methylprednisolone down-regulates the production of IL-17 by PBMC from asthmatic children or patients with rheumatoid arthritis.47,48 Moreover, the reducing effects of methylprednisolone on the frequency of Th17 lymphocyte were demonstrated in patients with MS disease.49 In addition, IFN-β and methylprednisolone may up regulate the expression of IL-35 (a Treg-type cytokine) in MS patients.50 Based on the present results, the immunomodulatory effects of IFN-β and/or methylprednisolone may perform in part, via the inhibition of the IL-17 production. This evidence concerns the gene IL17A and rheumatoid arthritis.