Controlling cytomegalovirus: helping the immune system take the lead

Cytomegalovirus-associated CD57 + KLRG1 + CD8 + TEMRA T cells are associated with reduced risk of CMV viremia in kidney transplantation and chronic allograft dysfunction in lung transplantation

Cytomegalovirus (CMV) infection threatens outcomes across solid organ transplantation, but organ-specific differences in CMV immunity are incompletely understood. We investigated whether lung and kidney CMV infection drove similar immune profiles, hypothesizing that CMV-associated T cells would be associated with graft function. We longitudinally examined 41 lung transplant (LTx) recipients and 31 kidney transplant (KTx) recipients with CMV viremia, alongside non-viremic controls. We performed flow cytometry and single-cell protein and transcriptomic profiling (CITE-seq) on blood cells. Chronic lung allograft dysfunction (CLAD)-free survival and glomerular filtration rate decline-free survival were assessed by Cox proportional-hazards models. Terminal effector memory (TEMRA) CD8+ T cells segregated by expression of CD57 and KLRG1. CMV viremia led to expansion of CD57+ TEMRA in both cohorts (P < 0.001). In KTx, increased frequency of CD57+KLRG1+ were associated with viremia control (P = 0.05). In LTx, frequency > median of CD57+KLRG1+ conferred a 67 % reduced risk for CLAD or death (95 % CI; 3-89 % P = 0.04). CD57+KLRG1+ TEMRA showed evidence of cytotoxic and effector function, whereas CD57-KLRG1+ TEMRA showed evidence of exhaustion. CD57+KLRG1+ TEMRA were most active against CMV and reduced risk for viremia in KTx and CLAD in LTx. This population merits increased attention for its potential role in mediating CMV-associated transplant outcomes.

Cytomegalovirus-Specific T-Cell-Receptor-like Antibodies Target In Vivo-Infected Human Leukocytes Inducing Natural Killer Cell-Mediated Antibody-Dependent Cellular Cytotoxicity

Cytomegalovirus (CMV) reactivation after stem cell or solid organ transplantation remains a major cause of morbidity and mortality in this setting. T-cell receptor (TCR)-like antibodies bind to intracellular peptides presented in major histocompatibility complex (MHC) molecules on the cell surface and may have the potential to replace T-cell function in immunocompromised patients. Three previously selected CMV-specific, human leukocyte antigen (HLA)-restricted (HLA-A*0101, HLA-A*0201 and HLA-B*0702) Fab-antibodies (A6, C1 and C7) were produced as IgG antibodies with Fc optimization. All antibodies showed specific binding to CMV peptide-loaded tumor cell lines and primary fibroblasts expressing the corresponding MHC-I molecules, leading to specific target cell lysis after the addition of natural killer (NK) cells. When deployed in combination as an antibody pool against target cells expressing more than one matching HLA allele, cytotoxic effects were amplified accordingly. CMV-specific TCR-like antibodies were also able to mediate their cytotoxic effects through neutrophils, which is important considering the delayed recovery of NK cells after stem cell transplantation. When tested on patient blood obtained during CMV reactivation, CMV-specific antibodies were able to bind to and induce cytotoxic effects in lymphocytes. CMV-specific TCR-like antibodies may find application in patients with CMV reactivation or at risk of CMV reactivation. In contrast to previous HLA/peptide-directed therapeutic approaches, the concept of a TCR-like antibody repertoire covering more than one HLA allele would make this therapeutic format available to a much larger group of patients.

Use of Specific T Lymphocytes in Treating Cytomegalovirus Infection in Hematopoietic Cell Transplant Recipients: A Systematic Review

Cytomegalovirus (CMV) poses a significant threat to post-hematopoietic cell transplantation (HCT). Control strategies include letermovir prophylaxis or ganciclovir pre-emptive therapy (PET). Without prophylaxis, 65-90% of seropositive recipients develop a clinically significant CMV infection. Due to PET drawbacks, letermovir prophylaxis is preferable, as it reduces CMV-related events and improves overall survival. However, refractory or resistant CMV-CS remains a challenge, with maribavir showing limited efficacy. This systematic review followed the Cochrane Manual and PRISMA guidelines and was registered in PROSPERO. Searches were conducted in PubMed, Scopus, Embase, and Web of Science. Out of 1895 identified records, 614 duplicates were removed, and subsequent screening excluded 1153 studies. Eleven included studies (2012-2024) involved 255 HCT recipients receiving adoptive immunotherapy (AI), primarily CMV-specific T-cell therapy. GvHD occurred in 1.82% of cases. Adverse events occurred in 4.4% of cases, while mild CRS was observed in 1.3% of patients. Efficacy, evaluated in 299 patients across eleven studies, showed an average response rate of 78.2%. CMV-CS recurrence was observed in 24.4% of 213 patients, and death due to CMV was reported in 9.7% of 307 patients across nine studies. Adoptive hCMV-specific T-cell immunotherapy appears to be a safe, effective alternative for refractory CMV-CS in HCT.

High-dimensional mass cytometry identified circulating natural killer T-cell subsets associated with protection from cytomegalovirus infection in kidney transplant recipients

Cytomegalovirus (CMV) infection is associated with poor kidney transplant outcomes. While innate and adaptive immune cells have been implicated in its prevention, an in-depth characterization of the in vivo kinetics of multiple cell subsets and their role in protecting against CMV infection has not been achieved. Here, we performed high-dimensional immune phenotyping by mass cytometry, and functional assays, on 112 serially collected samples from CMV seropositive kidney transplant recipients. Advanced unsupervised deep learning analysis was used to assess immune cell populations that significantly correlated with prevention against CMV infection and anti-viral immune function. Prior to infection, kidney transplant recipients who developed CMV infection showed significantly lower CMV-specific cell-mediated immune (CMI) frequencies than those that did not. A broad diversity of circulating cell subsets within innate and adaptive immune compartments were associated with CMV infection or protective CMV-specific CMI. While percentages of CMV (tetramer-stained)-specific T cells associated with high CMI responses and clinical protection, circulating CD3+CD8midCD56+ NK-T cells overall strongly associated with low CMI and subsequent infection. However, three NK-T cell subsets sharing the CD11b surface marker associated with CMV protection and correlated with strong anti-viral CMI frequencies in vitro. These data were validated in two external independent cohorts of kidney transplant recipients. Thus, we newly describe the kinetics of a novel NK-T cell subset that may have a protective role in post-transplantation CMV infection. Our findings pave the way to more mechanistic studies aimed at understanding the function of these cells in protection against CMV infection.

Case report: Autoimmune encephalomyelitis following cytomegalovirus infection after allogeneic hematopoietic stem cell transplantation

Introduction

Cytomegalovirus (CMV) can cause various end-organ diseases in immunocompromised hosts, including allogeneic hematopoietic cell transplant (allo-HSCT) recipients. Interestingly, CMV viremia has been associated with various complications and poor prognosis in allo-HSCT recipients. Complications involving the central nervous system (CNS) occur in 9-14% of patients following allo-HSCT. However, autoimmune encephalitis (AE) secondary to CMV infection after allo-HSCT has rarely been reported. Here we report a case of possible AE following CMV viremia after allo-HSCT, which was successfully treated with high-dose pulsed methylprednisolone and intravenous immunoglobulins (IVIg).

Case description

A 53-year-old female underwent allo-HSCT for T-lymphoblastic lymphoma/leukemia. The patient developed CMV viremia on day 36 after transplantation, and serum CMV-DNA remained positive after initiating ganciclovir antiviral therapy, turning negative one month later. Four months later, she started experiencing memory impairment, weakness in the left limbs, cognitive dysfunction, and hallucinations. A magnetic resonance imaging brain scan showed scattered ischemic lesions under the bilateral frontal cortex. Viral detection in cerebral spinal fluid (CSF) by next-generation gene sequencing technology showed no obvious abnormality. Antibodies specific to AE and paraneoplastic diseases in serum and CSF were absent. The oligoclonal bands in the CSF were detected using isoelectric focusing and immunofixation, and the results were negative. However, after extensive investigation regarding infections, autoimmune disorders, and recurrence of the malignancy, possible AE could not be excluded. The patient was treated with high-dose steroids combined with IVIg therapy; the patient's symptoms were significantly improved.

