CTLA-4 Polymorphism in Myasthenia Gravis

ABSTRACT

BACKGROUND: Cytotoxic T lymphocyte associated antigen 4 (CTLA-4) plays a role in down-regulating both the cellular and the humoral responses by suppressing the ongoing responses of activated T-cells. There are evidences to suggest the genetic contribution of the CTLA-4 locus to a number of autoimmune diseases, such as insulin dependent diabetes mellitus, multiple sclerosis and systemic lupus erythematosus. The aim of the present study is to analyze CTLA-4 gene polymorphism in patients with myasthenia gravis (MG) compared to healthy controls. METHODS: Thirty healthy controls and 31 patients with MG were genotyped into G/G, A/G and A/A of CTLA-4 gene polymorphism at position 49 and the relationship with the clinical feature was analysed. RESULTS: In the patients with MG, the genotype frequencies of G/G, A/G and A/A were 61.3%, 35.5% and 3.2%, respectively. In healthy controls, the frequencies of each genotype were 50%, 43% and 7%, respectively. There was no significant difference in the genotype frequencies of CTLA-4 gene between patients with MG and the control group. There were also no significant differences in the genotype frequencies of CTLA-4 gene between ocular and generalized MG. CONCLUSIONS: These data suggest that the CTLA-4 polymorphism at position 49 do not affect the development of MG. However, further study is needed to clarify the possible role of the CTLA-4 polymorphism in the susceptibility to MG.