Effect of the polymorphisms of tumor necrosis factor-α gene on the susceptibility to primary biliary cirrhosis: a meta-analysis

A Meta-Analysis of the Influence of Tumor Necrosis Factor-α-308 Gene Polymorphism on Liver Cirrhosis

Cirrhosis is an active hepatic inflammation process of the liver considered as the serious phase of different liver injuries. Epidemiological studies have evaluated the possible association between TNF-α-308G/A gene polymorphism and liver cirrhosis. In this study, we have furthered the study to assess the exact association of TNF-α-308G/A gene polymorphism with liver cirrhosis susceptibility by integrating all available data. Eligible case-control studies were carried out from the establishment of the project to September 2021. Published literature from multiple databases was retrieved, collected, and analyzed by two investigators independently. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for every study. Review Manager 5.2 and Stata 15.0 software were used for meta-analysis and stability was assessed by both subgroup analysis and sensitivity analysis. Begg's funnel plot and Egger's regression across the studies were also explored. We examined 22 case-control studies with 2683 cirrhosis patients and 2905 normal controls in four genetic models (GA vs. GG: OR = 0.95, 95%CI: (0.70, 1.30); AA vs. GG: OR = 1.11, 95% CI: (0.66, 1.85), GA + AA vs. GG: OR = 1.00, 95% CI: (0.73, 1.37); AA vs. GA + GG: OR = 1.07, 95%CI: (0.70,1.63)). TNF-α-308G/A gene polymorphism was relatively independent, and the results did not show a significant difference between the two groups. In the subgroup analysis by etiological classification of liver cirrhosis, cirrhosis after HCV infection was positively associated with the risk of TNF-α-308G/A polymorphism (AA vs. GG: OR = 3.02, 95% CI: (1.15, 7.88), AA vs. GA + GG: OR = 2.68, 95% CI: (1.04, 6.95)). The meta-analysis showed TNF-α-308G/A gene polymorphism might not have affected susceptibility for liver cirrhosis. Nevertheless, further and well-designed studies were needed to confirm the findings.

Tumour necrosis factor alpha (TNF-α) genetic polymorphisms and the risk of autoimmune liver disease: a meta-analysis

Epidemiological studies have evaluated the association between tumour necrosis factor alpha (TNF-α)- 308G/A and (TNF-α)- 238G/A polymorphisms, and the risk of autoimmune liver disease (AILD), yet the results are conflicting. To derive a more precise estimation of the relationship, we performed this meta-analysis. A systematic review was conducted to identify all eligible studies of TNF-α polymorphisms and AILD risk. We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the association between the two TNF-α polymorphisms and AILD risk. A total of 15 eligible studies were identified. Overall, positive associations of -308G/A polymorphism with AILD risk were found (A vs G allele: OR =1.45, 95%CI = 1.13- 1.86; AA vs GG: OR = 2.74, 95%CI = 1.51- 4.96; GA vs GG: OR = 1.46, 95%CI = 1.11- 1.92;dominant model: OR = 1.57, 95%CI = 1.18- 2.10; recessive model: OR = 2.22, 95%CI = 1.31- 3.76). In subgroup analysis by ethnicity, a significantly higher risk was found in Caucasians. In subgroup analysis by AILD category, significant association was observed in autoimmune hepatitis and primary sclerosing cholangitis, especially in Caucasians. Patients carrying TNF-α-238A allele had a slightly decreased risk of developing AILD (OR = 0.65, 95%CI = 0.48- 0.87). However, we found both TNF-α polymorphisms were not associated with primary biliary cirrhosis risk, even in subgroup analysis. Our meta-analysis suggests that the TNF-α-308G/A and -238G/A polymorphisms may contribute to AILD susceptibility in Caucasians,especially for autoimmune hepatitis and primary sclerosing cholangitis. Nevertheless, we found both TNF-α polymorphisms were unlikely to be associated with the risk of primary biliary cirrhosis

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.