The role of Th17 cells in patients with relapsing-remitting multiple sclerosis: interleukin-17A and interleukin-17F serum levels

Background and aims: Multiple sclerosis (MS) is an inflammatory condition of the central nervous system, with genetic and environmental factors having a role in its etiology. The condition is characterized by demyelination, acute inflammation, and chronic and acute lesions in the central nervous system. Human and experimental studies have shown that T-helper cells, and pro-inflammatory cytokines have a major role in the pathogenesis of MS. Recent researches have shown that IL-17 secreting T (Th17) cells have a role in inflammation and demyelination of the central nervous system. In the present study, the role of Interleukin-17A (IL-17A) and Interleukin-17F (IL-17F) in the immunopathogenesis and follow-up of the MS disease was evaluated.

Materials and methods: Thirty-five relapsing remitting (RR) form of MS patients were included in the present study. Blood samples were taken from 35 MS patients and 35 healthy individuals as controls. Enzyme-Linked Immunosorbent Assay (ELISA) was used to determine IL-17A and IL-17F serum levels.

Results: A statistically significant increase was noted in the serum levels of IL-17A and IL-17F in MS patients compared to the controls (P<0.001). There was a significant positive correlation of IL-17F serum levels with the number of relapses (rs=0.717, P<0.001). However, there was no significant relationship between the serum levels of these cytokines and Expanded Standard Disability Stated Scale (EDSS) and disease Progression Index (PI).

Conclusion: The data of the present study revealed a significant increase in the serum levels of IL-17A and IL-17F in MS patients compared with healthy controls and a significant positive correlation of IL-17F serum levels with the number of relapses. It appears that increased serum levels of IL-17 and especially IL-17F may lead to a raised risk of MS.