A regulatory polymorphism in interferon-gamma receptor 1 promoter is associated with the susceptibility to chronic hepatitis B virus infection

Deregulation of interferon-gamma receptor 1 expression and its implications for lung adenocarcinoma progression

Interferon-gamma (IFN-γ) plays a dual role in cancer; it is both a pro- and an antitumorigenic cytokine, depending on the type of cancer. The deregulation of the IFN-γ canonic pathway is associated with several disorders, including vulnerability to viral infections, inflammation, and cancer progression. In particular, the interplay between lung adenocarcinoma (LUAD) and viral infections appears to exist in association with the deregulation of IFN-γ signaling. In this mini-review, we investigated the status of the IFN-γ signaling pathway and the expression level of its components in LUAD. Interestingly, a reduction in IFNGR1 expression seems to be associated with LUAD progression, affecting defenses against viruses such as severe acute respiratory syndrome coronavirus 2. In addition, alterations in the expression of IFNGR1 may inhibit the antiproliferative action of IFN-γ signaling in LUAD.

Genome-wide association study identifies several loci for HEV seropositivity

Hepatitis E viral (HEV) infection imposes a heavy global health burden. The variability in the prevalence of serological markers of HEV infection between different ethnic groups proposes a host genetic influence. Here, we report genetic polymorphisms associated with anti-HEV antibody positivity and level using binary- and quantitative-trait genome-wide association studies (GWAS) on a population from Qatar (n = 5829). We identified a region in 12p11.1 (lead SNP: rs559856097, allele: A, p = 2.3 × 10-10) significantly associated with anti-HEV antibodies level. This intergenic variant is located near SNORD112, a small nucleolar RNA (snoRNA). Additional gene-set and pathway enrichment analyses highlighted a strong correlation with anti-viral response-related pathways, including IFNs (alpha/beta) and interleukin-21 (IL-21) signaling. This is the first GWAS on the response to HEV infection. Further replication and functional experimentation are warranted to validate these findings.

Infectious agents and pathogenesis of Behçet's disease: An extensive review

Behçet's disease (BD) is a multisystemic chronic vasculitis. Sustained and enhanced immune responses were reportedly associated with active BD. Although genetic polymorphisms increase development risk, genetic factors alone cannot account for BD development, suggesting the involvement of exogenous factors. Also, how various infectious agents promote BD in high-risk populations is not fully understood. In this review, we summarized the current findings on the associations of infectious agents with BD pathogenesis. The review also highlights the potential microbial risk factors and their pathogenic role in BD progression. Interactions between genetic and infectious risk factors was also discussed. Furthermore, evidence implied that after the eradication of infectious agents, BD symptoms and recurrence decreased, thus highlighting that combined use of antibiotics may be an effective therapy for BD. Finally, we summarized the main limitation of the current related studies, providing valuable insights and a basis for future studies on BD pathogenic factors.

Role of interferon-gamma (IFN-γ) and IFN-γ receptor 1/2 (IFNγR1/2) in regulation of immunity, infection, and cancer development: IFN-γ-dependent or independent pathway

IFN-γ, a soluble cytokine being produced by T lymphocytes, macrophages, mucosal epithelial cells, or natural killer cells, is able to bind to the IFN-γ receptor (IFNγR) and in turn activate the Janus kinase (JAK)-signal transducer and transcription protein (STAT) pathway and induce expression of IFN-γ-stimulated genes. IFN-γ is critical for innate and adaptive immunity and aberrant IFN-γ expression and functions have been associated with different human diseases. However, the IFN-γ/IFNγR signaling could be a double-edged sword in cancer development because the tissue microenvironments could determine its anti- or pro-tumorigenic activities. The IFNγR protein consists of two IFNγR1 and IFNγR2 chains, subunits of which play different roles under certain conditions. This review assessed IFNγR polymorphisms, expression and functions in development and progression of various human diseases in an IFN-γ-dependent or independent manner. This review also discussed tumor microenvironment, microbial infection, and vital molecules in the IFN-γ upstream signaling that might regulate IFNγR expression, drug resistance, and druggable strategy, to provide evidence for further application of IFNγR.

Hepatitis B virus reactivation: overview and management

Hepatitis B virus (HBV) can hide in the liver in the form of covalently closed circular DNA. When the body’s immunity changes, HBV reactivation (HBV-R) can occur. The risk of HBV-R is determined by the complex interaction among virological factors, medication factors and host factors. However, many patients do not know that they are infected with HBV, and doctors often do not invest enough time to systematically evaluate the patient’s HBV-R risk factors before immunosuppressive treatment. Therefore, HBV clinical screening should be vigorously promoted to achieve early detection and early prevention for patients with high risk of HBV-R. The mechanism, clinical features, risk factors, HBV-R under different disease etiologies, prevention and treatment of HBV-R were summarized to improve the in-depth understanding and awareness.

Genetic Association of a Gain-of-Function IFNGR1 Polymorphism and the Intergenic Region LNCAROD/DKK1 With Behçet's Disease

OBJECTIVE

Behçet's disease is a complex systemic inflammatory vasculitis of incompletely understood etiology. This study was undertaken to investigate genetic associations with Behçet's disease in a diverse multiethnic population.

