Influences of MxA gene -88 G/T and IFN-gamma +874 A/T on the natural history of hepatitis B virus infection in an endemic area

Interferon gamma gene polymorphisms and chronic hepatitis B infections in an Iranian population

BACKGROUND AND AIMS

Chronic hepatitis B is an important health problem in all countries. I Interferon gamma is a pro-inflammatory Th1 cytokines, which can exert antiproliferative and antitumor activity. Some SNPs in IFN-γ and IFN-γR1 genes may influence the susceptibility to HBV. Here, we evaluated the impact of interferon gamma (+874 T/A) and its receptor (-611A/G, +189G/C and +95C/T) polymorphisms and the risk of HBV in Iranian patients.

MATERIALS AND METHODS

SNPs of interferon gamma and its receptor genotypes were determined in 221 infected patients with HBV and 200 people without HBV using ARMS-PCR and PCR- RFLP method.

RESULTS

In this study, we showed an obvious relationship between IFN-γ SNPs and susceptibility to chronic HBV. Our findings suggest that IFN-γ-874A allele increases the risk of disease and carriers of the T allele have reduced susceptibility to infection. In addition, there was not any relationship between the -611A/G, +189G/C and +95C/T regions of IFN-γ R1 and HBV.

CONCLUSIONS

Our observations demonstrate +874 T/A SNP as a predicting factor in patients who have the risk of HBV.

Myxovirus resistance 1 gene polymorphisms and outcomes of viral hepatitis B and C infections in Moroccan patients

Host genetic factors may influence the establishment of chronicity or spontaneous clearance in viral hepatitis B and C infections. More light was shed on the role played by interferon-stimulated genes in the innate immunity. Myxovirus resistance 1 (MX1) is one of those key genes that have reported to inhibit several viruses. The present study aims to explore the possible association of -88G/T and -123C/A promoter variants of MX1 with susceptibility to chronic hepatitis B and C and/or with spontaneous clearance in a Moroccan population. The -88G/T and -123C/A SNPs were genotyped by PCR-RFLP in 538 individuals stratified into HBV chronically infected patients (n = 120), HCV-chronically infected patients (n = 115), HBV spontaneously resolved subjects (n = 114), HCV spontaneously resolved group (n = 52), and healthy controls (n = 137). A significant association of -123C allele with HBV spontaneous clearance has been found (P = 0.002, OR = 2.34; 95%CI [1.36-4]). In addition, a significant correlation between the MX1-GC haplotype and HBV spontaneous clearance (P < 0.001) was found. No significant association of -88G/T and -123C/A polymorphisms with regard to HCV infection was observed in this study. Here, we show that for North African patients with chronic hepatitis, MX1 gene variation at position -123 may influence the outcome of HBV infection but not HCV infection. J. Med. Virol. 89:647-652, 2017. © 2016 Wiley Periodicals, Inc.

Interferon Gamma +874T/A Polymorphism Increases the Risk of Hepatitis Virus-Related Diseases: Evidence from a Meta-Analysis

Background

Interferon gamma (IFN-γ) is a key regulatory cytokine, which plays an important role in antiviral defense of an infected host. However, the association between the IFN-γ +874T/A gene polymorphism and hepatitis virus-related diseases is heterogeneous.

Methods

Based on the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement, a comprehensive literature search of eligible studies in Embase, Pubmed, and the Cochrane Library was undertaken through November 2014. Odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) were used to measure the strength of the models.

Results

Seventeen case-control articles, including 24 studies with 5503 individuals, met the inclusion criteria. The results indicated a statistically significant association between the IFN-γ +874T/A polymorphism and hepatitis virus—related diseases in a recessive gene model (AA vs. TT+TA: OR=1.350, 95% CI=1.101-1.657, P=0.004, I²%=54.3, and P_Q=0.001 for heterogeneity), especially in Asians (OR=1.407, 95% CI=1.035-1.911, P=0.029, I²%=61.9, and P_Q=0.005 for heterogeneity) and hepatitis B virus (HBV)–related disease (OR=1.486, 95% CI=1.195–1.849, P=0.000, I²%=40.4, and P_Q=0.053 for heterogeneity).

Conclusions

The evidence suggests that the IFN-γ +874T/A polymorphism increases the risk of hepatitis virus—related diseases, especially in Asians and HBV—related diseases. Further studies on this topic in different ethnicities, especially genome-wide association studies, should be conducted to strengthen our results.