Conclusion

The mechanisms of AE after allo-HSCT and the relationship with CMV infection should be further studied. Therefore, reporting this and similar cases will improve our awareness and understanding of the underlying disease mechanisms.

Comparison of Three Renal Function Formulas for Ganciclovir/Valganciclovir Dose Individualization in CMV-Infected Solid Organ Transplantation Patients Using a Population Approach

BACKGROUND AND OBJECTIVE

The gold standard treatment of established cytomegalovirus infection or prevention in solid organ transplantation is the intravenous administration of ganciclovir (GCV) or oral administration of valganciclovir (VGCV), both adjusted to the renal function. In both instances, there is a high interindividual pharmacokinetic variability, mainly owing to the wide range of variation of both the renal function and body weight. Therefore, accurate estimation of the renal function is crucial for GCV/VGCV dose optimization. This study aimed to compare three different formulas for estimating the renal function in solid organ transplantation patients with cytomegalovirus infection, for individualizing antiviral therapy with GCV/VGCV, using a population approach.

METHODS

A population pharmacokinetic analysis was performed using NONMEM 7.4. A total of 650 plasma concentrations obtained after intravenous GCV and oral VGCV administrations were analyzed, from intensive and sparse sampling designs. Three different population pharmacokinetic models were built with the renal function given by Cockcroft-Gault, Modification of Diet in Renal Disease, or Chronic Kidney Disease EPIdemiology Collaboration (CKD-EPI) formulas. Pharmacokinetic parameters were allometrically scaled to body weight.

RESULTS

The CKD-EPI formula was identified as the best predictor of between-patient variability in GCV clearance. Internal and external validation techniques showed that the CKD-EPI model had better stability and performed better compared with the others.

CONCLUSIONS

The model based on the more accurate estimation of the renal function with the CKD-EPI formula and body weight as a size metric most used in the clinical practice can refine initial dose recommendations and contribute to GCV and VGCV dose individualization when required in the prevention or treatment of cytomegalovirus infection in solid organ transplantation patients.

Comprehensive Investigations Relationship Between Viral Infections and Multiple Sclerosis Pathogenesis

Multiple sclerosis (MS) is a chronic autoimmune disease that affects the central nervous system (CNS). Compared to other types of self-limiting myelin disorders, MS compartmentalizes and maintains chronic inflammation in the CNS. Even though the exact cause of MS is unclear, it is assumed that genetic and environmental factors play an important role in susceptibility to this disease. The progression of MS is triggered by certain environmental factors, such as viral infections. The most important viruses that affect MS are Epstein-Barr virus (EBV), human herpes virus 6 (HHV-6), human endogenous retrovirus (HERV), cytomegalovirus (CMV), and varicella zoster virus (VZV). These viruses all have latent stages that allow them to escape immune detection and reactivate after exposure to various stimuli. Furthermore, their tropism for CNS and immune system cells explains their possible deleterious function in neuroinflammation. In this study, the effect of viral infections on MS disease focuses on the details of viruses that can change the risk of the disease. Paying attention to the most recent articles on the role of SARS-CoV-2 in MS disease, laboratory indicators show the interaction of the immune system with the virus. Also, strategies to prevent viruses that play a role in triggering MS are discussed, such as EBV, which is one of the most important.

Mouse Models for Cytomegalovirus Infections in Newborns and Adults

This article describes procedures for infecting adult mice with murine cytomegalovirus (MCMV) and for infecting newborn mice to model congenital CMV infection. Methods are included for propagating MCMV in cell cultures and preparing a more virulent form of MCMV from the salivary glands of infected mice. A plaque assay is provided for determining MCMV titers of infected tissues or virus stocks. Also, methods are described for preparing the murine embryonic fibroblasts used for propagating MCMV, and for the plaque assay. © 2022 Wiley Periodicals LLC.

Stimulatory Effect of CMV Immunoglobulin on Innate Immunity and on the Immunogenicity of CMV Antigens

Background.

Cytomegalovirus (CMV) immunoglobulin (CMVIG) is used for the prophylaxis of CMV infection after transplantation. Beyond providing passive CMV-specific immunity, CMVIG exerts enhancing and suppressive immunomodulatory functions. Although the anti-inflammatory activities of CMVIG have been extensively documented, its immunostimulatory activities remain poorly characterized.

Methods.

This exploratory study analyzed the capacity of CMVIG to modulate cell-mediated innate and adaptive immunities in vitro on freshly isolated peripheral blood mononuclear cells (PBMCs) of CMV-seropositive and -seronegative healthy individuals, using interferon-γ (IFN-γ) enzyme-linked immunospot and intracellular cytokine staining assays.

Results.

We showed that CMVIG treatment increases the number of IFN-γ–secreting PBMCs of both CMV-seronegative and -seropositive individuals, indicating a global stimulatory effect on innate immune cells. Indeed, CMVIG significantly increased the frequency of natural killer cells producing the T helper cell 1–type cytokines tumor necrosis factor and IFN-γ. This was associated with the induction of interleukin-12–expressing monocytes and the activation of cluster of differentiation (CD) 4⁺ and CD8⁺ T cells, as measured by the expression of tumor necrosis factor and IFN-γ. Interestingly, stimulation of PBMCs from CMV-seropositive subjects with CMVIG-opsonized CMV antigens (phosphoprotein 65, CMV lysate) enhanced CD4⁺ and CD8⁺ T-cell activation, suggesting that CMVIG promotes the immunogenicity of CMV antigens.

Conclusions.

Our data demonstrate that CMVIG can stimulate effector cells of both innate and adaptive immunities and promote the immunogenicity of CMV antigens. These immunostimulatory properties might contribute to the protective effect against CMV infection mediated by CMVIG.

ELISPOT assay of interferon-γ secretion for evaluating human cytomegalovirus reactivation risk in allo-HSCT recipients

Human cytomegalovirus (HCMV) is a common cause of significant morbidity and mortality in transplant recipients after allogeneic hematopoietic stem cell transplantation (allo-HSCT). We evaluated interferon-γ (IFN-γ) secretion by HCMV NLV-specific CD8⁺ T cells in HCMV-reactivated allo-HSCT recipients using an enzyme-linked immunospot (ELISPOT) assay at 3 months post-transplantation. Blood samples from 47 recipients were tested for HCMV DNAemia, HCMV pp65 antigenemia, and anti-HCMV immunoglobulins (IgG/IgM) over 3 months post-transplantation. Of the 47 transplant recipients, 26 were HLA-A*02 positive and 21 were HLA-A*02 negative. The results were essentially consistent between the 47 transplant recipients and the HLA-A*02-positive recipients. HCMV DNAemia was not linearly correlated with IFN-γ spot-forming cells (SFCs) counts; IFN-γ SFCs counts did not differ significantly between the HCMV DNAemia-positive and -negative groups, whereas the HCMV-DNA virus loads were inversely correlated with the IFN-γ SFCs counts. HCMV pp65 antigenemia was not linearly correlated with IFN-γ SFCs counts; IFN-γ SFCs counts in the HCMV pp65 antigenemia-positive and -negative groups were similar. More IFN-γ SFCs counts were detected in transplant recipients with high anti-HCMV-IgG antibody titers than in those with low anti-HCMV-IgG titers pre-transplantation in the 47 recipients. Anti-HCMV-IgG antibody titers were positively linearly correlated with IFN-γ SFCs counts in HLA-A*02-positive recipients. The HCMV infection indicators used to monitor HCMV reactivation had different values in transplant recipients. The use of the IFN-γ SFCs counts measured by ELISPOT to evaluate the risk of HCMV reactivation needs further study.

Cytomegalovirus DNA in non-glioblastoma multiforme brain tumors of infants

PURPOSE

CMV antigens have been detected in some brain tumors specially glioblastoma multiforme (GBM). As brain tumors in the first years of life are among the most aggressive neoplasms with poor prognosis, novel therapeutic options like targeted therapy against virus antigens are demanded. Infantile central nervous system tumors, other than GBM, have not been so far studied for CMV. To our best knowledge, this is the first study in which the presence of CMV-DNA, as a potential viral target for therapy, in non-GBM infantile brain tumors has been investigated.

