrated human herpesvirus 6 among congenitally infected children. METHODS Infants with and without congenital human herpesvirus 6 infection were prospectively monitored. Cord blood mononuclear cell, peripheral blood mononuclear cell, saliva, urine, and hair follicle samples were examined for human herpesvirus 6 DNA. Human herpesvirus 6 RNA, serum antibody, and chromosomally integrated human herpesvirus 6 levels were also assessed. RESULTS Among 85 infants, 43 had congenital infections and 42 had postnatal infections. Most congenital infections (86%) resulted from chromosomally integrated human herpesvirus 6; 6 infants (14%) had transplacental infections. Children with chromosomally integrated human herpesvirus 6 had high viral loads in all sites (mean: 5-6 log(10) genomic copies per mug of cellular DNA); among children with transplacental infection or postnatal infection, human herpesvirus 6 DNA was absent in hair samples and inconsistent in other samples, and viral loads were significantly lower. One parent of each child with chromosomally integrated human herpesvirus 6 who had parental hair samples tested had hair containing human herpesvirus 6 DNA. Variant A caused 32% of chromosomally integrated human herpesvirus 6 infections, compared with 2% of postnatal infections. Replicating human herpesvirus 6 was detected only among chromosomally integrated human herpesvirus 6 samples (8% of cord blood mononuclear cells and peripheral blood mononuclear cells). Cord blood human herpesvirus 6 antibody levels were similar among children with chromosomally integrated human herpesvirus 6, transplacental infection, and postnatal infection and between children with maternal and paternal chromosomally integrated human herpesvirus 6 transmission. CONCLUSIONS Human herpesvirus 6 congenital infection results primarily from chromosomally integrated virus which is passed through the germ-line. Infants with chromosomally integrated human herpesvirus 6 had high viral loads in all specimens, produced human herpesvirus 6 antibody, and mRNA. The clinical relevance needs study as 1 of 116 newborns may have chromosomally integrated human herpesvirus 6 blood specimens.
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Affiliation(s)
- Caroline Breese Hall
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, 601 Elmwood Ave, Box 689, Rochester, NY 14642, USA.
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Management of CMV, HHV-6, HHV-7 and Kaposi-sarcoma herpesvirus (HHV-8) infections in patients with hematological malignancies and after SCT. Bone Marrow Transplant 2008; 42:227-40. [PMID: 18587440 DOI: 10.1038/bmt.2008.162] [Citation(s) in RCA: 238] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
These recommendations were prepared by the European Conference on Infections in Leukaemia following a predefined methodology. Literature searches were made to identify studies pertinent to management of CMV, HHV-6, -7 and -8 infections. For CMV, 76 studies were reviewed: 72 published and 4 presented as abstracts. Twenty-nine of these studies were prospective randomized trials. For the other herpesviruses, HHV-6, -7 and -8, no randomized controlled trial has been performed, although data from some studies with other primary endpoints have been used to assess the management of HHV-6 infection. Works presented only as abstracts were used to a very limited extent. The quality of evidence and level of recommendation were graded according to the Center for Disease Control (CDC) criteria.
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32
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Multicenter comparison of PCR assays for detection of human herpesvirus 6 DNA in serum. J Clin Microbiol 2008; 46:2700-6. [PMID: 18550745 DOI: 10.1128/jcm.00370-08] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Human herpesvirus 6 (HHV-6) is a ubiquitous virus with which infections have been associated with pathologies ranging from delayed bone marrow engraftment to a variety of neurological diseases. The lack of a standardized assay that can be used to detect and estimate HHV-6 DNA contents in various clinical specimens can lead and has led to discordant results among investigators and on the potential association of HHV-6 to diseases. To identify the most reliable and sensitive assays, an identical set of 11 coded serum samples spiked with various quantities of the HHV-6A variant (range, 4 to 400,000 genome copies/ml) was sent to eight independent laboratories around the world. Each laboratory was asked to estimate the HHV-6 DNA content by use of its own protocols and assays. Among the various assays, three TaqMan-based real-time PCR assays yielded quantities that were closest to the quantity of HHV-6 that had been spiked. To provide better homogeneity between the results from the different laboratories working on HHV-6, we propose that investigators interested in quantifying HHV-6 in clinical samples adopt one of these assays.
