The tumour necrosis factor-α-238A allele increases the risk of chronic HBV infection in European populations.

Tumour necrosis factor-α (TNF-α) plays a pivotal role in viral clearance and host immune response to hepatitis B virus (HBV) infection, of which the production capacity in individuals is demonstrated to be influenced by a single nucleotide polymorphism within the promoter region of TNF-α genes. However, there have been conflicting results reported in previous studies on TNF-α-238 and TNF-α-863 gene promoter polymorphisms in chronic HBV infection. To derive a more precise estimation of their relationship, we searched Pubmed (January, 1966-August, 2010) and China Biological Medicine Database (January, 1978-August, 2010) and carried out a meta-analysis involving nineteen studies that included 5245 chronic HBV infection cases and 3181 controls describing G238A genotypes, and eleven studies totalling 3576 cases and 2044 controls describing C863A genotypes. The overall meta-analysis did not suggest significant associations of TNF-α-238 and TNF-α-863 gene promoter polymorphisms with chronic HBV infection. However, in subgroup analysis by ethnicity, it indicated that TNF-α-238A allele carriers (GA + AA) in European populations had an increased risk of developing chronic HBV infection (OR = 2.22, 95% CI: 1.07-4.58, P = 0.032; OR = 4.46, 95% CI: 1.75-11.38, P = 0.002, respectively), when compared with spontaneous recovered and healthy populations, respectively. However, no significant associations were found in Asian populations in all genetic models. So, we draw the conclusion that the TNF-α-238A allele may increase the risk of chronic HBV infection in European populations.