CROI 2015 Program and Abstracts

Abstract Listing

Poster Abstracts

Conclusions: Despite an important decrease of HIV reservoir during myeloablation due to the severe aplasia, peripheral blood HIV reservoirs persist after cytotoxic chemotherapy and ASCT. In some patients, decrease of the number of HIV infected cell observed after 6 months is probably due to the long-term control of HIV viremia under antiretroviral therapy. 430 HIV-1 Reservoirs and Humoral Immunity in Allogeneic Stem Cell Transplantation Patients Kathryn E. Stephenson 1 ; George H. Neubauer 1 ; Emily Hanhauser 2 ; Marcelo J.Wolff 3 ; Cristian Carvallo 3 ; Francisco M. Marty 4 ; Steven G. Deeks 5 ; Daniel R. Kuritzkes 6 ; Dan H. Barouch 1 ;Timothy J. Henrich 6 1 Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, US; 2 Brigham and Women’s Hospital, Boston, MA, US; 3 Clinica Santa Maria, Santiago, Chile; 4 Dana-Farber Cancer Institute, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, US; 5 University of California San Francisco (UCSF), San Francisco, CA, US; 6 Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, US Background: Previous studies have shown that HIV-1 reservoirs are reduced following allogeneic hematopoietic stem cell transplantation (HSCT), but that HIV-specific antibodies (Abs) remain detectable over time. It is unknown whether these Abs reflect new responses to occult antigen or the persistence of recipient-derived Abs. Therefore, we characterized HIV-1 reservoirs and evolution of humoral immunity in 6 allogeneic HSCT patients with wild-type (WT, N=4) and CCR5 Δ 32/ Δ 32 (N=2) donors. Methods: IgG binding titers to a panel of 9 gp140 trimers of different clades by ELISA and quantitation of HIV-1 reservoirs were performed. IgG binding signatures were measured by novel peptide microarray containing 6,564 peptides covering the entire HIV-1 proteome. Results: Like the previously described Boston and Berlin patients, an additional subject who received CCR5 Δ 32/ Δ 32 donor cells had no detectable cell-associated HIV-1 DNA and RNA 3.4 months after HSCT in the setting of ART. HIV-1 DNA levels also markedly decreased in 2 other patients within 8 months following WT HSCT. Despite these reductions in viral reservoirs, HIV-1-specific Ab titers and binding signatures were detectable in all patients at all time points, up to 5 years post-HSCT, though the magnitude of responses steadily declined over time. In 2 patients with baseline samples, pre-HSCT Ab signatures were detected following WT transplantation and did not evolve over 6-8 months of follow-up, suggesting that recipient-derived HIV-1-specific Abs persist post-HSCT. In Boston patients A and B, the Ab signature detected 2-4 years post-HSCT did not evolve until treatment interruption and viral rebound, at which point both signatures acquired new Env specificities suggestive of donor-derived acute Ab responses. The Ab signature of the Berlin patient 3 years post-HSCT remained unchanged over a 2 year period. In both CCR5 Δ 32/ Δ 32 HSCT patients, Env gp140 Ab levels were 0.5-1 log lower than WT HSCT patients at the same time points. Conclusions: Viral reservoirs are substantially reduced within 8 months by allogeneic HSCT with WT or CCR5 Δ 32/ Δ 32 donor cells. Nevertheless, our data suggests that recipient- derived HIV-1-specific Abs may persist for years, despite the lack of recipient peripheral B cells or detectable antigen stimulus. Characterization of these Abs may provide insight into tissue lymphocyte and HIV-1 persistence, and a better understanding of durable immune memory. 431 Breakthrough of Preexisting X4-Capable HIV After Allogeneic Stem-Cell Transplantation Jens Verheyen 1 ; AlexanderThielen 2 ; Miriam Dirks 1 ; Nadine Lübke 3 ; MarekWidera 1 ; Lambros Kordelas 1 ; Martin Däumer 2 ; Rolf Kaiser 3 ; Stefan Esser 1 1 University Hospital Essen, University Duisburg-Essen, Essen, Germany; 2 Institute of Immunology and Genetics, Kaiserslautern, Germany; 3 University of Cologne, Cologne, Germany; 4 University Hospital Essen, University Duisburg-Essen, Essen, Germany; 5 University Hospital Essen, University Duisburg-Essen, Essen, Germany Background: Recently, we reported the case of an HIV-infected patient diagnosed with T-cell lymphoma who subsequently underwent allogeneic stem-cell transplantation (alloSCT) from a CCR5 delta32 homozygously mutated donor. In this case HIV replication could not be controlled by the immune system and the patient died after a relapse of the T-cell lymphoma. So far, the evolutionary pathways of the HIV tropism in this patient has remained unclear. Methods: The tropism of HIV was analyzed from viral RNA and proviral DNA using the