Sex-specific association of estrogen receptor 2 polymorphisms with hepatitis C virus infection outcomes in a high-risk Chinese Han population

Impact of CYP2R1, CYP27A1 and CYP27B1 genetic polymorphisms controlling vitamin D metabolism on susceptibility to hepatitis C virus infection in a high-risk Chinese population

CYP27A1, CYP2R1 and CYP27B1 hydroxylases are involved in the synthesis of 1, 25-hydroxyvitamin D₃, which plays a role in the immune regulation and pathogenesis of hepatitis C virus (HCV) infection. The aim of the present study was to investigate the relationships between polymorphisms in vitamin D pathway genes and HCV infection outcomes in a Chinese population. Nine single-nucleotide polymorphisms (SNPs) of CYP27A1, CYP2R1 and CYP27B1 were genotyped in a high-risk Chinese population. The distributions of these SNPs were compared among groups with different outcomes of HCV infection, including 863 cases of persistent HCV infection, 524 cases of spontaneous clearance, and 1079 uninfected controls. The results showed that the CYP2R1 rs12794714-G, rs10741657-A, rs1562902-C, and rs10766197-G alleles were significantly associated with increased susceptibility to HCV infection (all P_FDR < 0.05, in additive/dominant models), and the combined effect of the four unfavorable alleles was related to an elevated risk of HCV infection in a locus-dosage manner (P_trend = 0.008). Moreover, haplotype analysis suggested that, compared with the most frequent haplotype (A_rs12794714G_rs10741657T_rs1562902A_rs10766197), the haplotype containing four unfavorable alleles, GACG, was associated with a higher risk of HCV infection. The results of our study suggest that genetic variants in CYP2R1 may be biomarkers for predicting the susceptibility to HCV infection in the Chinese population.

The Effect of Female Sex on Hepatitis C Incidence Among People Who Inject Drugs: Results From the International Multicohort InC3 Collaborative

Background

The objective of this study was to assess differences in hepatitis C virus (HCV) incidence by sex in people who inject drugs (PWID), using a large international multicohort set of pooled biological and behavioral data from prospective observational studies of incident human immunodeficiency virus (HIV) and HCV infections in high-risk cohorts (the InC3 Collaborative).

Methods

HCV infection date was estimated based on a hierarchy of successive serological (anti-HCV), virological (HCV RNA), and clinical (symptoms and/or liver function tests) data. We used a Cox proportional hazards model to calculate the crude and adjusted female to male (F:M) hazard ratio (HR) for HCV incidence using biological sex as the main exposure.

Results

A total of 1868 PWID were observed over 3994 person-years of observation (PYO). Unadjusted F:M HR was 1.38 (95% confidence interval [CI], 1.15-1.65) and remained significant after adjusting for behavioral and demographic risk factors (1.39 [95% CI, 1.12-1.72]). Although syringe and equipment sharing were associated with the highest HCV incidence rate in women (41.62 and 36.83 PYO, respectively), we found no sex differences attributed to these risk factors.

Conclusions

Our findings indicate that women who inject drugs may be at greater risk of HCV acquisition than men, independent of demographic characteristics and risk behaviors. Multiple factors, including biological (hormonal), social network, and differential access to prevention services, may contribute to increased HCV susceptibility in women who inject drugs.

The association of LMP7 and TAP2 gene polymorphisms with treatment response to interferon/ribavirin in patients with genotype 1 chronic hepatitis C

Previous studies have highlighted the important role of genes related to antigen presentation in the spontaneous clearance of hepatitis C virus. The present study aimed to explore the association between TAP, LMP and tapasin gene polymorphism and treatment response in chronic hepatitis C virus (CHC) patients. Six single nucleotide polymorphisms in TAP, LMP and tapasin genes were genotyped among 352 Chinese genotype 1 CHC patients with pegylated interferon-α and ribavirin (pegIFN-α/RBV) treatment. There were 232 cases achieving sustained virological response (SVR), which yielded an SVR rate of 65.9%. LMP7 rs2071543 variant genotypes [additive model: odds ratio (OR), 0.52; 95% confidence interval (CI), 0.33-0.82; P=0.005] and TAP2 rs1800454 variant genotypes (additive model: OR, 0.66; 95% CI, 0.45‑0.98; P=0.039) were suggested to decrease the possibility of achieving an SVR. After conducting combined effect analysis of rs2071543 and rs1800454, the authors found that the SVR rate was lower among patients carrying more unfavorable rs1800454-A and rs2071543-A alleles, and the SVR rate of carrying 3-4 alleles was 20%. In addition, carrying two unfavorable alleles led to significantly decreased possibility for SVR (OR, 0.30; 95% CI, 0.14-0.61; P=0.001). Multivariate stepwise analysis indicated that rs2071543, rs1800454, glucose, α-fetoprotein, platelets and baseline viral load were risk factors of SVR that were independent of each other. The area under the curve (AUC) consisting of all the above factors produced an AUC of 0.704 (95% CI, 0.647‑0.761; P<0.001). The line charts indicated that the drop in viral load was significantly faster in GG patients than in GC/CC patients during the whole therapy, which was in accordance with the decline of viral load in rs2071543. The present study illustrated that the carriage of LMP7 rs2071543-AA and TAP2 rs1800454-AA had a negative effect on treatment response to pegIFN-α/RBV among genotype 1 patient with CHC in a Chinese Han population.

Higher incidence of HCV in females compared to males who inject drugs: A systematic review and meta-analysis

Women who inject drugs have been shown to have higher incidence of HIV and risk behaviours than men, but there are conflicting reports about hepatitis C virus (HCV) incidence. We systematically reviewed the literature to examine the female-to-male (F:M) HCV incidence in female and male persons who inject drugs (PWID), and also to explore the heterogeneity (i.e. methodological diversity) in these differences. We searched PubMed and EMBASE for studies published between 1989 and March 2015 for research that reported incidence of HCV infection by sex or HCV incidence F:M rate ratio. A total of 28 studies, which enrolled 9325 PWID, were included. The overall pooled HCV incidence rate (per 100 person-years observation) was 20.36 (95% CI: 13.86, 29.90) and 15.20 (95% CI: 10.52, 21.97) in females and males, respectively. F:M ratio was 1.36:1 (95% CI: 1.13, 1.64) with substantial heterogeneity (I-squared=71.6%). The F:M ratio varied by geographic location from 4.0 (95% CI: 1.80, 8.89) in China to 1.17 (95% CI: 0.95, 1.43) in the U.S. In studies which recruited participants from community settings, the F:M ratio was 1.24 (95% CI: 1.03, 1.48), which was lower than that reported in the clinical settings (1.72, 95% CI: 0.86, 3.45). The number of studies included provided sufficient statistical power to detect sex differences in this analysis. Our findings raise questions and concerns regarding sex differences with respect to the risk of HCV. Both behavioural and biological studies are needed to investigate causes and potential mechanisms as well as sex-specific prevention approaches to HCV infection.