Brief Article
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World J Gastroenterol. Oct 28, 2013; 19(40): 6888-6893
Published online Oct 28, 2013. doi: 10.3748/wjg.v19.i40.6888
Relationship between interleukin-6 polymorphism and susceptibility to chronic hepatitis B virus infection
Xiao-Miao Zhao, Yu-Feng Gao, Qin Zhou, Fa-Ming Pan, Xu Li
Xiao-Miao Zhao, Qin Zhou, Xu Li, Department of Infectious Diseases, The First Affiliated Hospital of Anhui Medical University, Hefei 230032, Anhui Province, China
Yu-Feng Gao, Department of Hepatopathy, The Second Affiliated Hospital of Anhui Medical University, Hefei 230601, Anhui Province, China
Fa-Ming Pan, Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei 230032, Anhui Province, China
Author contributions: Zhao XM and Gao YF contributed equally to this work; Zhao XM and Gao YF wrote the manuscript; Zhao XM ,Gao YF and Zhou Q performed the majority of experiments; Gao YF designed the study; Pan FM did the data analysis; and Li X provided the financial support for this work.
Supported by Grants from the National Natural Science Foundation of China, No. 81072342
Correspondence to: Xu Li, Professor, Department of Infectious Diseases, The First Affiliated Hospital of Anhui Medical University, 218 Jixi Road, Hefei 230032, Anhui Province, China. aaylixu@qq.com
Telephone: +86-551-2922912 Fax: +86-551-2922912
Received: August 5, 2013
Revised: September 6, 2013
Accepted: September 16, 2013
Published online: October 28, 2013
Processing time: 99 Days and 16.9 Hours
Abstract

AIM: 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.

METHODS: 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.

RESULTS: 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.

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

Keywords: Chronic hepatitis B virus infection, Interleukin-6, Single nucleotide polymorphism, Genetic susceptibility, Haplotype

Core tip: This study included a large number of subjects with a single ethnic background (Chinese). This would further add to the statistical power of the analysis and identify more single nucleotide polymorphisms. We selected self-limiting hepatitis B virus-infected subjects, but not unexposed subjects as controls, therefore, our results may be more reliable than other studies that recruited blood donors as controls. In addition, we included only antiviral-naive subjects.