METHODS

The paraffin blocks of non-GBM brain neoplasms of 36 infants (age < 24 months) who were operated on between 2006 and 2016 were examined for CMV-DNA, using real-time polymerase chain reaction (PCR). Paraffin blocks of CMV infected lung tissue were used as positive control. Extraction and amplification of β2 microglobulin gene from each tumor tissue were carried as positive internal control. We also assayed 25 paraffin blocks of meningomyelocele for CMV DNA as negative tissue controls.

RESULTS

Histopathological diagnoses consisted of 13 glial/neuroglial tumors (36.1%), 8 ependymomas (22.2%), 7 medulloblastomas (19.4%), 3 choroid plexus tumors (8.3%), 2 atypical teratoid rhabdoid tumors (5.6%), 2 embryonal CNS tumors (5.6%), and 1 germ cell tumor (2.8%). We could not detect CMV DNA in all samples examined.

CONCLUSION

Although CMV may be associated with GBM, no role could be proposed for this virus in development of non-GBM infantile brain tumors. Further investigations on larger series of brain tumors should be conducted to confirm or rule out our conclusion.

Potential Impact of Human Cytomegalovirus Infection on Immunity to Ovarian Tumours and Cancer Progression

Ovarian cancer (OC) is one of the most common, and life-threatening gynaecological cancer affecting females. Almost 75% of all OC cases are diagnosed at late stages, where the 5-year survival rate is less than 30%. The aetiology of the disease is still unclear, and there are currently no screening method nor effective treatment strategies for the advanced disease. A growing body of evidence shows that human cytomegalovirus (HCMV) infecting more than 50% of the world population, may play a role in inducing carcinogenesis through its immunomodulatory activities. In healthy subjects, the primary HCMV infection is essentially asymptomatic. The virus then establishes a life-long chronic latency primarily in the hematopoietic progenitor cells in the bone marrow, with periodic reactivation from latency that is often characterized by high levels of circulating pro-inflammatory cytokines. Currently, infection-induced chronic inflammation is considered as an essential process for OC progression and metastasis. In line with this observation, few recent studies have identified high expressions of HCMV proteins on OC tissue biopsies that were associated with poor survival outcomes. Active HCMV infection in the OC tumour microenvironment may thus directly contribute to OC progression. In this review, we highlight the potential impact of HCMV infection-induced immunomodulatory effects on host immune responses to OC that may promote OC progression.

Cytomegalovirus reactivation during adult acute lymphoblastic leukemia maintenance: do we underestimate (un)expected guest of pediatric approach?

Among acute lymphoblastic leukemia (ALL), 40% of affected patients are diagnosed after the age of 20. Compared to pediatricians, adult hemato-oncologists are less familiar with complex pediatric ALL regimens and have perceived that pediatric ALL regimens are too toxic in the adult population. Meanwhile, multiple retrospective analyzes showed the superiority of pediatric regimens among the older adults and young adolescents (AYAs) group over adult regimens. A series of prospective studies have made it apparent that pediatric-inspired ALL regimens are feasible in AYAs, with manageable toxicities and potentially more encouraging results. However, the complications in the adult population are still to be explored. Although cytomegalovirus (CMV) viremia and infections are increasingly recognized in pediatric ALL cases, we generally do not experience it frequently in adult cases with conventional strategies. Herein we represent a 38-year-old man diagnosed with ALL and treated with pediatric inspired GRAALL-2003 protocol. Following a successful induction phase, he had pancytopenia, deep lymphopenia, fever and diarrhea in the 9^th month of maintenance therapy. With increased serum ferritin and triglyceride levels, he had features of macrophage activation syndrome. The bone marrow biopsy did not reveal any relapse or hemophagocytosis. We detected highly increased levels of CMV DNA (657.262 copies/mL) in blood analysis.

Management of cytomegalovirus corneal endotheliitis

Background

Cytomegalovirus (CMV) can manifest as corneal endotheliitis in immunocompetent individuals. Early diagnosis is prudent to prevent endothelial cell loss, which could ultimately lead to corneal decompensation. CMV DNA was first detected in an eye with corneal endotheliitis in 2006; since then, clinical evidence from numerous case reports and case series have accumulated.

Main text

In this narrative review, we identified several drugs, including ganciclovir, valganciclovir, and their combination in oral, intravenous, intravitreal, and topical forms in different concentrations, together with the judicious use of topical steroids, have reported variable success. There has yet to be any prospective comparative study evaluating the efficacy and safety of these assorted forms of treatment; clinical evidence is based on case reports and case series. CMV endotheliitis presenting with corneal edema can masquerade as other corneal diseases and thus poses a great challenge especially in post-keratoplasty eyes. Heightened awareness is needed before and after keratoplasty to start prompt prophylaxis and treatment.

Conclusion

There is no consensus on the management of CMV endotheliitis. Further studies are much needed to elucidate the optimal treatment modality, regime, and duration in the treatment and prophylaxis of CMV endotheliitis.

Nuclear Egress Complexes of HCMV and Other Herpesviruses: Solving the Puzzle of Sequence Coevolution, Conserved Structures and Subfamily-Spanning Binding Properties

Herpesviruses uniquely express two essential nuclear egress-regulating proteins forming a heterodimeric nuclear egress complex (core NEC). These core NECs serve as hexameric lattice-structured platforms for capsid docking and recruit viral and cellular NEC-associated factors that jointly exert nuclear lamina as well as membrane-rearranging functions (multicomponent NEC). The regulation of nuclear egress has been profoundly analyzed for murine and human cytomegaloviruses (CMVs) on a mechanistic basis, followed by the description of core NEC crystal structures, first for HCMV, then HSV-1, PRV and EBV. Interestingly, the highly conserved structural domains of these proteins stand in contrast to a very limited sequence conservation of the key amino acids within core NEC-binding interfaces. Even more surprising, although a high functional consistency was found when regarding the basic role of NECs in nuclear egress, a clear specification was identified regarding the limited, subfamily-spanning binding properties of core NEC pairs and NEC multicomponent proteins. This review summarizes the evolving picture of the relationship between sequence coevolution, structural conservation and properties of NEC interaction, comparing HCMV to α-, β- and γ-herpesviruses. Since NECs represent substantially important elements of herpesviral replication that are considered as drug-accessible targets, their putative translational use for antiviral strategies is discussed.

Human Immunodeficiency Virus Exposure but Not Early Cytomegalovirus Infection Is Associated With Increased Hospitalization and Decreased Memory T-Cell Responses to Tetanus Vaccine

BACKGROUND

Human immunodeficiency virus (HIV)-exposed, uninfected (HEU) infants experience high rates of infectious morbidity. We hypothesized that early cytomegalovirus (CMV) infection was associated with increased hospitalization rates and decreased vaccine responses in HEU compared with HIV-unexposed (HUU) infants.

METHODS

Among infants enrolled in the Tshipidi study in Botswana, we determined CMV infection status by 6 months of age and compared hospitalization rates and responses to tetanus and Bacille Calmette-Guérin vaccines among HEU and HUU vaccinees.

RESULTS

Fifteen of 226 (6.6%) HEU infants and 17 (19.3%) of 88 HUU infants were CMV-infected by 6 months. The HEU infants were approximately 3 times as likely to be hospitalized compared with HUU infants (P = .02). The HEU peripheral blood cells produced less interleukin (IL)-2 (P = .004), but similar amounts of interferon-γ, after stimulation with tetanus toxoid. Antitetanus immunoglobulin G titers were similar between groups. Cellular responses to purified protein derivative stimulation did not differ between groups. Maternal receipt of 3-drug antiretroviral therapy compared with zidovudine was associated with increased IL-2 expression after tetanus toxoid stimulation. The infants' CMV infection status was not associated with clinical or vaccine response outcomes.

CONCLUSIONS

We observed that increased rates of hospitalization and decreased memory T-cell responses to tetanus vaccine were associated with HIV exposure and incomplete treatment of maternal HIV infection, but not early CMV infection.

