To understand a relation between frequencies of IL-17-producing CD4+ or CD8+ T cells and a response to DMF, we analyzed 72 cryopreserved peripheral blood mononuclear cell (PBMC) samples isolated from peripheral blood (PB) of a cohort of 36 patients with MS before and after initiation of DMF therapy, which did (responders, n = 18) or did not fulfill (non-responders n = 18) no evidence of disease activity-3 (NEDA-3) criteria after about one year of treatment (Supplementary Fig. 1a, Supplementary Tables 1–3). This evidence concerns the gene IL17A and myeloid sarcoma.