A novel polymorphism near HLA class II region is associated with spontaneous clearance of HCV and response to interferon treatment in Chinese patients

Like a Rolling Stone? A Review on Spontaneous Clearance of Hepatitis C Virus Infection

Elimination of hepatitis C virus (HCV) without the need for medical intervention, known as spontaneous clearance (SC), occurs at a significantly lower rate than in the case of hepatitis B virus infection and only in selected individuals, such as reportedly in Keith Richards, a guitarist of The Rolling Stones. The present paper provides an updated narrative review of the research devoted to the phenomenon in order to identify and discuss the demographic, lifestyle-related, clinical, viral genotype-related, and host genetic factors underpinning the SC occurrence. The body of evidence indicates that the likelihood of SC is decreased in older individuals, men, Black people, HIV-coinfected subjects, and intravenous drug and alcohol users. In turn, HBV coinfection and specific polymorphism of the genes encoding interferon lambda 3 (particularly at rs8099917) and interferon lambda 4 (particularly at rs12979860) and HLA genes increase the odds of SC. Numerous other host-specific genetic factors could be implicated in SC, but the evidence is limited only to certain ethnic groups and often does not account for confounding variables. SC of HCV infection is a complex process arising from a combination of various factors, though a genetic component may play a leading role in some cases. Understanding factors influencing the likelihood of this phenomenon justifies better surveillance of high-risk groups, decreasing health inequities in particular ethnic groups, and may guide the development of a prophylactic vaccine, which at present is not available, or novel therapeutic strategies. Further research is needed to elucidate the exact mechanisms underlying SC and to explore potential interventions that could enhance this natural antiviral response.

Genetic Factors That Affect Spontaneous Clearance of Hepatitis C or B Virus, Response to Treatment, and Disease Progression

Hepatitis C virus (HCV) and hepatitis B virus (HBV) infections can lead to cirrhosis, end-stage liver disease, and hepatocellular carcinoma. Over the past decade, studies of individuals infected with these viruses have established genetic associations with the probability of developing a chronic infection, risk of disease progression, and likelihood of treatment response. We review genetic and genomic methods that have been used to study risk of HBV and HCV infection and patient outcomes. For example, genome-wide association studies have linked a region containing the interferon lambda genes to spontaneous and treatment-induced clearance of HCV. We review the genetic variants associated with HCV and HBV infection, and how these variants affect specific expression or activities of their products. Further studies of these variants could provide insights into risk factors for and mechanisms of chronic infection and disease progression, as well as new strategies for treatment.

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.

Influence of IL28B and MxA gene polymorphisms on HCV clearance in Han Chinese population

The high rate of chronic hepatitis C (CHC) was one of the key issues of global public health concern. Interferon (IFN)-λ relevant genes were in the antiviral treatment pathway, not only influenced hepatitis C virus (HCV) spontaneous clearance, but also affected the IFN-mediated viral clearance. The aim of this study was to identify the association of interleukin 28B (IL28B), myxovirus resistance A (MxA) gene polymorphisms with HCV spontaneous clearance and therapeutic response in Chinese CHC patients. IL28B and MxA gene genotypes were detected among 231 CHC carriers, 428 subjects with HCV spontaneous clearance and 662 CHC patients with pegylated IFN-α and ribavirin (pegIFN-α/RBV) treatment. Patients with MxA rs2071430 TT genotype were more likely to develop HCV infection chronicity (additive model: odds ratio (OR) 1.22, 95% confidence interval (CI) 1.01-1.48, P = 0.042). IL28B rs1298075 variant genotypes (additive model: OR 0.58, 95% CI 0.34-0.98, P = 0.040) and MxA rs17000900 variant genotypes (additive model: OR 0.54, 95% CI 0.30-0.99, P = 0.048) were less likely to achieve a sustained virological response. The life table indicated that patients with IL28B rs1298075 AG genotype were slower to achieve a viral load 106 copies/ml (all P < 0.05). This study illustrated that the carriage of IL28B rs12980275 AA had a positive effect on treatment response to pegIFN-α/RBV among Chinese CHC patients.

