Association Of Cytokine Gene Polymorphisms With The Susceptibility Of HBV-related Hepatic Cirrhosis

Background and Objective: Only limited patients with chronic hepatitis B virus (HBV) infection will finally develop hepatic cirrhosis. Except environmental and viral factors, the host genetic immune background is closely associated with cirrhosis development. There are many reports about the association of cytokine gene polymorphisms with the clinical outcomes of HBV infection, in which only a few reports are involved in the susceptibility of HBV-related hepatic cirrhosis and also lack of systematic research. The aims of our study were to detect eight gene polymorphisms in five cytokine genes and systematically analyze the relationship between them and the susceptibility of HBV-related hepatic cirrhosis, and screen out the mainly related gene polymorphisms for our future studies about the molecule prediction of the cirrhosis risk in chronic HBV infectors.Methods:(1) Subjects: 165 HBV infectors with cirrhosis (case group) and 136 asymptomatic HBsAg carriers (control group) were recruited for the study.(2) Gene polymorphism analysis: Genomic DNA was extracted from the peripheral blood by phenol-chloroform method. The genotypes of IL-1α(-889), IL-1β(-511, +3953), IL-10 (-592), TNF-α(-308, -238) and IFN-γ(+884, +2109) genes were determined by PCR-RFLP or PCR-SSP.(3) Data analysis: The genotype and allele frequencies in each site were calculated and their differences between two groups were compared by chi-square test. The Hardy-Weinberg equilibriums of genotypes in each site were verified by chi-square test. The OR and its 95%CI of each genotype and allele were calculated by univariate Logistic regression analysis in total sample and gender-stratified sub-samples. The independent risk and protective genotypes and alleles were screened out by multivariate Logistic regression analyses.Results:(1) The differences of all genotype and allele frequencies at positions -308G/A and -238G/A of TNF-αgene were not significant between case group and control group (P>0.10). Univariate and multivariate Logistic regression analyses did not showed that these genotypes and alleles were associated with the susceptibility of HBV-related hepatic cirrhosis.(2) The differences of all genotype and allele frequencies at position -889C/T of IL-1αgene were not significant between case group and control group (P>0.10). However, multivariate Logistic regression analysis indicated that this polymorphism site was associated with the susceptibility of cirrhosis, in which genotype CC is a protect genotype (OR=0.416,P=0.040) and allele T is the risk allele (OR=2.361,P=0.044).(3) The differences of all genotype and allele frequencies at positions -511C/T and +3953C/T of IL-1β-889C/T were not significant between case group and control group (P>0.10). But multivariate analysis indicated -511C/T site was associated with the male cirrhosis susceptibility, in which CC was a risk genotype (OR=2.719, P=0.036) and T was a protective allele (OR=0.411, P=0.056), while +3953C/T site might be associated with female cirrhosis susceptibility, the ORs of genotype CC, CT and allele T nearly significant (P=0.071).(4) The differences of all genotype and allele frequencies at position -592A/C of IL-10 gene were not significant between case group and control group (P>0.10). Univariate analysis indicated the genotype AC and the allele C might be associated with cirrhosis, their ORs nearly significant (P=0.077, 0.057). Multivariate analysis confirmed that AC was a risk genotype (OR=1.795, P=0.048), and C was a risk allele (OR=1.755, P=0.046). Multivariate analysis in gender-stratified sub-samples indicated that this site was mainly associated with the male cirrhosis susceptibility, in which AC was a risk genotype (OR=2.865, P=0.006), C was a risk allele (OR=2.665, P=0.012).(5) The frequencies of genotype TT and TA of IFN-γ+874 site were significant between case group and control group (P=0.038, 0.023). Univariate analysis indicated that genotype TT and TA and allele A might be associated with liver cirrhosis, their ORs nearly significant (P=0.064, 0.080 and 0.057), but those were not confirmed in multivariate analysis. The differences of all genotype and allele frequencies at position +2109 A/G of IFN-γgene were not significant between case group and control group (P>0.10). Multivariate analyses also indicated that there were not associated with the susceptibility of HBV-related hepatic cirrhosis.(6) Multivariate analyses showed that some genotypes or alleles in sites IL1α-889, IL1β-511, IL-10 -592 and INF +2109 were associated with the HBV-related cirrhosis susceptibility in male patients (P=0.006~0.093), but did not show significant genotypes or alleles in female patients, only INF +2109 AA was probably associated with female susceptibility of HBV-related hepatic cirrhosis (P=0.071).Conclusions:(1) Both of the gene polymorphism sites -238G/A and -308G/A of TNF-αare not associated with the susceptibility of HBV-related hepatic cirrhosis.(2) The gene polymorphisms of IL-1α-889C/T site are associated with the susceptibility of HBV-related hepatic cirrhosis, and they are independent related factors.(3) The gene polymorphisms of IL-1β-511C/T and +3953C/T sites are associated with the susceptibility of HBV-related hepatic cirrhosis, in which, -511C/T site is related to male susceptibility of HBV-related hepatic cirrhosis, and +3953C/T site may related to female susceptibility of HBV-related hepatic cirrhosis.(4) The gene polymorphisms of -592A/C of IL-10 are associated with the susceptibility of HBV-related hepatic cirrhosis, especially in male patients.(5) The gene polymorphisms of +874T/A of IFN-γare associated with the susceptibility of HBV-related hepatic cirrhosis, but it is not independent related factors. The gene polymorphisms of +2109A/G of IFN-γare probably associated with the male susceptibility of HBV-related hepatic cirrhosis.(6) Cytokine gene polymorphisms are closely associated with male susceptibility of HBV-related hepatic cirrhosis, but not with female susceptibility. This may be an explanation for HBV-related cirrhosis more frequent in male than female.