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Crawford JR, Kadom N, Santi MR, Mariani B, Lavenstein BL. Human herpesvirus 6 rhombencephalitis in immunocompetent children. J Child Neurol 2007; 22:1260-8. [PMID: 18006954 DOI: 10.1177/0883073807307086] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This article describes the clinical presentation, diagnostic workup, and neurologic outcome of 3 immunocompetent pediatric patients diagnosed with human herpesvirus 6 (HHV6) rhombencephalitis. Presentation of HHV6 rhombencephalitis included new onset seizures, ataxia, encephalopathy, and opsoclonus-myoclonus. Neurologic examination revealed cranial neuropathies, cerebellar dysfunction, and extremity weakness. Magnetic resonance imaging abnormalities located in the cerebellum, basal ganglia/thalamus, and cerebral hemispheres were detected in 2 patients. Diagnosis of HHV6 encephalitis was made by real-time and nested polymerase chain reaction of serum and cerebrospinal fluid. The HHV6 variant A was detected in 2 patients by sequence analysis, and HHV6 protein was detected by immunomicroscopy in a patient who underwent biopsy secondary to progressive clinical and neuroradiographic findings. Therapy with intravenous ganciclovir did not correlate with resolution of neurologic symptoms, despite eventual non-detectable HHV6. Human herpesvirus 6 should be considered in the differential diagnosis of unexplained cases of rhombencephalitis in immunocompetent children. Features may be rapidly progressive and include profound encephalopathy, seizures, ataxia, and opsoclonus-myoclonus.
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Affiliation(s)
- John R Crawford
- Department of Neurology Children's National Medical Center, George Washington University, Washington District of Columbia, USA.
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34
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Detection and typing of human herpesvirus 6 by molecular methods in specimens from patients diagnosed with encephalitis or meningitis. J Clin Microbiol 2007; 45:3972-8. [PMID: 17942643 DOI: 10.1128/jcm.01692-07] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human herpesvirus 6 (HHV-6) was detected in specimens from patients hospitalized with symptoms of encephalitis or meningitis. A real-time PCR assay was developed which has a linear dynamic range of 5 to 5 x 10(6) copies of HHV-6 and a sensitivity of five gene copies per reaction. While the assay detects both subtypes, HHV-6A and HHV-6B, it is specific and does not cross-react with a selected specificity panel. A total of 1,482 patient specimens, which were collected between 2003 and 2007, were tested; 26 specimens from 24 patients were found to be positive for HHV-6 by real-time PCR. The HHV-6 detection rate in this population was therefore 1.75%. The majority of the specimens tested (>95%) were cerebrospinal fluid (CSF) specimens. We were able to type 20 of the 26 positive specimens by conventional PCR and sequence analysis; all were HHV-6B. Forty-two percent of the patients were 3 years of age or younger, which may indicate a primary infection in these patients. Given the ages of the remaining patients (from 4 to 81 years), their infections were most probably due to virus reactivations. Where information was available, symptoms of patients included fever (71%), altered mental status (67%), and abnormal CSF profile (75%). Fifty percent of patients of 3 years of age or younger suffered from seizures. The detection of HHV-6 in specimens from patients diagnosed with encephalitis or meningitis, in the absence of a positive PCR result for other agents, strongly suggests a role for HHV-6 in the pathogenesis of these central nervous system diseases.
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Hubacek P, Hyncicova K, Muzikova K, Cinek O, Zajac M, Sedlacek P. Disappearance of pre-existing high HHV-6 DNA load in blood after allogeneic SCT. Bone Marrow Transplant 2007; 40:805-6. [PMID: 17704794 DOI: 10.1038/sj.bmt.1705813] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Kamble RT, Clark DA, Leong HN, Heslop HE, Brenner MK, Carrum G. Transmission of integrated human herpesvirus-6 in allogeneic hematopoietic stem cell transplantation. Bone Marrow Transplant 2007; 40:563-6. [PMID: 17637686 DOI: 10.1038/sj.bmt.1705780] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Human herpesvirus 6 (HHV-6) viremia, as detected by polymerase chain amplification, occurs in approximately half of allogeneic hematopoietic stem cell transplant recipients. The significance of such viremia is incompletely understood, but HHV-6 encephalitis and bone marrow suppression are increasingly being recognized in patients with high viral DNA. We report two patients in whom donor-to-recipient transmission occurred through hematopoietic transplant by means of chromosomally integrated (CI) HHV-6. Iatrogenic transmission manifested at engraftment as asymptomatic elevation of HHV-6 viral DNA of 3600 and 15 400 DNA copies/ml in plasma and 6.1 x 10(6) and 9.7 x 10(5) DNA copies/ml in the whole blood. Both donors had elevated plasma HHV-6 PCR at 5.6 x 10(4) and 1.3 x 10(5) DNA copies/ml and strikingly elevated whole blood HHV-6 levels at 4.1 x 10(6) and 4.7 x 10(6) DNA copies/ml, respectively. CI of the virus was traced to the mother of one patient and his donor. CI of HHV-6 may confound the interpretation of HHV-6 viremia after stem cell transplantation; consideration of the possibility of CI HHV-6 will avoid unnecessary antiviral therapy.