Association of interferon lambda polymorphisms with elevated baseline viral loads in chronic hepatitis C virus genotype 6 infection

Globally, hepatitis C virus (HCV) is one of the major causes of hepatocellular carcinoma and liver cirrhosis. For clinical decision making, genetic variation in the interferon-λ (IFNL) cluster has been utilised as a baseline predictor of natural and interferon-based treatment-induced viral clearance. In Vietnam, where HCV genotypes 1 (g1) and g6 predominate, no prior studies have been conducted investigating associations of IFNL3/4 polymorphisms with spontaneous clearance (SC) or HCV viral load (VL) in chronic infection. In this study, we have investigated the host genetic variations in IFNL loci to determine the association of IFNL3/4 polymorphisms with HCV SC and baseline VLs in a Vietnamese HCV-seropositive cohort. The majority of the cohort harboured major homozygous polymorphisms in IFNL3/4 cluster (i.e. rs12979860-CC: 82.7%; rs8099917-TT: 84.8% and rs368234815-TT/TT: 85.5%) and the SC rates in these groups were 15.8%, 16.3% and 15.7%, respectively. In the minor allele groups, the resolution rates were lower (12% in rs12979860 non-CC, 9.1% in rs8099917 non-TT and 9.5% in rs368234815 non-TT/TT). Furthermore, in individuals harbouring minor alleles, females achieved higher SC rates than males. HCV g6-infected rs12979860 major homozygous individuals had significantly higher viral loads than individuals with minor alleles (CC: 6.56 log IU/ml vs. non-CC: 5.66 log IU/ml; P = 0.021). The association between IFNL3/4 genotypes with elevated HCV VL observed in HCV g6-infected individuals may have implications for the progression of liver disease in Southeast Asian countries where this viral genotype predominates and therefore warrants further studies.

The impact of genetic variation in IL28B, IFNL4 and HLA genes on treatment responses against chronic hepatitis C virus infection

Single nucleotide polymorphisms (SNPs) near the interleukin-28B (IL28B), interferon lambda 4 (IFNL4) and the human leukocyte antigen (HLA) gene are associated with treatment responses in patients with chronic hepatitis C (CHC) virus infection treated with pegylated interferon-α and ribavirin (pegIFN-α/RBV). We compared the role of IL28B SNPs (rs12979860, rs12980275, and rs8099917), IFNL4 ss469415590 and HLA rs4273729 with treatment outcomes in patients with CHC virus. A total of 520 Iranian patients with CHC infection were enrolled. SNPs in IL28B, IFNL4 ss469415590 and HLA rs4273729 were genotyped by PCR-restriction fragment length polymorphism, TaqMan® Real-Time PCR and direct sequence. Out of 520 CHC treatment-naive patients, 42.9% were infected with HCV-1a, 15.4% with HCV-1b, 9.8% with HCV-2, and 31.9% with HCV-3a. Rapid virologic response (RVR), complete early virologic response (cEVR), and sustained virologic response (SVR) were 53.3%, 73.8%, and 66.7%, respectively. Multivariate logistic regression analysis showed that IL28B rs12980275 and IFNL4 ss469415590 in all HCV genotypes were associated with RVR. In addition, IL28B rs12979860 and RVR in all HCV genotypes and IL28B rs12980275, IFNL4 ss469415590, and HLA rs4273729 in HCV subtypes 1a, 1b, and 3a correlated with cEVR. In patient's achieving-SVR, IL28B rs12980275, and RVR in all HCV genotypes and IL28B rs12979860, IFNL4 ss469415590, and HLA rs4273729 in HCV subtypes 1a, 1b, and 3a were the powerful predictor factors. As the first report of its kind published in Iran, we indicated that beside IL28B SNPs and HLA rs4273729, IFNL4 ss469415590 was a powerful predictor factor for RVR, cEVR and SVR. Genotyping these SNPs may be a helpful priority in the treatment of patients with HCV infection, especially in countries where access to triple or double therapy with a viral protease inhibitor is limited.

