RESUMEN
Although, the cytotoxic T lymphocyte antigen-4 gene polymorphism at position 49 of exon-1 has been strongly elucidated in different autoimmune diseases, but its role in predisposition to systemic sclerosis (SSc) is yet controversial. This study intends to analyze the genetic correlation of the ctla-4 gene locus with diffuse systemic sclerosis (dSSc), as well as to understand the influence of these genotypes in disease expression. Seventy known cases of SSc, and 151 age-matched healthy controls, were participated in this investigation. The frequencies of AA, GG and AG genotypes were found to be 26 (37.1%), 5 (7.2%) and 39 (55.7%) in patients, and 60 (39.7%), 19 (12.6%) and 72 (47.7%) in controls, respectively. As indicated, the differences in genotype and allele frequencies between patients and controls were insignificant (P>0.05). Moreover, the distribution of CTLA-4 polymorphism between patients did not differ significantly according to clinical and serologic features. In Iranian patients, susceptibility to SSc is not influenced by a bi-allelic ctla-4 gene (A49G) polymorphism.