CROI 2017 Abstract e-Book

Abstract eBook

Poster and Themed Discussion Abstracts

different serological profiles. Our aimwas to further dissect B-cell responses in ET with different HIV Ab profiles and relate those to the predicted size of the HIV-reservoir (Total HIV-DNA). Methods: Ab responses in 15 ET under stable viral control (undetectable at least 4 years) against 9 HIV proteins (gp120, gp160, gp 41, p24, p17, p51, p45, p39, p31) were analysed by Chemiluminescent Microparticle Immuno-Assay (CMIA),Western Blot (WB), ELISA to 4 different Env proteins (UG37 gp14, CN54 gp120, BX08 gp140, Bal.26 gp120) and Neutralization Activity. B-cell Fluorospot was performed to simultaneously detect IgM and IgG responses to gp120, gp160, gp41, p24, p66. Total HIV-DNA was quantified at the same time points for all patients using an in house assay. Results: Five out of 15 ET were seronegative (SNP) for all HIV-Ags tested by CMIA, WB and ELISA assays. No statistical difference in terms of age at the time of viral control (<1year in both), or timing of ART initiation was observed between SNP and seropositive patients (SPP). Among SPP 4 patients presented NA vs 2 different pseudoviruses (Bal.26 clade B and 96ZM965.01 clade C). Secondary ELISA vs the pseudoviruses showed any IgM anti-HIV activity in these 4 patients. Total HIV-DNA was markedly reduced in SNP (median=27 cp/106 PBMCs) compared to SPP (median=239 cps per million PBMCs) (p=0.008). To further investigate the in-vitro ability of SNP to develop cellular responses for p24, gp41, gp120, gp160 and RT we performed B cell Fluorospot to simultaneously detect IgM and IgG secreting cells. A predominant IgM response to HIV-Ags (gp41 (p=0.04), p24 (p=0.01) and p17(0.02) was observed in the SNP compared to age matched SPP. Conclusion: SNP present lower total HIV-DNA compared to SPP. The predominant IgM Ab response to HIV Ags, shown in SNP, is suggestive of a B-cell primary response with low/ absent neutralizing activity in case of viral rebound. These patients will most likely require immunotherapy to mount an effective immune response. 799 RAPID RESTORATION OF EFFECTIVE ANTI-HIV CD4+ T-CELL ACTIVITY IN ART-TREATED CHILDREN Emily Adland 1 , Luisa Mori 2 , Leana Laker 2 , Alice Swordy 2 , Anna Csala 1 , Masahiko Mori 1 , Philippa C. Matthews 3 , Pieter Jooste 2 , Philip J. Goulder 1 1 Univ of Oxford, Oxford, UK, 2 Kimberley Hosp Complex, Kimberley, South Africa, 3 Oxford Univ Hosps NGS Trust, John Radcliffe Hosp, Oxford, UK Background: The successes of strategies to prevent mother-to-child transmission (pMTCT) of HIV and to implement antiretroviral therapy (ART) in sub-Saharan Africa have brought about new challenges. In particular, HIV-infected children facing a lifetime of ART dependence frequently run up against major problems of non-adherence, especially moving into adolescence. Alternative strategies to a lifetime of ART are needed, especially for HIV-infected children. We here investigate the impact of ART on recovery of HIV- specific T-cell immune function in HIV-infected children, that would set the stage for future immune-based therapies designed to facilitate cure. Methods: We studied functional patterns of HIV-specific T-cell responses in a total of 58 treatment naïve children and 84 ART treated children with chronic HIV-1 C-clade infection from Kimberley, South Africa. A whole blood ICS assay was used to determine intracellular responses to HIV antigen stimulation based on expression of IL-2, IFNγ, MIP1β and TNFα. Results: In ART-naïve children, a high absolute CD4 count was strongly correlated with a predominant IL-2 Gag-specific CD4+ T-cell response and with CD4+ and CD8+ T-cell polyfunctionality. Viral load in the same children was directly correlated with the magnitude of the CD4+ IFN-γ Gag-specific response and inversely related to IL-2, TNFα and MIP1β responses. In ART-treated children, a similar and consistent binary pattern emerged. Unsuppressed, viraemic children maintained predominantly IFN-γ responses, whereas those with suppression of viraemia, even for 12 months only, showed strong IL-2 responses. In ART-treated children, duration of viral suppression was associated with increasing polyfunctionality on CD4+ but not CD8+ T-cells, and with decreasing expression levels of immune activation and inhibitory receptors. Conclusion: These findings support previous studies indicating that CD4 T-cell function is central to the maintenance of normal CD4 T-cell counts and non-pathogenesis in paediatric infection but that CD8+ T-cells play a less clear role. These studies highlight the fact that even short duration suppression of viral replication by ART in paediatric infection is associated with highly polyfunctional HIV-specific CD4 T-cell activity, characterized by strong IL-2 responses. These data support the notion that ART can bring about rapid immune recovery in paediatric infection, and can provide a setting in which immunotherapies around HIV cure such as CTL vaccination could be optimally effective. 