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Kent SJ, Reece JC, Petravic J, Martyushev A, Kramski M, De Rose R, Cooper DA, Kelleher AD, Emery S, Cameron PU, Lewin SR, Davenport MP. The search for an HIV cure: tackling latent infection. THE LANCET. INFECTIOUS DISEASES 2013; 13:614-21. [PMID: 23481675 DOI: 10.1016/s1473-3099(13)70043-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Strategies to eliminate infectious HIV that persists despite present treatments and with the potential to cure HIV infection are of great interest. One patient seems to have been cured of HIV infection after receiving a bone marrow transplant with cells resistant to the virus, although this strategy is not viable for large numbers of infected people. Several clinical trials are underway in which drugs are being used to activate cells that harbour latent HIV. In a recent study, investigators showed that activation of latent HIV infection in patients on antiretroviral therapy could be achieved with a single dose of vorinostat, a licensed anticancer drug that inhibits histone deacetylase. Although far from a cure, such studies provide some guidance towards the logical next steps for research. Clinical studies that use a longer duration of drug dosing, alternative agents, combination approaches, gene therapy, and immune-modulation approaches are all underway.
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Affiliation(s)
- Stephen J Kent
- Department of Microbiology and Immunology, University of Melbourne, VIC, Australia.
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Eriksson S, Graf EH, Dahl V, Strain MC, Yukl SA, Lysenko ES, Bosch RJ, Lai J, Chioma S, Emad F, Abdel-Mohsen M, Hoh R, Hecht F, Hunt P, Somsouk M, Wong J, Johnston R, Siliciano RF, Richman DD, O'Doherty U, Palmer S, Deeks SG, Siliciano JD. Comparative analysis of measures of viral reservoirs in HIV-1 eradication studies. PLoS Pathog 2013; 9:e1003174. [PMID: 23459007 PMCID: PMC3573107 DOI: 10.1371/journal.ppat.1003174] [Citation(s) in RCA: 489] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2012] [Accepted: 12/19/2012] [Indexed: 12/15/2022] Open
Abstract
HIV-1 reservoirs preclude virus eradication in patients receiving highly active antiretroviral therapy (HAART). The best characterized reservoir is a small, difficult-to-quantify pool of resting memory CD4+ T cells carrying latent but replication-competent viral genomes. Because strategies targeting this latent reservoir are now being tested in clinical trials, well-validated high-throughput assays that quantify this reservoir are urgently needed. Here we compare eleven different approaches for quantitating persistent HIV-1 in 30 patients on HAART, using the original viral outgrowth assay for resting CD4+ T cells carrying inducible, replication-competent viral genomes as a standard for comparison. PCR-based assays for cells containing HIV-1 DNA gave infected cell frequencies at least 2 logs higher than the viral outgrowth assay, even in subjects who started HAART during acute/early infection. This difference may reflect defective viral genomes. The ratio of infected cell frequencies determined by viral outgrowth and PCR-based assays varied dramatically between patients. Although strong correlations with the viral outgrowth assay could not be formally excluded for most assays, correlations achieved statistical significance only for integrated HIV-1 DNA in peripheral blood mononuclear cells and HIV-1 RNA/DNA ratio in rectal CD4+ T cells. Residual viremia was below the limit of detection in many subjects and did not correlate with the viral outgrowth assays. The dramatic differences in infected cell frequencies and the lack of a precise correlation between culture and PCR-based assays raise the possibility that the successful clearance of latently infected cells may be masked by a larger and variable pool of cells with defective proviruses. These defective proviruses are detected by PCR but may not be affected by reactivation strategies and may not require eradication to accomplish an effective cure. A molecular understanding of the discrepancy between infected cell frequencies measured by viral outgrowth versus PCR assays is an urgent priority in HIV-1 cure research. Efforts to cure HIV-1 infection have focused on a small pool of CD4+ T cells that carry viral genetic information in a latent form. These cells persist even in patients on optimal antiretroviral therapy. Novel therapeutic strategies targeting latently infected cells are being developed, and therefore practical assays for measuring latently infected cells are urgently needed. These cells were discovered using a virus culture assay in which the cells are induced to release virus particles that are then expanded in culture. This assay is difficult, time-consuming, and expensive. Here we evaluate alternative approaches for measuring persistent HIV-1, all of which rely on the detection of viral genetic information using the polymerase chain reaction (PCR). None of the PCR-based assays correlated precisely with the virus culture assay. The fundamental problem is that infected cell frequencies determined by PCR are at least 2 logs higher than frequencies determined by the culture assay. Much of this difference may be due to cells carrying defective forms of the virus. These cells may not be eliminated by strategies designed to target latently infected cells. In this situation, successful clearance of latently infected cells might be masked by a large unchanging pool of cells carrying defective HIV-1.