Diagnosis of viral infections using myxovirus resistance protein A (MxA)

BACKGROUND

Myxoma resistance protein 1 (MxA) is induced during viral infections. MxA testing could be helpful to differentiate between viral and bacterial infections.

METHODS

A prospective multicenter cohort study was performed in pediatric emergency departments. MxA blood values were measured in children with confirmed viral or bacterial infections, uninfected controls, and infections of unknown origin. First patients were used to determine MxA threshold for viral infection. The diagnostic performance of MxA was determined by using receiver operating characteristic (ROC) analysis. Sensitivities (Se), specificities (Sp), and positive and negative likelihood ratios (LR+, LR-) were calculated.

RESULTS

The study included 553 children; 44 uninfected controls and 77 confirmed viral infections (mainly respiratory syncytial virus and rotavirus) were used to determine an MxA threshold at 200 ng/mL. In the 193 other patients with confirmed infections and uninfected controls (validation group), MxA was significantly higher in patients with viral than in those with bacterial infections and uninfected controls (P < .0001). The area under the ROC curve (AUC) were 0.98, with 96.4% Se and 85.4% Sp, for differentiating uninfected from virus-infected patients and 0.89, with 96.4% Se and 66.7% Sp, for differentiating bacterial and viral infections. MxA levels were significantly higher in patients with clinically diagnosed viral versus clinically diagnosed bacterial infections (P < .001). Some patients with Streptococcus pneumonia infections had high MxA levels. Additional studies are required to elucidate whether this was due to undiagnosed viral coinfections.

CONCLUSIONS

MxA is viral infection marker in children, at least with RSV and rotavirus. MxA could improve the management of children with signs of infection.

Interferon gamma polymorphisms and hepatitis B virus-related liver cirrhosis risk in a Chinese population

Background

Previous studies proved that interferon gamma (IFN-γ) gene polymorphisms were associated with the risk of hepatitis B virus (HBV) infection. However, the association between IFN-γ polymorphisms and HBV-related liver cirrhosis (HBV-LC) risk is still unclear.

Methods

IFN-γ +874 T/A and +2109G/A genotypes were determined in 126 HBV-LC patients, 129 chronic hepatitis B(CHB) patients, and 173 early HBV infection controls using a sequence-specific primer-polymerase chain reaction and a polymerase chain reaction-restriction fragment length polymorphism, respectively.

Results

Significant associations were observed between +2109A/G polymorphisms and HBV-LC risk in the co-dominant model (GG vs. AA: OR = 0.321, 95% CI = 0.130-0.793, P = 0.014), the allelic model (OR = 0.565, 95% CI = 0.388-0.825, P = 0.003), the dominant model (OR = 0.551, 95% CI = 0.344-0.883, P = 0.013), and the recessive model (OR = 0.385, 95% CI = 0.159-0.930, P = 0.034). In addition, haplotype analysis indicated that the T⁺⁸⁷⁴G⁺²¹⁰⁹ haplotype significantly decreased the HBV-LC risk (OR = 0.106, 95% CI = 0.022-0.502, P = 0.000), and A⁺⁸⁷⁴A⁺²¹⁰⁹ haplotype significantly increased the LC risk (OR = 1.485, 95% CI = 1.065-2.070, P = 0.019). No significant associations were observed between IFN-γ +874 T/A polymorphisms and HBV-LC risk, as well as the two single-nucleotide polymorphisms (SNPs) and CHB risk (P > 0.05).

Conclusions

Our observations suggested a significant association of IFN-γ polymorphisms with HBV-LC risk in the Chinese population.

Associations of IFN-γ rs2430561 T/A, IL28B rs12979860 C/T and ERα rs2077647 T/C polymorphisms with outcomes of hepatitis B virus infection: a meta-analysis

