CROI 2017 Abstract e-Book

Abstract eBook

Poster and Themed Discussion Abstracts

Methods: Cross-sectional, single-site study. HIV-infected patients on antiretroviral therapy for≥24 months and plasma HIV-RNA<50 cp/mL for≥12 months, matched for nadir CD4 T cell count were enrolled. Presence of opportunistic AIDS-related diseases, HBV or HCV coinfection, chronic inflammatory disorders, ongoing immunosuppressive therapy were exclusion criteria. Patients were classified as immunological responders (IR) or non responders (INR) if CD4 count was ≥500 or ≤350 cells/μL, respectively. Expression of inflammasome, caspases 1, 3, 4, and 5, pro-inflammatory cytokines and of IFI16 genes was measured in unstimulated and in AT2-HIV-1 stimulated cells of all IRs and INRs Results: 39 patients (22 IR; 17 INR, 77%M, medians: age 47 years, time from HIV diagnosis 10 years, time with HIV-RNA<50cp/mL 57 months) were enrolled. INR patients were older (median 60vs.43 years, p<0.001) and had a higher prevalence of past AIDS-defining illnesses (76%vs.18%, p<0.001). Median CD4 count was 840 (IQR 718-1131) cells/µL in IR vs. 295 (IQR 256-343) cells/µL in INR. AT2 stimulation induced NLRP3 gene expression in both IR and INR; NLRP3 and IL-18 expression were nevertheless significantly increased in INR compared to IR (p=0.009 and p=0.004). Significant higher caspase-1 expression was seen as well in both unstimulated (p=0.02) and AT2-stimulated cells of INR (p=0.003), whereas caspase 3, 4 and 5 expression was similar in both groups. Finally, IFI16 expression as well plasma concentration of caspase-1 and IL-1β were higher in INR compared to IR patients Conclusion: Increased inflammasome and caspase-1 activation is observed in INR patients. The upregulation of these proinflammatory mechanisms plausibly contributes to the persistent immune activation that characterize INRs. Notably, caspase-1 activation is likely to induce CD4 T cell loss via pyroptosis, contributing to the unsatisfactory CD4 recovery seen in INRs 223 INCREASED IL-18/IL-1Β RATIO BLUNTS CCL20 PRODUCTION AND TH17 GUT HOMING DURING CART Claire Loiseau 1 , Mary Requena 2 , Anne Laure Iscache 1 , Michelle Cazabat 2 , Nicolas Carrere 2 , Bertrand Suc 2 , Bruno Marchou 2 , Jacques Izopet 2 , Pierre Delobel 2 1 INSERM, Toulouse, France, 2 CHU Toulouse, Toulouse, France Background: HIV-1 infection is characterized by a disruption of the intestinal immune barrier integrity. During immune reconstitution, HIV-1-infected individuals under cART do not fully reconstitute gut CD4+ T cells, especially Th17 cells, partly due to the alteration of the CCR6-CCL20 chemotactic axis. The paucity of Th17 cells in the gut mucosa contrasts with the abundance of Th1 cells in these subjects. IL-18 and IL-1β, both inflammasome-dependent mediators, govern the expansion and survival of Th1 and Th17 cells, respectively. We thus explored the role of IL-18 and IL-1β on CCL20 production by enterocytes. Methods: IL-18 and IL-1β were quantified in blood and small intestine samples from HIV-1-infected individuals under effective cART (n=20) and uninfected controls (n=10). The direct effect of IL-18 and IL-1β on CCL20 expression was assessed ex vivo on human primary enterocytes. To explore the impact of an IL-18- or IL-1β-enriched gut microenvironment, Th1 and Th17 cells were sorted by flow cytometry on the basis of their CXCR3+CCR4-CCR6- and CXCR3-CCR4+CCR6+CD161+ phenotype respectively and ex-vivo expanded with either IL-1β/IL-23 or IL-18/IL-12. Then, cocultures between T cells and primary enterocytes were done to mimick the gut microenvironment. The transcriptome of the enterocytes and the production of cytokines/chemokines by both enterocytes and lymphocytes were evaluated by mRNA and protein multiplex assays. Results: HIV-1-infected individuals under cART have a significant increase of IL-18 concentration compared to uninfected controls (P<0.05), leading to an increased IL-18/IL-1β ratio. Ex vivo on primary enterocytes, IL-18 induces a decrease of CCL20 expression by about 100-fold whereas a strong increase was observed after IL-1β stimulation (>100-fold). IFN- ɣ , the classical Th1-associated cytokine, also reduces CCL20 production by the enterocytes while it increases IL-18 production. In coculture experiments, CCL20 expression (mRNA and protein) decreases when epithelial cells interact with lymphocytes previously expanded in presence of IL-18. IL-18 thus contributes to reduce the production of CCL20 by the enterocytes, both directly and indirectly by promoting IFN- ɣ -producing Th1 cells. Conclusion: An IL-18/IL-1β ratio skewing from IL-1β to IL-18 in HIV-1-infected individuals could be one of the mechanisms involved in the reduced production of CCL20 by the enterocytes, and in the imbalance between reduced Th17 and increased Th1 cells in the gut mucosa.