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Affiliation(s)
- R T Kamble
- Center for Cell and Gene Therapy, Baylor College of Medicine, The Methodist Hospital, Houston, TX, USA.
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Ward KN, Leong HN, Thiruchelvam AD, Atkinson CE, Clark DA. Human herpesvirus 6 DNA levels in cerebrospinal fluid due to primary infection differ from those due to chromosomal viral integration and have implications for diagnosis of encephalitis. J Clin Microbiol 2007; 45:1298-304. [PMID: 17229866 PMCID: PMC1865851 DOI: 10.1128/jcm.02115-06] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The prevalence and concentration of human herpesvirus 6 (HHV-6) DNA in the cerebrospinal fluid (CSF) of the immunocompetent in primary infection was compared with that in viral chromosomal integration. Samples from 510 individuals with suspected encephalitis, 200 young children and 310 older children and/or adults, and 12 other patients were tested. HHV-6 DNA concentration (log(10) copies/ml) was measured in CSF, serum, and whole blood using PCR. Serum HHV-6 immunoglobulin G antibody was measured by indirect immunofluorescence. Primary infection was defined by antibody seroconversion and/or a low concentration of HHV-6 DNA (<3.0 log(10) copies/ml) in a seronegative serum. Chromosomal integration was defined by a high concentration of viral DNA in serum (>/=3.5 log(10) copies/ml) or whole blood (>/=6.0 log(10) copies/ml). The prevalences of CSF HHV-6 DNA in primary infection and chromosomal integration were 2.5% and 2.0%, respectively, in the young children (<2 years) and 0% and 1.3%, respectively, in the older children and/or adults. The mean concentration of CSF HHV-6 DNA in 9 children with primary infection (2.4 log(10) copies/ml) was significantly lower than that of 21 patients with viral chromosomal integration (4.0 log(10) copies/ml). Only HHV-6B DNA was found in primary infection, whereas in viral integration, 4 patients had HHV-6A and 17 patients HHV-6B. Apart from primary infection, chromosomal integration is the most likely cause of HHV-6 DNA in the CSF of the immunocompetent. Our results show that any diagnosis of HHV-6 encephalitis or other type of active central nervous system infection should not be made without first excluding chromosomal HHV-6 integration by measuring DNA load in CSF, serum, and/or whole blood.
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MESH Headings
- Adult
- Antibodies, Viral/analysis
- Blood/virology
- Cerebrospinal Fluid/virology
- Child, Preschool
- Chromosomes/virology
- DNA, Viral/cerebrospinal fluid
- Encephalitis, Viral/diagnosis
- Encephalitis, Viral/virology
- Female
- Fluorescent Antibody Technique, Indirect
- Herpesvirus 6, Human/immunology
- Herpesvirus 6, Human/isolation & purification
- Herpesvirus 6, Human/physiology
- Humans
- Immunoglobulin G/analysis
- Infant
- Infant, Newborn
- Middle Aged
- Polymerase Chain Reaction
- Prevalence
- Roseolovirus Infections/diagnosis
- Roseolovirus Infections/virology
- Serum/virology
- Virus Integration
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Affiliation(s)
- Katherine N Ward
- Centre for Virology, Division of Infection and Immunity, Royal Free and University College Medical School (UCL campus), Windeyer Institute of Medical Sciences, 46 Cleveland Street, London W1T 4JF, United Kingdom.
