[Study on the relationship of CTLA-4 -318, +49 polymorphisms with autoimmune hepatitis and primary biliary cirrhosis in a Chinese population].

Objective: To investigate the association between Chinese patients with autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC) and the polymorphisms of cytotoxic T lymphocyte -associated antigen-4 (CTLA-4) gene promoter (-318) and exon 1 (+49).

Methods: The CTLA-4 promoter (-318 T/C) and exon 1 (+49A/G) polymorphisms were genotyped via restriction fragment length polymorphism methods in 62 Chinese AIH patients, 77 Chinese PBC patients and 160 healthy controls.

Results: There was no difference in the distribution of CTLA-4 promoter -318 T/C polymorphisms between AIH patients and controls, but the C allele frequency was significantly increased in patients with AIH, compared to controls (P=0.02, OR=2.43). The distribution of CTLA-4 gene exon 1 49 A/G genotypes exhibited significant difference between PBC patients and controls (P=0.006), and the frequency of G allele showed a significant increase in PBC group as compared with controls (P=0.0046, OR=1.8). Although the genotype distribution of the CTLA-4 exon 1-promoter gene displayed no significant difference between AIH and PBC patients and controls, the occurrence of GG-CC was increased in the patients of the two groups (AIH: 32.3%, PBC: 37.7%; control: 22.5%).

Conclusion: The above findings suggest that the polymorphisms of CTLA-4 gene probably confer susceptibility to AIH and PBC in the Chinese population.