Objective: To explore the contribution of blood and colon myeloid cells to HIV persistence during antiretroviral therapy (ART). Design: Leukapheresis were collected from HIV-infected individuals with undetectable plasma viral load during ART (HIV+ART; n=15) and viremics untreated (HIV+; n=6). Rectal sigmoid biopsies were collected from n=8 HIV+ART. Methods: Myeloid cells (total monocytes (Mo), CD16 + /CD16-Mo, CD1c + dendritic cells (DC)) and CD4 + T-cells were isolated by MACS and/or FACS from peripheral blood. Matched myeloid and CCR6 + CD4 + T-cells were isolated from blood and rectal biopsies by FACS. Levels of early (RU5 primers), late (Gag primers), and/or integrated HIV-DNA (Alu/HIV primers) were quantified by nested real-time PCR. Replication-competent HIV was amplified by co-culturing cells from HIV+ individuals with CD3/CD28-activated CD4 + T-cells from uninfected donors.

Classical CD16− vs intermediate/nonclassical CD16+ monocytes differ in their homing potential and biological functions, but whether they differentiate into dendritic cells (DCs) with distinct contributions to immunity against bacterial/viral pathogens remains poorly investigated. Here, we employed a systems biology approach to identify clinically relevant differences between CD16+ and CD16− monocyte-derived DCs (MDDCs). Although both CD16+ and CD16− MDDCs acquire classical immature/mature DC markers in vitro, genome-wide transcriptional profiling revealed unique molecular signatures for CD16+ MDDCs, including adhesion molecules (ITGAE/CD103), transcription factors (TCF7L2/TCF4), and enzymes (ALDH1A2/RALDH2), whereas CD16− MDDCs exhibit a CDH1/E-cadherin+ phenotype. Of note, lipopolysaccharides (LPS) upregulated distinct transcripts in CD16+ (eg, CCL8, SIGLEC1, MIR4439, SCIN, interleukin [IL]-7R, PLTP, tumor necrosis factor [TNF]) and CD16− MDDCs (eg, MMP10, MMP1, TGM2, IL-1A, TNFRSF11A, lysosomal-associated membrane protein 1, MMP8). Also, unique sets of HIV-modulated genes were identified in the 2 subsets. Further gene set enrichment analysis identified canonical pathways that pointed to “inflammation” as the major feature of CD16+ MDDCs at immature stage and on LPS/HIV exposure. Finally, functional validations and meta-analysis comparing the transcriptome of monocyte and MDDC subsets revealed that CD16+ vs CD16− monocytes preserved their superior ability to produce TNF-α and CCL22, as well as other sets of transcripts (eg, TCF4), during differentiation into DC. These results provide evidence that monocyte subsets are transcriptionally imprinted/programmed with specific differentiation fates, with intermediate/nonclassical CD16+ monocytes being precursors for pro-inflammatory CD103+RALDH2+TCF4+ DCs that may play key roles in mucosal immunity homeostasis/pathogenesis. Thus, alterations in the CD16+/CD16− monocyte ratios during pathological conditions may dramatically influence the quality of MDDC-mediated immunity.

Background: Increased intestinal barrier permeability and subsequent gut microbial translocation are significant contributors to inflammatory non-AIDS comorbidities in people living with HIV (PLWH). Evidence in animal models have shown that markers of intestinal permeability and microbial translocation vary over the course of the day and are affected by food intake and circadian rhythms. However, daily variations of these markers are not characterized yet in PLWH. Herein, we assessed the variation of these markers over 24 h in PLWH receiving antiretroviral therapy (ART) in a well-controlled environment. Methods: As in Canada, PLWH are predominantly men and the majority of them are now over 50 years old, we selected 11 men over 50 receiving ART with undetectable viremia for more than 3 years in this pilot study. Blood samples were collected every 4 h over 24 h before snacks/meals from 8:00 in the morning to 8:00 the next day. All participants consumed similar meals at set times, and had a comparable amount of sleep, physical exercise and light exposure. Plasma levels of bacterial lipopolysaccharide (LPS) and fungal (1→3)-β-D-Glucan (BDG) translocation markers, along with markers of intestinal damage fatty acid binding protein (I-FABP) and regenerating islet-derived protein-3α (REG3α) were assessed by ELISA or the fungitell assay. Results: Participants had a median age of 57 years old (range 50 to 63). Plasma levels of BDG and REG3α did not vary significantly over the course of the study. In contrast, a significant increase of LPS was detected between 12:00 and 16:00 (Z-score: − 1.15 ± 0.18 vs 0.16 ± 0.15, p = 0.02), and between 12:00 and 24:00 (− 1.15 ± 0.18 vs 0.89 ± 0.26, p < 0.001). The plasma levels of I-FABP at 16:00 (− 0.92 ± 0.09) were also significantly lower, compared to 8:00 the first day (0.48 ± 0.26, p = 0.002), 4:00 (0.73 ± 0.27, p < 0.001) or 8:00 on secondary day (0.88 ± 0.27, p < 0.001). Conclusions: Conversely to the fungal translocation marker BDG and the gut damage marker REG3α, time of blood collection matters for the proper evaluation for LPS and I-FABP as markers for the risk of inflammatory non-AIDS comorbidities. These insights are instrumental for orienting clinical investigations in PLWH.