CROI 2017 Abstract e-Book

Abstract eBook

Poster and Themed Discussion Abstracts

211 INFLAMMATORY GUT ILCs ASSOCIATE WITH DYSBIOSIS DURING UNTREATED HIV-1 INFECTION Stephanie Dillon 1 , Daniel N. Frank 1 , Gregory Austin 1 , Sara Gianella 2 , Moriah Castleman 1 , Andrew Cogswell 3 , Alan Landay 3 , Edward Barker 3 , Cara Wilson 1 1 Univ of Colorado Anschutz Med Campus, Aurora, CO, USA, 2 Univ of California San Diego, La Jolla, CA, USA, 3 Rush Univ, Chicago, IL, USA Background: HIV-1 infection is associated with a breakdown in intestinal homeostasis and changes in the enteric microbiota including increased abundances of pathobionts (e.g. Prevotella spp.). Normally, NKp44+ innate lymphoid cells (ILCs) within the mucosa maintain gut homeostasis through production of IL-22. ILCs also display functional plasticity and can produce inflammatory cytokines (e.g., IFNγ) in response to cytokine milieu and stimulatory signals in the colon. We hypothesized that frequencies of inflammatory gut NKp44+ ILCs would be increased during HIV-1 infection and thus contribute to HIV-1 gut pathogenesis. Methods: Following informed consent, colonic cells were collected from 22 untreated, chronic HIV-1-infected study participants (HIV+; median plasma viral load: 51,350 HIV-1 RNA/ml; median CD4 count: 425 cells/μl) and 9 HIV-1 uninfected controls (HIV-). Flow cytometry was used to determine frequencies of CD3-NKp44+CD56± ILCs and CD3+CD4 T cells expressing IL-22 or IFNγ after in vitro mitogenic stimulation and to measure myeloid dendritic cell (mDC) activation (CD40 expression) and T cell activation (CD38+HLA-DR+). Microbiome analysis was performed on colon tissue from a subset of subjects using bacterial 16S ribosomal DNA sequences. Non-parametric tests were performed. Results: In HIV- persons, NKp44+CD56- ILCs primarily produced IL-22 (6.1%, 0-13.6%) versus IFNγ (0.6%, 0-4.0%; p=0.01). Similar percentages of NKp44+CD56+ ILCs expressed IL-22 (8.7%, 2.0-23.2%) and IFNγ (10.9%, 0.6-20.8%; p=0.91). Frequencies (#/g) of IFNγ+NKp44+CD56- and IFNγ+NKp44+CD56+ ILCs were significantly increased in HIV+ persons (P=0.002 (N=21), P=0.04 (N=22) respectively). In HIV+ persons, frequencies of IFNγ+NKp44+CD56- ILCs positively correlated with relative abundance of mucosa- associated Prevotella spp. (P. copri: R=0.68, P=0.01; P. stercorea: R=0.63, P=0.02; N=14) and frequencies of IFNγ+ CD4 T cells (R=0.53, P=0.01; N=21). IFNγ+NKp44+CD56+ ILCs positively correlated with activation of colon mDCs (R=0.56, P=0.02; N=18) and T cells (CD4: R=0.43, P=0.04; CD8: R=0.64, P=0.002; N=22). Conclusion: Cytokine profiles of gut NKp44+ ILCs are altered during untreated, chronic HIV infection. The switch to an IFNγ-dominated ILC phenotype is associated with dysbiosis and gut mDC and T cell activation suggesting a critical interplay between gut ILCs, the microbiome and local immune responses. This inflammatory ILC functional profile likely contributes to gut mucosal inflammation and epithelial barrier breakdown. 212 GUT-MICROBIOTA–RELATED METABOLIC PATHWAYS IN ELITE CONTROLLERS AND HIV PROGRESSORS Piotr Nowak 1 , Javier Rivera 2 , Jan Vesterbacka 1 , Marc Noguera-Julian 2 , Kajsa Noyan 1 , Maria L. Calle 3 , Roger Paredes 2 , Anders Sönnerborg 4 1 Karolinska Inst, Stockholm, Sweden, 2 IrsiCaixa Inst for AIDS Rsr, Badalona, Spain, 3 Univ of Vic–Central Univ of Catalonia, Barcelona, Spain, 4 Karolinska Univ Hosp, Stockholm, Sweden Background: Gut microbiota dysbiosis features progressive HIV infection, with subsequent microbial translocation and systemic immune activation. Still, the microbial composition in gut of elite controllers (EC) has not been extensively explored, neither the corresponding metabolic pathways. Methods: 16 EC and 32 ART naïve progressors were recruited from a Swedish HIV cohort, and also 16 healthy controls (HC). Subjects were matched by age, gender and sexual practice. Fecal microbiota composition was determined by 16S rRNA sequencing. Plasma markers of tryptophan catabolism pathway were analyzed by HPLC. Functional content of the bacterial 16srRNA metagenome was inferred by PICRUSt software. Results: The number of observed genera was significantly higher in EC vs progressors (median 87 vs 70; HC 78), and several α-diversity indexes were lower in patients with progressive infection (median Chao1: 95 vs 80, ACE: 93 vs 79; in HC 83 and 85, respectively). At genus level, Succinivibrio, Sutterella, Rhizobium, Delftia, Anaerofilum and Oscillospira were more abundant in EC, whereas Blautia and Anaerostipes were