Several studies investigated associations of IFN-γ rs2430561 T/A, IL28B rs12979860 C/T and ERα rs2077647 T/C gene polymorphisms with outcomes of hepatitis B virus (HBV) infection, but the results were controversial. Therefore, we performed a meta-analysis of all published observational studies to address this inconsistency. Literature was searched in online database and a systematic review was conducted based on the search results. A total of 24 studies were included and dichotomous data were presented as odds ratio (OR) with a 95% confidence interval (CI). The rs2430561 T allele was associated with reduced persistent HBV infection risk (T vs. A: OR, 0.690; 95% CI, [0.490, 0.971]), while the rs2077647 T allele significantly increased the risk of persistent HBV infection (T vs. C: OR, 1.678; 95% CI, [1.212, 2.323]). Rs 2077647 CC might play a role in protecting individuals against HBV persistence (TT vs. CC: OR, 4.109; 95% CI, [2.609, 6.473]). Furthermore, carriers of the rs2430561 TT genotype were more likely to clear HBV spontaneously compared with those of the AA genotype (TT vs. AA: OR, 0.555; 95% CI, [0.359, 0.856]). For rs12979860 C/T polymorphism, no significant correlation with HBV infection outcomes was found. In subgroup analyses, the results were similar to those of overall analysis. However, for rs2077647 TT vs. TC+CC, significantly increased risks were observed in the Asian and hospital-based population, but not in the overall analysis. IFN-γ rs2430561 T/A and ERα rs2077647 T/C genetic polymorphisms were associated with outcomes of HBV infection, but no association was found between IL28B rs12979860 C/T and HBV infection.

The interferon-gamma (IFN-γ) +874T allele reduces the risk of hepatitis B infection in an Asian population

Increasing evidence suggests that polymorphism of the interferon-gamma (IFN-γ) gene in the first intron at position +874 may be associated with chronic hepatitis B virus (HBV) infection and/or HBV clearance. However, the results of relevant studies have been inconsistent. To derive a more precise estimation of the association, we performed a meta-analysis. In total, 10 independent studies including 1661 chronic HBV-infected patients and 1142 controls were included in this meta-analysis. In studies following Hardy-Weinberg equilibrium (HWE), a significantly decreased risk of chronic HBV infection was associated with the IFN-γ + 874TT genotype in the overall population (TT vs AA: odds ratio (OR) = 0.714, 95% confidence interval (CI) = 0.526-0.969, P = 0.031) when compared with a spontaneously recovered population. Subgroup analysis by ethnicity revealed a similar association in Asian individuals (TT vs AA: OR = 0.706, 95% CI = 0.518-0.962, P = 0.028). Moreover, when compared with a healthy control group, the 874T allele was associated with a significant lower risk of chronic HBV infection in the overall populations (TA vs AA: OR = 0.439, 95% CI = 0.193-0.997, P = 0.049; TT + TA vs AA: OR = 0.475, 95% CI = 0.271-0.832, P = 0.009) and in Asian individuals (TA vs AA: OR = 0.862, 95% CI = 0.744-0.999, P = 0.048). In conclusion, the IFN-γ + 874TT genotype and 874T allele reduce the risk of chronic HBV infection in Asian individuals.

MxA transcripts with distinct first exons and modulation of gene expression levels by single-nucleotide polymorphisms in human bronchial epithelial cells

Myxovirus resistance A (MxA) is a major interferon (IFN)-inducible antiviral protein. Promoter single-nucleotide polymorphisms (SNPs) of MxA near the IFN-stimulated response element (ISRE) have been frequently associated with various viral diseases, including emerging respiratory infections. We investigated the expression profile of MxA transcripts with distinct first exons in human bronchial epithelial cells. For primary culture, the bronchial epithelium was isolated from lung tissues with different genotypes, and total RNA was subjected to real-time reverse transcription polymerase chain reaction. The previously reported MxA transcript (T1) and a recently registered transcript with a distinct 5′ first exon (T0) were identified. IFN-β and polyinosinic–polycytidylic acid induced approximately 100-fold higher expression of the T1 transcript than that of the T0 transcript, which also had a potential ISRE motif near its transcription start site. Even without inducers, the T1 transcript accounted for approximately two thirds of the total expression of MxA, levels of which were significantly associated with its promoter and exon 1 SNPs (rs17000900, rs2071430, and rs464138). Our results suggest that MxA observed in respiratory viral infections is possibly dominated by the T1 transcript and partly influenced by relevant 5′ SNPs.

Functional characterization of new allelic polymorphisms identified in the promoter region of the human MxA gene

The Mx proteins are high-molecular-weight dynamin-like proteins whose expression depends strictly on type-I and type-III interferons (IFN). Some isoforms are able to inhibit the life cycle of one or several viruses and are thus components of innate immune response. The human MxA protein displays the broadest antiviral spectrum which makes it appear as a key antiviral effector of innate immunity. Allelic polymorphisms located in the MxA gene promoter can be expected to affect the magnitude of MxA mRNA transcription in response to IFNs and therefore to alter the severity of viral diseases in humans. Here, three single nucleotide polymorphism sites (-309, -101 and +20) were examined for their ability to alter MxA gene promoter-driven reporter expression. We show that, besides the previously reported role of -123A and -88T, the presence of -101G is equally important. Moreover, when a promoter construct carries these three critical nucleotides, a first additional positive effect is conferred by a C at position -309 and, in this latter case, a second additional effect is produced by a A at position +20. This finding is clinically useful to improve prediction of IFN-responsiveness in patients not only with viral diseases for which type-I IFN therapy is used.

