CROI 2016 Abstract eBook

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Oral Abstracts

DNA was extracted from 1 PBMC aliquot to compare the genetics of CAR to the proviral population. fPVE was determined by serial dilution of PBMCs and measuring levels of HIV DNA and unspliced CAR by qPCR in 6 replicates at each dilution. The fraction of the infected cells expressing CAR was calculated by maximum likelihood estimates. Results: The proportion of the proviruses that expressed unspliced CAR was not different between viremic and ART-suppressed individuals (median 7% vs. 6% respectively). By contrast, the fraction of cells that were “high CAR producers” (>20 CAR copies/cell by CARD-SGS and >50 CAR copies/cell by fPVE, corrected for the shorter amplicon used for fPVE) was greater in viremic than suppressed individuals (2.5% vs. <0.3%, p=0.02, by CARD-SGS and 12% vs. <2%, p=0.01, by fPVE). Frequent detection of identical CAR sequences across multiple aliquots of PBMCs from ART-suppressed individuals revealed that expanded clones commonly express unspliced HIV RNA. Conclusions: The differences in HIV RNA expression levels in single cells between ART-suppressed and viremic individuals but not in the fraction of proviruses that express HIV RNA suggest that cells producing high levels of HIV RNA are associated with active virus replication and are eliminated by viral CPE or CTL responses, whereas the more frequent cells expressing low levels of HIV RNA can persist and expand despite ART. Expanded proviruses that express unspliced HIV RNA may be the source of rebound viremia when ART is interrupted. 86 Restricted HIV-1 Diversity and Clonal Expansion Following Cytoreductive Chemotherapy Timothy J. Henrich 1 ; Eileen P. Scully 2 ; Kristen S. Hobbs 1 ; Emily Hanhauser 1 ; Louise Hogan 1 ; Christine D. Palmer 3 ;Yvonne P. Robles 4 ; Kaitlyn S. Leadabrand 1 ; Ann S. LaCasce 5 ; Daniel Kuritzkes 6 1 Univ of California San Francisco, San Francisco, CA, USA; 2 Massachusetts General Hosp, Boston, MA, USA; 3 Ragon Inst of MGH, MIT, and Harvard, Cambridge, MA, USA; 4 Brigham and Women’s Hosp, Harvard Med Sch, Boston, MA, USA; 5 Dana-Farber Cancer Inst, Boston, MA, USA; 6 Harvard Med Sch, Boston, MA, USA Background: Cytoreductive chemotherapy for malignancies does not lead to consistent changes in HIV-1 DNA or RNA. However, observed reductions in CD4 T cells during

chemotherapy suggest that total body reservoirs decrease. We hypothesize that constriction and subsequent oligoclonal expansion of HIV diversity may be a better measure of the reservoir response to cytoreductive therapy or novel HIV eradication strategies. We therefore examined HIV sequence evolution in the context of immune correlates, and quantified HIV levels in cells responding to non-HIV stimuli. Methods: Longitudinal, single-genome analysis of HIV envelope sequences was performed in a cohort of 10 infected individuals on suppressive ART receiving chemotherapy. Findings were compared with changes in T cell subsets, activation/ proliferation and HIV-specific immune responses measured by ELISpot. HIV DNA levels in CD4 T cells were quantified from cells sorted based on intracellular IL2 and/or INFγ staining after stimulation with αCD3/αCD28 antibodies or combined Epstein–Barr virus (EBV) and cytomegalovirus (CMV) lysates.