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Affiliation(s)
- Susanne Eriksson
- Department of Diagnostics and Vaccinology, Swedish Institute for Communicable Diseases and Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
| | - Erin H. Graf
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Viktor Dahl
- Department of Diagnostics and Vaccinology, Swedish Institute for Communicable Diseases and Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
| | - Matthew C. Strain
- University of California San Diego, La Jolla, California and Veterans Affairs San Diego Healthcare System, San Diego, California, United States of America
| | - Steven A. Yukl
- San Francisco VA Medical Center, San Francisco, California, United States of America
- Department of Medicine, University of California, San Francisco, San Francisco, California, United States of America
| | - Elena S. Lysenko
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Ronald J. Bosch
- Department of Biostatistics, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Jun Lai
- Department of Medicine Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Stanley Chioma
- Department of Medicine Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Fatemeh Emad
- Department of Medicine Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Mohamed Abdel-Mohsen
- Department of Medicine, University of California, San Francisco, San Francisco, California, United States of America
| | - Rebecca Hoh
- Department of Medicine, University of California, San Francisco, San Francisco, California, United States of America
| | - Frederick Hecht
- Department of Medicine, University of California, San Francisco, San Francisco, California, United States of America
| | - Peter Hunt
- Department of Medicine, University of California, San Francisco, San Francisco, California, United States of America
| | - Ma Somsouk
- Department of Medicine, University of California, San Francisco, San Francisco, California, United States of America
| | - Joseph Wong
- San Francisco VA Medical Center, San Francisco, California, United States of America
- Department of Medicine, University of California, San Francisco, San Francisco, California, United States of America
| | - Rowena Johnston
- amfAR, The Foundation for AIDS Research, New York, New York, United States of America
| | - Robert F. Siliciano
- Department of Medicine Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Howard Hughes Medical Institute, Baltimore, Maryland, United States of America
| | - Douglas D. Richman
- University of California San Diego, La Jolla, California and Veterans Affairs San Diego Healthcare System, San Diego, California, United States of America
| | - Una O'Doherty
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Sarah Palmer
- Department of Diagnostics and Vaccinology, Swedish Institute for Communicable Diseases and Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
| | - Steven G. Deeks
- Department of Medicine, University of California, San Francisco, San Francisco, California, United States of America
| | - Janet D. Siliciano
- Department of Medicine Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Howard Hughes Medical Institute, Baltimore, Maryland, United States of America
- * E-mail:
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Mexas AM, Graf EH, Pace MJ, Yu JJ, Papasavvas E, Azzoni L, Busch MP, Di Mascio M, Foulkes AS, Migueles SA, Montaner LJ, O’Doherty U. Concurrent measures of total and integrated HIV DNA monitor reservoirs and ongoing replication in eradication trials. AIDS 2012; 26:2295-306. [PMID: 23014521 PMCID: PMC4692807 DOI: 10.1097/qad.0b013e32835a5c2f] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVES Interest in targeting HIV reservoirs is fueling trials that may decrease reservoir size and/or induce viral replication. Therefore, we aimed to develop strategies to sensitively measure changes in these parameters in patients on and off antiretroviral therapy (ART). Achieving these goals may help evaluate the effects of future clinical trials. DESIGN To determine the relationship between measurements of total and integrated HIV DNA and their role as markers of reservoir size and ongoing replication, these parameters were measured during the first year of ART, during long-term effective ART, and during a clinical trial aimed at targeting reservoirs. METHODS Total and integrated HIV DNA were measured in patient samples using quantitative PCR techniques. CD4(+)T cell counts and plasma viremia were also monitored. RESULTS Unintegrated HIV DNA became undetectable during the first year of ART. Total and integrated HIV DNA levels were generally equal in well controlled patients on ART, and low-level plasma viremia correlated best with integration measures. Finally, patients who controlled plasma viremia (<400 copies/ml) during interferon-α monotherapy exhibited a decrease in the level of integrated but not total HIV DNA and a rise in the ratio of total to integrated HIV DNA over time. CONCLUSION Our findings suggest that appearance of unintegrated HIV DNA reflects residual HIV expression and de-novo reverse transcription, providing insight into the mechanism by which interferon-α reduces the HIV reservoir. We conclude that concurrent measurements of total and integrated HIV DNA provide information regarding reservoir size and ongoing replication in trials targeting HIV.