Absolute Lymphocyte Count: A Predictor of Recurrent Cytomegalovirus Disease in Solid Organ Transplant Recipients

Background

Recurrent cytomegalovirus (CMV) disease in solid organ transplant recipients frequently occurs despite effective antiviral therapy. We previously demonstrated that patients with lymphopenia before liver transplantation are more likely to develop posttransplant infectious complications including CMV. The aim of this study was to explore absolute lymphocyte count (ALC) as a predictor of relapse following treatment for CMV disease.

Methods

We performed a retrospective cohort study of heart, liver, and kidney transplant recipients treated for an episode of CMV disease. Our primary outcome was time to relapse of CMV within 6 months. Data on potential predictors of relapse including ALC were collected at the time of CMV treatment completion. Univariate and multivariate hazard ratios (HRs) were calculated with a Cox model. Multiple imputation was used to complete the data.

Results

Relapse occurred in 33 of 170 participants (19.4%). Mean ALC in relapse-free patients was 1.08 ± 0.69 vs 0.73 ± 0.42 × 103 cells/μL in those who relapsed, corresponding to an unadjusted hazard ratio of 1.11 (95% confidence interval, 1.03-1.21; P = .009, n = 133) for every decrease of 100 cells/μL. After adjusting for potential confounders, the association between ALC and relapse remained significant (HR, 1.11 [1.03-1.20]; P = .009).

Conclusions

Low ALC at the time of CMV treatment completion was a strong independent predictor for recurrent CMV disease. This finding is biologically plausible given the known importance of T-cell immunity in maintaining CMV latency. Future studies should consider this inexpensive, readily available marker of host immunity.

Reactivation of latent cytomegalovirus infection in patients with rheumatologic disease: a case-control study

The disease burden, risk factors and clinical sequelae of CMV reactivation in patients with rheumatologic conditions is poorly understood. We have described a cohort with underlying rheumatic disease and CMV, and compared a subgroup with systemic lupus erythematosus (SLE) to controls to identify potential risk factors for CMV reactivation. Adults with rheumatic disease and CMV infection from 2000-2015 were identified. SLE cases were matched 3:1 with controls based on age, sex and year of admission, and compared. Fourteen patients were included (6 SLE, 4 rheumatoid arthritis, 2 sarcoidosis, 1 psoriatic arthritis, 1 microscopic polyangiitis). Seven had viremia alone, the remainder tissue-invasive disease. Thirteen received glucocorticoids prior to CMV reactivation. Fever was the most common symptom, and coinfections were seen in eight including four with bacteremia. Thirteen received antiviral therapy (median 33 days), four died during hospitalization. Six patients with underlying SLE and CMV reactivation were compared to 18 SLE controls. Cases received more glucocorticoids prior to admission (median 36.5 vs. 2.5 mg/day, p = 0.006), had longer hospitalizations (median 47 vs. 7 days, p = 0.006) and more coinfections (67% vs. 17%, p = 0.04). There were no significant differences in symptoms at presentation. CMV reactivation occurs in patients with rheumatologic disease, can result in severe clinical sequelae, and is difficult to distinguish from a flare of the underlying disease. Patients with CMV received higher doses of glucocorticoids and developed more co-infections. CMV should be considered during the evaluation of a febrile illness in this complex patient population.

Monitoring of cytomegalovirus infection in non-transplant pediatric acute lymphoblastic leukemia patients during chemotherapy

Cytomegalovirus (CMV) infection is a significant cause of morbidity and mortality in the posttransplant setting; however, it is increasingly recognized in pediatric leukemia during chemotherapy. This study assessed the prevalence and associated factors of CMV infection in pediatric non-transplant leukemia patients.This was a cross-sectional study of 50 pediatric acute lymphoblastic leukemia (ALL) patients receiving chemotherapy at Ramathibodi Hospital from December 2015 to December 2016. CMV viral load quantified by DNA polymerase chain reaction (PCR) was monitored in different phases of chemotherapy: enrolment, post-induction, post-consolidation, post-intensification, and maintenance.One hundred forty one blood tests were evaluated from 50 patients. Overall prevalence of CMV DNAemia (≥20 copies/mL) and high-level CMV DNAemia (≥1000 copies/mL) was 52% (26 of 50) and 16.0% (8 of 50), respectively. All patients with high-level CMV DNAemia were in the maintenance phase of chemotherapy. One patient had CMV retinitis, while the rest had no end-organ CMV diseases. Increased lymphocyte count was significantly associated with protection from high-level CMV DNAemia (odds ratio 0.997, P = .02). Receiver operating characteristic curve identified a cut-off value of 798 cells/mm of absolute lymphocyte count (ALC) as a discriminator for the presence of high-level CMV DNAemia (area under the curve 0.756, 95% CI 0.645-0.867, P = .001) with 88.9% sensitivity and 50.4% specificity.CMV infection predominantly occurred during maintenance chemotherapy. Low ALC was significantly associated with high-level CMV DNAemia. CMV infection surveillance by quantitative CMV DNA PCR during maintenance chemotherapy in patients with ALC <800 cells/mm may be considered.

CMV and EBV targets recognized by tumor-infiltrating B lymphocytes in pancreatic cancer and brain tumors

Targeted antiviral immune responses to the widespread human pathogens cytomegalovirus (CMV) and Epstein-Barr virus (EBV) play a pivotal role in determining immune fitness. We show here for the first time that tumor-infiltrating B cell (TIB)- derived immunoglobulin G (IgG) from patients with pancreatic cancer or glioblastoma have unique anti-CMV/EBV immune recognition patterns compared to serum IgG. There is also great heterogeneity between patients, as well as between serum and TIB-IgG, while some viral targets elicited strongly both T-cell and IgG reactivity in tumor infiltrating T- and B-cells. These observations suggest that the anti-CMV/EBV humoral immune response in situ is highly unique and can be instrumental in developing next-generation immuno-biomarkers in addition to supplementing cellular therapy strategies for personalized cancer therapy targeting CMV or EBV in the tumor microenvironment.

Human cytomegalovirus and Epstein-Barr virus infections, risk factors, and their influence on the liver function of patients with acute-on-chronic liver failure

Background

Studies on human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV) have focused primarily on the immunosuppressed population. Few studies have considered immunocompetent and not severely immunocompromised patients. We determined the infection rates of HCMV and EBV, their risk factors and their influence on liver function in patients with HBV-related acute-on-chronic liver failure (ACLF).

Methods

Patients infected with ACLF-based hepatitis B virus (HBV) from 1 December 2016 to 31 May 2018 were enrolled in our study and were divided into infected and uninfected groups. The risk factors for HCMV and EBV infection and their influence on liver function were analysed.

Results

A total of 100 hospitalized patients with ACLF due to HBV infection were enrolled in this study. Of these patients, 5% presented HCMV deoxyribonucleic acid (DNA) and 23.0% presented EBV DNA. An HBV DNA count of < 1000 IU/mL increased the occurrence of HCMV infection (P = 0.003). Age, especially older than 60 years, was a risk factor for EBV infection (P = 0.034, P = 0.033). HCMV-infected patients had lower alanine aminotransferase (ALT) levels; albumin levels and Child–Pugh scores in EBV-infected patients were higher than those in uninfected patients.

Conclusions

HCMV and EBV were detected in patients with ACLF caused by HBV infection. Lower replication of HBV (HBV DNA < 1000 IU/mL) may increase the probability of HCMV infection; age, especially older than 60 years of age, was a risk factor for EBV infection. HCMV infection may inhibit HBV proliferation and did not increase liver injury, while co-infection with EBV may influence liver function and may result in a poor prognosis.