Poster and Themed Discussion Abstracts

224 GENITAL HIV SHEDDING WHEN ANTIRETROVIRAL THERAPY (ART) SUPPRESSES PLASMA HIV RNA Marta E. Bull 1 , Caroline Mitchell 2 , Corey Williams 3 , Jaime Soria 4 , Eduardo Ticona 5 , Alberto M. La Rosa 6 , Joan Dragavon 1 , Robert Coombs 1 , Lisa Frenkel 1 1 Univ of Washington, Seattle, WA, USA, 2 Massachusetts General Hosp, Boston, MA, USA, 3 Seattle Children’s Rsr Inst, Seattle, WA, USA, 4 Hosp Nacional Dos de Mayo, Lima, Peru, 5 Hosp Dos de Mayo, Lima, Peru, 6 Asociación Civil Impacta Salud y Educación, Lima, Peru Background: HIV RNA shedding from the genital tract (GT) during antiretroviral therapy (ART) that suppresses plasma HIV RNA <30copies/mL (c/mL) (defined as discordant (DSC) shedding) has been reported in up to 50% of persons, possibly due to poor drug penetration or genital inflammation. We hypothesized DSC shedding is caused by production of HIV RNA from infected cells without full-cycles of viral replication. Methods: HIV-infected Peruvians initiating ART were followed quarterly for 24 months to detect DSC shedding in cervicovaginal lavage (CVL) at >40c/mL, seminal plasma (SP) at >120c/mL, and rectal secretions (RS) >1,525c/mL) by real-time PCR. Subject’s pre-ART specimens and DSC shedding specimens underwent single-genome-amplification (SGA) of env and pol for phylogenetic analyses. Results: 126 ART-naïve Peruvians were enrolled; 90 completed all study visits with 82/90 (91%) having sustained ART-suppression. Subjects overall had pre-ART CD4 counts consistent with AIDS (median: 127 cells/uL, IQR: 63-213), with no differences noted in HIV RNA or PBMC DNA concentrations in those with DSC shedding compared to those with sustained genital tract suppression. DSC shedding was detected in genital secretions of 23/82 (28%) subjects at 40/726 (5%) visits. Median HIV RNA in DSC shedding specimens were: CVL 82c/mL, IQR: 53-189c/mL; SP 350c/mL IQR: 207-509c/mL; and RS 5,880c/mL, IQR: 1,758-14,484c/mL. SGA yielded HIV RNA env and pol sequences from 2/40 DSC shedding specimens (one CVL and one SP). Genital HIV RNA sequences (and DNA from the female) from these subjects clustered into a single monotypic clade in their respective

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