The association between Cytotoxic T lymphocyte associated antigen-4, Fas, tumour necrosis factor-α gene polymorphisms and autoimmune hepatitis: a meta-analysis.

BACKGROUND

Several previous studies have assessed the association of Cytotoxic T Lymphocyte Associated Antigen-4, Fas, and Tumour Necrosis Factor-α gene polymorphisms with autoimmune hepatitis risk, but the results were inconsistent and inconclusive. We performed a meta-analysis to better evaluate these associations.

METHODS

PubMed, EMBASE and MEDLINE were searched in all languages. Overall odd ratios with 95% confidence intervals were calculated to assess the strength of associations using a fixed-effects or random-effects models.

RESULTS

15 relevant studies were identified. No significant association was found between CTLA-4+49A/G and AH. TNF-α-308A/G was significantly associated with autoimmune hepatitis risk. Individuals with the "A" allele had a 67% increased risk of autoimmune hepatitis (odds ratio=1.67, 95% confidence interval 1.11-2.52). The genotype "AA" was a potential predisposing factor for autoimmune hepatitis, when compared with the genotype "GG" and "AG+GG" (odds ratio=2.71, 95% confidence interval 1.12-6.57; odds ratio=2.14, 95% confidence interval 1.30-3.52). Besides, no significant association was found between the Fas-670G/A and TNF-α-238A/G polymorphisms and autoimmune hepatitis risk using any model.

CONCLUSION

The meta-analysis identified the TNF-α-308 "A" allele as a predisposing factor for autoimmune hepatitis, whereas the genotype "GG" was a protective factor. This study did not find a significant association between CTLA-4+49A/G, Fas-670G/A, TNF-α-238A/G and susceptibility to autoimmune hepatitis.