Comparison of Expression Levels of miR-29b-3p and miR-326 in T Helper-1 and T Helper-17 Cells Isolated from Responsive and Non-responsive Relapsing-remitting Multiple Sclerosis Patients Treated with Interferon-beta.

T helper type 1 (Th1) and Th17 Cells with distinct cytokine profiles including interferon-gamma (IFN-γ) and interleukin 17 (IL-17) have a pivotal role in neuroinflammation and myelin destruction in the central nervous system (CNS) in MS. MicroRNA-29b (MiR-29b) and miR-326 contribute to regulating Th1 and Th17 differentiation and altered expression of the miRNAs could be associated with response to treatment in multiple sclerosis (MS). Therefore, our study aimed to evaluate the percentage of Th1 and Th17 and determining the expression levels of miR-29b-3p and miR-326 in these lymphocyte subpopulations between responsive and non-responsive to interferon beta (IFN-β) therapy in relapsing-remitting multiple sclerosis (RRMS) patients. The present study was performed on 40 RRMS patients following treatment with IFN-β. The percentage of Th1 cells and Th17 cells were determined by flow cytometry in responsive and non-responsive patients. The expression levels of miR-29b-3p and miR-326 were assessed in Th1 and Th17 cells by quantitative polymerase chain reaction (PCR). Enzyme-linked immunosorbent assay (ELISA) was applied to evaluate the plasma levels of IFN-γ and IL-17A. No significant difference was observed in the percentage of Th1 and Th17 cells as well as the expression levels of miR-29b-3p and miR-326 (in Th1 and Th17, respectively) in treated patients. Also, we did not find any significant difference in IFN-γ and IL-17A plasma concentration between responsive or non-responsive to IFN-β therapy in patients with RRMS. IFN-β may regulate other miRNAs in Th1 and Th17 cells than miR29b-3p and miR-326 in MS patients.