METHODS

A total of 9,444 patients and controls from 7 different populations were included in this study. Genotyping was performed using an Infinium ImmunoArray-24 v.1.0 or v.2.0 BeadChip. Analysis of expression data from stimulated monocytes, and epigenetic and chromatin interaction analyses were performed.

RESULTS

We identified 2 novel genetic susceptibility loci for Behçet's disease, including a risk locus in IFNGR1 (rs4896243) (odds ratio [OR] 1.25; P = 2.42 × 10-9 ) and within the intergenic region LNCAROD/DKK1 (rs1660760) (OR 0.78; P = 2.75 × 10-8 ). The risk variants in IFNGR1 significantly increased IFNGR1 messenger RNA expression in lipopolysaccharide-stimulated monocytes. In addition, our results replicated the association (P < 5 × 10-8 ) of 6 previously identified susceptibility loci in Behçet's disease: IL10, IL23R, IL12A-AS1, CCR3, ADO, and LACC1, reinforcing the notion that these loci are strong genetic factors in Behçet's disease shared across ancestries. We also identified >30 genetic susceptibility loci with a suggestive level of association (P < 5 × 10-5 ), which will require replication. Finally, functional annotation of genetic susceptibility loci in Behçet's disease revealed their possible regulatory roles and suggested potential causal genes and molecular mechanisms that could be further investigated.

CONCLUSION

We performed the largest genetic association study in Behçet's disease to date. Our findings reveal novel putative functional variants associated with the disease and replicate and extend the genetic associations in other loci across multiple ancestries.

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.

Single Nucleotide Polymorphisms in IFN-γ Signaling Pathway Associated with Risk of Hepatitis B Virus Infection in Chinese Children

Hepatitis B virus (HBV) infection is a challenging public health problem in China and worldwide. Mother-to-child transmission is one of the main transmission routes of HBV in highly endemic regions. However, the mechanisms of HBV perinatal transmission in children have not been clearly defined. The aim of this study was to demonstrate the association between single-nucleotide polymorphisms (SNPs) in IFN-γ signaling pathway and HBV infection or breakthrough infection in children. Two hundred and seventy-four HBV-infected children defined as test positive for hepatitis B surface antigen (HBsAg) and 353 controls defined as negative for HBsAg in China were recruited from October 2013 to May 2015. SNPs in IFN-γ signaling pathway including IFNG, IFNGR1, IFNGR2, and IL12B were genotyped. Rs2234711 in IFNGR1 was significantly associated with HBV infection in children (OR = 0.641, 95% CI: 0.450–0.913). In addition, rs2234711 was also significantly associated with HBV breakthrough infection in children born to HBsAg-positive mothers (OR = 0.452, 95% CI: 0.205–0.998). Our study confirmed that genetic variants in IFN-γ signaling pathway have significant associations with HBV infection, especially with HBV breakthrough in children. This study provides insight into HBV infection in children and could be used to help design effective strategies for reducing immunoprophylaxis failure.

Association between TGFβ1 polymorphisms and chronic hepatitis B infection in an Iranian population

INTRODUCTION:

Transforming growth factor-beta 1 (TGFβ1) is a potent suppressive cytokine that contributes to chronic hepatitis B (CHB) infection. Disparities in TGFβ1 production among individuals have been attributed to TGFβ1 genetic polymorphisms. We examined whether three putative polymorphisms in TGFβ1[-509 C/T (rs1800469), +869 C/T (rs1800470), and +11929 C/T (rs1800472)]are associated with CHB infection in a South-Eastern Iranian population.

METHODS:

In total, 341 subjects were recruited, including 178 patients with CHB and 163 healthy individuals as controls. Genotyping of the three TGFβ1 SNPs was performed by tetra amplification refractory mutation system-PCR.

RESULTS:

TheTGFβ1 +869 TT vs.CC genotype in codominant (OR=0.445, p=0.012) and TT vs. TC+CC in the recessive (OR=0.439, p=0.003) model as well as the variant allele T vs. C(OR=0.714, p=0.038) were associated with lower CHB infection risk. However, the +11929 C/T polymorphism was associated with increased CHB risk, and the CT vs. CC genotype (OR=2.77, P=0.001) and T variant allele (OR=2.53, P=0.002) were risk factors for CHB. Furthermore, TTT (+869/-509/+11929) and CCC haplotypes were risk and protective factors for CHB, respectively. We found no significant association between viral DNA load and TGFβ1 genotype or hepatic enzyme levels (p >0.05).

CONCLUSIONS:

Results indicated that the TGFβ1+869TT genotype and T allele were protective factors, whereas the +11929 CT genotype and T allele were risk factors for CHB infection.

聚乙二醇干扰素α-2a对慢性乙型肝炎患者外周血单个核细胞表面IFNGR1的影响

目的

研究聚乙二醇干扰素α-2a(polyethylene glycol interferon α-2a, PEG-IFNα-2a)对慢性乙型肝炎(chronic hepatitis B, CHB)患者外周血中干扰素-γ(interferon-gamma, IFN-γ)及γ干扰素受体1(interferon gamma receptor 1, IFNGR1)水平的影响.

