Perfluorinated substances, risk factors for multiple sclerosis and cellular immune activation

Perfluorinated alkylated substances (PFASs) have immunomodulatory effects but the impact on multiple sclerosis (MS) and cellular immune functions is only sparsely described. In the present study, we found lower concentrations of the long chain PFAS perfluorooctane sulfonic acid (PFOS) in MS than in healthy controls (HC). In HC, we did not detect associations between PFOS concentrations and immune phenotypes. Analyzing the impact of known MS risk factors on cellular immune functions, we found that smoking and Epstein–Barr nuclear antigen 1 antibodies were associated with distinct circulating immune cell changes. In summary, current background PFAS exposure is not an important risk factor for MS. [Display omitted] •PFAS exposure is not an environmental risk factor for multiple sclerosis.•Patients with multiple sclerosis have lower serum-PFOS than healthy controls.•Lower frequencies of circulating MAIT-like cells in healthy controls who smokes.