Trottier, B. | bioRxiv Science

bioRxiv2022

Subclinical Atherosclerosis is Associated with Discrepancies in BAFF and APRIL Levels and Altered Breg Potential of Precursor-like Marginal Zone B-Cells in HIV Treated Individuals

Chronic inflammation persists in people living with HIV (PLHIV) despite antiretrovial therapy (ART), and is involved in their premature development of cardiovascular diseases (CVD) such as atherosclerosis. We have previously reported that an excess of "B-cell activating factor" (BAFF), an important molecule for the selection and activation of first line Marginal Zone (MZ) B-cell populations, is associated with deregulations of precursor-like MZ (MZp), whose potent B-cell regulatory (Breg) capacities are altered in PLHIV, early on and despite 1-2 years of ART. Based on these observations, and growing evidence that MZ populations are involved in atherosclerosis control, we designed a cross sectional study to explore the associations between BAFF and its analogue "A proliferation-inducing ligand" (APRIL) with subclinical CVD in long time treated individuals of the Canadian HIV and Aging Cohort Study (CHACS) imaging sub-study group. We also characterized the Breg profile of MZp from the blood of these individuals. Results were correlated with the total volume of atherosclerotic plaques (TPV) and with CVD risk factors and biomarkers. TPV was measured using cardiac computerised tomography angiography, and presence of CVD was defined as TPV > 0. We report that blood levels of BAFF are elevated and correlate positively with CVD and its risk factors in PLHIV from the CHACS, in contrast to APRIL levels, which correlate negatively with these factors. Expression levels of Breg markers such as NR4A3, CD39, CD73 and CD83 are significantly lower in PLHIV when compared to those of HIV-uninfected controls. In vitro experiments show that APRIL upregulates the expression of Breg markers by blood MZp from HIV-uninfected individuals, while this modulation is dampened by the addition of recombinant BAFF. Altogether, our observations suggest that strategies viewed to modulate levels of BAFF and/or APRIL could eventually represent a potential treatment target for CVD in PLHIV.

immunology↗

bioRxiv2021

Covid-19 vaccine immunogenicity in people living with HIV-1

IntroductionCOVID-19 vaccine efficacy has been evaluated in large clinical trials and in real-world situation. Although they have proven to be very effective in the general population, little is known about their efficacy in immunocompromised patients. HIV-infected individuals response to vaccine may vary according to the type of vaccine and their level of immunosuppression. We evaluated immunogenicity of an mRNA anti-SARS CoV-2 vaccine in HIV-positive individuals. MethodsHIV-positive individuals (n=121) were recruited from HIV clinics in Montreal and stratified according to their CD4 counts. A control group of 20 health care workers naive to SARS CoV-2 was used. The participants Anti-RBD IgG responses were measured by ELISA at baseline and 3 to 4 weeks after receiving the first dose of an mRNA vaccine). ResultsEleven of 121 participants had anti-COVID-19 antibodies at baseline, and a further 4 had incomplete data for the analysis. Mean anti-RBD IgG responses were similar between between the HIV negative control group (n=20) and the combined HIV+ group (n=106) (p = 0.72). However, these responses were significantly lower in the group with <250 CD4 cells/mm3. (p<0.0001). Increasing age was independently associated with decreased immunogenicity. ConclusionHIV-positive individuals with CD4 counts over 250 cells/mm3 have an anti-RBD IgG response similar to the general population. However, HIV-positive individuals with the lowest CD4 counts (<250 cells/mm3) have a weaker response. These data would support the hypothesis that a booster dose might be needed in this subgroup of HIV-positive individuals, depending on their response to the second dose.

immunology↗