Relationship between interleukin-6 polymorphism and susceptibility to chronic hepatitis B virus infection

To identify the relationship between tag single nucleotide polymorphisms (tag SNPs) of interleukin-6 (IL-6) gene and susceptibility to chronic hepatitis B virus (HBV) infection in a Han Chinese population.

We performed a case-control study of 501 Chinese patients with chronic HBV infection and 301 self-limiting HBV-infected individuals as controls. Genomic DNA was isolated from the whole blood of all subjects using phenol/chloroform with MaXtract high-density tubes. Tag SNPs were identified using genotype data from the panel (Han Chinese in Beijing) of the phase II HapMap Project. Four tag SNPs in IL-6 (rs17147230A/T, rs2066992G/T, rs2069837A/G and rs2069852A/G) were genotyped by the Multiplex Snapshot technique. The genotype and allele frequencies were calculated and analyzed.

Five haplotypes were involved in the analysis, with frequencies higher than 0.03. One of the haplotypes, TTAA, was significantly different between the two groups. Overall haplotype P values were: ATAA, P = 0.605, OR (95%CI) = 1.056 (0.860-1.297); TGAG, P = 0.385, OR (95%CI) = 1.179 (0.813-1.709); TGGG, P = 0.549, OR (95%CI) = 1.087 (0.827-1.429); TTAA, P = 0.004, OR (95%CI) = 0.655 (0.491-0.873); TTAG, P = 0.266, OR (95%CI) = 1.272 (0.832-1.944). However, the four SNPs showed no significant genotype/allele associations with susceptibility to chronic HBV infection. Overall allele P values were: rs17147230, P = 0.696, OR (95%CI) = 1.041 (0.850-1.276); rs2066992, P = 0.460, OR (95%CI) = 1.090 (0.868-1.369); rs2069837, P = 0.898, OR (95%CI) = 0.983 (0.759-1.274); rs2069852, P = 0.165, OR (95%CI) = 0.859 (0.693-1.064). Overall genotype P values were: rs17147230, P = 0.625; rs2066992, P = 0.500; rs2069837, P = 0.853; and rs2069852, P = 0.380.

The four tag SNPs of IL-6 gene may be associated with susceptibility to chronic HBV infection in the Han Chinese population.