Seasonal variations in the concentration of particulate matter in the air of Cracow affect the magnitude of CD4+ T Cell subsets cytokine production in patients with inflammatory and autoimmune disorders

Recently, the increased prevalence of chronic civilization diseases triggered by environmental pollution has been observed. In this context, the role of air pollution in the pathogenesis of autoimmune and/or inflammatory disorders is poorly elucidated. Here, we asked whether seasonal changes in the air quality of the city of Cracow affect the polarization of T cell subsets in healthy donors (HD) and patients with rheumatoid arthritis (RA), multiple sclerosis (MS), and atherosclerosis (AS). Peripheral blood mononuclear cells (PBMCs) from HD and patients were exposed in vitro to particulate matter isolated from the air of Cracow (PM CRC). Blood samples were collected in two seasons (winter and summer), with differences in air concentration of particulate matter of 10 μm (PM10) (below or above a daily limit of 50 µg/m$^{3}$). The obtained data showed a significantly elevated frequency of CD4$^{+}$ lymphocytes specific for IFN-γ and IL-17A after the exposure of PBMCs to PM CRC. This was observed for all patients’ groups and HD. In the case of patients, this effect was dependent on the seasonal concentration of PM in the air, paradoxically being less pronounced in the season with a higher concentration of air pollution. These observations may suggest the role of air pollution on the course of inflammatory and autoimmune disorders.