Is air pollution associated with adaptive immune responses, measured by polyclonal elevation of serum free light chains?-Results from the prospective Heinz Nixdorf Recall Study

Abstract

OPS 52: Air pollution and respiratory health, Room 110, Floor 1, August 28, 2019, 10:30 AM - 12:00 PM Background/Aim: Residential exposure to particulate matter (PM2.5 and PM10) air pollution (AP) has been shown to activate the immune system (IS). While innate immune responses to AP have been studied extensively, investigations on the adaptive IS are scarce. Objective: To investigate the association between short- to long-term AP exposure and polyclonal free light chains (FLC: κ+λ) produced by plasma cells. Methods: We used repeated data from three examinations (t0: 2000-2003, t1: 2006-2008, t2: 2011-2015) of the Heinz Nixdorf Recall study, a population-based German cohort of initially 4,814 participants (45-75 years). Residential exposure to total and source-specific particulate matter, nitrogen dioxide (NO2) and particle number concentrations (accumulation mode) was estimated using a chemistry transport model with different time windows (28-, 91-, 182-, 270- and 365-day means) before blood draw. We applied linear mixed models with a random participant intercept to estimate associations between air pollution (AP) exposures and log-transformed FLC, controlling for year of enrollment, age, sex, socioeconomic status, lifestyle variables, estimated glomerular filtration rate (eGFR) and season. Results: Analyzing 10,017 observations from 4,207 participants, we mostly observed positive associations between AP exposures and FLC. The strongest associations were observed with 91-day exposures, e.g. 2.9% increase in FLC (95%-Confidence Interval [CI]: 1.6%; 4.1%) per interqurartile range increase in NO2 (14.1 µg/m3). While most AP exposures also showed significant positive effect estimates with an exposure window of 182 days, weaker associations were observed for the other time windows. Across the different pollutants, PM10 and NO2 showed the strongest associations with FLC. Conclusions: Our results suggest that in particular 91-and 182-day mean AP exposures might be positively associated with activation of the adaptive IS.