方法

应用PEG-IFNα-2a治疗的不同时间点抽取CHB患者及健康对照组静脉血, 酶联免疫吸附法检测其血清IFN-γ浓度, 实时荧光定量RT-PCR技术检测其外周血单个核细胞(peripheral blood mononuelear cells, PBMCs)表面IFNGR1的表达情况.

结果

CHB组患者IFN-γ及IFNGR1均高于健康对照组(P<0.05). 在使用聚乙二醇干扰素抗病毒治疗过程中, CHB患者IFN-γ及IFNGR1在12 wk时达到高峰, 此后开始下降, 至48 wk时低于治疗前水平, 但仍高于健康对照组(P<0.05). 抗病毒治疗12 wk时, 乙型肝炎病毒(hepatitis B virus，HBV)DNA阴转组IFNGR1的表达水平高于HBV DNA未阴转组(2.22±0.65 vs 1.35±0.71), 两者差异有统计学意义(P<0.05).

结论

IFN-γ参与了CHB的发病, 治疗12 wk时患者PBMCs表面IFNGR1的表达水平可能作为干扰素抗HBV治疗早期预测干扰素疗效的因子.

Single nucleotide polymorphisms of IFNγ (+874 A/T) and IFNγR1 (-56 C/T) in Iranian patients with TB

BACKGROUND

Two important genes for controlling TB are IFNγ and IFNγR1. However, little information exists regarding genetic susceptibility of the Iranian TB population.

METHODS

We investigated the single nucleotide polymorphisms (SNPs) in genes of IFNγ (+874 A/T) and IFNγR1 (-56 C/T) and serum level of IFNγ and their influence on TB in patients; 300 patients with TB and 300 healthy controls were enrolled in this study. PCR-restriction fragment length polymorphism was used to identify SNPs and serum level of IFNγ was measured by ELISA.

RESULTS

The allelic and the genotypic form of IFNγ+874 A/T SNP of the studied population were not significant (p>0.05). Allele T frequencies of IFNγR1 -56 C/T promoter region in patients with pulmonary TB (PTB) or extrapulmonary TB (EPTB) were significantly greater than allele C. The -56 TT motif of IFNγR1 is associated with both forms of TB (p<0.05). The serum level of IFNγ was significantly higher in patients with TB than in controls, but there was no significant difference between serum level of IFNγ and the studied genotypes (p>0.05).

CONCLUSIONS

The cause of active TB in the patients seems to be due to the lack of effective IFNγ function or the lack of effective signaling connection between IFNγ and its receptor in presence of -56 C/T polymorphism in promoter region of IFNγR1 gene.

Missense splice variant (g.20746A>G, p.Ile183Val) of interferon gamma receptor 1 (IFNGR1) coincidental with mycobacterial osteomyelitis - a screen of osteoarticular lesions

Previously, dominant partial interferon-gamma receptor 1 (IFN-g-R1) susceptibility to environmental mycobacteria was found with IFNGR1 deletions or premature stop. Our aim was to search for IFNGR1 variants in patients with mycobacterial osteoarticular lesions. Biopsies from the patients were examined for acid-fast bacilli, inflammatory cell infiltration, and mycobacterial niacin. Mycobacterial rRNA was analyzed using a target-amplified rRNA probe test. Peripheral-blood-leukocyte genomic DNA was isolated from 19 patients using the QIAamp DNA Mini Kit, and all IFNGR1 exons were sequenced using an ABIPRISM 3130 device. After the discovery of an exon 5 variant, a Polish newborn population sample (n = 100) was assayed for the discovered variant. Splice sites and putative amino acid interactions were analyzed. All patients tested were positive for mycobacteria; one was heterozygous for the IFNGR1 exon 5 single-nucleotide-missense substitution (g.20746A>G, p.Ile183Val). No other variant was found. The splice analysis indicated the creation of an exonic splicing silencer, and alternatively, molecular graphics indicated that the p.Ile183Val might alter beta-strand packing (loss of van der Waals contacts; Val183/Pro205), possibly altering the IFN-g-R1/IFN-g-R2 interaction. The probability of non-deleterious variant was estimated as <10%. Heterozygous IFNGR1:p.Ile183Val (frequency 0.003%) was found to be coincidental with mycobacterial osteomyelitis. The small amount of variation detected in the patients with osteoarticular lesions indicates that screens should not yet be restricted: Intronic variants should be analyzed as well as the other genes affecting Type 1 T-helper-cell-mediated immunity.

