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BackgroundTh17 cells are permissive to HIV-1 infection and their depletion from the gut of infected individuals leads to microbial translocation, a major cause for non-AIDS co-morbidities. Most recent evidence supports the contribution of long-lived Th17 cells to HIV persistence during antiretroviral therapy (ART). However, the identity of long-lived Th17 cells remains unknown.ResultsHere, we performed an in-depth transcriptional and functional characterization of four distinct Th17 subsets and investigated their contribution to HIV reservoir persistence during ART. In addition to the previously characterized CCR6(+)CCR4(+) (Th17) and CCR6(+)CXCR3(+) (Th1Th17) subsets, we reveal the existence of two novel CCR6(+) subsets, lacking (double negative, CCR6(+)DN) or co-expressing CXCR3 and CCR4 (double positive, CCR6(+)DP). The four subsets shared multiple Th17-polarization markers, a fraction of cells proliferated in response to C. albicans, and exhibited lineage commitment and plasticity when cultured under Th17 and Th1 conditions, respectively. Of note, fractions of CCR6(+)DN and Th17 demonstrated stable Th17-lineage commitment under Th1-polarization conditions. Among the four subsets, CCR6(+)DN expressed a unique transcriptional signature indicative of early Th17 development (IL-17F, STAT3), lymph-node homing (CCR7, CD62L), follicular help (CXCR5, BCL6, ASCL2), and self-renewal (LEFI, MYC, TERC). Cross sectional and longitudinal studies demonstrated that CCR6(+)DN cells were the most predominant CCR6(+) subset in the blood before and after ART initiation; high frequencies of these cells were similarly observed in inguinal lymph nodes of individuals receiving long-term ART. Importantly, replication competent HIV was isolated from CCR6(+)DN of ART-treated individuals.ConclusionsTogether, these results provide new insights into the functional heterogeneity of Th17-polarized CCR6(+)CD4(+) T-cells and support the major contribution of CCR6(+)DN cells to HIV persistence during ART.

Objective: Our objective was to determine the frequency at which CD4 counts drop below 200 cells/mm3 during pregnancy in women living with HIV and to identify factors associated with this. Methods: Data from 2005 to 2020 from two prospective Canadian cohorts of pregnant women living with HIV were extracted. As per national guidelines, women received antiretroviral therapy and CD4 counts were monitored once per trimester and at delivery. Results: Among 775 included cases, 72 (9.3%) had CD4 counts <200 cells/mm3 at the first pregnancy visit. Of the 703 remaining pregnancies with CD4 counts ≥200 cells/mm3 at the initial visit, 20 (2.8%) were associated with a drop to <200 cells/mm3. In univariate analysis, factors associated with this drop were coinfection with hepatitis B virus or hepatitis C virus (odds ratio [OR] 4.0, 95% confidence interval [CI] 1.52–10.50), lower first visit CD4 counts (OR 0.165, 95% CI 0.08–0.34), and baseline haemoglobin levels <11 g/dL (OR 2.89, 95% CI 1.04–8.00). In multivariable analysis, only CD4 count at first visit remained independently associated with this drop. A cut‐off CD4 count ≤450 cells/mm3 at the first pregnancy visit had a sensitivity of 100% to detect cases of CD4 drop to <200 cells/mm3. Conclusion: A drop of CD4 count to <200 cells/mm3 is uncommon during pregnancy in women living with HIV. Our results suggest that CD4 monitoring only once in pregnancy would be safe in women whose CD4 count is >450 cells/mm3 at the first pregnancy visit. [ABSTRACT FROM AUTHOR]

Perinatally infected children living with HIV (CLWH) face lifelong infection and associated inflammatory injury. Chitinase-like 3 protein-1 (CHI3L1) is expressed by activated neutrophils and may be a clinically informative marker of systemic inflammation in CLWH. We conducted a multi-centre, cross-sectional study of CLWH, enrolled in the Early Pediatric Initiation Canadian Child Cure Cohort Study (EPIC4). Plasma levels of CHI3L1, pro-inflammatory cytokines, and markers of microbial translocation were measured by enzyme-linked immunosorbent assays. Longitudinal clinical characteristics (viral load, neutrophil count, CD4+ and CD8+ T-lymphocyte counts, and antiretroviral (ARV) regimen) were abstracted from patient medical records. One-hundred-and-five (105) CLWH (median age 13 years, 62% female) were included in the study. Seventy-seven (81%) had viral suppression on combination antiviral therapy (cART). The median CHI3L1 level was 25 μg/L (IQR 19–39). CHI3L1 was directly correlated with neutrophil count (ρ = 0.22, p = 0.023) and inversely correlated with CD4/CD8 lymphocyte ratio (ρ = −0.35, p = 0.00040). Children with detectable viral load had higher levels of CHI3L1 (40 μg/L (interquartile range, IQR 33–44) versus 24 μg/L (IQR 19–35), p = 0.0047). CHI3L1 levels were also correlated with markers of microbial translocation soluble CD14 (ρ = 0.26, p = 0.010) and lipopolysaccharide-binding protein (ρ = 0.23, p = 0.023). We did not detect differences in CHI3L1 between different cART regimens. High levels of neutrophil activation marker CHI3L1 are associated with poor virologic control, immune dysregulation, and microbial translocation in CLWH on cART. [ABSTRACT FROM AUTHOR]

HIV-1 displays extensive genetic diversity. Group M includes 9 subtypes and >45 circulating recombinant forms (CRFs) (1). In western and central Africa, where the highest levels of HIV-1 genetic heterogeneity [...]

We studied HIV genetic diversity in a cohort of 127 pregnant, HIV-infected women who received prenatal care at Sainte-Justine Hospital in Montreal, Canada, between 1999 and 2003. Clade assignments were [...]

Down-regulation of the initial burst of viremia during primary HIV infection is thought to be mediated predominantly by HIV-specific cytotoxic T lymphocytes, and the appearance of this response is associated with major perturbations of the T cell receptor repertoire. Changes in the T cell receptor repertoire of virus-specific cytotoxic T lymphocytes were analyzed in patients with primary infection to understand the failure of the cellular immune response to control viral spread and replication. This analysis demonstrated that a significant number of HIV-specific T cell clones involved in the primary immune response rapidly disappeared. The disappearance was not the result of mutations in the virus epitopes recognized by these clones. Evidence is provided that phenomena such as high-dose tolerance or clonal exhaustion might be involved in the disappearance of these monoclonally expanded HIV-specific cytotoxic T cell clones. These findings should provide insights into how HIV, and possibly other viruses, elude the host immune response during primary infection.