IRF4 and myeloid sarcoma: Our results demonstrated preferential Th17 cell differentiation in RR MS patients in comparison to HCs, since the gene expression of IL-1R1, IRF4, RORc, IL-17A, IL-17F, IL-21, IL-22, and IL-23R were higher in MS patients than in HCs at baseline and following Th17 cell differentiation (Figures 3A,B).