Human Cytokine Genetic Variants Associated With HBsAg Reverse Seroconversion in Rituximab-Treated Non-Hodgkin Lymphoma Patients

Hepatitis B virus (HBV) reactivation has been noted in HBV surface antigen (HBsAg)-seronegative patients with CD20 B-cell non-Hodgkin lymphoma (NHL) undergoing rituximab treatment. Clinically, hepatitis flares are usually associated with the reappearance of HBsAg (reverse seroconversion of HBsAg, HBV-RS). It is unclear whether human genetic factors are related to rituximab-associated HBV reactivation. Unvaccinated HBsAg-seronegative adults (n = 104) with CD20 NHL who had received rituximab-containing therapy without anti-HBV prophylaxis were enrolled. Eighty-nine candidate single nucleotide polymorphisms (SNPs) of 49 human cytokine genes were chosen and were analyzed using the iPLEX technique. Competing risk regression was used to identify the factors associated with HBV-RS. Participants had a median age of 66.1 years and 56.7% were male (n = 59). The anti-HBs and anti-HBc positivity rates were 82.4% and 94.1%, respectively, among patients for whom data were available (approximately 81%). A mean of 7.14 cycles of rituximab therapy were administered, and a total of 14 (13.4%) patients developed HBV-RS. Nine SNPs showed significant differences in frequency between patients with or without HBV-RS: CD40 rs1883832, IL4 rs2243248 and rs2243263, IL13 rs1295686, IL18 rs243908, IL20 rs1518108, and TNFSF13B rs12428930 and rs12583006. Multivariate analysis showed that ≥6 cycles of rituximab therapy, IL18 rs243908, and the IL4 haplotype rs2243248∼rs2243263 were independently associated with HBV-RS. The IL4 haplotype rs2243248∼rs2243263 was significantly associated with HBV-RS regardless of anti-HBs status. Polymorphisms in human cytokine genes impact the risk of rituximab-associated HBV-RS.

Association of Genetic Polymorphisms of IFNGR1 with the Risk of Pulmonary Tuberculosis in Zahedan, Southeast Iran

Aim. The present study was undertaken to find out the possible association between interferon-gamma (IFN-γ) receptor 1 (IFNGR1) gene polymorphisms and risk of pulmonary tuberculosis (PTB) in a sample of Iranian population. Methods. Polymorphisms of IFNGR1 rs1327474 (−611 A/G), rs11914 (+189 T/G), rs7749390 (+95 C/T), and rs137854905 (27-bp ins/del) were determined in 173 PTB patients and 164 healthy subjects. Results. Our findings showed that rs11914 TG genotypes decreased the risk of PTB in comparison with TT (OR = 0.36, 95% CI = 0.21–0.62, and p = 0.0002). The rs11914 G allele decreased the risk of PTB compared with T allele (OR = 0.41, 95% CI = 0.25–0.68, and p = 0.0006). IFNGR1 rs7749390 CT genotype decreased the risk of PTB in comparison with CC genotype (OR = 0.55, 95% CI = 0.32–0.95, and p = 0.038). No significant association was found between IFNGR1 rs1327474 A/G polymorphism and risk/protective of PTB. The rs137854905 (27-bp I/D) variant was not polymorphic in our population. Conclusion. Our findings showed that IFNGR1 rs11914 and rs7749390 variants decreased the risk of PTB susceptibility in our population.

Host genetic variants influencing the clinical course of hepatitis B virus infection

The clinical course of hepatitis B virus (HBV) infection greatly differs in individuals. Various viral, host, and environmental factors influence the natural history of HBV infection. Recent genome-wide association studies identified several host genetic factors influencing the clinical course of HBV infection. Genetic variations in HLA class II loci were significantly associated with susceptibility to persistent HBV infection. Other polymorphisms in or near the genes EHMT2, TCF19, and HLA-C, located near HLA class II loci, and UBE2L3 were also associated with persistent HBV infection. Meanwhile, polymorphisms in KIF1B, GRIK1, and STAT4 were associated with HBV-related hepatocellular carcinoma (HCC). Interestingly, HLA class II genetic variations were strongly associated with not only persistent HBV infection, but also disease progression and HBV-related HCC in chronic hepatitis B. Understanding the various genetic factors associated with the clinical course of HBV infection is essential for personalized treatment and surveillance of disease progression and HCC.

Insights into the possible role of IFNG and IFNGR1 in Kala-azar and Post Kala-azar Dermal Leishmaniasis in Sudanese patients

BACKGROUND

Little is known about the parasite/host factors that lead to Post Kala-azar Dermal Leishmaniasis (PKDL) in some visceral leishmaniasis (VL) patients after drug-cure. Studies in Sudan provide evidence for association between polymorphisms in the gene (IFNGR1) encoding the alpha chain of interferon-γ receptor type I and risk of PKDL. This study aimed to identify putative functional polymorphisms in the IFNGR1 gene, and to determine whether differences in expression of interferon-γ (IFNG) and IFNGR1 at the RNA level are associated with pathogenesis of VL and/or PKDL in Sudan.

METHODS

Sanger sequencing was used to re-sequence 841 bp of upstream, exon1 and intron1 of the IFNGR1 gene in DNA from 30 PKDL patients. LAGAN and SYNPLOT bioinformatics tools were used to compare human, chimpanzee and dog sequences to identify conserved noncoding sequences carrying putative regulatory elements. The relative expression of IFNG and IFNGR1 in paired pre- and post-treatment RNA samples from the lymph nodes of 24 VL patients, and in RNA samples from skin biopsies of 19 PKDL patients, was measured using real time PCR. Pre- versus post-treatment expression was evaluated statistically using the nonparametric Wilcoxon matched pairs signed-rank test.