IL28B rs12980275 and HLA rs4273729 genotypes as a powerful predictor factor for rapid, early, and sustained virologic response in patients with chronic hepatitis C

Single-nucleotide polymorphisms (SNPs) in the Interleukin-28B (IL28B) gene and rs4273729 in the human leukocyte antigen (HLA) gene in chronic hepatitis C (CHC) virus infection are important for predicting treatment outcome. In this study, the distribution of IL28B SNPs (rs12979860 and rs12980275) and HLA rs4273729 in rapid virologic response (RVR), complete early virologic response (cEVR) and sustained virologic response (SVR) in HCV Iranian patients with CHC virus infection was assessed. IL28B genotyping and rs4273729 were performed using the amplification refractory mutation system (ARMS)-PCR and direct sequencing in 190 CHC virus infections, respectively. RVR, cEVR, and SVR were 53.2 %, 78.9 %, and 65.8 %, respectively. Multivariate regression analysis demonstrated that the responses significantly predicted SVR in patients with age <40 years (p = 0.008), HCV genotypes (p = 0.032), IL28B rs12979860 CC genotype (p < 0.001), rs12980275 AA genotype (p < 0.001), rs4273729 GG genotype (p < 0.001), RVR (p < 0.001) and cEVR (p = 0.024). Three critical predictor factors based on RVR response were rs12979860 CC genotype (p = 0.033), rs12980275 AA genotype (p < 0.001) and rs4273729 GG genotype (p < 0.001), while rs12980275 AA (p = 0.003) and rs4273729 GG genotypes (p < 0.001) predicted cEVR. For the first time in Iran, these results revealed that the rs12980275 and HLA rs4273729 are important for the treatment of CHC infection. These findings may help predict responses to CHC infection treatment and reduce the cost and side effects of therapy.

A systematic review of treatment response rates in Pakistani hepatitis C virus patients; current prospects and future challenges

BACKGROUND

The estimated hepatitis C virus (HCV) carriers are approximately 10 million in Pakistan which usually progresses to chronic hepatitis, with rare cases of spontaneous viral eradication. The present article reviews the treatment status of HCV infection in Pakistani population and various factors associated with the treatment response rates.

METHODS

Literature on anti-HCV therapy was searched in PubMed, Google Scholar and PakMediNet. Thirty three different studies representing different geographic regions of Pakistan published from 2002 to 2016 were included in the present review. Weighted mean, standard error estimates (SE) and standard deviation (SD) were determined for each population group.

RESULTS

Mean value for sustained virological response (SVR) for standard IFN plus ribavirin (RBV) combination therapy was 68.38% ± 14.13% (range 33.8%-87.10%; SE 3.08) and pegylated-IFN plus RBV combination therapy 64.38% ± 8.68% (range 55.0%-76.00%; SE 3.88). The lowest value for SVR has been reported to be 24.3% (for genotype 1; administering INF-α 2b 3MU 3 times/week and RBV 1000-1200 mg/day for 48 weeks) while highest of 87.5% (genotype 3a; INF-α 2a 3MU 3 times/week and RBV 1000-1200 mg/day for 24 weeks). The mean value for rapid virological response (RVR) was found to be 48.18% ± 29.20% (SE 9.73). As PEG-interferon and direct acting antivirals (DAAs) are relatively expensive, interferon-alfa (IFN-α) and RBV combination therapy have been used widely to treat HCV infected patients in Pakistan for the last one and half decade. On average, 2.45% of the patients discontinued treatment due to severe side effects.

CONCLUSION

We encourage further studies on understanding host and viral factors associated with specific focus on harder to treat viral variants (relapsers and nonresponders). These variants are currently rising in the country.