Evodiamine alleviates severe pneumonia induced by methicillin-susceptible Staphylococcus aureus following cytomegalovirus reactivation through suppressing NF-κB and MAPKs

Viral and bacterial severe pneumonia are leading causes of mortality across the globe. Evodiamine (Evo), a botanical alkaloid, has anti-inflammatory and antibacterial properties. In the present study, the effect of Evo on severe pneumonia induced by methicillin-susceptible Staphylococcus aureus (MSSA) following cytomegalovirus (CMV) reactivation, and its mechanism, were evaluated. In vitro, the protein and mRNA expression levels of inflammatory cytokines were determined by enzyme-linked immunosorbent assay and reverse transcription-quantitative polymerase chain reaction analysis, respectively. The expression levels of associated proteins of the nuclear factor (NF)-κB and mitogen-activated protein kinase (MAPK) signaling pathways were measured by western blot analysis. In vivo, mortality rate, weight loss, histological changes, lung bacteria count, inflammatory cytokines, and the expression proteins of associated with the NF-κB and MAPK signaling pathways were examined. The results revealed that Evo dose-dependently reduced the protein and mRNA expression levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-1β, and inhibited the levels of phosphorylated (p-) inhibitor of NF-κBα, p-extracellular signal-regulated kinase, p-c-Jun N-terminal kinase and p-p38, and decreased the nuclear trans-location of NF-κB/p65 in BEAS-2B cells infected with MSSA. Furthermore, Evo markedly improved survival rate, decreased body weight loss and bacterial count, and attenuated lung histological alterations and the levels of inflammatory factors. In addition, the NF-κB and MAPK signaling pathways were significantly inhibited. Taken together, Evo effectively alleviated pneumonia via the NF-κB and MAPK pathways and may be a potential therapeutic agent for treating severe pneumonia.

CMV specific T cell immunity predicts early viremia after liver transplantation

BACKGROUND

Cytomegalovirus (CMV) infection is one of the most important factors affecting liver transplant with direct and indirect effects. However, CMV disease after transplant remains poorly predicted.

OBJECTIVE

In this study, preoperative CMV-specific cell-mediated immunity was evaluated in recipients of liver transplant in Korea, where most people are seropositive.

METHODS

A total of 32 patients were enrolled in a prospective study, and blood samples were collected before liver transplant to determine CMV-specific cell-mediated immunity. Testing using ELiSpot IFN-γ (CMVspot) and CMV serology were performed simultaneously.

RESULTS

CMVspot results showed that 30 recipients had CMV-specific cell-mediated immunity, of which 29 were positive for phosphoprotein 65 and 14 for immediate early protein 1 (IE-1). All patients were positive for CMV IgG before transplantation, and 17 patients had a CMV viremia episode after transplantation. CMVspot showed 100% specificity and positive predictive value, and 11.76% sensitivity to predict CMV viremia. Patients with positive or borderline results for IE-1 did not show viremia two months after transplantation (p = .041).

CONCLUSION

CMVspot may be helpful in establishing a treatment strategy that includes regular monitoring for risk stratification of CMV reactivation.

Cytomegalovirus Infection: Mouse Model

This unit describes procedures for infecting newborn and adult mice with murine cytomegalovirus (MCMV). Methods are included for propagating MCMV in cell cultures and for preparing a more virulent form of MCMV from salivary glands of infected mice. A plaque assay is provided for determining MCMV titers of infected tissues or virus stocks. Also, a method is described for preparing the murine embryonic fibroblasts used for propagating MCMV and for the plaque assay. © 2018 by John Wiley & Sons, Inc.

Analysis of the QuantiFERON-CMV assay, CMV viraemia and antiviral treatment following solid organ transplantation in Western Australia

Prevention of cytomegalovirus (CMV) infection remains an important aspect of improving long term outcomes of solid organ transplantation and currently relies on prophylactic antiviral medication and early detection of viraemia or disease. Uptake of diagnostic tools to personalise assessment of CMV immunity and guide interpretation of viral testing remains low. We assessed the QuantiFERON-CMV assay in 54 Western Australian recipients of renal, heart, lung or liver allografts to determine the relationship between CMV-specific immunity, viraemia and disease following cessation of antiviral prophylaxis. We carried out an initial validation study which demonstrated that the QuantiFERON-CMV assay is highly precise and strongly correlated with CMV-specific antibodies in 30 healthy blood donors (sensitivity 82%, specificity 95%). In the solid organ transplant recipients we examined, the prevalence of asymptomatic CMV viraemia was high at 61% but only two patients ultimately developed CMV disease, both of whom had negative QuantiFERON-CMV responses, indicating lack of CMV T-cell immunity. The vast majority (94%) of patients who had spontaneous resolution or stability of asymptomatic CMV viraemia without any antiviral treatment had positive QuantiFERON-CMV responses. Positive QuantiFERON-CMV responses at cessation of antiviral prophylaxis were significantly associated with pre-transplant CMV seropositivity and the development of asymptomatic viraemia post-transplantation. Overall, 27% of patients were recommenced on antiviral therapy because of asymptomatic CMV viraemia. Patients with non-reactive QuantiFERON-CMV responses had earlier onset, higher level CMV viraemia compared to those with positive QuantiFERON-CMV responses, although the difference did not reach statistical significance. QuantiFERON-CMV results may contribute to decision making in concert with the serological risk profile, net state of immunosuppression and CMV viral load.

The First Reported Case of Cytomegalovirus Gastritis in a Patient With End-Stage Renal Disease

Cytomegalovirus (CMV) infection is a common infectious complication in immunocompromised patients. The colon is the most common site of CMV infection in the gastrointestinal tract. Rarely, however, invasion of the upper gastrointestinal tract, such as the esophagus or stomach, has been reported. Herein, we describe the first reported case of CMV gastritis in a patient with end-stage renal disease and uremic symptoms (including nausea, vomiting, and poor appetite) who had begun hemodialysis therapy. This patient was not a transplant recipient and was not receiving immunosuppressant treatment. As CMV gastritis is easily over looked in patients with end-stage renal disease, physicians should maintain a high index of suspicion and establish the diagnosis as early as possible using an upper GI endoscopic biopsy and adequate staining.

Cytomegalovirus-Specific CD8+ T-Cells With Different T-Cell Receptor Affinities Segregate T-Cell Phenotypes and Correlate With Chronic Graft-Versus-Host Disease in Patients Post-Hematopoietic Stem Cell Transplantation

Virus-specific T-cell responses are crucial to control cytomegalovirus (CMV) infections/reactivation in immunocompromised individuals. Adoptive cellular therapy with CMV-specific T-cells has become a viable treatment option. High-affinity anti-viral cellular immune responses are associated with improved long-term immune protection against CMV infection. To date, the characterization of high-affinity T-cell responses against CMV has not been achieved in blood from patients after allogeneic hematopoietic stem cell transplantation (HSCT). Therefore, the purpose of this study was to describe and analyze the phenotype and clinical impact of different CMV-specific CD8+ cytotoxic T-lymphocytes (CMV-CTL) classes based on their T-cell receptor (TCR) affinity. T-cells isolated from 23 patients during the first year following HSCT were tested for the expression of memory markers, programmed cell death 1 (PD-1), as well as TCR affinity, using three different HLA-A*02:01 CMVNLVPMVATV-Pp65 tetramers (wild-type, a245v and q226a mutants). High-affinity CMV-CTL defined by q226a tetramer binding, exhibited a higher frequency in CD8+ T-cells in the first month post-HSCT and exhibited an effector memory phenotype associated with strong PD-1 expression as compared to the medium- and low-affinity CMV-CTLs. High-affinity CMV-CTL was found at higher proportion in patients with chronic graft-versus-host disease (p < 0.001). This study provides a first insight into the detailed TCR affinities of CMV-CTL. This may be useful in order to improve current immunotherapy protocols using isolation of viral-specific T-cell populations based on their TCR affinity.

Cyclophilin A as a target in the treatment of cytomegalovirus infections

BACKGROUND

Viruses are obligate parasites that depend on the cellular machinery of the host to regenerate and manufacture their proteins. Most antiviral drugs on the market today target viral proteins. However, the more recent strategies involve targeting the host cell proteins or pathways that mediate viral replication. This new approach would be effective for most viruses while minimizing drug resistance and toxicity.

