Association Between CTLA4 Gene Microsatellite Polymorphism And Inflammatory Bowel Disease

Objective Inflammatory bowel disease (IBD) is characterized by chronic intestinal inflammation as a result of an exaggerated T-cell response. Cytotoxic T lymphocyte associated antigen-4 (CTLA-4) expressed mainly on activated T cells, inhibits T cell activation by combining B7 through competing CD28 and maintains immune system homeostasis. Polymorphisms in the CTLA-4 gene are known to be associated with several autoimmune diseases, but very few studies related to IBD. The aim of the study is to investigate an association between CTLA-4 gene microsatellite polymorphisms and IBD.Methods Unrelated 68 Chinese Han patients with IBD (54 ulcerative colitis and 14 Crohn' s disease) and 140 healthy controls were studied. The (AT)n repeats in the 3' untranslated region of exon 4 of CTLA-4 gene were amplified by allele-specific PCR. The amplified products were electrophoresed by 12% polyacrylamid gel and followed by silver staining.Results Eighteen alleles of CTLA-4 microsatellite were found in Chinese patients and healthy individuals. Long allele, 122bp was apparently increased in patients with ulcerative colitis compared with healthy controls (7.4% vs 0.3%, P=0.0002/Pc=Sig, OR=22.32, 95%CI: 2.76~180.80).Conclusion CTLA-4 gene microsatellite polymorphism was strongly associated with ulcerative colitis in Chinese Han patients in Hubei province.