RESULTS

Ten variants were identified in the 841 bp of sequence, four of which are novel polymorphisms at -77A/G, +10 C/T, +18C/T and +91G/T relative to the IFNGR1 initiation site. A cluster of conserved non-coding sequences with putative regulatory variants was identified in the distal promoter of IFNGR1. Variable expression of IFNG was detected in lymph node aspirates of VL patients before treatment, with a marked reduction (P = 0.006) in expression following treatment. IFNGR1 expression was also variable in lymph node aspirates from VL patients, with no significant reduction in expression with treatment. IFNG expression was undetectable in the skin biopsies of PKDL cases, while IFNGR1 expression was also uniformly low.

CONCLUSIONS

Uniformly low expression of IFN and IFNGR1 in PKDL skin biopsies could explain parasite persistence and is consistent with prior demonstration of genetic association with IFNGR1 polymorphisms. Identification of novel potentially functional rare variants at IFNGR1 makes an important general contribution to knowledge of rare variants of potential relevance in this Sudanese population.

Single nucleotide polymorphisms within interferon signaling pathway genes are associated with colorectal cancer susceptibility and survival

Interferon (IFN) signaling has been suggested to play an important role in colorectal carcinogenesis. Our study aimed to examine potentially functional genetic variants in interferon regulatory factor 3 (IRF3), IRF5, IRF7, type I and type II IFN and their receptor genes with respect to colorectal cancer (CRC) risk and clinical outcome. Altogether 74 single nucleotide polymorphisms (SNPs) were covered by the 34 SNPs genotyped in a hospital-based case-control study of 1327 CRC cases and 758 healthy controls from the Czech Republic. We also analyzed these SNPs in relation to overall survival and event-free survival in a subgroup of 483 patients. Seven SNPs in IFNA1, IFNA13, IFNA21, IFNK, IFNAR1 and IFNGR1 were associated with CRC risk. After multiple testing correction, the associations with the SNPs rs2856968 (IFNAR1) and rs2234711 (IFNGR1) remained formally significant (P = 0.0015 and P<0.0001, respectively). Multivariable survival analyses showed that the SNP rs6475526 (IFNA7/IFNA14) was associated with overall survival of the patients (P = 0.041 and event-free survival among patients without distant metastasis at the time of diagnosis, P = 0.034). The hazard ratios (HRs) for rs6475526 remained statistically significant even after adjustment for age, gender, grade and stage (P = 0.029 and P = 0.036, respectively), suggesting that rs6475526 is an independent prognostic marker for CRC. Our data suggest that genetic variation in the IFN signaling pathway genes may play a role in the etiology and survival of CRC and further studies are warranted.

Genetic polymorphisms of IFNG and IFNGR1 in association with the risk of pulmonary tuberculosis

OBJECTIVE

Genetic host factors play an important role in controlling individual's susceptibility to the pathogen. This study aims to explore the single and joint effect of genetic polymorphisms of interferon-gamma (IFNG) and its receptor (IFNGR1) in association with the pulmonary tuberculosis in a Chinese Han population.

METHODS

This population-based case control study consisted of 1434 pulmonary tuberculosis patients and 1412 healthy controls. Six tag SNPs in IFNG/IFNGR1 were genotyped using TaqMan allelic discrimination technology. The logistic regression model was carried out to analyze the associations between the genotypes and haplotypes and the risk of tuberculosis by calculating the odds ratio (OR) and 95% confidence interval (CI).

RESULTS

After the Bonferroni correction for multiple comparisons, three SNPs (rs2234711, rs1327475 and rs7749390) in IFNGR1 gene were observed to be significantly associated with the altered risks of tuberculosis. For the SNP rs2234711, individuals carrying C allele (vs. T) showed a decreased risk, with the adjusted OR(95% CI) of 0.82(0.76-0.91). The additive model revealed that each additional allele contributed about 14% decreased risk (OR: 0.86, 95% CI: 0.77-0.95). Moreover, we observed a strong linkage disequilibrium between rs2234711 and rs3799488. Compared with the common rs2234711C-rs3799488C haplotype, the haplotype rs2234711T-rs3799488C contributed to a significant increase in the risk of tuberculosis (adjusted OR: 1.24, 95% CI: 1.09-1.41).

CONCLUSIONS

Our results suggest that genetic polymorphisms in IFNGR1 gene are involved in the risk of tuberculosis in the Chinese population. Future studies should include a comprehensive sequencing analysis to identify the specific causative sequence variants underlying the observed associations.