depleted. Plasma K/T ratio was significantly increased in progressors as compared to EC and HC. The PICRUSt analysis revealed several significant differences between groups in different metabolic pathways. Carbohydrate metabolism pathway was less represented in EC fecal microbiome. Conversely, several other metabolic pathways (fatty acid metabolism, PPAR-signalling and lipid biosynthesis proteins) were enriched in EC than in progressors. Secondary, bile acid synthesis pathway was underrepresented in EC as compared to naïve progressors and HC. Additionally, pathways related to pentose-phosphate (PPP), pentose-glucoronate interconversions, and phenylalanine-tyrosine-tryptophan biosynthesis were reduced both in EC and HC when compared to naïve progressors. Differences between EC and HC were less frequent and included pathways related to carbohydrate metabolism, biosynthesis and biodegradation of secondary metabolites, PPP and bacterial toxins. Conclusion: EC have a richer gut microbiota than untreated HIV patients, with a unique bacterial signature at genus level. We confirm that tryptophan metabolism is altered during HIV infection, mostly in naive progressors. Functional analysis of the 16srRNA metagenome shows that EC have a distinct profile in several metabolic pathways, including metabolism of carbohydrates, lipids and tryptophan. 213 CHANGES IN THE ORAL MICROBIOME WITH ART INITIATION Rachel Presti 1 , Scott Handley 2 , Lindsay Droit 2 , Mahmoud Ghannoum 3 , Mark Jacobson 4 , Caroline H. Shiboski 4 , Jennifer Webster-Cyriaque 5 , Todd Brown 6 , Michael T. Yin 7 , Edgar T. Overton 8 1 Washington Univ in St. Louis, St. Louis, MO, USA, 2 Washington Univ, St. Louis, MO, USA, 3 Case Western Reserve Univ, Cleveland, OH, USA, 4 Univ of California San Francisco, San Francisco, CA, USA, 5 Univ of North Carolina at Chapel Hill, NC, USA, 6 The Johns Hopkins Univ, Baltimore, MD, USA, 7 Columbia Univ, New York, NY, USA, 8 Univ of Alabama at Birmingham, Birmingham, AL, USA Background: Changes in human oral microbiota have been linked to diseases of aging that are common in HIV, including atherosclerosis and certain cancers. Oral pathology, including thrush, oral hairy leukoplakia and periodontal disease, is common in chronic HIV infection. HIV has been associated with shifts in the microbiome at several sites, although no studies have longitudinally assessed oral microbiome change in the setting of controlled ART initiation. Here, we characterize the oral bacterial microbiome before and after 24 weeks of ART. Methods: Thirty-five participants co-enrolled in two ACTG studies, A5272 and A5280, were assessed. All participants were ART-naïve at baseline and received EFV/FTC/TDF in A5280. Saliva was collected as part of A5272. Paired saliva samples from both studies were evaluated for bacterial microbiome using 16S rDNA PCR followed by Illumina sequencing. Reads were analyzed using QIIME. Operational taxonomic units (OTUs) were assigned, and differences in distribution and abundance before and after ART were assessed. Results: At entry, median age was 35 years; (89%male; 46%white, 31% African American, 20% Hispanic). Median CD4 count was 326 cells/mm3 (range: 7-804); 5 participants had CD4 counts <200 cells/mm3. Median viral load was 30,136 cp/mL; 9 participants had viral load >100,000 cp/mL. All participants suppressed on EFV/FTC/TDF to HIV VL<200, although one rebounded at week 24 after suppression. No significant change was seen between baseline and week 24 samples in either alpha or beta diversity (p>0.05 for both). Overall, the distribution of OTUs in the oral samples remained similar at weeks 0 and 24. However, participants with CD4<200 cells/mm3 had fewer Firmicutes, Actinobacteria, Bacteroidetes, and Fusobacteria, and more Proteobacteria, than those with CD4>200 cells/mm3. Importantly, these differences persisted at week 24 of ART. Conclusion: In this prospective study of ART naïve individuals, we identified relative stability within the oral microbiome after 24 weeks of ART. However, persons with advanced HIV disease had greater representation of the phylum Proteobacteria, which has also been reported in the gut microbiome of persons with advanced HIV disease. This shift to a greater representation of pathogenic Gram-negative bacteria is a potential contributor to excess inflammation in the setting of advanced disease, and is not completely reversed by 24 weeks of effective ART.

Poster and Themed Discussion Abstracts

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CROI 2017