Decreased expression of IL-27 and its correlation with Th1 and Th17 cells in progressive multiple sclerosis

Progressive multiple sclerosis (MS) is an immune-mediated demyelinating disease in which both imbalanced T helper (Th) subsets and aberrant cytokine profiles have been found. Interleukin-27 (IL-27), a cytokine with pro-inflammatory and anti-inflammatory effects, plays pleiotropic roles in immunomodulation. In the present study, plasma levels of IL-27, interferon-gamma (IFN-γ), IL-17 and frequencies of peripheral Th1, Th17 cells were determined by enzyme-linked immunosorbent assay (ELISA) and flow cytometry in 45 progressive MS and 25 healthy controls. mRNA expression levels of IL-27, IFN-γ, T-bet, IL-17 and RAR-related orphan receptor gamma t (RORγt) in peripheral blood mononuclear cells (PBMCs) were also quantified by real-time polymerase chain reaction. Plasma and mRNA levels of IL-27 in progressive MS patients were significantly lower than those in healthy controls, while plasma concentrations of IL-17, frequencies of circulating Th17, and mRNA expression levels of IL-17 as well as RORγt were all increased remarkably compared with healthy controls. No statistical significance was observed in IFN-γ and T-bet mRNA expression or plasma IFN-γ levels between progressive MS patients and healthy controls. Moreover, plasma levels of IL-27 were found to be negatively correlated to the percentages of circulating Th17 or plasma IL-17 concentrations in patients with progressive MS. Our data showed that progressive MS patients had decreased plasma and mRNA expression levels of IL-27, suggesting that it might be involved in the pathophysiological process of MS.