Association of rs2111485 and rs1990760 Polymorphisms of Interferon Induced with Helicase C Domain 1 Gene with Hepatitis C Virus Clearance in Chinese Han Population

Abstract

Interferon induced with helicase C domain 1 (IFIH1), which is a type of cytological RNA helicase protein and an important initiator of innate immune response to RNA virus infection, may play an important role in hepatitis C virus (HCV) infection outcomes. This study was conducted to investigate the association of IFIH1 gene polymorphisms with HCV clearance in Chinese Han population. A total of 1,527 subjects positive for anti-HCV and 357 chronic hepatitis C (CHC) patients were enrolled in this study. Two single nucleotide polymorphisms in IFIH1 gene (rs2111485 and rs1990760) were selected and genotyped by TaqMan real-time polymerase chain reaction. Haplotypes analysis was further performed by HaploView software and PHASE software. Our results demonstrated that the mutant alleles of rs2111485 (dominant model: odds ratio [OR] = 1.41, 95% confidence interval [CI] = 1.11–1.79) and rs1990760 (dominant model: OR = 1.63, 95% CI = 1.30–2.06) decreased the possibility of spontaneous HCV clearance, but it had no association with HCV clearance induced by interferon-alfa (IFN-α). And, CHC risk increased with the increasing number of unfavorable alleles (p _trend < 0.001). In addition, haplotype analysis also showed that the A-C protective haplotype (rs2111485-rs1997060) promoted spontaneous HCV clearance (p < 0.001). Variants of rs2111485 and rs1990760 at IFIH1 may be associated with spontaneous HCV clearance in Chinese Han population, but have no effect on HCV clearance induced by IFN-α.

Introduction

Hepatitis C is a type of infectious disease caused by hepatitis C virus (HCV), and it is estimated that ∼71 million chronic hepatitis C (CHC) patients around the world (1). The frequency of HCV infection varies widely, and over 40 million Chinese were persistently infected with HCV (25). CHC can eventually result in serious consequences such as hepatic fibrosis, liver cirrhosis, and hepatocellular carcinoma (29). Nowadays, the prevention and treatment of HCV is of great importance owing to the absence of an effective vaccine. Fortunately, the direct-acting antiviral drugs (DAAs) that have just been marketed can improve the sustained virological response (SVR) rate, safety, and efficiency of HCV treatment (9). However, due to the high price and poor accessibility of DAAs, the mainstream treatment of HCV in many developing countries is still the therapeutic schedule of pegylated interferon-α (PEG-IFN-α) and ribavirin (RBV) (21,28).

The ability to clear the foreign pathogen largely relies on the immune response of the host. As the first defense line against HCV, innate immunity influences the outcomes of HCV infection (14,31). As a family member of the mammalian retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs), interferon induced with helicase C domain 1 (IFIH1) was identified as an RNA sensor in the innate immune responses against viral infection (19). Once IFIH recognizes viral RNA as a non-self pattern in the cytoplasm, it rapidly activates downstream signaling and the body's stress response, producing stress-like aggregates that promote antiviral immunity (30). After recognition of viral RNA ligands, IFIH1 binds to common adaptors through CARD-CARD interactions to activate several kinases of the IKK family (6). Transcription factors activated by these kinases, such as IFN regulatory factors 3 and 7 (IRF3/7), NF-κB, and ATF2/c-Jun, induce transcription of interferon (IFN) and proinflammatory cytokines, thereby promoting the expression of hundreds of IFN-stimulated genes (ISGs) (6,8). Therefore, IFIH1 plays a vital role in antiviral immunity.

With the rapid development of single nucleotide polymorphism (SNP) detection technology, the role of genetic variation associated with the immune system to HCV infection was brought into attention. It has been reported that some SNPs were associated with the outcomes of HCV infection, such as rs12979860 and rs8099917 located upstream of the IL28B gene, HLA-DRB1*11:01, HLA-A*02:01, and MICA rs2596542 (13,18,26). Many recent studies have suggested that mutations at IFIH1 gene were associated with autoimmune diseases (2,7) and involved in the clearance of various viruses (7,10,27). Considering the important role of the IFIH1 in the innate immune system, we speculated that IFIH1 gene polymorphisms may be an influencing factor of HCV infection outcome as well. Therefore, we performed this study to explore the association between SNPs in human IFIH1 and host HCV clearance both spontaneous and IFN-α induced in Chinese Han population.