IFNG and IFNGR1 gene polymorphisms in children with nonresponse to the hepatitis B vaccine

ABSTRACT: 

Aim: We investigated the +874 T/A polymorphism in the first intron of the IFNG gene and intronic (CA)n polymorphic microsatellite marker of the IFNGR 1 gene in child nonresponders to hepatitis B vaccination. Materials & methods: A total of 100 children who had anti-HBs antibody levels <10 mIU/ml after vaccination against hepatitis B were included as a nonresponder group and 100 children who had anti-HBs antibody levels >10 mIU/ml after vaccination against hepatitis B were included as a responder group. Results: The frequency of the TT genotype of the IFNG (+874 T/A) gene polymorphism was higher in nonresponders (p = 0.003). The frequencies of alleles 170 and 182 for (CA)n alleles for the intronic (CA)n microsatellite of IFNGR1 were significantly higher in nonresponders (for each, p < 0.05). Conclusion: The TT genotype of the IFNG (+874 T/A) gene, and alleles 170 and 182 for (CA)n alleles for the intronic (CA)n microsatellite of the IFNGR1 gene, may be associated with nonresponse to hepatitis B vaccination.

Host Gene Polymorphisms in Relation to Helicobacter Pylori Infection and Associated Diseases in a Population Based Cohort

Background

This prospective population based cohort study explores possible associations between host gene polymorphisms, blood group and life style factors on the one hand, and Helicobacter pylori infection, peptic ulcer, and the grade of inflammation, atrophy and intestinal metaplasia of the gastric mucosa, on the other hand.

Methods

The study population (472 volunteers) has previously undergone screening with gastroduodenoscopy, biopsy and blood sampling. The host gene polymorphisms of IL1B-31C/T, IFNGR1-56T/C, the IL1RN VNTR in exon 2 and the HLA-DRB1 gene alleles were analyzed using PCR and pyrosequencing.

Results

H. pylori infection was negatively related to HLA DRB1*03 (odds ratio (OR) 95% CI: 0.388 - 0.989) and was more frequent in individuals with blood group O than A (OR 95% CI: 1.121 - 2.677). There was a lower risk of moderate to severe inflammation in the antrum among individuals with IL1B-31 TC compared to CC carriers (OR 95% CI: 0.094 - 0.733). The IL1RN*L2 genotype was associated with higher risk of IM in the antrum than the *LL genotype (OR 95% CI: 1.570 - 15.878). There was a negative relation between the HLA DRB1 alleles *04 (OR 95% CI: 0.234 - 0.831) and *08 (OR 95% CI: 0.013 - 0.915), and IM in the antrum.

Conclusion

The IL1RN VNTR and the IL1β-31 alleles seem to be associated with intestinal metaplasia of the corpus mucosa and the grade of inflammation of the antrum, respectively. However, no unambiguous correlations could be identified between the host polymorphisms and the occurrence of H. pylori infection, peptic ulcer, and the grade of inflammation, atrophy and IM of the gastric mucosa.

Genome-wide association study of chronic hepatitis B virus infection reveals a novel candidate risk allele on 11q22.3

BACKGROUND

Hepatitis B virus (HBV) affects millions of people worldwide. While some people are able to clear the virus following the first encounter, those who develop chronic infection manifest remarkable clinical heterogeneity that ranges from asymptomatic carrier state to cirrhosis and hepatocellular carcinoma. Despite extensive studies, little is known about genetic host factors that influence the outcome of chronic HBV infection. Thus, we conducted this study to investigate the genetic risk of developing active liver disease among chronic carriers of HBV.

METHODS

In this study, we conducted a genome-wide association study (GWAS) on a cohort of patients with chronic HBV infection.

RESULTS

One particular SNP that is 16 kb upstream of Ferredoxin 1 was found to have an association with complicated chronic HBV infection (cirrhosis and hepatocellular carcinoma) that reached GWAS significance, and was successfully validated on an independent set of samples.

CONCLUSIONS

This first GWAS in an Arab population further demonstrates the utility of this approach in elucidating the genetic risk of HBV infection-related complications and highlights the advantage of conducting GWAS in different ethnicities to achieve that goal.

Type I IFNs downregulate myeloid cell IFN-γ receptor by inducing recruitment of an early growth response 3/NGFI-A binding protein 1 complex that silences ifngr1 transcription

The ability of type I IFNs to increase susceptibility to certain bacterial infections correlates with downregulation of myeloid cell surface IFNGR, the receptor for the type II IFN (IFN-γ), and reduced myeloid cell responsiveness to IFN-γ. In this study, we show that the rapid reductions in mouse and human myeloid cell surface IFNGR1 expression that occur in response to type I IFN treatment reflect a rapid silencing of new ifngr1 transcription by repressive transcriptional regulators. Treatment of macrophages with IFN-β reduced cellular abundance of ifngr1 transcripts as rapidly and effectively as actinomycin D treatment. IFN-β treatment also significantly reduced the amounts of activated RNA polymerase II (pol II) and acetylated histones H3 and H4 at the ifngr1 promoter and the activity of an IFNGR1-luc reporter construct in macrophages. The suppression of IFNGR1-luc activity required an intact early growth response factor (Egr) binding site in the proximal ifngr1 promoter. Three Egr proteins and two Egr/NGFI-A binding (Nab) proteins were found to be expressed in bone macrophages, but only Egr3 and Nab1 were recruited to the ifngr1 promoter upon IFN-β stimulation. Knockdown of Nab1 in a macrophage cell line prevented downregulation of IFNGR1 and prevented the loss of acetylated histones from the ifngr1 promoter. These data suggest that type I IFN stimulation induces a rapid recruitment of a repressive Egr3/Nab1 complex that silences transcription from the ifngr1 promoter. This mechanism of gene silencing may contribute to the anti-inflammatory effects of type I IFNs.

