Vitamin D is known to have immunomodulatory properties and its deficiency is identified as an environmental risk factor for the development of autoimmune diseases, including multiple sclerosis. The aim of this study was to assess whether low-dose vitamin D supplementation could normalize the 25(OH)D serum levels in patients with relapsing-remitting multiple sclerosis (RRMS) and vitamin D deficiency (serum 25(OH)D < 75 nmol/L), and whether it may impact serum levels of selected cytokines. Among 44 patients (mean age 38.4 ± 10.1 years, 33 women and 11 men), after 12 months of low-dose vitamin D supplementation, serum levels of 25(OH)D normalized in 34 (77.3%) of the patients. Together with vitamin D increase, median levels of anti-inflammatory cytokines (IL10, TGF-β) and regulatory IFN-γ increased, while proinflammatory IL-17 remained unchanged. Moreover, an increase of inorganic phosphorus levels and decrease of PTH levels were observed, but without changes in total calcium concentration. These results may indicate that long-term supplementation with low doses of vitamin D is sufficient to compensate its deficiency in patients with RRMS and may help to maintain beneficial anti-inflammatory cytokine profile.
Keywords: cytokine; multiple sclerosis; supplementation; vitamin D.