Short-term associations of PM2.5 and PM2.5 constituents with immune biomarkers: A panel study in people living with HIV/AIDS.

Studies on associations of fine particulate matter (PM2.5) with immunity in people living with HIV/AIDS (PLWHA) were absent. We aimed to explore whether changes of immune biomarkers were associated with short-term exposure to PM2.5 in PLWHA. Based on a panel study in Wuhan, we selected 163 PLWHA as participants with up to 4 repeated visits from March 2020 to January 2021. Immune biomarkers, including CD4+T cell count, CD8+T cell count, HIV viral load (VL) and CD4+T/CD8+T ratio were tested for all participants at each visit. Residential exposures of PM2.5 and PM2.5 constituents for each participant were assessed using spatial-temporal models. Linear mixed-effect models and general linear mixed models were applied to evaluate the associations between PM2.5 and immune biomarkers. To estimate the combined effect of PM2.5 constituents, weighted quantile sum regression and Bayesian kernel machine regression were employed. Each 10 μg/m3 increase of 7-day average PM2.5 concentrations was associated with an 8.75 cells/mm3 (95%CI: -15.55, -1.98) decrease in CD4+T cell count and a 92% (OR: 1.92, 95%CI: 1.43, 2.58) increased odds ratio of detectable HIV VL. However, the odds ratio of inverted CD4+T/CD8+T was only positively associated with PM2.5 concentrations at lag2 day (OR:1.27, 95%CI:1.02, 1.57). CD4+T may be a potential mediator between PM2.5 and detectable HIV VL with 3.83% mediated proportion. Besides, the combined effect of PM2.5 chemical constituents indicated that NO3- and SO42- were the main constituents in reducing CD4+T cell count and increasing odds ratio of detectable HIV VL. Our finding revealed that short-term exposure to PM2.5 was negatively associated with CD4+T cell count but positively related to the odds ratio of detectable HIV VL in PLWHA. This research may provide new evidence in associations between PM2.5 and immune biomarkers as well as improving prognosis of PLWHA.