Vitamin D supplementation could limit T helper‐17 response in multiple sclerosis

Abstract

ObjectivesLow vitamin D and high response of T helper‐17 (Th17) are two main risk factors in multiple sclerosis (MS). The purpose of the present study was to investigate whether vitamin D supplementation can reduce Th17 responses and interleukin‐17A (IL‐17A) production.MethodsSerum samples of 17 relapsing–remitting MS patients were collected at onset of disease. They were supplemented with 50 000 IU/week vitamin D3 for 6 months. After 6 months, sampling was repeated from the patients. The serum level of 25‐hydroxyvitamin D and IL‐17A were measured at baseline, and after 6 months using commercially available enzyme‐linked immunosorbent assay. Statistical analyses were carried out by Wilcoxon test and Spearman's rho correlation coefficient.ResultsThe levels of 25‐hydroxyvitamin D were generally deficient (29.4%) and insufficient (47%) in the patients at baseline. The initial IL‐17A levels (mean 3.9, standard error 0.28) were significantly decreased after vitamin D supplementation (mean 2.2, standard error 0.18, P < 0.0001). Furthermore, a positive correlation was seen between pre‐supplementation IL‐17A levels and reduction after supplementation (Spearman's rho = 0.61, P = 0.008).ConclusionIn the present study, it was shown that vitamin D supplementation could reduce the level of IL‐17A in MS patients, and there was an association between these two risk factors in MS disease.