Association between CTLA-4 gene polymorphism and the risk of systemic lupus erythematosus: brief report

Background: Cytotoxic lymphocyte antigen-4 (CTLA-4) plays an important role in regulating T cell activation. CTLA-4 gene polymorphisms are related with genetic susceptibility to various autoimmune diseases, including systemic lupus erythematosus (SLE). We analyzed the role of CTLA-4 polymorphisms at positions -318CT in patients who suffer from SLE. Methods: This study was performed on 180 SLE patients referred to 5th Azar University Hospital in Gorgan, Iran. Three hundred and four ethnically-and age-matched healthy controls with no history of autoimmune diseases entered the study between 5th May 2008 and 23rd October 2009. DNA was extracted from blood samples according to the standard procedure. Polymerase chain reaction- restriction fragments length polymorphism (PCR-RFLP) was used to analyze the genotype and allele frequencies of this polymorphism. PCR was carried out using the following primers: forward 5′-AAATGAATTGGACTGGATGGT-3′ and reverse 5′-TTACGAGAAAGGAAGCCGT G-3′. The frequency of alleles and genotypes were assessed using direct counting. Chi-square test and Fisher’s exact test were used to compare the association between the alleles and genotype frequencies and SLE. P