Abstract

BACKGROUND: Multiple sclerosis (MS) is an autoimmune disease whereby myelin sheath of the central nervous system is destroyed. Vitamin A is known to play a role in the immune system. It has been recognized that some metabolites of vitamin A can be used effectively to treat experimental autoimmune encephalomyelitis (EAE). AIMS: The effect of vitamin A as retinyl palmitate on T-cell proliferation in MS patients. SETTING AND DESIGN: This study is a double blind clinical trial of two test groups over a period of 6 months. MATERIALS AND METHODS: Thirty five multiple sclerosis (MS) patients were divided into two groups. One group received 25,000 IU/day vitamin A (as retinyl palmitate) and the other group were administered a placebo. The peripheral blood mononuclear cells (PBMCs) were separated and stimulated with myelin oligodendrocyte glycoprotein (MOG) and phytohemagglutinin (PHA) before and after the trial period. BrdU calorimetric assay was performed to measure cell proliferation. STATISTICAL ANALYSIS: Analysis of covariance (ANCOVA) and paired t-test were used to analyze the data. RESULTS: Observations showed statistical significant differences in the reduction of cell proliferation in the presence of MOG and fetal calf serum (FCS) in the culture medium, between patients receiving vitamin A and the placebo (P = 0.046). Although, this difference was not significant between the two vitamin A and placebo groups in MOG treatment with human serum, a decrease was observed in the group of patients taking vitamin A supplements (P = 0.019). Phytohemagglutinin did not cause any change in cell proliferation between the two groups. CONCLUSION: The results suggest supplementation with retinyl palmitate in patients with MS reduce MOG stimulatory effects on T-cells.