METHODS

Cytomegalovirus replication, latency, and immune response are mediated by the intermediate early protein 2, the main protein that determines the effectiveness of drugs in cytomegalovirus inhibition. This review explains how intermediate early protein 2 can modify the action of cyclosporin A, an immunosuppressive, and antiviral drug. It also links all the pathways mediated by cyclosporin A, cytomegalovirus replication, and its encoded proteins.

RESULTS

Intermediate early protein 2 can influence the cellular cyclophilin A pathway, affecting cyclosporin A as a mediator of viral replication or anti-cytomegalovirus drug.

CONCLUSION

Cyclosporin A has a dual function in cytomegalovirus pathogenesis. It has the immunosuppressive effect that establishes virus replication through the inhibition of T-cell function. It also has an anti-cytomegalovirus effect mediated by intermediate early protein 2. Both of these functions involve cyclophilin A pathway.

Association between γ marker, human leucocyte antigens and killer immunoglobulin-like receptors and the natural course of human cytomegalovirus infection: a pilot study performed in a Sicilian population

Natural killer (NK) cells provide a major defence against human cytomegalovirus (HCMV) infection through the interaction of their surface receptors, including the activating and inhibitory killer immunoglobulin-like receptors (KIRs), and human leucocyte antigen (HLA) class I molecules. Also γ marker (GM) allotypes, able to influence the NK antibody-dependent cell-mediated cytotoxicity, appear to be involved in the immunological control of virus infections, including HCMV. In some cases, their contribution requires epistatic interaction with other genes of the immune system, such as HLA. In the present report, with the aim of gaining insight into the immune mechanisms controlling HCMV, we have studied the possible associations among humoral and NK responses, and HCMV infections. In a previous study we assessed whether the KIR and HLA repertoire might influence the risk of developing symptomatic (n = 60) or asymptomatic (n = 60) disease after primary HCMV infection in the immunocompetent host. In the present study, the immunocompetent patients with primary symptomatic HCMV infection were genotyped for GM3/17 and GM23 allotypes, along with the 60 participants with a previous asymptomatic infection as controls. Notwithstanding the presence of missing data record, advanced missing data recovery techniques were able to show that individuals carrying the GM23 allotypes, both homozygous and heterozygous, GM17/17, HLA-C2 and Bw4^T KIR-ligand groups are associated with the risk of developing symptomatic infection. Our findings on the role of both cellular and humoral immunity in the control of HCMV infection should be of value in guiding efforts to reduce HCMV-associated health complications in the elderly, including immunosenescence, and in transplantation.

Lack of Association Between Cytomegalovirus Infection and Hypertensive Disorders in Pregnancy: A Case-Control Study in Durango, Mexico

It is not clear whether infection with cytomegalovirus (CMV) is associated with hypertensive disorders in pregnant women. Through a case-control study design, 146 women suffering from hypertensive disorders in pregnancy (cases) and 146 age-matched normotensive pregnant women (controls) were examined for the presence of anti-CMV IgG and IgM antibodies with enzyme-linked immunoassays. IgM seropositive samples were further assayed by enzyme-linked fluorescent assay (ELFA).

Anti-CMV IgG antibodies were found in 138 (94.5%) controls and in 136 (93.2%) cases (odds ratio [OR] = 0.78; 95% confidence interval [CI]: 0.30–2.05; P = 0.62). High (>18 IU/ml) levels of anti-CMV IgG antibodies were found in 37.7% of the 138 seropositive controls and in 34.6% of the 136 seropositive cases (OR = 0.87; 95% CI: 0.53–1.43; P = 0.59). Anti-CMV IgM antibodies were found in 1 (0.7%) of the controls but in none of the cases using ELFA (P = 1.0). Seropositivity to CMV was not associated with a previous preeclampsia and was similar among cases regardless their mean systolic and diastolic blood pressures, and mean arterial blood pressure.

No serological evidence of an association between CMV infection and hypertensive disorders of pregnancy was found. Further research to elucidate the role of CMV in hypertensive disorders in pregnancy should be conducted.

The human cytomegalovirus nuclear egress complex unites multiple functions: Recruitment of effectors, nuclear envelope rearrangement, and docking to nuclear capsids

BACKGROUND

Nuclear replication represents a common hallmark of herpesviruses achieved by a number of sequentially unrolled regulatory processes. A rate-limiting step is provided by nucleo-cytoplasmic capsid export, for which a defined multiregulatory protein complex, namely, the nuclear egress complex (NEC), is assembled comprising both viral and cellular components. The NEC regulates at least 3 aspects of herpesviral nuclear replication: (1) multimeric recruitment of NEC-associated effector proteins, (2) reorganization of the nuclear lamina and membranes, and (3) the docking to nuclear capsids. Here, we review published data and own experimental work that characterizes the NEC of HCMV and other herpesviruses.

METHODS

A systematic review of information on nuclear egress of HCMV compared to selected alpha-, beta-, and gamma-herpesviruses: proteomics-based approaches, high-resolution imaging techniques, and functional investigations.

RESULTS

A large number of reports on herpesviral NECs have been published during the last two decades, focusing on protein-protein interactions, nuclear localization, regulatory phosphorylation, and functional validation. The emerging picture provides an illustrated example of well-balanced and sophisticated protein networking in virus-host interaction.

CONCLUSIONS

Current evidence refined the view about herpesviral NECs. Datasets published for HCMV, murine CMV, herpes simplex virus, and Epstein-Barr virus illustrate the marked functional consistency in the way herpesviruses achieve nuclear egress. However, this compares with only limited sequence conservation of core NEC proteins and a structural conservation restricted to individual domains. The translational use of this information might help to define a novel antiviral strategy on the basis of NEC-directed small molecules.

Improvement of cytomegalovirus pp65 DNA vaccine efficacy by co-administration of siRNAs targeting BAK and BAX

The efficacy of DNA vaccines may be improved by small interfering (si)RNA adjuvants targeting pro-apoptotic genes. The aim of the present study was to investigate the capacity of siRNAs targeting B-cell lymphoma 2 homologous antagonist killer (BAK) and B-cell lymphoma 2-associated X protein (BAX) to improve the efficacy of a cytomegalovirus (CMV) vaccine. BALB/c mice were divided into four groups (n=18 in each): unimmunized and immunized with pcDNA 3.1-pp65 expressing CMV 65 kDa matrix phosphoprotein and BAK + BAX siRNAs, pcDNA 3.1-pp65 and control siRNA, or control pcDNA 3.1 and BAK + BAX siRNAs. Immunizations were performed twice with an interval of 3 weeks. CMV-specific mouse splenocyte interferon (IFN)-γ secretion was assessed by ELISPOT; furthermore, an in vivo cytotoxic T lymphocyte assay was performed 2 weeks after the last immunization. After lethal CMV challenge of the mice, body weight, virus titers in the spleens and salivary glands as well as survival were recorded. The amount of splenocytes secreting IFN-γ in response to CMV pp65 peptides and specific lysis of peptide-pulsed target cells were significantly higher in mice administered pcDNA3.1-pp65 and BAK + BAX siRNAs than those in mice administered pcDNA3.1-pp65 and control siRNA (P<0.05 for each). After the virus challenge, the virus titers in the spleens and salivary glands of mice given pcDNA3.1-pp65 and BAK + BAX siRNAs were significantly lower than those in mice immunized with pcDNA3.1-pp65 and control siRNA (P<0.05 for each). Furthermore, mice immunized with pcDNA 3.1-pp65 and control siRNA or BAK + BAX siRNAs survived for longer, and at 21 days after lethal CMV challenge, 66 and 100% of these mice survived, respectively. These mice also experienced less weight loss compared with mice immunized with pcDNA3.1-pp65 and control siRNA (P<0.05). In conclusion, intradermal administration of siRNAs targeting BAK and BAX improved the efficacy of CMV pp65 DNA vaccine.