Methods

Study subjects

The study was conducted in accordance with the Declaration of Helsinki, and the protocol was approved by the Ethics Committee of Nanjing Medical University (Project identification code: 2017-445). During 2006–2015, all of the participants were recruited from hemodialysis centers, Nanjing compulsory detoxification center and several administrative villages in Jiangsu Province. A face-to-face questionnaire survey was conducted for each subject using a standard questionnaire after they signed the informed consent form. Subsequently, 10 mL of venous blood was collected from each subject for further testing. Only participants who met the following inclusion criteria were included in the final study: participants who were infected with HCV but not co-infected with hepatitis B virus (HBV) and human immunodeficiency virus (HIV), not suffering from other liver diseases, and had no IFN-based therapy experience. Finally, a total of 1,527 eligible subjects were included in this study and divided into 2 groups, including persistent HCV infection group and spontaneous HCV clearance group, according to Diagnostic criteria for viral hepatitis C (ws213-2018) issued by the Chinese Ministry of Health. Persistent HCV infection was defined as having detectable HCV antibodies (anti-HCV) and HCV RNA in the serum and spontaneous HCV clearance was defined as anti-HCV and HCV RNA negative in this study.

To further investigate the effects of candidate SNPs on HCV clearance induced IFN-α, 357 Chinese HCV genotype 1-infected patients who had been treated under standard IFN therapy were recruited between 2011 and 2016 from Jurong Hospital Affiliated to Jiangsu University. All patients conformed to these requirements: (i) over 18 years old; (ii) HCV antibody positive and HCV RNA positive for more than 6 months; (iii) initial treatment; (iv) not co-infected with HBV or HIV; (v) free of diseases including blood diseases, liver diseases, thyroid diseases, and diabetes. The serum viral load (HCV RNA) and liver and kidney function of each patient were measured regularly at 4, 8, 12, 24, and 48 weeks of treatment and 24 weeks after cessation of treatment. Finally, treatment response of patients was judged based on the patients' serum viral load obtained during the follow-up. The treatment response was indicated by SVR, which was defined as the absence of serum HCV RNA for at least 24 weeks after the end of treatment.

Laboratory testing

All samples were screened for anti-HCV, HIV antibody (anti-HIV), and hepatitis B surface antigen (HBsAg) using enzyme-linked immunosorbent assay (Beijing Wantai Biological Pharmacy Engineering Co., Ltd., Beijing, China) according to manufacturer's instructions. The detection of HCV RNA was performed by using PrimeScript Real time polymerase chain reaction (RT-PCR) kit (Dalian, China). Total DNA from the white blood cell (WBC) was extracted by TRIzol method. All samples were stored at −40°C for further assessments. For the treatment cohort, HCV RNA quantification was performed at 4, 8, 12, 24, and 48 weeks after the patient received treatment and 24 weeks after cessation of treatment.

Genotyping

IFIH1 rs2111485 and rs1990760 were included in this study, and the screening process was as follows. First, the detailed information about candidate SNPs were obtained from the Ensembl database (http://grch37.ensembl.org/Homo_sapiens/Tools/VcftoPed?db=core) and imported into Haploview 4.2 software to screen for blocks with strong linkage disequilibrium (LD; r ² > 0.8). Second, based on the NCBI dbSNP database (www.ncbi.nlm.nih.gov/SNP) and the Chinese Han population database of HapMap (www.hapmap.org), SNPs that met the criteria wherein minor allele frequency value was not <0.05 were selected as candidate SNPs for further analysis. Third, we further searched the existing literature related to candidate SNPs to identify the potentially functional SNPs that may be associated with autoimmune disease/infectious disease. The genotyping assays of two candidate SNPs in this study was done by TaqMan allelic discrimination assay on real-time polymerase chain reaction (PCR) system Lightcycler 480 (Roche). The PCR procedure was as follows: 50°C for 2 min, 95°C for 10 min, 95°C for 15 sec, and 60°C for 1 min followed by 45 cycles. For each SNP, 10% of the total samples were selected at random to repeat experiments with concordances of 100%. Primers and probes (Nanjing BioSteed Biotechnologies Co., Ltd., Nanjing, China) applied in this study are listed in Supplementary Table S1.