Results: Although CD4 T cell counts transiently decreased by up to 75% during chemotherapy, CD4 T cell HIV DNA did not change and RNA increased following completion of therapy (P=0.203 and P=0.037 by paired Wilcoxon test). Despite reductions in total cell counts, no changes in the percentage of naive, central or effector memory, or terminally differentiated CD4 and CD8 T cell subsets were observed before or after treatment (all P>0.05). Markers of activation (CD38/HLA-DR) and proliferation (Ki67) either decreased or remained stable in all populations. HIV-1 specific T cell responses either increased or developed novel peptide signatures following completion of chemotherapy. Furthermore, clonal expansion of HIV-1 envelope sequences following chemotherapy was observed in 3 of 6 patients for whom data was obtained; sequence clustering was only seen following completion of chemotherapy. Finally, CD4 T cells that responded to EBV/CMV lysates had higher HIV-1DNA levels compared to those that responded to αCD3/αCD28 stimulation or did not express IL2/INFγ (Fig 1). Conclusions: Despite the lack of changes in peripheral blood HIV DNA, our results suggest that cytoreductive therapy reduces HIV reservoirs in some patients manifesting as a constriction of HIV sequence diversity. Our data also suggest that response to non-HIV antigens can lead to oligoconal expansion of the DNA reservoir. Virological Remission After ART Interruption in African HIV-1 Seroconverters Morgane Gossez 1 ; Gita Ramjee 2 ; Jacob Hurst 1 ; Pontiano Kaleebu 3 ; Helen Rees 4 ; Kholoud Porter 5 ; Abdel Babiker 6 ; Sarah J. Fidler 7 ; John Frater 1 ; for the SPARTACTrial Investigators 1 Univ of Oxford, Oxford, UK; 2 South African Med Rsr Council, Cape Town, South Africa; 3 Med Rsr Council/Uganda Virus Rsr Inst Uganda Rsr Unit on AIDS, Entebbe, Uganda; 4 Wits Reproductive Hlth and HIV Inst, Johannesburg, South Africa; 5 Med Rsr Council, London, UK; 6 Univ Coll London, London, UK; 7 Imperial Coll London, London, UK Background: Increasing evidence supports virological remission in a subset of individuals after treatment with antiretroviral therapy (ART) in primary HIV infection (PHI). We present the first analysis of treatment interruption (TI) in individuals with PHI in Africa, to explore the prevalence and predictors of post-treatment control (PTC). Methods: 137 individuals within 6 months of seroconversion were recruited to the SPARTAC RCT from South Africa and Uganda. We analysed samples from those randomised to ‘no treatment’ (NT) and 48 weeks of ART (ART48). We measured HIV-1 DNA in CD4 T cells (Total, Integrated), CD4 count, plasma viral load (VL) and markers of T cell activation (CD25, CD38, CD69, HLA-DR) and exhaustion (Lag-3, PD-1, Tim-3). We explored associations with both clinical progression and time to viral load rebound. Data were compared with those for UK SPARTAC participants (n=151) recruited under the same protocol. Results: Of individuals recruited to SPARTAC in Africa, 91 were randomised to ART48 or NT, and of these, samples were available for 44 and 38, respectively. Of those in the ART48 arm, 22 received the full 48 weeks of ART and had VL < 400 copies/mL at TI. All were female; 19/22 were infected with subtype C. Of UK patients all were MSM infected with subtype B. Pre-therapy VL was significantly lower in Africans compared with the UK cohort (median 4.16 vs 4.62 log10 copies/mL; p<0.001). CD4 T cell count and Total HIV-DNA were similar in UK and African patients, although Integrated HIV-1 DNA was lower in the latter (median 3.60 vs 3.06 log10 copies/million CD4+ T-cells; p < 0.001). Measured pre-ART, Total HIV-1 DNA, VL and CD4 count in Africans were associated with clinical progression (p=0.001, HR (CI95) 5.37 (1.95-14.79); p<0.001, 1.99 (1.35-2.94) and p<0.001, 0.34 (0.24-0.48), respectively). From TI after 48 weeks of ART, 5/22 (22.7%) Africans maintained VL<400 copies/ml over a median 188 weeks follow-up (range 147-203). In multivariable analyses, Africans experienced significantly longer duration of viral remission than UK participants (p<0.001; HR 3.90 (1.75-8.71). Total DNA at TI was a predictor of time to rebound, but the effect was much weaker in African than in UK patients. Conclusions: We present the first analysis of PTC in Africans with PHI. The difference in virus-free remission post-TI in these individuals compared to the UK patients is striking. Further studies are needed to explore mechanisms and discriminate the distinct effects of sex, ethnicity and HIV subtype.

Oral Abstracts

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CROI 2016