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Affiliation(s)
- Angela M. Mexas
- Dept of Pathology and Laboratory Medicine, Division of Transfusion Medicine, University of Pennsylvania. Philadelphia, PA 19104. USA
| | - Erin H. Graf
- Dept of Pathology and Laboratory Medicine, Division of Transfusion Medicine, University of Pennsylvania. Philadelphia, PA 19104. USA
| | - Matthew J. Pace
- Dept of Pathology and Laboratory Medicine, Division of Transfusion Medicine, University of Pennsylvania. Philadelphia, PA 19104. USA
| | - Jianqing J. Yu
- Dept of Pathology and Laboratory Medicine, Division of Transfusion Medicine, University of Pennsylvania. Philadelphia, PA 19104. USA
| | - Emmanouil Papasavvas
- HIV-1 Immunopathogenesis Laboratory, The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104. USA
| | - Livio Azzoni
- HIV-1 Immunopathogenesis Laboratory, The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104. USA
| | - Michael P. Busch
- Blood Systems Research Institute, University of California, San Francisco, 270 Masonic Ave, San Franscisco, CA USA
| | | | - Andrea S. Foulkes
- Division of Biostatistics and Epidemiology, School of Public Health and Health Sciences, University of Massachusetts, Amherst, MA 01003
| | | | - Luis J. Montaner
- HIV-1 Immunopathogenesis Laboratory, The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104. USA
| | - Una O’Doherty
- Dept of Pathology and Laboratory Medicine, Division of Transfusion Medicine, University of Pennsylvania. Philadelphia, PA 19104. USA
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Savkovic B, Symonds G, Murray JM. Stochastic model of in-vivo X4 emergence during HIV infection: implications for the CCR5 inhibitor maraviroc. PLoS One 2012; 7:e38755. [PMID: 22866173 PMCID: PMC3398969 DOI: 10.1371/journal.pone.0038755] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 05/11/2012] [Indexed: 12/30/2022] Open
Abstract
The emergence of X4 tropic viral strains throughout the course of HIV infection is associated with poorer prognostic outcomes and faster progressions to AIDS than for patients in whom R5 viral strains predominate. Here we investigate a stochastic model to account for the emergence of X4 virus via mutational intermediates of lower fitness that exhibit dual/mixed (D/M) tropism, and employ the model to investigate whether the administration of CCR5 blockers in-vivo is likely to promote a shift towards X4 tropism. We show that the proposed stochastic model can account for X4 emergence with a median time of approximately 4 years post-infection as a result of: 1.) random stochastic mutations in the V3 region of env during the reverse transcription step of infection; 2.) increasing numbers of CXCR4-expressing activated naive CD4+ T cells with declining total CD4+ T cell counts, thereby providing increased numbers of activated target cells for productive infection by X4 virus. Our model indicates that administration of the CCR5 blocker maraviroc does not promote a shift towards X4 tropism, assuming sufficient efficacy of background therapy (BT). However our modelling also indicates that administration of maraviroc as a monotherapy or with BT of suboptimal efficacy can promote emergence of X4 tropic virus, resulting in accelerated progression to AIDS. Taken together, our results demonstrate that maraviroc is safe and effective if co-administered with sufficiently potent BT, but that suboptimal BT may promote X4 emergence and accelerated progression to AIDS. These results underscore the clinical importance for careful selection of BT when CCR5 blockers are administered in-vivo.
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Affiliation(s)
- Borislav Savkovic
- School of Mathematics and Statistics, University of New South Wales, Sydney, Australia.
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