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Ward KN, Leong HN, Nacheva EP, Howard J, Atkinson CE, Davies NWS, Griffiths PD, Clark DA. Human herpesvirus 6 chromosomal integration in immunocompetent patients results in high levels of viral DNA in blood, sera, and hair follicles. J Clin Microbiol 2006; 44:1571-4. [PMID: 16597897 PMCID: PMC1448653 DOI: 10.1128/jcm.44.4.1571-1574.2006] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2006] [Accepted: 02/13/2006] [Indexed: 11/20/2022] Open
Abstract
Six immunocompetent patients with human herpesvirus 6 (HHV-6) chromosomal integration had HHV-6 and beta-globin DNA quantified in various samples by PCR. The mean HHV-6 DNA concentration (log(10) copies/milliliter) in blood was 7.0 (>/=1 HHV-6 DNA copies/leukocyte), and in serum it was 5.3 (>/=1 HHV-6 DNA copies/lysed cell). The mean HHV-6 DNA load (log(10) copies)/hair follicle was 4.2 (>/=1 copies/hair follicle cell), demonstrating that viral integration is not confined to blood cells. The characteristically high HHV-6 DNA levels in chromosomal integration may confound laboratory diagnosis of HHV-6 infection and should be given due consideration.
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Affiliation(s)
- Katherine N Ward
- Centre for Virology, Division of Infection and Immunity, Royal Free and University College Medical School (UCL campus), Windeyer Institute of Medical Sciences, 46 Cleveland St., London W1T 4JF, United Kingdom.
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Abstract
PURPOSE OF REVIEW To summarize the biology and clinical consequences of infection with the closely related human herpesviruses-6 and -7 (HHV-6/7) in children. RECENT FINDINGS Over the last year there has been a paucity of paediatric publications on HHV-6 and only two studies focused on HHV-7. Steady progress has been made regarding the biology and clinical consequences of HHV-6 infection whereas the effect of HHV-7 infection remains a neglected topic. However, both viruses have been shown to contribute significantly and equally to the burden of disease in young children with suspected encephalitis or severe convulsions with fever. There continues to be uncertainty as to the effects of HHV-6 infection after stem cell transplant, although there is general agreement that it contributes to encephalitis. In contrast, HHV-7 seems to have little clinical impact after stem cell transplant, although central nervous system infection and disease have recently been reported in children. Understanding the contribution of chromosomal integration and inheritance of both HHV-6 variants A and B (HHV-6A/B) and their effect on diagnosis is emerging. SUMMARY There is an urgent need for more research on HHV-6 and -7 in children, particularly in relation to chromosomal integration of HHV-6A and B, and clinical consequences of HHV-7 infection.
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Affiliation(s)
- Katherine N Ward
- Centre for Virology, Department of Infection, Royal Free and University College Medical School, Windeyer Institute of Medical Sciences, London, UK.
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De Bolle L, Naesens L, De Clercq E. Update on human herpesvirus 6 biology, clinical features, and therapy. Clin Microbiol Rev 2005; 18:217-45. [PMID: 15653828 PMCID: PMC544175 DOI: 10.1128/cmr.18.1.217-245.2005] [Citation(s) in RCA: 341] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Human herpesvirus 6 (HHV-6) is a betaherpesvirus that is closely related to human cytomegalovirus. It was discovered in 1986, and HHV-6 literature has expanded considerably in the past 10 years. We here present an up-to-date and complete overview of the recent developments concerning HHV-6 biological features, clinical associations, and therapeutic approaches. HHV-6 gene expression regulation and gene products have been systematically characterized, and the multiple interactions between HHV-6 and the host immune system have been explored. Moreover, the discovery of the cellular receptor for HHV-6, CD46, has shed a new light on HHV-6 cell tropism. Furthermore, the in vitro interactions between HHV-6 and other viruses, particularly human immunodeficiency virus, and their relevance for the in vivo situation are discussed, as well as the transactivating capacities of several HHV-6 proteins. The insight into the clinical spectrum of HHV-6 is still evolving and, apart from being recognized as a major pathogen in transplant recipients (as exemplified by the rising number of prospective clinical studies), its role in central nervous system disease has become increasingly apparent. Finally, we present an overview of therapeutic options for HHV-6 therapy (including modes of action and resistance mechanisms).
