Case Control Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Apr 14, 2015; 21(14): 4232-4239
Published online Apr 14, 2015. doi: 10.3748/wjg.v21.i14.4232
Interleukin-21 gene polymorphisms and chronic hepatitis B infection in a Chinese population
Jia-Yan Yao, Kang Chao, Min-Rui Li, Yan-Qing Wu, Bi-Hui Zhong
Jia-Yan Yao, Kang Chao, Min-Rui Li, Yan-Qing Wu, Bi-Hui Zhong, Department of Gastroenterology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, Guangdong Province, China
Author contributions: Yao JY wrote the manuscript and performed the data analysis; Yao JY, Li MR and Wu YQ performed the majority of experiments; Chao K and Yao JY designed the research; Zhong BH revised the paper.
Supported by National Natural Science Foundation of China, No. 81170392.
Ethics approval: The study was reviewed and approved by the First Affiliated Hospital of Sun Yat-Sen University Institutional Review Board.
Informed consent: All study participants, or their legal guardian, provided informed written consent prior to study enrollment.
Data sharing: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Bi-Hui Zhong, MD, PhD, Division of Gastroenterology, The First Affiliated Hospital of Sun Yat-Sen University, No. 58 Zhongshan Road II, Guangzhou 510080, Guangdong Province, China. sophiazhong@medmail.com.cn
Telephone: +86-20-87755766 Fax: +86-20-87332916
Received: October 30, 2014
Peer-review started: October 31, 2014
First decision: November 26, 2014
Revised: December 19, 2014
Accepted: February 16, 2015
Article in press: February 16, 2015
Published online: April 14, 2015
Abstract

AIM: To investigate the relationship between interleukin-21 (IL21) gene polymorphisms and chronic hepatitis B virus (HBV) infection in a Chinese population.

METHODS: In this case-control study, 366 Chinese HBV-infected patients were recruited and divided into hepatocellular carcinoma (HCC; n = 94) and non-HCC (n = 272) groups at The First Affiliated Hospital of Sun Yat-Sen University, from April 2009 to December 2012. In the non-HCC group, the patients were classified into three clinical subsets, 76 patients had chronic hepatitis B, 101 were HBV carriers and 95 patients had HBV-related cirrhosis. Two hundred eight unrelated healthy controls were also included. Genomic DNA was extracted from peripheral blood. Single nucleotide polymorphisms (SNPs) rs13143866, rs2221903, and rs907715 were subsequently genotyped using the SNaPshot SNP technique.

RESULTS: There were no significant differences in allele and genotype frequencies of SNPs rs13143866, rs2221903, and rs907715 between chronic HBV-infected patients and control subjects. Furthermore, no significant differences were found in the frequencies of all alleles and genotypes between the HCC group and the non-HCC group. However, in the subgroup analysis, IL21 rs13143866 genotype AA frequency in the HBV carrier group was higher than in controls (OR = 6.280, 95%CI: 1.238-31.854; P = 0.019), and the effect of the recessive model (AA vs GG + GA, OR = 6.505, 95%CI: 1.289-32.828) was observed in the HBV carrier group. IL21 rs2221903 genotype TC frequency in the HBV carrier group was higher than in controls (OR = 1.809, 95%CI: 1.043-3.139; P = 0.035). In the haplotype analysis, the ATA haplotype (rs13143866, rs2221903, and rs907715) of IL21 was more frequent in the HCC group than in the non-HCC group (0.165 vs 0.104, P = 0.044; OR = 1.700, 95%CI: 1.010-2.863).

CONCLUSION: Genotypes rs13143866 AA and rs2221903 TC are risk factors for carrying HBV; ATA haplotype increases the risk of HBV-related HCC onset in a Chinese population.

Keywords: Chinese population, Chronic hepatitis B virus infection, Interleukin-21 gene, rs13143866, rs2221903, rs907715, Single-nucleotide polymorphism

Core tip: This study is the first to investigate the relationship between single nucleotide polymorphism rs13143866 of the interleukin-21 gene and chronic hepatitis B virus (HBV) infection in a Chinese population. We found that genotypes rs13143866 AA and rs2221903 TC were risk factors for carrying HBV, and the ATA haplotype (rs13143866, rs2221903 and rs907715) increased the risk of HBV-related hepatocellular carcinoma.