800 PD-1+ MEMORY CD4 T CELLS, PROLIFERATIVE CAPACITY, AND INFLAMMATION IN HIV+ CHILDREN Julia Foldi 1 , Lina Kozhaya 1 , Max Kilberg 1 , Mussa Mwamzuka 2 , Fatma Marshed 2 , Aabid Ahmed 2 , William Borkowsky 1 , Derya Unutmaz 1 , Alka Khaitan 1 1 New York Univ, New York, NY, USA, 2 Bomu Hosp, Mombasa, Kenya Background: During HIV infection loss of HIV-specific proliferative capacity and cytokine production defines T cell exhaustion. PD-1 is a negative immune modulator that marks exhausted CD8 T cells in HIV, but its function on CD4 T cells remains unclear. We examined PD-1+ CD4 T cells in HIV+ children, their association with HIV disease progression, and their functional capacity. Methods: In a Kenyan cohort of 82 perinatally-infected HIV+ children, comprising 41 untreated (ART-) and 41 on antiretroviral therapy (ART+), and 36 HIV uninfected-unexposed controls between 5-18 years old, we evaluated peripheral blood samples by flow cytometry to identify these markers: CD3, CD4, CD8, PD-1, CD45RO, CD27, CD38, HLA-DR, and Ki67. For proliferation experiments, PD-1+ and PD-1- memory CD4 T cells sorted from healthy adults or total PBMCs from HIV+ children were labeled then stimulated with OKT3 (TCR stimulus) or gag peptide pools for 7 days and analyzed by flow cytometry. Cytokines were identified by staining for IFNγ, IL-17A and IL-2 after PMA/Ionomycin activation. Statistical analysis was performed on GraphPad Prismwith Mann-Whitney, Spearman’s correlation, and linear regression analyses. Results: Both ART- and ART+ children have significantly higher PD-1+memory CD4 T cell percentages compared to HIV- controls (ART- p<0.0001; ART+ p=0.004). Increased PD-1+ CD4 T cells correlate with HIV disease progression, measured by viral load (p=0.04), %CD4 (p=0.0001), and CD4:CD8 ratios (p<0.0001). Moreover, PD-1+ CD4 T cells associate with markers of immune activation, CD38+HLA-DR+ CD4 (p<0.0001) and CD8 (p=0.009) and Ki67+ CD4 T cells (p=0.003). PD-1+ CD4 T cells demonstrate low proliferative capacity compared to PD-1- populations (median: PD-1+ 35%; PD-1- 81%; p=0.003) yet increased production of Th1 (p<0.05) and Th17 (p=0.007) cytokines. In HIV+ children, increased PD-1+ CD4 T cell levels predict lower proliferative capacity in response to OKT3 (p=0.009; R2=0.65), with a similar trend after HIV-specific stimulus. Finally, in HIV+ children, PD-1+ CD4 T cells produce significantly more IFNγ (p<0.0001) and IL-17A (p=0.003) compared to PD-1- cells and correlate with higher IFNγ (p-0.04) and lower IL-2 (p=0.008) cytokine levels. Conclusion: HIV+ children have markedly elevated PD-1+memory CD4 T cells that correlate with advancing disease. This population exhibits weak proliferative capacity yet enhanced production of inflammatory cytokines. Future studies are necessary for potential immune-checkpoint therapies in HIV. 801 MICROBIAL TRANSLOCATION DOES NOT DRIVE IMMUNE ACTIVATION IN UGANDAN CHILDREN WITH HIV Felicity Fitzgerald 1 , Edouard Lhomme 2 , Kathryn Harris 3 , Julia Kenny 1 , Ronan Doyle 4 , Cissy Kityo 5 , Sarah Walker 4 , Rodolphe Thiébaut 2 , Nigel Klein 4 , for the CHAPAS-3TrialTeam 1 Univ Coll London Great Ormond Street Inst of Child Hlth, London, UK, 2 INSERM, Bordeaux, France, 3 Great Ormond Street NHS Fndn Trust, London, UK, 4 Univ Coll London, London, UK, 5 Joint Clinical Rsr Cntr, Kampala, Uganda Background: Immune activation (IA), potentially driven by microbial translocation (MT), is linked to increased morbidity despite ART in HIV. We investigated MT as a driver of IA in HIV-infected African children Methods: ART-naïve and ART-experienced children were recruited to a Ugandan site of the CHAPAS-3 Trial (ISRCTN69078957), with HIV-uninfected age-matched controls from the same communities. HIV-infected children were followed up for 96 weeks including viral load & CD4%. 19 markers (cellular and humoral) of IA, inflammation, vascular injury & disordered thrombogenesis were measured. Intestinal fatty acid binding protein (I-FABP) was used to quantify gut damage. MT was assessed using a panel of specific bacterial polymerase chain reactions (PCRs), broad-range 16S rDNA PCR & next generation sequencing (NGS)(Illumina method). Cluster analysis of IA & MT markers was performed in R. Results: 249 children were included: 120 ART naïve & 22 ART experienced (median(IQR) age 2.8(1.7-4.0) & 6.5(5.9-9.2) years; median baseline CD4% 20(14-24) & 34(31-39) respectively) & 107 age-matched HIV-uninfected controls. Immune recovery was good (ART-naïve: median(IQR) CD4% change 17(12-22)) & viral load suppression <100 copies/ml at 96 weeks was 76%(ART-naïve) and 91%(ART-experienced). IA decreased over time on ART: median CD4+HLA-DR+CD38+ decreased from 7% to 2% at 96 weeks(p<0.0001). Cluster analysis at Week 96 identified 4 clusters(Table 1): the first(n=105, 65% HIV+ virally suppressed, 32% HIV-) was characterized by low levels of

Poster and Themed Discussion Abstracts

CROI 2017 346