CTLA4 Gene Polymorphisms in Dutch and Chinese Patients with Inflammatory Bowel Disease

Background: Inflammatory bowel diseases (IBDs) are characterized by chronic intestinal inflammation as a result of an exaggerated T-cell response. CTLA4, a receptor of activated T cells, has an inhibitory function in regulating T-cell activation. Since CTLA4 gene polymorphisms have been associated with several autoimmune diseases, the aim was to study these gene polymorphisms in patients with IBD in two different populations. Methods: The C-318T polymorphism in the promoter region and A+49G polymorphism in exon 1 of the CTLA4 gene were investigated by a PCR-SSP method. We studied 139 unrelated patients with ulcerative colitis (UC), 163 patients with Crohn disease (CD) and 174 healthy controls of Dutch Caucasian origin as well as 35 patients with UC and 62 healthy controls from the Chinese Han population. Results: No significant differences in the distribution of allele, genotype and haplotype frequencies were observed between C-318T and A+49G gene polymorphisms and IBD in Dutch Caucasians and UC in the Chinese Han population. Although the haplotypes of the C-318T and A+49G polymorphisms were distributed differently between Dutch Caucasian and Chinese Han populations, there were no differences in the subgroups of patients with CD classified according to age, localization and behaviour in the Vienna classification and in those with UC classified according to age at onset, disease extension and presence of colectomy in the Dutch patients. However, the CTLA4-318 genotype CC was more frequent in patients with CD over 40 years (93%) than in younger patients (74%) ( P = 0.045). Conclusion: C-318T and A+49G CTLA4 gene polymorphisms and their haplotypes are not associated in Dutch Caucasian patients with IBD and in Chinese patients with UC.