CROI 2017 Abstract e-Book

Abstract eBook

Poster and Themed Discussion Abstracts

320 PERSISTENCE OF HIV DNA IN TISSUES EARLY AFTER TRANSPLANTATION WITH CCR5Δ32 STEM CELLS Kobus Bosman 1 , Monique Nijhuis 1 , Anke Bruns 1 , Maria Salgado 2 , Gero Hütter 3 , Lodewijk Brosens 1 , Javier Martinez-Picado 4 , Jürgen Kuball 1 , Annemarie Wensing 1 , for the IciStem Consortium 1 Univ Med Cntr Utrecht, Utrecht, Netherlands, 2 AIDS Rsr Inst IrsiCaixa, Badalona, Spain, 3 Cellex, Dresden, Germany, 4 ICREA, Barcelona, Spain Background: Cure of HIV infection was observed following stem cell transplantation (SCT) with homozygous CCR5Δ32 donor cells in the Berlin patient. In contrast, in the Boston patients, transplanted with a regular donor, HIV rebound was observed after treatment interruption despite loss of detectable HIV DNA in PBMCs. It is unclear which reservoir fueled HIV rebound. Methods: The impact of SCT on HIV-1 reservoir size in IciStem patients 5 and 11 was investigated. SCT was performed using HLA-matched CCR5Δ32 donors. Before SCT we performed: 1) Phenotypic and genotypic co-receptor tropism analysis 2) Quantification of the HIV reservoir in CD4 T-cell subsets subsets (Tn, Tcm, Ttm, Tem, and Tscm) and bone marrow using ddPCR 3) Single copy assay (SCA) on plasma. After graft failure, patient 11 was re-transplanted with CCR5Δ32 heterozygous donor cells. Post-SCT viral dynamics and the post-mortem viral reservoir were analyzed using ddPCR. Results: Patients 5 and 11 harboured CCR5-tropic virus (FPR 89% and 33-49%), were treated with ART since 1999 and 1996, and were effectively suppressed for 5 and 16 years prior to SCT, respectively. Before SCT, no viral RNA was detected in routine diagnostics while SCA in plasma detected 15 c/ml (patient 5) and 2 c/ml (patient 11). In patient 5, HIV DNA was detected in PBMCs (983 c/10^6), naive T-cells (635 c/10^6) and memory T-cells (Tcm, Tm and Tem, 1537, 2832 and 3462 c/10^6). In patient 11, HIV DNA was detected in PBMCs (295 c/10^6), bone marrow (80 c/10^6), stem cell-like CD4 T-cells (490 c/10^6), naive T-cells (579 c/10^6) and memory T-cells (Tcm, Ttm and Tem, 2237, 2854, and 4687 c/10^6). SCT led to full chimerism in the PBMCs of both patients and diminished HIV DNA to undetectable levels (<1 c/10^6). Following the death of patients 5 and 11, 10-15 weeks after SCT, post-mortem analysis revealed that HIV DNA could be detected in ileum (274 and 22 c/10^6), liver (27 and 10 c/10^6), spleen (22 and 30 c/10^6) and lung (31 and 8 c/10^6), and additionally in patient 11 in bone marrow (19 c/10^6) and in CD4 cells from lymph node (40 c/10^6). Conclusion: Within IciStem, we show that after long-term effective ART HIV DNA can readily be detected in various T-cell subsets. In the neutropenic phase post-SCT, HIV DNA could no longer be detected in PBMCs. In contrast, early after SCT, HIV DNA was still found in ileum, liver, spleen, lung, bone marrow and lymph node, indicating that tissue reservoirs may play an important role as long-standing viral reservoirs. 321 IMMUNE DYSREGULATION DICTATES SHIV REBOUND AFTER STEM-CELL TRANSPLANT IN MACAQUES Christopher Peterson 1 , Clarisse Benne 2 , Patricia Polacino 3 , Keith Jerome 1 , Shiu-Lok Hu 4 , Nichole Klatt 4 , Stephen DeRosa 1 , Rafick-Pierre Sekaly 2 , Hans-Peter Kiem 1 1 Fred Hutchinson Cancer Rsr Cntr, Seattle, WA, USA, 2 Case Western Reserve Univ, Cleveland, OH, USA, 3 Washington Natl Primate Rsr Cntr, Seattle, WA, USA, 4 Univ of Washington, Seattle, WA, USA Background: The conditioning regimen used as part of the Berlin patient’s hematopoietic stem cell transplant (HSCT) likely contributed to his eradication of HIV infection. We studied the impact of conditioning (total body irradiation, TBI) in simian-human immunodeficiency virus (SHIV)-infected macaques suppressed by combination antiretroviral therapy (cART). The goal of this study was to identify the mechanism by which myeloablative conditioning impacts the latent viral reservoir. Methods: Two cohorts of 5 pigtailed macaques were challenged with CCR5-tropic, HIV enveloped SHIV, and suppressed by three-drug cART following viral set point. In one cohort, autologous HSCT was performed following stable suppression of plasma viremia. Flow cytometry and ELISA were used to monitor changes in immune homeostasis between the two cohorts, and quantitative PCR and viral reservoir assays were used to identify virologic changes between transplanted and untransplanted control animals. Results: The conditioning regimen resulted in a dramatic, but incomplete depletion of CD4+, CD8+ T-cells and B-cells, increased T-cell activation and exhaustion, and a significant loss of SHIV-specific antibodies in transplanted animals. The disrupted T-cell homeostasis and markers of microbial translocation positively correlated with increased viral rebound after cART interruption, which was observed in peripheral blood and in tissues. Quantitative viral outgrowth and Tat/Rev-induced limiting dilution assays showed that the size of the latent SHIV reservoir did not correlate with viral rebound. Conclusion: These findings identify perturbations of the immune system as a mechanism for the failure of autologous transplantation to eradicate HIV, and highlight the importance of an intact immune system for viral control after cART withdrawal. Our data further demonstrate that the ability of myeloablative conditioning to decrease the size of the latent viral reservoir is limited. Our findings suggest several “next generation” HIV cure strategies that balance killing of virus-infected immune cells with retention of greater immune function. These may include immune modulators to prevent disrupted immune homeostasis, gene editing to protect transplanted cells, and/or additional gene therapy approaches to actively target latently infected cells during ongoing cART. 322 CONTROL OF PATHOGENIC SHIV INFECTION IN TRANSPLANTED MACAQUES Christopher Peterson 1 , Kevin G. Haworth 1 , Bryan P. Burke 2 , Patricia Polacino 3 , Shiu-Lok Hu 4 , Brandon Keele 5 , Jeffrey S. Bartlett 2 , Geoff P. Symonds 2 , Hans-Peter Kiem 1 1 Fred Hutchinson Cancer Rsr Cntr, Seattle, WA, USA, 2 Calimmune, Inc., Pasadena, CA, USA, 3 Washington Natl Primate Rsr Cntr, Seattle, WA, USA, 4 Univ of Washington, Seattle, WA, USA, 5 NCI, Frederick, MD, USA Background: Nearly 10 years have passed since the Berlin Patient achieved stable remission/functional cure of HIV infection, yet the relative contributions of the transplant procedure, the allogeneic “graft versus reservoir” effect, and infection-resistant donor cells, remain unclear. We have previously described a cohort of pigtailed macaques transplanted with gene-engineered hematopoietic stem and progenitor cells (HSPCs) expressing the enfuvirtide-like small peptide inhibitor of HIV/SIV fusion, mC46, which should

Poster and Themed Discussion Abstracts

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