An association study of functional polymorphic genes IRF-1, IFNGR-1, and IFN-γ with disease progression, aspartate aminotransferase, alanine aminotransferase, and viral load in chronic hepatitis B and C

BACKGROUND

Investigational approaches based on genome-wide association studies have proven useful in identifying genetic predictors for many diseases, including susceptibility to chronic hepatitis B and C. In these studies, the majority of genetic variants that have shown a positive association have been identified in genes involved in the immune response. In this study IFN-γ, IFNGR-1, and IRF-1 genes were analyzed for their role in susceptibility to the development of chronic hepatitis B and chronic hepatitis C in a Turkish population.

METHODS

Polymorphic genes IRF-1 (-410, -388), IFNGR-1 (-56, -611), and IFN-γ (+874) were analyzed in a total of 400 individuals: 100 chronic hepatitis B patients, 100 hepatitis B carriers, 100 chronic hepatitis C patients, and 100 healthy controls. A single base primer extension assay was used. Correlations between genes and gender, viral load, and aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were also investigated.

RESULTS

The IRF-1 gene at positions -388 and -410 were observed to be candidate gene markers for susceptibility to the development of chronic hepatitis B and C (p<0.05). IFN-γ +874 and IFNGR-1 (-56 and -611) correlated with chronic hepatitis B but not chronic hepatitis C. Correlation of functional genotype with viral load and AST and ALT levels revealed an association of IFN-γ +874 and IFNGR-1 -611 with chronic hepatitis C and IFN-γ +874 with viral load and chronic hepatitis B (p<0.05).

CONCLUSIONS

Findings suggest that IFN-γ (+874), IRF-1 (-410, -388), and IFNGR-1 (-56, -611) are candidate gene markers for determining patient susceptibility to the development of chronic hepatitis B and C.

IFNγR signaling mediates alloreactive T-cell trafficking and GVHD

The clinical goal of allogeneic hematopoietic stem cell transplantation (allo-HSCT) is to minimize GVHD while maintaining GvL. Here, we show that interferon γ receptor-deficient (IFNγR(-/-)) allogeneic Tconv, which possess normal alloreactivity and cytotoxicity, induce significantly less GVHD than wild-type (WT) Tconv. This effect is mediated by altered trafficking of IFNγR(-/-) Tconv to GVHD target organs, especially the gastrointestinal (GI) tract. We show that the chemokine receptor CXCR3 is induced via IFNγR-mediated signaling and partially contributes to the trafficking of WT Tconv to GVHD target organs. Indeed, CXCR3(-/-) Tconv recapitulate the reduced GVHD potential of IFNγR(-/-) Tconv in a minor-mismatched GVHD model. Most importantly, IFNγR(-/-) (and CXCR3(-/-)) Tconv mediate a robust and beneficial GvL effect. In addition, we show that IFNγR(-/-) regulatory T cells (Tregs) are fully suppressive in vitro although defective in suppressor function in vivo and that WT Tregs suppress GVHD in vivo only when allogeneic Tconv produce interferon γ (IFNγ), suggesting that the IFNγR signaling pathway is the major mechanism for both Tregs and Tconv to migrate to GVHD target organs. Finally, pharmacologic inhibition of IFNγR signaling with inhibitors of JAK1/JAK2, which are mediators of IFNγR signaling, results in the decreased expression of CXCR3 and reduced GVHD and improved survival after allo-HSCT and this effect is mediated by altered trafficking of Tconv to GVHD target organs.

Polymorphisms within the Promoter Region of the Gamma Interferon (IFN-γ) Receptor1 Gene are Associated with the Susceptibility to Chronic HBV Infection in an Iranian Population

BACKGROUND

chronic hepatitis B virus (HBV) infection is a multifactorial disease that can result in serious clinical complications. Host genetic background especially the genes that encode immunologic factors like INF-γ and its receptor (IFN-γ R) are critical in the pathogenesis of infection.

OBJECTIVES

The current study aimed to investigate the association between two single nucleotide polymorphisms (SNPs) at positions -611 and -56 within the promoter region of gamma interferon receptor1 gene (IFN-γ R1) and chronic HBV infection.

MATERIALS AND METHODS

Genomic DNA from peripheral blood samples of 200 chronically HBV infected patients and 200 healthy blood donors, as controls, were collected and genomic DNA was extracted by phenol-chloroform method and DNA analysis genotype identification was performed by PCR-RFLP.

RESULTS

The results indicated that both SNP's frequency had a significant difference in the patient and control groups. At position -56, TT genotype was associated with patient group and P value was 0.002 and at position -611, GG genotype was further observed in control group and P value was 0.006.