Peptide vaccination in the presence of adjuvants in patients after hematopoietic stem cell transplantation with CD4+ T cell reconstitution elicits consistent CD8+ T cell responses

Rationale: Patients receiving an allogeneic stem cell graft from cytomegalovirus (CMV) seronegative donors are particularly prone to CMV reactivation with a high risk of disease and mortality. Therefore we developed and manufactured a novel vaccine and initiated a clinical phase I trial with a CMV phosphoprotein 65 (CMVpp65)-derived peptide. Methods: Ten patients after allogeneic stem cell transplantation received four vaccinations at a biweekly interval. All patients were monitored for CMVpp65 antigenemia. Flow cytometry for CMV-specific CD8+ and γδ T cells as well as neutralizing anti-CMV antibodies were correlated to clinical parameters. Results: The vaccination was well tolerated. Seven of nine patients cleared CMVpp65 antigenemia after four vaccinations and are still free from antigenemia to this day. Two patients with CMV reactivation showed persisting CMV antigenemia. One patient received prophylactic vaccination and did not develop antigenemia. An increase of up to six-fold in frequency of both CMV-specific CD8+ T cells and/or Vδ2negative γδ T cells was detected. Titers of neutralizing antibodies increased up to the tenfold. Humoral and cellular immune responses correlated with clearance of CMV. Conclusion: In summary, CMVpp65 peptide vaccination for patients after allogeneic stem cell transplantation at high risk for CMV reactivation was safe, well tolerated and clinically encouraging. A study in solid-organ transplant patients is ongoing.

Cytomegalovirus infection exacerbates autoimmune mediated neuroinflammation

Cytomegalovirus (CMV) is a latent virus which causes chronic activation of the immune system. Here, we demonstrate that cytotoxic and pro-inflammatory CD4⁺CD28^null T cells are only present in CMV seropositive donors and that CMV-specific Immunoglobulin (Ig) G titers correlate with the percentage of these cells. In vitro stimulation of peripheral blood mononuclear cells with CMVpp65 peptide resulted in the expansion of pre-existing CD4⁺CD28^null T cells. In vivo, we observed de novo formation, as well as expansion of CD4⁺CD28^null T cells in two different chronic inflammation models, namely the murine CMV (MCMV) model and the experimental autoimmune encephalomyelitis (EAE) model for multiple sclerosis (MS). In EAE, the percentage of peripheral CD4⁺CD28^null T cells correlated with disease severity. Pre-exposure to MCMV further aggravated EAE symptoms, which was paralleled by peripheral expansion of CD4⁺CD28^null T cells, increased splenocyte MOG reactivity and higher levels of spinal cord demyelination. Cytotoxic CD4⁺ T cells were identified in demyelinated spinal cord regions, suggesting that peripherally expanded CD4⁺CD28^null T cells migrate towards the central nervous system to inflict damage. Taken together, we demonstrate that CMV drives the expansion of CD4⁺CD28^null T cells, thereby boosting the activation of disease-specific CD4⁺ T cells and aggravating autoimmune mediated inflammation and demyelination.

Validation of T-Track® CMV to assess the functionality of cytomegalovirus-reactive cell-mediated immunity in hemodialysis patients

Background

Uncontrolled cytomegalovirus (CMV) replication in immunocompromised solid-organ transplant recipients is a clinically relevant issue and an indication of impaired CMV-specific cell-mediated immunity (CMI). Primary aim of this study was to assess the suitability of the immune monitoring tool T-Track® CMV to determine CMV-reactive CMI in a cohort of hemodialysis patients representative of patients eligible for renal transplantation. Positive and negative agreement of T-Track® CMV with CMV serology was examined in 124 hemodialysis patients, of whom 67 (54%) revealed a positive CMV serostatus. Secondary aim of the study was to evaluate T-Track® CMV performance against two unrelated CMV-specific CMI monitoring assays, QuantiFERON®-CMV and a cocktail of six class I iTAg™ MHC Tetramers.

Results

Positive T-Track® CMV results were obtained in 90% (60/67) of CMV-seropositive hemodialysis patients. In comparison, 73% (45/62) and 77% (40/52) positive agreement with CMV serology was achieved using QuantiFERON®-CMV and iTAg™ MHC Tetramer. Positive T-Track® CMV responses in CMV-seropositive patients were dominated by pp65-reactive cells (58/67 [87%]), while IE-1-responsive cells contributed to an improved (87% to 90%) positive agreement of T-Track® CMV with CMV serology. Interestingly, T-Track® CMV, QuantiFERON®-CMV and iTAg™ MHC Tetramers showed 79% (45/57), 87% (48/55) and 93% (42/45) negative agreement with serology, respectively, and a strong inter-assay variability. Notably, T-Track® CMV was able to detect IE-1-reactive cells in blood samples of patients with a negative CMV serology, suggesting either a previous exposure to CMV that yielded a cellular but no humoral immune response, or TCR cross-reactivity with foreign antigens, both suggesting a possible protective immunity against CMV in these patients.

Conclusion

T-Track® CMV is a highly sensitive assay, enabling the functional assessment of CMV-responsive cells in hemodialysis patients prior to renal transplantation. T-Track® CMV thus represents a valuable immune monitoring tool to identify candidate transplant recipients potentially at increased risk for CMV-related clinical complications.

Electronic supplementary material

The online version of this article (doi:10.1186/s12865-017-0194-z) contains supplementary material, which is available to authorized users.

An optimized IFN-γ ELISpot assay for the sensitive and standardized monitoring of CMV protein-reactive effector cells of cell-mediated immunity

Background

In healthy individuals, Cytomegalovirus (CMV) infection is efficiently controlled by CMV-specific cell-mediated immunity (CMI). Functional impairment of CMI in immunocompromized individuals however can lead to uncontrolled CMV replication and severe clinical complications. Close monitoring of CMV-specific CMI is therefore clinically relevant and might allow a reliable prognosis of CMV disease as well as assist personalized therapeutic decisions.

Methods

Objective of this work was the optimization and technical validation of an IFN-γ ELISpot assay for a standardized, sensitive and reliable quantification of CMV-reactive effector cells. T-activated® immunodominant CMV IE-1 and pp65 proteins were used as stimulants. All basic assay parameters and reagents were tested and optimized to establish a user-friendly protocol and maximize the signal-to-noise ratio of the ELISpot assay.

Results

Optimized and standardized ELISpot revealed low intra-assay, inter-assay and inter-operator variability (coefficient of variation CV below 22%) and CV inter-site was lower than 40%. Good assay linearity was obtained between 6 × 10⁴ and 2 × 10⁵ PBMC per well upon stimulation with T-activated® IE-1 (R² = 0.97) and pp65 (R² = 0.99) antigens. Remarkably, stimulation of peripheral blood mononuclear cells (PBMC) with T-activated® IE-1 and pp65 proteins resulted in the activation of a broad range of CMV-reactive effector cells, including CD3⁺CD4⁺ (Th), CD3⁺CD8⁺ (CTL), CD3⁻CD56⁺ (NK) and CD3⁺CD56⁺ (NKT-like) cells. Accordingly, the optimized IFN-γ ELISpot assay revealed very high sensitivity (97%) in a cohort of 45 healthy donors, of which 32 were CMV IgG-seropositive.

Conclusion

The combined use of T-activated® IE-1 and pp65 proteins for the stimulation of PBMC with the optimized IFN-γ ELISpot assay represents a highly standardized, valuable tool to monitor the functionality of CMV-specific CMI with great sensitivity and reliability.

Electronic supplementary material

The online version of this article (doi:10.1186/s12865-017-0195-y) contains supplementary material, which is available to authorized users.

Murine Cytomegalovirus Infection Induces Susceptibility to EAE in Resistant BALB/c Mice

In contrast to C57BL/6 mice, BALB/c mice are relatively resistant to the induction of experimental autoimmune encephalomyelitis (EAE) after challenge with MOG_35–55 peptide. Here, we provide the first evidence that infection with murine cytomegalovirus (MCMV) in adulthood abrogates this resistance. Infected BALB/c mice developed clinical and histological signs similar to those seen in susceptible C57BL/6 mice. In addition to CD4⁺ cells, large proportion of cells in the infiltrate of diseased BALB/c mice was CD8⁺, similar with findings in multiple sclerosis. CD8⁺ cells that responded to ex vivo restimulation with MOG_35–55 were not specific for viral epitopes pp89 and m164. MCMV infection favors proinflammatory type of dendritic cells (CD86⁺CD40⁺CD11c⁺) in the peripheral lymph organs, M1 type of microglia in central nervous system, and increases development of Th1/Th17 encephalitogenic cells. This study indicates that MCMV may enhance autoimmune neuropathology and abrogate inherent resistance to EAE in mouse strain by enhancing proinflammatory phenotype of antigen-presenting cells, Th1/Th17, and CD8 response to MOG_35–55.