Statistical analysis

All statistical analyses in this study were performed by Stata/MP version 14.0 software (StataCorp LP, College Station, TX) for Windows 64 bits. The difference of demographic characteristics and baseline clinical characteristics were analyzed between two groups using chi-square test (χ² ) for categorical variables and Student's t test for continuous variables. Co-dominant, dominant, and additive models were performed for each SNP. And multivariate logistic regression analysis was used to explore the association of selected SNPs with HCV infection and the results were presented as odds ratios (ORs) and 95% confidence intervals (CIs). The Cochran-Armitage test was further used for trend analysis to explore the association between the number of unfavorable alleles and HCV clearance. Stratified analyses and heterogeneity tests were performed to rule out the effects of confounding factors on the final results. In our study, HaploView software (v4.2) was applied to generate LD parameter (i.e., D′ and r ²). PHASE software (v2.1) was used to conduct the haplotype block structure (rs2111485-rs1990760) and estimate the haplotype frequencies based on the observed genotypes in our study. Then, the association between haplotypes frequencies of IFIH1 and HCV clearance was evaluated by logistic regression model. p-Value of <0.05 for the two-sided test was considered statistically significant.

Results

Association of candidate SNPs (rs2111485 and rs1990760) with spontaneous HCV clearance

A total of 1,527 subjects with anti-HCV positive were enrolled in this study, including 576 spontaneous HCV clearance cases and 951 persistent HCV infection patients. Demographic characteristics of these two groups were shown in Table 1. Subjects over 50 years and subjects with high levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were more frequent in persistent HCV infection group (p < 0.001).

Table 1.

Demographic Characteristics in Subjects with Different Hepatitis C Virus Infection Outcomes

Variables	Spontaneous clearance, N = 576	Persistent infection, N = 951	p
Age (%)
<50 years	268 (46.53)	305 (32.07)	<0.001
≥50 years	308 (53.47)	646 (67.93)
Sex (%)
Male	208 (36.11)	316 (33.23)	0.250
Female	368 (63.89)	635 (66.77)
AST (%)
<40 U/L	462 (80.21)	549 (57.73)	<0.001
≥40 U/L	114 (19.79)	402 (42.27)
ALT (%)
<40 U/L	446 (77.43)	574 (60.36)	<0.001
≥40 U/L	130 (22.57)	377 (39.64)

Bold values indicate statistically significant results.

ALT, alanine aminotransferase; AST, aspartate transaminase.

Among 1,527 participants, both SNPs were successfully used for genotyping, demonstrating a high average success rate of 97.68%. The results of multivariate logistic regression after adjusting for age, sex, and ALT and AST levels revealed that variants of rs2111485 and rs1990760 were associated with increasing risk of CHC (Table 2). The mutant G allele of IFIH1 rs2111485 (dominant model: OR = 1.41, 95% CI = 1.11–1.79, p = 0.005; additive model: OR = 1.27, 95% CI = 1.04–1.56, p = 0.020) and T allele at rs1990760 (dominant model: OR = 1.63, 95% CI = 1.30–2.06, p < 0.001; additive model: OR = 1.44, 95% CI = 1.23–1.69, p < 0.001) were found more common in persistent HCV infection group. Then, combined analysis was further performed to explore the cumulative effect of unfavorable alleles (rs2111485-G and rs1997060-T) with CHC risk and the results demonstrated that the risk of CHC increased as the number of unfavorable alleles increased (p _trend < 0.001) (Table 3). The risk of CHC in patients who carried three to four unfavorable alleles was more than two times higher than patients who did not carry the unfavorable alleles (OR = 2.22, 95% CI = 1.53–3.22, p < 0.001). In addition, the results of stratified analyses and heterogeneity test (Supplementary Tables S2 and S3) suggested that no obvious evidence of heterogeneity association for candidate SNPs on chronic HCV infection was observed, ensuring the reliability of our results.

Table 2.

Association of Selected Single Nucleotide Polymorphisms with Spontaneous Hepatitis C Virus Clearance

Genotype	Spontaneous clearance	Persistent infection	Persistent infection rate (%)	OR (95% CI)	p
rs2111485
AA	418 (73.33)	635 (67.63)	60.30	1.00	—
AG	130 (22.81)	275 (29.29)	67.90	1.47 (1.14–1.89)	0.003
GG	22 (3.86)	29 (3.09)	56.86	1.04 (0.58–1.88)	0.887
Dominant				1.41 (1.11–1.79)	0.005
Additive				1.27 (1.04–1.56)	0.020
rs1990760
CC	375 (67.93)	528 (57.27)	58.47	1.00	—
CT	121 (21.92)	239 (25.92)	66.39	1.42 (1.09–1.86)	0.009
TT	56 (10.14)	155 (16.81)	73.46	2.11 (1.49–2.98)	<0.001
Dominant				1.63 (1.30–2.06)	<0.001
Additive				1.44 (1.23–1.69)	<0.001

Bold values indicate statistically significant results.

