Air pollution exposure and immunological and systemic inflammatory alterations among schoolchildren in China

Exposure to air pollution is associated with an increased risk of respiratory infection, to which children are more susceptible than adults. However, epidemiological evidence regarding the association of chronic exposure to air pollution with the immune and systemic inflammatory function of children is scarce, especially in the context of higher exposure levels. In this study, we included 163 chronically exposed schoolchildren from a polluted area and 110 schoolchildren from a control area in Licheng district, Jinan, China. Immune biomarkers, including the absolute counts of lymphocyte subsets and the levels of immunoglobulins G, A, and M, C3, and C4 were determined. To explore the related biological process of altered immune biomarkers, 2 systemic inflammatory biomarkers, including C-reactive protein and the neutrophil-to-lymphocyte ratio, were also determined. After adjusting for confounders, the decreased B lymphocyte count (p = 0.021) and C3 and C4 levels (both p < 0.001) and the increased monocyte count (p = 0.009) and CD8+ T lymphocyte proportion (p = 0.054) were associated with living in the polluted area. Significant differences in the C4 and C3 levels between the areas were only seen in male schoolchildren and in schoolchildren without passive smoking exposure (P_interaction = 0.036 and 0.042, respectively). The alterations in immune biomarkers suggested that air pollution-induced immunotoxic effects and relevant adaptive responses were simultaneously present in schoolchildren exposed to a higher level of air pollution. Future studies investigating the temporal patterns of these biomarkers among children are warranted.