CONCLUSIONS

Presence of G allele at position -611 within promoter of IFN-γ R1 gene in the enrolled population for the study was related to lower risk of disease, and presence of T allele at position -56 was also related to susceptibility to chronic HBV infection. Men had higher frequency of chronic HBV infection, which might be the result of high risk behavior.

Gamma interferon controls mouse polyomavirus infection in vivo

Human polyomaviruses are associated with substantial morbidity in immunocompromised patients, including those with HIV/AIDS, recipients of bone marrow and kidney transplants, and individuals receiving immunomodulatory agents for autoimmune and inflammatory diseases. No effective antipolyomavirus agents are currently available, and no host determinants have been identified to predict susceptibility to polyomavirus-associated diseases. Using the mouse polyomavirus (MPyV) infection model, we recently demonstrated that perforin-granzyme exocytosis, tumor necrosis factor alpha (TNF-α), and Fas did not contribute to control of infection or virus-induced tumors. Gamma interferon (IFN-γ) was recently shown to inhibit replication by human BK polyomavirus in primary cultures of renal tubular epithelial cells. In this study, we provide evidence that IFN-γ is an important component of the host defense against MPyV infection and tumorigenesis. In immortalized and primary cells, IFN-γ reduces expression of MPyV proteins and impairs viral replication. Mice deficient for the IFN-γ receptor (IFN-γR(-/-)) maintain higher viral loads during MPyV infection and are susceptible to MPyV-induced tumors; this increased viral load is not associated with a defective MPyV-specific CD8(+) T cell response. Using an acute MPyV infection kidney transplant model, we further show that IFN-γR(-/-) donor kidneys harbor higher MPyV levels than donor kidneys from wild-type mice. Finally, administration of IFN-γ to persistently infected mice significantly reduces MPyV levels in multiple organs, including the kidney, a major reservoir for persistent mouse and human polyomavirus infections. These findings demonstrate that IFN-γ is an antiviral effector molecule for MPyV infection.

Molecular immunity to mycobacteria: knowledge from the mutation and phenotype spectrum analysis of Mendelian susceptibility to mycobacterial diseases

Understanding molecular immunity against mycobacterial infection is critical for the development of effective strategies to control tuberculosis (TB), which is a major health issue in the developing world. Host immunogenetic studies represent an indispensable approach to understand the molecular mechanisms against mycobacterial infection. A superb paradigm is the identification of rare mutations causing Mendelian susceptibility to mycobacterial diseases (MSMD). Mutations in the interferon-gamma (IFN-γ) receptor genes are highly specific (although not exclusive) for mycobacterial infection. Only dominant negative mutations of STAT1 have specific susceptibility to mycobacterial infection. Mutations in the interleukin-12 (IL-12) signaling genes have phenotypes with non-specificity. Current studies highlight a complex molecular network in antimycobacterial immunity, centered on IFN-γ signaling.

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.

Association of NKG2D genetic polymorphism with susceptibility to chronic hepatitis B in a Han Chinese population

Natural killer (NK) cells are important antiviral effectors of innate immunity because of their contribution to virus elimination. NK cell-mediated immunological reaction to hepatitis B virus (HBV) infection depends on a fine balance between inhibitory and activating receptors. The aim of the study was to investigate genetic polymorphisms in NK cell receptors (NKR)-KLRD1 (CD94), KLRK1 (NKG2D), KLRC4 (NKG2F), and KLRC1 (NKG2A)-to evaluate the association of NKR genetic polymorphisms with susceptibility to chronic hepatitis B in a Han Chinese population. Twelve single nucleotide polymorphisms (SNPs), including rs2302489 in CD94; rs2255336, rs2617160, rs7980470, rs 2734565, and rs17513986 in NKG2D; rs2617170, rs17549004, and rs3825295 in NKG2F; rs2734414, rs7301582, and rs2734440 in NKG2A, were selected in the present study. SNP genotyping was undertaken in 500 Han Chinese patients (285 patients with chronic hepatitis B and 215 patients who cleared HBV spontaneously) by a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and by the TaqMan method. Single marker association analysis was conducted and the SNP rs2617160 with a TT genotype in NKG2D was associated significantly with an increased risk of chronic hepatitis B (P = 0.044; OR = 1.49; 95% CI = 1.01-2.19). Haplotype analysis with multiple loci indicated that there was no significant association between the haplotypes of the NKR genes and susceptibility to chronic hepatitis B. The SNP rs2617160 in NKG2D associated with susceptibility to chronic hepatitis B in a Han Chinese population.

Viral hepatitis: human genes that limit infection

Treatment response and susceptibility to chronic viral hepatitis C and B may be modified by host genetic factors. The majority of genetic variants that confer a significant risk have been localized in genes involved in immune response. However, many findings could not be replicated and almost none of the identified risk factors had a noticeable impact on clinical decisions. In contrast, recent findings in independent large genome wide association studies confirmed genetic variants in the interferon gamma gene locus as strong predictors of outcome with outstanding clinical relevance. This review gives an overview on significant genetic susceptibility factors for susceptibility and treatment outcome in chronic viral hepatitis C and B that have been identified by the classical candidate gene approach and genome wide studies and also highlights some recent findings on genetic factors for common adverse drug reactions.