Mechanisms Underlying T Cell Immunosenescence: Aging and Cytomegalovirus Infection

The ability of the human immune system to protect against infectious disease declines with age and efficacy of vaccination reduces significantly in the elderly. Aging of the immune system, also termed as immunosenescence, involves many changes in human T cell immunity that is characterized by a loss in naïve T cell population and an increase in highly differentiated CD28- memory T cell subset. There is extensive data showing that latent persistent human cytomegalovirus (HCMV) infection is also associated with age-related immune dysfunction in the T cells, which might enhance immunosenescence. Understanding the molecular mechanisms underlying age-related and HCMV-related immunosenescence is critical for the development of effective age-targeted vaccines and immunotherapies. In this review, we will address the role of both aging and HCMV infection that contribute to the T cell senescence and discuss the potential molecular mechanisms in aged T cells.

Marek's disease in chickens: a review with focus on immunology

Marek's disease (MD), caused by Marek's disease virus (MDV), is a commercially important neoplastic disease of poultry which is only controlled by mass vaccination. Importantly, vaccines that can provide sterile immunity and inhibit virus transmission are lacking; such that vaccines are only capable of preventing neuropathy, oncogenic disease and immunosuppression, but are unable to prevent MDV transmission or infection, leading to emergence of increasingly virulent pathotypes. Hence, to address these issues, developing more efficacious vaccines that induce sterile immunity have become one of the important research goals for avian immunologists today. MDV shares very close genomic functional and structural characteristics to most mammalian herpes viruses such as herpes simplex virus (HSV). MD also provides an excellent T cell lymphoma model for gaining insights into other herpesvirus-induced oncogenesis in mammals and birds. For these reasons, we need to develop an in-depth knowledge and understanding of the host-viral interaction and host immunity against MD. Similarly, the underlying genetic variation within different chicken lines has a major impact on the outcome of infection. In this review article, we aim to investigate the pathogenesis of MDV infection, host immunity to MD and discuss areas of research that need to be further explored.

Cytomegalovirus in immunocompromised children

PURPOSE OF REVIEW

The purpose of this study is to explore the latest developments in the risk factors, prevention and treatment of cytomegalovirus (CMV) infection in immunocompromised children, including those with congenital immunodeficiency or iatrogenic immune suppression related to solid organ transplantation (SOT) or haematopoietic cell transplantation (HCT).

RECENT FINDINGS

CMV viral load measurements now have international standards, allowing for more reliable comparison across sites and within individuals. Preemptive and prophylactic therapy with routine CMV monitoring in transplant patients has yielded significant reduction in CMV morbidity and mortality in these patients. The majority of U.S. states have adopted routine newborn screening for severe combined immunodeficiency (SCID). Viral infections, including CMV, are a major obstacle preventing optimal curative transplantation in these patients. Several new antiviral agents are currently being investigated for CMV infection in immunocompromised patients. Knowledge on CMV drug resistance in children is emerging and requires further study.

SUMMARY

Conditions that diminish cell-mediated immunity impact the development of CMV infection and disease. These conditions include certain congenital immunodeficiencies and SOT and HCT. Infants identified as having SCID should be screened for CMV risk factors. A preemptive or prophylactic strategy should be chosen for CMV management in children who are high risk posttransplantation. In those who develop disease, viral loads should be monitored and resistance testing considered if response is not deemed adequate. Oral valganciclovir is being used as an alternative to ganciclovir in children, although pharmacokinetic data are limited. Other oral antiviral agents under development are promising future options for paediatric CMV therapy.

Cytomegalovirus Genotype Distribution Among Congenitally and Postnatally Infected Patients: Association of Particular Glycoprotein (g)B and gN Types With Symptomatic Disease

Background. Human cytomegalovirus is a leading cause of congenital infection, and there are limited data on prognosis markers in disease development. We aimed to study 3 virology targets (glycoprotein [g]B, gN, and UL144) to assess their correlation with congenital infection and various organ system involvement.

Methods. Forty-eight congenital cases and 58 postnatally infected children were included (2003–2014). Genotyping for the 3 targets and distribution among the cohorts were investigated, and the relationship between the gB, gN, and UL144 types with clinical manifestations in congenital infection was also studied.

Results. All of the genotypes were similarly represented among cohorts, and the most prevalent were the UL144B, gB1, and gN1 genotypes. The gB2 genotype was associated with abnormal image findings by ultrasound and/or magnetic resonance in congenital infection (odds ratio [OR], 6.2; 95% confidence interval [CI], 1.1–34.3; P = .036); the gN1 genotype was associated with an elevated risk of developing neurological disorders (OR, 7.0; 95% CI, 1.1–45.9; P = .043). Both gN1 and gB2 were independent factors for symptomatic infection. Statistical analyses showed no association between any UL144 genotype and disease severity.

Conclusions. All of the genotypes can be involved in congenital infection, although the gB2 and gN1 genotypes might be associated with a more serious illness.

Polymorphisms in cytomegalovirus genotype in immunocompetent patients with corneal endotheliitis or iridocyclitis

Cytomegalovirus (CMV) that caused corneal endotheliitis and iridocyclitis in immunocompetent patients was genotyped. The gB type1 was detected in seven endotheliitis samples (77.8%) and five iridocyclitis samples (100%), and the gB type 3 was detected in two endotheliitis samples (22.2%). The UL144 type 1 was found in five endotheliitis samples (45.5%) and five iridocyclitis samples (83.3%). The UL144 type 2 was found in two endotheliitis samples (18.2%) and one iridocyclitis sample (16.7%). The gB type 1 was predominant in endotheliitis and iridocyclitis, and the CMV genotypes in eyes with endotheliitis and iridocyclitis were similar.

Anti-CMV-IgG positivity of donors is beneficial for alloHSCT recipients with respect to the better short-term immunological recovery and high level of CD4+CD25high lymphocytes

Hematopoietic stem cell transplantation from anti-cytomegalovirus immunoglobulin G (anti-CMV-IgG) positive donors facilitated immunological recovery post-transplant, which may indicate that chronic CMV infection has an effect on the immune system. This can be seen in the recipients after reconstitution with donor lymphocytes. We evaluated the composition of lymphocytes at hematologic recovery in 99 patients with hematologic malignancies post hematopoietic stem cell transplantation (HSCT). Anti-CMV-IgG seropositivity of the donor was associated with higher proportions of CD4+ (227.963 ± 304.858 × 106 vs. 102.050 ± 17.247 × 106 cells/L, p = 0.009) and CD4+CD25high (3.456 ± 0.436 × 106 vs. 1.589 ± 0.218 × 106 cells/L, p = 0.003) lymphocytes in the blood at hematologic recovery. The latter parameter exerted a diverse influence on the risk of acute graft-versus-host disease (GvHD) if low (1.483 ± 0.360 × 106 vs. 3.778 ± 0.484 × 106 cells/L, p < 0.001) and de novo chronic GvHD (cGvHD) if high (3.778 ± 0.780 × 106 vs. 2.042 ± 0.261 × 106 cells/L, p = 0.041). Higher values of CD4+ lymphocytes in patients who received transplants from anti-CMV-IgG-positive donors translated into a reduced demand for IgG support (23/63 vs. 19/33, p = 0.048), and these patients also exhibited reduced susceptibility to cytomegalovirus (CMV), Epstein-Barr virus (EBV) and/or human herpes 6 virus (HHV6) infection/reactivation (12/50 vs. 21/47, p = 0.032). Finally, high levels (³0.4%) of CD4+CD25high lymphocytes were significantly associated with better post-transplant survival (56% vs. 38%, four-year survival, p = 0.040). Donors who experience CMV infection/reactivation provide the recipients with lymphocytes, which readily reinforce the recovery of the transplanted patients' immune system.