Detection of new biallelic polymorphisms in the human MxA gene

The interferon-inducible human MxA protein plays an important role in innate defense against an array of viruses. One might expect allelic diversity at the MxA locus to influence the timing and magnitude of its expression or even the range of viruses whose biological cycle is inhibited by the encoded product. Here we have collected 267 samples of genomic DNA from three distinct populations (European, Asian, and African) and have systematically sequenced the promoter of the MxA gene and its 17 exons in order to inventory its allelic variants. Eighteen single-nucleotide polymorphisms were detected, four of which had never been identified before. Two of these, located in the promoter (at positions -309 and -101 respectively), might affect the MxA expression pattern. The other two result in substitutions (Gly255Glu and Val268Met) in the protein's N-terminal region that might directly affect its antiviral function.

Single nucleotide polymorphism at exon 7 splice acceptor site of OAS1 gene determines response of hepatitis C virus patients to interferon therapy

BACKGROUND AND AIM

Response to interferon therapy and disease progression in hepatitis C virus (HCV) infected patients differs among individuals, suggesting a possibility of a contribution of host genetic factors. 2'-5'-oligoadenylate synthetase 1 (OAS1), an important component of the innate immune system with a proven antiviral function, may therefore have a relationship with the response to interferon therapy and clinical course of HCV disease. Our aim was to determine the frequency of single nucleotide polymorphism (SNP) at exon 7 splice acceptor site (SAS) of the OAS1 gene in relation to the interferon response and status of HCV infection.

METHODS

A 203 bp fragment containing exon 7 SAS was amplified in 70 HCV chronic patients and 50 healthy controls. SNP was examined using restriction fragment length polymorphism (RFLP) genotyping method. Correlations of SNP genotypes with response to interferon and clinical status of patients were statistically analyzed.

RESULTS

There was an increasing trend of response from AA to AG to GG genotypes (P = 0.007). Genotype AA was associated with non-response to interferon and higher degree of liver fibrosis (P = 0.05). Multivariate analysis showed this SNP as independent and a significant determinant of the outcome of interferon therapy (odds ratio 4.913 [95% confidence interval 1.365-8.2], P = 0.006).

CONCLUSIONS

This is the first study to show a significant association between the functional SNP at exon 7 SAS of OAS1 gene and the viral response to interferon in chronic HCV patients. Patients with AA genotype were associated with progressive HCV disease and viral resistance to interferon therapy. This OAS SNP is a potential bio-marker to predict IFN response in chronic hepatitis C patients.

Non-association of IL-12 +1188 and IFN-γ +874 polymorphisms with cytokines serum level in occult HBV infected patients

BACKGROUND/AIM

Occult hepatitis B infection (OBI) is identified as a form of hepatitis in which despite the absence of detectable HBsAg, HBV-DNA is observed in peripheral blood of patients. The main aim of this study has been to investigate the association between polymorphisms in +874 of IFN-γ and +1188 of IL-12 with their serum level in patients suffering from OBI.

MATERIALS AND METHODS

In this experimental study, plasma samples of 3700 blood donors were tested for the presence of hepatitis B surface antigen (HBsAg) and anti-HBc by ELISA. The HBsAg-/anti-HBc+ samples were selected and screened for HBV-DNA by PCR. HBV-DNA positive samples were assigned as OBI cases and ARMS-PCR techniques were performed to examine the two known polymorphisms within IL-12 and IFN-γ. In addition, the serum levels of IL-12 and IFN-γ were also determined by ELISA.

RESULTS

Results of this study demonstrated that, 352 (9.5%) out of 3700 blood samples were HBsAg-/anti-HBc+ and HBV-DNA was detected in 57/352 (16.1%) of HBsAg-/anti-HBc+ samples. Our results showed that groups showed significant difference in CC allele of +1188 region of IL-12 and no difference was observed in the other evaluated genes. Our results also showed that the alleles of +1188 region of IL-12 and alleles of +874 of IFN-γ were also not associated with serum level of cytokines.