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Affiliation(s)
- Leen De Bolle
- Rega Institute for Medical Research, Minderbroedersstraat 10, B-3000 Leuven, Belgium
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Daibata M, Taguchi T, Taguchi H. A novel t(16;20)(q22;p13) in polycythemia vera. CANCER GENETICS AND CYTOGENETICS 2002; 137:29-32. [PMID: 12377410 DOI: 10.1016/s0165-4608(02)00543-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We report a patient with polycythemia vera whose bone marrow cells carried a novel t(16;20)(q22;p13) as detected by karyotype analysis using G- and Q-banding techniques. The reciprocal translocation was confirmed by fluorescence in situ hybridization (FISH) using DNA libraries of chromosomes 16 and 20. To our knowledge, t(16;20)(q22;p13) has not been reported previously. The core binding factor beta (CBFbeta) gene located on 16q22 is known to be frequently involved in acute myelocytic leukemia. On the other hand, the 20p13 locus contains a gene encoding protein kinase CK2alpha, which is closely related to cell proliferation and cell cycle regulation. The t(16;20)(q22;p13) may be one of the cytogenetic aberrations in myeloproliferative disorders, and therefore, our observation warrants further studies on a possible involvement of the genes resulting from this translocation.
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Affiliation(s)
- Masanori Daibata
- Department of Medicine, Kochi Medical School, 783-8505, Kochi, Japan.
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Abstract
Normal hematopoietic cells express telomerase activity, however the presence of telomerase does not necessarily imply stable and thus unchanging telomere length. Gradual telomere loss with aging and rapid cycling of hematopoietic stem cells might contribute to immunosenescence, exhausted hematopoiesis, and increased likelihood of malignant transformation. In leukemias and lymphomas, telomere length may reflect the cellular proliferative history, prior to immortalization. The level of telomerase activity is generally influenced by the fraction of cells in the proliferative pool. Shortened telomeres and high telomerase activity almost always correlates with disease severity in hematologic neoplasias such as relapsed leukemia and high-grade lymphomas, indicating that measurement of telomere length and telomerase activity might be useful to monitor disease condition. Since the mode of action of telomerase inhibitors may require telomeric shortening before induction of apoptosis, anti-telomerase therapy might be helpful for adjuvant therapy following conventional chemotherapy, in vitro purging of neoplastic cells in stem cell transplantation, and treating minimal residual disease. Some promising areas of tissue engineering include rejuvenation of hematopoietic stem cells for improving stem cell transplants or enhancing general immunity for older patients.
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Affiliation(s)
- Junko H Ohyashiki
- Department of Virology, Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Japan.
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Abstract
A number of herpes- and poxviruses encode 7TM G-protein coupled receptors most of which clearly are derived from their host chemokine system as well as induce high expression of certain 7TM receptors in the infected cells. The receptors appear to be exploited by the virus for either immune evasion, cellular reprogramming, tissue targeting or for cell entry. Through their efficient evolutionary machinery and through in vivo selection performed directly on the human cellular and molecular targets, virus have been able to optimize the encoded receptors for distinct pharmacological profiles to help in various parts of the viral life cyclus. Most of the receptors encoded by human pathogenic virus are still orphan receptors, i.e. the endogenous ligand is unknown. In the few cases where it has been possible to characterize these receptors pharmacologically, they have been found to bind a broad spectrum of either CC chemokines, US28 from human cytomegalovirus, or CXC chemokines, ORF74 from human herpesvirus 8. Nevertheless, US28 has been specifically optimized for recognition of the membrane bound chemokine, fractalkine, conceivably involved in cell-cell transfer of virus; whereas ORF74 among the endogenous CXC chemokines has selected angiogenic chemokines as agonists and angiostatic/modulatory chemokines as inverse agonists. ORF74 possess substantial cell-transforming properties and signals with high constitutive activity through the phospholipase C and MAP kinase pathways. Interestingly, transgenic expression of this single gene in certain lymphocyte cell lineages leads to the development of lesions which are remarkably similar to Kaposi's sarcoma, a human herpesvirus 8 associated disease. Thus, this and other virally encoded 7TM receptors appear to be attractive future drug targets.
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Affiliation(s)
- M M Rosenkilde
- Laboratory for Molecular Pharmacology, Department of Pharmacology, Panum Institute, DK-2200, Denmark
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