Illumina MiSeq platform for deep sequencing of gp120 V3. Samples were taken before (-287d: RNA, -103d: RNA/DNA) and after alloSCT (+20d: RNA, +280d: DNA, +373d: RNA). Viral tropismwas predicted by using geno2pheno [coreceptor] indicating the probability of classifying a R5-tropic virus falsely as a CXCR4-capable virus (FPR). Results: Several distinct virus populations could be observed before and after alloSCT, which harbored specific mutational patterns (I14L, A19V, G24-, H34Y). Before alloSCT two virus populations were dominantly found in viral RNA and DNA only distinguished by mutation (R18K) with FPR of 10.5 (R18wt) and 8.5 (R18K), respectively. Apart from these two virus populations several minority variants could be detected carrying additional amino acid substitutions (N7S, K10R, H13T, R18W, Q32K, H34F) resulting in FPR from 7.8 to 4.2. These minority variants were especially detected in proviral DNA (-103d). One HIV variant detected in proviral DNA (4.4%) before alloSCT (-103d) had a unique mutational pattern (S11A, H13T, I14L, A19V, F20Y, T21K, Q32K) classified as clearly X4-capable (FPR 0.4). This sequence was identical to the sequence of the dominant HIV variant replicating in the patient after alloSCT. Overall, the viral variability was limited in sequences obtained after alloSCT from viral RNA and proviral DNA. Only a small fraction of the virus population displayed further unique amino acid substitutions marginally influencing the FPR (FPR 0.2: H13A, I26T and I26V, respectively; FPR 0.5: A19I; FPR 0.7: G28E). Conclusions: The selective pressure exerted by the transplantation of allogeneic stem-cells homozygous for the CCR5 delta32 mutation resulted in the selection of already preexisting X4 capable HIV. Even the presence of only a minor X4 variant before alloSCT prevented the control of HIV in the absence functional CCR5 receptor. 432 Allogeneic TransplantationWith CCR5 Δ 32/ Δ 32 Cord Blood Hematopoietic Cells in an HIV-1-Infected Patient Rafael Duarte 1 ; Maria Salgado 2 ; Isabel Sanchez-Ortega 1 ; Sara Morón-López 2 ; Maria C. Puertas 2 ; Lawrenze D. Petz 4 ; Sergi Querol 3 ; Bonaventura Clotet 2 ; Javier Martínez-Picado 2 1 Institut Català d’Oncologia, L’Hospitalet del Llobregat, Spain; 2 IrsiCaixa Institute for AIDS Research, Badalona, Spain; 3 Barcelona Cord Blood Bank, Barcelona, Spain; 4 StemCyte International Cord Blood Center, Covina, CA, US Background: The Berlin patient provides the only evidence to date of long-term control of HIV-1 infection after an allogeneic hematopoietic cell transplantation (HCT). Low prevalence of Δ 32/ Δ 32 genotype (<1%) made the search for “patient number 2” unsuccessful for years. Since just a 4/6 match is necessary for cord blood transplantations (CBT), chances to find a CCR5 Δ 32/ Δ 32 donor are higher. Here, we describe a case of allogeneic HCT using CCR5 Δ 32/ Δ 32 cord blood (CB) cells in a patient with diffuse large B-cell lymphoma (DLBCL) and HIV-1 infection. Methods: The myeloablative CB alloHCT was performed using CCR5 Δ 32/ Δ 32 CBU (from Stemcyte) plus CD34 + cells from a haploidentical brother. HIV-1 reservoir was measured before and post-transplantation. qVOA was performed in peripheral CD4 + T cells. Total cellular HIV-1 DNA and cell associated RNA was determined with ddPCR. Viral tropismwas genotypic and phenotypically determined. Results: A 36 year-old man with antiretroviral-treated HIV-1 infection from 2009 was diagnosed with DLBCL stage IIA in 2012. At that time, plasma viral load was 2.5 log copies/ mL (single copy assay), and the replication competent reservoir size was of 1.2 copies/10 7 peripheral CD4 + T cells. Indeed, viral reservoir was detected as HIV-1 DNA and cell- associated HIV-1-RNA in peripheral CD4 + T cells, as well as HIV-1 DNA in GALT and free HIV-1-RNA in cerebrospinal fluid. Patient’s virus was CCR5-tropic and no minor CXCR4-tropic strain was detected. During HCT, ART continued with abacavir, lamivudine and raltegravir. Chimerism reached 100% by day +73. At this point, the patient became CCR5 Δ 32/ Δ 32. Ultrasensitive SCA viral load analysis decreased right after HCT, reaching minimal levels at the time of full CB-chimera. No HIV-DNA was detected using ddPCR quantification or semiquantitative tests of amplification, and recipient CD4+T cells responded to stimuli but were not able to generate a productive infection in vitro after spinoculation with laboratory viral strains, or the patient’s viral isolate. Regretfully, the patient developed an aggressive DLBCL progression followed by very rapid clinical deterioration and died from disease progression three months after HCT.

Poster Abstracts

302

CROI 2015