The genetic models: co-dominant (wild homozygote vs. heterozygote and wild homozygote vs. mutational homozygote), dominant (wild homozygote vs. heterozygote+mutational homozygote) and additive (wild homozygote vs. heterozygote vs. mutational homozygote). p-Value was calculated by Logistic regression analyses adjusted for age, sex, ALT, AST.

95% CI, 95% confidence interval; OR, odds ratio.

Table 3.

The Combined Effects of Unfavorable Alleles to Spontaneous Hepatitis C Virus Clearance

Variables ^a	Spontaneous clearance	Persistent infection	Persistent infection rate (%)	OR (95% CI)	p^b
0	362 (66.30)	523 (57.47)	59.10	1.00	—
1	44 (8.06)	91 (10.00)	67.41	1.30 (0.87–1.93)	0.200
2	93 (17.03)	157 (17.25)	62.80	1.27 (0.94–1.71)	0.119
3–4	47 (8.61)	139 (15.27)	74.73	2.22 (1.53–3.22)	<0.001
Trend					<0.001 ^c
0	362 (66.30)	523 (57.47)	59.10	1.00	—
1–4	184 (33.70)	387 (42.53)	67.78	1.51 (1.20–1.90)	<0.001

Bold values indicate statistically significant results.

Number of unfavorable alleles (rs2111485-G and rs1990760-T). The genetic models of additive were used.

p-Value was calculated by Logistic regression analyses adjusted for age, sex, ALT, AST.

p-Value was from Cochran-Armitage trend test.

Analysis of association between candidate SNPs (rs2111485 and rs1990760) and HCV clearance induced by IFN-α

There were 357 patients selected to our treatment cohort and divided into 2 groups according to the assessment of serum HCV RNA at 24 weeks after the end of treatment, including 118 N-SVR patients and 239 SVR patients. Demographic characteristics and baseline clinical characteristics were shown in Table 4. No difference was discovered in the distribution of age, sex, baseline levels of ALT and AST, total protein, hemoglobin, and WBC. However, the baseline levels of HCV RNA, albumin (ALB), glucose (GLU), and platelets (PLT) were different between two groups. Compared to SVR group, pretreated levels of HCV RNA and GLU were higher while levels of ALB and PLT were lower in non-SVR group (all p < 0.05).

Table 4.

Baseline Clinical Characteristics of Interferon Treatment Cohort

Variables	N-SVR, N = 118	SVR, N = 239	p
Age (years)	53.47 ± 8.08	53.68 ± 8.60	0.820
<50	36 (30.51)	77 (32.22)	0.744
≥50	82 (69.49)	162 (67.78)
Sex (%)
Male	29 (24.58)	60 (25.10)	0.914
Female	89 (75.42)	179 (74.90)
ALT (%)
<40 U/L	40 (33.90)	98 (41.00)	0.195
≥40 U/L	78 (66.10)	141 (59.00)
AST (%)
<40 U/L	49 (41.53)	116 (48.54)	0.211
≥40 U/L	69 (58.47)	123 (51.46)
Log HCV RNA	6.15 ± 0.86	5.81 ± 1.20	0.006
TP (g/L)	77.78 ± 5.94	78.26 ± 6.03	0.477
ALB (g/L)	42.60 ± 4.21	43.82 ± 4.11	0.009
GLU (mmol/L)	6.34 ± 1.65	5.75 ± 1.50	<0.001
HGB (g/L)	132.91 ± 17.63	134.22 ± 16.13	0.484
PLT (10⁹/L)	122.40 ± 60.01	137.51 ± 53.27	0.016
WBC (10⁹/L)	4.89 ± 2.64	5.00 ± 1.77	0.643

Bold values indicate statistically significant results.

ALB, albumin; ALT, alanine aminotransferase; AST, aspartate aminotransferase; GLU, glucose; HCV, hepatitis C virus; HGB, hemoglobin; N-SVR, non-sustained virological response; PLT, platelets; SVR, sustained virological response; TP, total protein; WBC, white blood cell.

Among 357 CHC patients, an average success rate of more than 97% was reached for the genotypic assays of 2 SNPs. As shown in the Table 5, the results from multivariate logistic regression after adjusting for age, sex, ALB, GLU, PLT, and baseline HCV viral load suggested that there was no significant association between the candidate SNPs (rs2111485 and rs1990760) and HCV clearance induced by IFN-α (p > 0.05).

Table 5.

