Interleukin-28B genetic variations and spontaneous clearance of hepatitis C antibody-positive blood donors in China

Feasibility of Hepatitis C Elimination in China: From Epidemiology, Natural History, and Intervention Perspectives

Hepatitis C imposes a heavy burden on many countries, including China, where the number of reported cases and the incidence of hepatitis C virus (HCV) increased yearly from 2005 to 2012, with a stable trend after 2012. The geographical distribution of HCV infections varies widely in China, with the northwest and southwest regions and the Henan Province showing a high disease burden. Elderly, men, sexually active people, drug users, migrants, blood transfusion recipients, and renal dialysis patients have become the target populations for hepatitis C prevention and control. It is important to improve the diagnosis rate in high-risk groups and asymptomatic people. Identifying secondary HCV infections, especially in HCV patients co-infected with the human immunodeficiency virus (HIV) is a priority of hepatitis C prevention and control. Enhancing universal access to direct antiviral agents (DAAs) treatment regimens is an effective way to improve the cure rate of HCV infection. For China to contribute to the WHO 2030 global HCV elimination plan, strategic surveillance, management, and treatment program for HCV are needed.

An outbreak of HCV genotype 6a and 2a infection in South China: Confirmation of iatrogenic transmission by phylogenetic analysis of the NS5B region

An outbreak of hepatitis C virus (HCV) infections, for which the risk factor was unknown, was previously identified in North Guangdong, China. In the present study, a total of 736 local residents were surveyed regarding their lifetime risk factors for HCV infection. Serum anti‑HCV antibodies and HCV RNA were examined to confirm infection. In the HCV‑positive samples, the core and nonstructural protein 5B sequences were amplified, and phylogenetic analysis was performed to determine the association between HCV subtypes and transmission routes. A total of 374 individuals were positive for anti‑HCV antibodies. Blood transfusion, blood product transfusion, people who inject drugs and intravenous injection at a local clinic were identified as independent risk factors for HCV infection. Phylogenetic analysis revealed that the two predominant subtypes of HCV, 2a and 6a, were primarily focused in four homologous clusters. Patients with a history of intravenous injection at a local clinic were more likely to be found in the four clusters, compared with patients exposed to other risk factors. The present emergency retrospective survey showed a specific epidemiological feature of HCV infection in Zijin County and found genetic homology among individuals exposed to intravenous injection at a local clinic. Further evidence is required to confirm the causal association between the outbreak of HCV infection and intravenous injection.

Association with Spontaneous Hepatitis C Viral Clearance and Genetic Differentiation of IL28B/IFNL4 Haplotypes in Populations from Mexico

AIM

To analyze the genetic heterogeneity of the Amerindian and admixed population (Mestizos) based on the IL28B (rs12979860, rs8099917) and IFNL4 (rs368234815) haplotypes, and their association with spontaneous clearance (SC) and liver damage in patients with hepatitis C infection from West Mexico.

METHODS

A total of 711 subjects from West Mexico (181 Amerindians and 530 Mestizos) were studied for the prevalence of IL28B (rs12979860C/T, rs8099917G/T) and IFNL4 (rs368234815∆G/TT) genotypes. A case-control study was performed in 234 treatment-naïve HCV Mestizos (149 chronic hepatitis C and 85 with SC) for the association of haplotypes with SC and liver damage. A real-time PCR assay was used for genotyping, and transitional elastography staged liver damage.

RESULTS

Significant Fst-values indicated differentiation between the studied populations. The frequencies of the protective C, T, TT alleles were significantly lower in the Amerindians than in Mestizos (p<0.05). The r2 measure of linkage disequilibrium was significant for all variants and the T/G/ΔG risk haplotype predominated in Amerindians and secondly in Mestizos. The protective C/T/TT haplotype was associated with SC (OR = 0.46, 95% IC 0.22-0.95, p = 0.03) and less liver damage (OR = 0.32, 95% IC 0.10-0.97, p = 0.04) in chronic patients. The Structure software analysis demonstrated no significant differences in ancestry among SC and chronic patients.

CONCLUSIONS

West Mexico's population is genetically heterogeneous at the IL28B/IFNL4 polymorphisms. The T/G/ΔG high-risk haplotype predominated in Amerindians and the beneficial alternative haplotype in Mestizos. The C/T/TT haplotype was associated with SC and less liver damage in chronically infected Mestizo patients.

Association of Hepatitis C Virus Infection and Interleukin-28B Gene Polymorphism in Chinese Children

Objective: To preliminarily explore the association of rs12979860 and rs8099917 SNPs with chronic HCV infection in Chinese Han children.

Methods: Chronic HCV infection patients (n=277; 1-17 years old, 4.5 years old in average) and healthy subjects (n=150, children; 2-17 years old, 5.2 years old in average) were recruited and tested by PCR combining direct sequencing. The differences between the rs12979860 and rs8099917 genotypes in patients and healthy subjects were compared.

Results: The genetic variations at rs12979860 and rs8099917 in chronic hepatitis C (CHC) children and healthy subjects did not differ significantly. The frequency of spontaneous clearance in CHC children was higher (47%), which is related to the genetic variations. The histological changes of patients were more significant compared to their clinical and biochemical indices, but they did not correlate with the genetic mutations at rs12979860 and rs8099917 significantly.

Conclusion: The rs12979860 and rs8099917 SNPs are independent factors predicting the spontaneous clearance of Chinese CHC children patients. The correlation between diseases outcomes are in need of further study.