Polymorphisms of HLA-DM on Treatment Response to Interferon/Ribavirin in Patients with Chronic Hepatitis C Virus Type 1 Infection

Background: HLA-DM gene, which is related to antigen processing and presentation and located in the non-classical class-II region of human leukocyte antigen (HLA) region, may play a crucial role in chronic hepatitis C virus (HCV) infection treatment outcomes. The study was conducted to evaluate the role of the variant of several single nucleotide polymorphisms (SNPs) in HLA-DM gene in HCV treatment outcomes. Methods: We genotyped four SNPs from the candidate genes (HLA-DMA and DMB) in 336 patients who were treated with pegylated interferon-alpha and ribavirin (PEG IFN-α/RBV). Multivariate analysis of factors predicting sustained virological response (SVR) was conducted. Results: HLA-DMA rs1063478 and DMB rs23544 were independent factors of HCV treatment outcomes in Chinese Han population. Individuals who carried favorable genotypes of rs1063478TT and rs23544GG were more likely to achieve SVR {Dominant model: odds ratio (OR) = 2.05, 95% confidence interval (CI) = 1.24–3.41; OR = 2.04, 95% CI =1.23–3.35, respectively}. Rs23544, rs1063478, baseline glucose, baseline platelet and T4 level were independent predictors of SVR. The area under the receiver operating characteristic (ROC) curve (AUC) was 0.740. Conclusions: The genetic variation of rs1063478 and rs23544 are associated with the treatment outcomes in the Chinese Han population.

Genetic variations of the NPC1L1 gene associated with hepatitis C virus (HCV) infection and biochemical characteristics of HCV patients in China

OBJECTIVES

About 2% of the world population is infected with hepatitis C virus (HCV), a leading cause of hepatic cirrhosis and hepatocellular carcinoma. The Niemann-Pick C1-like 1 cholesterol absorption receptor (NPC1L1) was recently identified to be an important factor for HCV entry into host cells. Whether genetic variations of the NPC1L1 gene are associated with HCV infection is unknown.

METHODS

In this study, five single nucleotide polymorphisms (SNPs) of the NPC1L1 gene were analyzed in 261 HCV-infected individuals and 265 general controls from Yunnan Province, China.

RESULTS

No significant differences were identified in genotypes or alleles of the SNPs between the two groups. After constructing haplotypes based on the five SNPs, a significant difference between HCV-infected individuals and general controls was shown for two haplotypes. Haplotype GCCTT appeared to be a protective factor and haplotype GCCCT was a risk factor for HCV-infected individuals. Genotypes of four SNPs correlated with biochemical characteristics of HCV-infected persons. Genotypes of SNPs rs799444 and rs2070607 were correlated with total bilirubin. Genotype TT of rs917098 was a risk factor for the gamma-glutamyltransferase level. Furthermore, HCV-infected individuals carrying genotype GG of rs41279633 showed statistically higher gamma-glutamyltransferase levels than HCV-infected persons with GT and TT.

CONCLUSION

The results of this study identified the association between genetic susceptibility of the NPC1L1 gene and HCV infection, as well as biochemical characteristics of HCV-infected persons in Yunnan, China.

The Associations of HLA-A*02:01 and DRB1*11:01 with Hepatitis C Virus Spontaneous Clearance Are Independent of IL28B in the Chinese Population

Spontaneous clearance of hepatitis C virus (HCV) occurs in 10-40% of the infections. Specific human leukocyte antigen (HLA) alleles have been identified in associating with HCV clearance. However, data on the association of HLA with the spontaneous clearance of HCV are scarce in the Chinese population. In the current study we studied the HLA class I and class II genes in 231 Chinese voluntary blood donors who had cleared HCV infection spontaneously compared to 429 subjects with chronic HCV infections. We also studied their IL28B SNP (rs8099917) genotype, since a number of investigators have found a strong association of IL28B with spontaneous or treatment induced HCV clearance. We found that HLA-A*02:01 and DQB1*05:02 distributed differently between the two groups after Bonferroni correction (odds ratio [OR] = 1.839, Pc = 0.024 and OR = 0.547, Pc = 0.016, respectively). Multivariate logistic regression analysis suggested that A*02:01 and DRB1*11:01 (OR = 1.798, P = 0.008 and OR = 1.921, P = 0.005, respectively) were associated with HCV spontaneous clearance, independent of age, gender and IL28B polymorphism. We concluded that in the Chinese population, HLA-A*02:01 and DRB1*11:01 might be associated with the host capacity to clear HCV independent of IL28B, which suggesting that the innate and adaptive immune responses both play an important role in the control of HCV.