Association of Selected Single Nucleotide Polymorphisms with Hepatitis C Virus Clearance Induced by Interferon-Alfa

Genotype	N-SVR	SVR	SVR rate (%)	OR (95% CI)	p
rs2111485
AA	87 (73.73)	165 (71.74)	34.52	1.00	—
AG	29 (24.58)	58 (25.22)	33.33	0.95 (0.54–1.65)	0.846
GG	2 (1.69)	7 (3.04)	22.22	2.35 (0.44–12.42)	0.314
Dominant				1.03 (0.61–1.76)	0.901
Additive				1.11 (0.70–1.76)	0.660
rs1990760
CC	83 (70.34)	167 (71.37)	33.20	1.00	—
CT	33 (27.97)	60 (25.64)	35.48	0.80 (0.47–1.37)	0.426
TT	2 (1.69)	7 (2.99)	22.22	2.25 (0.43–11.85)	0.340
Dominant				0.88 (0.53–1.48)	0.640
Additive				0.98 (0.63–1.54)	0.936

Haplotype analysis

LD and haplotype analyses between rs2111485 and rs1997060 of IFIH1 were further conducted by HaploView software and PHASE software (D′ = 1.0). Four haplotypes were constructed and divided into three categories, including A-C, G-T, and others, and the frequencies were 72.59%, 16.57%, and 10.84%, respectively (Table 6). When compared with the protective A-C haplotype, all other haplotypes containing variant alleles of the two SNPs were significantly associated with the high risk of CHC, which was consistent with the single SNP analyses (G-T: OR = 1.48, 95% CI: 1.20–1.83, p < 0.001; others: OR = 1.74, 95% CI: 1.33–2.26, p < 0.001). These results further confirmed that A allele of rs2111485 and C allele of rs1990760 had a protective effect against persistent HCV infection.

Table 6.

Haplotypes Frequencies of IFIH1 in Two Groups and Spontaneous Hepatitis C Virus Clearance

Haplotypes (rs2111485-rs1990760)	Spontaneous clearance	Persistent infection	Persistent infection rate (%)	OR (95% CI)	p
AC	894 (77.60)	1,323 (69.56)	59.68	1.00	—
GT	166 (14.41)	340 (17.88)	67.19	1.48 (1.20–1.83)	<0.001
Others	92 (7.99)	239 (12.57)	72.21	1.74 (1.33–2.26)	<0.001

Bold values indicate statistically significant results.

Haplotypes (AT+GC) with a frequency <5% were combined as others. OR (95% CI) and p-value were calculated using logistic regression model adjusted for age, sex, ALT, AST.

IFIH1, interferon induced with helicase C domain 1.

Discussion

To provide genetic evidence of the association of IFIH1 gene polymorphisms with HCV clearance, our study first explored the association of rs2111485 and rs1990760 at IFIH1 gene with HCV clearance both spontaneous and IFN-α induced in Chinese Han population. And the results argued that mutations of candidate SNPs were associated with spontaneous HCV clearance, but not related to HCV clearance induced by IFN-α.

As an important member of the innate immune system, IFIH1 can block the HCV life cycle after HCV infection, impacting HCV RNA replication >80% (23). Upon recognition of viral RNA by the IFIH1 molecule in the infected cell, a complex signaling cascade network involving transcription factors was then triggered after interacting with downstream molecules, eventually resulting in expression of the ISGs and type I IFNs (24,30). Thus, significant antiviral responses were generated, including being directly effective against pathogens and promoting the adaptive immune response (22). In addition, Cao also demonstrated the fact that IFIH1 can induce IFN production after HCV infection using a new HCV infectious cell culture model (4). Nevertheless, the mechanism of IFIH1 detecting HCV RNA has not been fully explained and requires further study.

More and more studies have begun to explore the association between IFIH1 related gene polymorphisms and diseases. As a class of genes encoding IFN-inducible RNA helicase, IFIH1 is involved in antiviral innate immune responses and its polymorphisms have been proved to be associated with type 1 diabetes (T1D), Graves' disease (GD), multiple sclerosis, psoriasis, and systemic lupus erythematosus (SLE) (16,17,24). However, little is known about the association between IFIH1 gene polymorphisms and HCV infection. Our study was the first to explore the association of genetic variation in IFIH1 rs2111485 and rs1990760 with HCV clearance in Chinese Han population, demonstrating that rs2111485-G and rs1990760-T alleles were associated with higher risk of CHC in Chinese Han population and accumulation of mutant alleles (rs2111485-G and rs1997060-T, respectively) were strongly related to higher persistent infection rates. In addition, the results from the haplotype analysis further confirmed the protective effects of the A allele of rs2111485 and the C allele of rs1990760 on HCV persistent infection.

