Polymorphisms of interleukin-1β in Japanese patients with hepatitis B virus infection

Background/Aims Hepatitis B virus (HBV) induces liver cirrhosis (LC) and hepatocellular carcinoma (HCC) mainly by causing chronic necro-inflammatory hepatic disease. Our aim was to investigate the relationships between the polymorphisms of the interleukin-1B (IL-1B) promoter region and the interleukin-1 receptor antagonist gene (IL-1RN) and disease progression in an HBV-infected Japanese population. Methods Genomic DNA was extracted from the peripheral blood of 237 HBV carriers. Polymorphisms in IL-1B and IL-1RN were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and PCR with confronting two-pair primers (PCR-CTPP) methods. These polymorphic sites include the promoter regions of IL-1B at positions −511 and −31, and IL-1RN variable tandem repeats. Results The IL-1B −31 and −511 loci were in complete linkage disequilibrium, and the frequency of the IL-1B −31 T carrier (IL-1B −31 T/T or T/C) was significantly higher in HBV carriers with LC compared to those without LC (LC; 86.1% vs non-LC; 72.1%, P = 0.009). There was no difference in the genotype distribution of the IL-1RN polymorphism. Conclusions This is the first report describing the association between IL-1B polymorphism and HBV-related hepatic fibrosis, and our data suggest that IL-1B polymorphisms may be related to disease progression of HBV-related hepatitis in Japan.