CROI 2016 Abstract eBook

Abstract Listing

Poster Abstracts

235 A20 May Contribute to Recovery of Intestinal Epithelial Function in Treated HIV Avantika Chitre ; Ma Somsouk; PeterW. Hunt; Charlie C. Kim; Joseph M. McCune Univ of California San Francisco, San Francisco, CA, USA

Background: Untreated HIV infection is characterized by mucosal Th17 depletion, gut epithelial barrier dysfunction, and microbial translocation, which are reversed to variable degrees by suppressive antiretroviral therapy (ART). Little is known about the specific restorative mediators of intestinal epithelial cell (IEC) function during ART. Methods: Rectosigmoid biopsies were obtained from 9 risk-matched uninfected controls, 6 treatment-naive, and 20 ART-suppressed HIV-infected participants. IECs were isolated by EDTA treatment and gut lymphocytes were obtained by subsequent enzymatic digestion. Markers of epithelial function were assessed by qPCR on RNA extracted from isolated IECs. Full transcriptomes of IECs were assessed by RNAseq and compared across subgroups. Cytokine production of CD4 T cells was determined by ex vivo stimulation and intracellular flow cytometry. Results: Consistent with prior work, IL-17 producing CD4 T cells were significantly decreased in untreated HIV-infected participants and restored to normal levels in ART- suppressed participants. Expression of mucins and tight junction protein genes by IECs was significantly higher in participants on ART than in untreated participants. Trefoil factor 3, a key epithelial repair factor, was also elevated in IECs from ART-suppressed participants relative to both uninfected and untreated groups. RNAseq analysis in isolated IECs identified A20-encoding TNFAIP3 as one of the most highly upregulated genes in ART-suppressed participants compared to both uninfected and untreated participants. A20 is a ubiquitin-editing enzyme that is induced by IL-17 and NFκB signaling and which acts in a feedback manner to suppress the transcription of inflammatory mediators as well as to support maintenance of tight junctions between epithelial cells. Other genes involved in the regulation of the NFκB and A20 pathways ( IL1R2, NFKBIA ) were also among the most differentially expressed genes between groups, further supporting the prediction that NFκB activity is downregulated in ART-suppressed participants. Conclusions: Restoration of mucosal Th17 cells during suppressive ART appears to coincide with a restoration of intestinal epithelial cell barrier function and an active repair response, which may be in part mediated by upregulation of A20. While the causal pathways have yet to be defined, A20 expression in IECs could represent a novel interventional target for treated HIV-infected individuals with persistent intestinal epithelial dysfunction.

236 Compartment-Specific Alterations of the Intestinal ILC Pool in HIV(+) Patients Benjamin Krämer 1 ; Philipp Lutz 1 ; Felix Goeser 1 ; Andreas Glässner 1 ; Jürgen K. Rockstroh 2 ; Christoph Boesecke 3 ; Ulrich Spengler 1 ; Jacob Nattermann 1 1 Univ of Bonn, Bonn, Germany; 2 Medizinische Univsklinik, Bonn, Germany; 3 Univ Hosp Bonn, Bonn, Germany Background: Innate lymphoid cells (ILC) have been shown to display critical effector and regulatory functions in innate immunity and tissue remodeling. Recent reports demonstrate ILCs to promote anatomical containment of gut commensal bacteria and to play an important role in intestinal inflammation. However, most of these studies have been performed in mouse models and, thus, the distribution of ILCs in the human gastrointestinal (GI) tract remained unclear. Methods: In HIV(-) individuals biopsies frommacroscopically normal tissue were taken in the oesophagus (n=8), the stomach (n=11), the duodenum (n=11), the terminal ileum (n=13), and the left-sided colon (n=13) during routine endoscopy. Moreover, oral biopsies (n=6) as well as peripheral blood (n=14) was studied. In addition, biopsies from the oesophagus (n=7), the stomach (n=12), the duodenum (n=12), the terminal ileum (n=8), and the colon (n=8), as well as PBMC (n=14) from HIV-infected patients under effective cART were analyzed. ILCs were phenotypically characterized by flowcytometry and tested for expression of IFN-g, IL-13, and IL-22 following stimulation with PMA and ionomycin. Results: Frequency of total ILC (as % of Lin(-) cells) stepwise increased from the oral cavity to the distal GI-tract, with highest frequencies found in the colon. Frequency of CD94(-) ILC1 was significantly higher in upper GI-tract (mouth, stomach, duodenum) than in ileum and colon. Similar observations were made regarding the distribution of CD103(+)ILC1. The opposite was true regarding ILC3, which represented a major ILC population in the ileum and the colon but only a minor fraction in the oesophagus and stomach, respectively. Substantial proportions of ILC2 were only found in the stomach and the oral cavity. Expression of IL-13(ILC2), and IL-22(ILC3) did not differ significantly between the analysed GI-compartments, whereas frequency of IFN-g(+) cells was lowest in the colon. Frequency of total ILCs in HIV(+) patients was similar to that observed in healthy controls. However, HIV infection was associated with compartment-specific alterations of the ILC pool as frequency of ILC2 and ILC3 was increased in the duodenum of HIV(+) patients whereas in the colon we observed reduced numbers of ILC3 but increased numbers of NCR(-) ILC1. Conclusions: Conclusion: Our data indicate a compartment-specific distribution of ILCs in the human GI-tract, which is markedly dysregulated in HIV infection. 237 IL-33/ST2 Axis as an Inflammatory and Gut Damage Marker in Primary HIV Infection VikramMehraj 1 ; Mohammad-Ali Jenabian 2 ;Wei Cao 1 ; Rosalie Ponte 3 ; Bertrand Lebouché 4 ; RéjeanThomas 5 ; Jean-Guy Baril 6 ; Roger LeBlanc 7 ; CécileTremblay 8 ; Jean-Pierre Routy 1 1 Rsr Inst of the McGill Univ Hlth Cntr, Montreal, QC, Canada; 2 Univ du Québec à Montréal, Montreal, QC, Canada; 3 Rsr Inst of the McGill Univ Hlth Cntr, Montréal, QC, Canada; 4 McGill Univ Hlth Cntr, Montreal, QC, Canada; 5 Clinique Médicale l’Actuel, Montreal, QC, Canada; 6 Clinique Médicale Quartier Latin, Montreal, QC, Canada; 7 Clinique Médicale OPUS, Montreal, QC, Canada; 8 CRCHUM, Montreal, QC, Canada Background: The alarmin IL-33 and its receptor ST2 mainly expressed by innate lymphoid type 2 cells are involved in microbial invasion, cytokine induction and promotion of cytotoxic CD8 T cells. The soluble ST2 (sST2) binds IL-33 as a decoy receptor to negate its inflammatory/healing effects. sST2 has been validated as a prognostic marker in cardiac insufficiency, IBD, GVHD and been evaluated in HIV. We assessed relationship of IL-33/ST2 axis with gut mucosal damage markers in patients undergoing primary HIV infection (PHI).

Poster Abstracts

92

CROI 2016