The association between rs1990760-T and CHC risk was also observed in the Egyptian population, but was not observed in the European population (12,20). Differences may be caused by racial differences, as the first studies were conducted in Africa population and the latter in European population. The information of population genetics from ensemble database showed the fact that rs1990760-T was the major allele in European populations. In contrast, rs1990760-C was the major allele in Asian and African population (http://asia.ensembl.org/Homo_sapiens/Variation/Population?db=core;r=2:162267041-162268041;v=rs1990760;vdb=variation;vf=194708043). Besides, several autoimmune diseases that were driven by abnormalities in the immune system, such as GD, T1D, vitiligo, and SLE, were proved to be closely related to mutations at rs1990760 (5). Mutation at rs1990760 results in an amino acid change (p.A946T). And, rs1990760 is a quantitative trait locus (QTL) for IFIH1 expression. Jaeger et al. found that mutation at rs1990760 was a predisposing factor for Candida infections and was associated with lower expression of IFIH1 in peripheral blood mononuclear cell (15). Among patients with chronic mucocutaneous candidiasis, the mutation of IFIH1 increased susceptibility to candidemia and significantly reduced the production of IFIH1 in cells isolated. Therefore, we speculated that the missense mutation of rs1990760 can change the expression of IFIH1, thus affecting the body's ability to clear HCV by reducing the induction of IFN. In addition, Funabiki et al. found that the mutation may also cause IFIH1 to fail to respond to RNA ligands by affecting its ATPase activity, thus destroying the response to viral infection (11).

rs2111485 are located at 13 kb from the end of the 3′-UTR (untranslated region) of the IFIH1 gene. Our study first explored the effects of rs2111485 variant on HCV infection outcomes. Therefore, we hoped that our findings can be validated in different populations and studies with larger sample sizes. On the other hand, mutations at rs2111485 have been confirmed by a large number of studies to be closely related to T1D and vitiligo (17). These diseases are closely related to the immune status of the patient, which further proved that mutations at this SNP may affect HCV clearance by affecting the innate immune response (3). In addition, it is unknown whether they contribute to the regulation of IFIH1 expression. Therefore, further bioinformatics and functional tests are needed to verify this finding.

We acknowledge that several potential limitations existed in our study. First, our research lacks validation of further functional experiments. Second, our study only involved the patients treated with PEG-IFN-α and RBV. However, mainstream therapy for HCV in developing countries like China was still the IFN treatment regimen due to the high price and poor availability of DAAs. Third, our samples had a relatively poor representation since the participants of the case–control study were recruited during a large time span and the patients of the cohort study were all selected from the same hospital within 6 years. Besides, there were some advantages in our study. First of all, this is the first study to explore the association of IFIH1 rs2111485 and rs1990760 variants with HCV clearance both spontaneous and IFN-α induced in Chinese Han population. Second, the sample size of our sample was relatively larger, ensuring the sufficient statistical power of our study. Moreover, subjects enrolled in our study were all infected with HCV alone, which guaranteed the natural history of HCV and showed credible results.

Conclusion

In conclusion, mutations of IFIH1 rs2111485 and rs1990760 may increase the risk of CHC but were not related to HCV clearance induced by IFN-α in Chinese Han population. And CHC risk increased with the increasing number of unfavorable alleles. The function of these two SNPs should be further validated by bioinformatics predictions and functional assays.

Footnotes

Acknowledgments

We thank the doctors and nurses from Jurong Hospital Affiliated to Jiangsu University for helping with sample collection and all the participants for taking part in this research.

Author Disclosure Statement

The authors declare no conflicts of interest.

Authors' Contributions

P.H., S.Y., W.J., and L.Z. designed the study. W.J., X.W., J.S., X.Y., and Y.W. performed the experiment. L.Z. and S.Y. conducted the statistical analysis. X.X. and H.C. provided materials and analysis tools. W.J. and L.Z. wrote the draft manuscript. P.H. and R.Y. revised the article. All authors accepted the final article.

Funding Information

This study was sponsored by the National Natural Science Foundation of China (Nos. 81703273, 81473029, 81703321), Natural Science Foundation of Jiangsu Province (No. BK20171054), Key Research and Development Program of Zhenjiang, China (SH2018058), and Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).

Supplementary Material

Supplementary Table S1

Supplementary Table S2

Supplementary Table S3

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