CONCLUSION

According to the results of this study, it may be concluded that the polymorphisms in +1188 region of IL-12 and +874 region of IFN-γ would not affect the expression of both cytokines at serum level in OBI patients.

Significance of the myxovirus resistance A (MxA) gene -123C>a single-nucleotide polymorphism in suppressed interferon beta induction of severe acute respiratory syndrome coronavirus infection

Myxovirus resistance A (MxA) is an antiviral protein induced by interferon α and β (IFN-α, IFN-β) that can inhibit viral replication. The minor alleles of the -88G>T and -123C>A MxA promoter single-nucleotide polymorphisms (SNPs) are associated with increased promoter activity and altered response to IFN-α and IFN-β treatment. Here, we demonstrate that the 123A minor allele provided stronger binding affinity to nuclear proteins extracted from IFN-β-untreated cells than did the wild-type allele, whereas the -88T allele showed preferential binding after IFN-β stimulation. Endogenous IFN-α and IFN-β induction can be suppressed in severe acute respiratory syndrome (SARS) coronavirus infection. In support of our in vitro findings, a large case-control genetic-association study for SARS coronavirus infection confirmed that the -123A minor-allele carriers were significantly associated with lower risk of SARS coronavirus infection, whereas the -88T minorallele carriers were insignificant after adjustment for confounding effects. This suggests that -123C>A plays a more important role in modulating basal MxA expression, thus contributing more significantly to innate immune response against viral infections that suppress endogenous IFN-α and IFN-β induction such as SARS coronavirus.

The haplotype of the MxA gene promoter is associated with hepatitis B virus infection in a Chinese population

BACKGROUND/AIM

The Myxovirus resistance protein A gene (MxA) is a key component of the innate antiviral response and has previously been shown to inhibit several viruses. This study was designed to assess whether the haplotype in the MxA promoter region was associated with hepatitis B virus (HBV) infection in a Chinese population.

METHODS

Three hundred and twelve HBV-infected patients and 317 healthy volunteers were enrolled in this study. Two polymorphisms of -88 and -123 located in the MxA gene promoter were identified by the polymerase chain reaction-restriction fragment length polymorphism method.

RESULTS

The individual possessing haplotype GA, which was constructed by the two polymorphisms of -88G and -123A in the MxA gene promoter, was significantly associated with HBV infection [possessing one copy odds ratio (OR)=1.69, 95% confidence interval (CI) 1.21-2.35; two copy OR=2.84, 95% CI 1.12-7.21 respectively].

CONCLUSIONS

This case-control study suggested that the haplotype GA in the MxA gene promoter region would increase the susceptibility to HBV infection in a Chinese population.

Influence of a single nucleotide polymorphism in the P1 promoter of the furin gene on transcription activity and hepatitis B virus infection

Hepatitis B e antigen (HBeAg) is a viral strategy of immune response evasion associated with hepatitis B virus (HBV) persistence. Spontaneous HBeAg seroconversion is usually accompanied by liver disease remission. Unfortunately, this goal is difficult to achieve and requires expensive and time-consuming treatment. Furin, a proprotein convertase, is involved in HBeAg maturation and is therefore a potential therapeutic target or indicator for predicting disease progression and antiviral response. Here we demonstrate that healthy Han Chinese from southern China (an endemic area of HBV infection) harbor a common single nucleotide polymorphism (SNP; -229 C/T) in a 1268-bp region of the P1 promoter of the furin gene [FES upstream region (Fur)]. A luciferase reporter gene assay showed that transcription activity is about 3 times higher in allele T carriers than in allele C carriers of this SNP. Allele T includes a suboptimal transcription factor NF-E2 [i.e., nuclear factor (erythroid-derived 2)]-binding motif according to bioinformatics and studies using site-directed mutagenesis. We also observed that individuals carrying allele T were more likely to become persistently infected. When persistently infected patients were divided into subgroups according to recent guidelines and HBeAg-defective virus infection was taken into account, patients with allele T or genotype TT had a decreased likelihood of HBeAg seroconversion or an increased likelihood of progressing to HBeAg-negative chronic hepatitis B or liver cirrhosis if accompanied by HBeAg-defective virus infection.

CONCLUSION

The common SNP in the P1 promoter of the Fur gene affects furin transcription activity and HBV infection outcome, possibly by increasing furin messenger RNA expression, and this suggests that furin is a potential therapeutic target and that this SNP is a potential predictor of disease progression or therapeutic response.