Polymorphisms of chemokine receptor genes and clearance of hepatitis C virus infection in Chinese population

Study of CXCL9-11 gene polymorphisms in liver fibrosis among patients with chronic hepatitis C

Several factors are associated with the progression of chronic hepatitis C: comorbidities, lifestyle, and pathogenic factors, including immune response, apoptosis and heredity. Single nucleotide polymorphisms (SNPs) in the PNPLA3 and TM6SF2 genes are more widely studied genetic risk factors, while CXCL9-11 chemokines produced by hepatocytes in the process of infection are less well studied. Our aim was to evaluate the influence of CXCL9 rs10336, CXCL10 rs3921 and CXCL11 rs4619915 in liver fibrosis when analysed together with PNPLA3 rs738409 and TM6SF2 rs58542926. The study included 219 patients with chronic hepatitis C. SNP genotyping was performed by real-time PCR. Univariate and multivariate analyses were used to detect the association between SNPs and advanced fibrosis in a recessive genetic model. All SNPs had a minimum allele frequency >5%, and CXCL9 rs10336, CXCL10 rs3921 and CXCL11 rs4619915 were in high linkage disequilibrium (D' ≥ 0.84). In the multivariate analysis, we observed that male gender (P = 0.000), older age (P = 0.025), moderate to intense inflammatory activity (P = 0.002), moderate to accentuated hepatic steatosis (P = 0.026) and the CT genotype of the TM6SF2 rs58542926 SNP (P = 0.014) presented significant associations with advanced fibrosis. Overall, the CXCL9 rs10336, CXCL10 rs3921, CXCL11 rs4619915 and PNPLA3 rs738409 SNPs did not influence liver fibrosis among patients with chronic hepatitis C.

Association of CXCR2 genotype variations with HCV clearance in a Chinese population

Chemokines are known to play a vital role in guiding and regulating the immune response to viral infections. The chemokine CXC subfamily is a major subfamily in the chemokine family. Outcomes of hepatitis C virus (HCV) infection, as well as the response to treatment, depend on virus and host factors. Here we recruited chronic hepatitis C (CHC) patients to perform an association study between three single nucleotide polymorphisms (SNPs) (CXCR2 rs1126579, CXCL10 rs8878 and CXCL10 rs3921) and HCV infection outcomes and treatment responses among a Chinese population, using primarily a TaqMan assay. Multivariate logistic regression analysis was performed to identify the influencing factors on HCV infection outcome and treatment response. The results showed that subjects with the CXCR2 rs1126579 TT genotype had a significantly increased possibility of HCV spontaneous clearance (Dominant model: adjusted OR = 1.32, 95% CI = 1.06-1.64; P = 0.013). Additionally, CHC patients carrying the CXCR2 rs1126579 TT genotype were also more likely to achieve a sustained virological response (SVR) (Dominant model: adjusted OR = 0.49, 95% CI = 0.29-0.84; P = 0.010). We also established a predictive model for HCV treatment response including the CXCR2 rs1126579 SNP status, albumin (ALB) levels and baseline HCV RNA levels, which produced an area under the curve (AUC) of about 0.660. These findings highlight that variant CXCR2 rs1126579 genotypes are associated with HCV clearance within the Chinese population.

The association of CCL3 and CCL4 polymorphisms with HCV clearance in Chinese Han population

AIM

To explore the association of CCL3 (rs1063340) and CCL4 (rs1049807) polymorphisms with hepatitis C virus (HCV) clearance and sustained virologic response (SVR).

METHODS

Two populations were enrolled in the current study; one was a general population including 1585 untreated individuals, with HCV infection and the other was a treatment population comprising 353 HCV-infected patients treated with pegylated interferon-α and ribavirin (pegIFN-α/RBV). Two single nucleotide polymorphisms (SNPs) were genotyped, and the relationship between HCV clearance and treatment outcome was analysed.

RESULTS

The general population comprised 995 persistent HCV cases (both HCV RNA and anti-HCV were positive) and 590 spontaneous clearance cases (HCV RNA was negative, but anti-HCV was positive). An association between the SNPs and HCV clearance was not found in our study. The treatment population consisted of 235 patients who achieved SVR and 118 non-responders. Variants of both SNPs (rs1063340-C and rs1049807-G) were associated with a reduction in SVR following IFN treatment (dominant model: P = 0.026 for rs1063340 and P = 0.048 for rs1049807). In addition, the ancestral alleles of rs1063340 and rs1049807 increased the likelihood of virus clearance by 62% compared to both the derived and minor alleles of the two SNPs (P = 0.040).The interaction analysis showed that the level of glucose interacted with the association of rs1063340 and SVR.

CONCLUSIONS

Our results suggested that genetic variants at the CCL3 and CCL4 loci may be marker SNPs for risk of HCV treatment outcome.