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

Genetic associations in chronic hepatitis B infection: toward developing polygenic risk scores

Chronic hepatitis B (CHB) infection results in multiple clinical phenotypes of varying severity. One of the critical gaps in CHB management is the lack of a genetic-based tool to aid existing hepatocellular carcinoma and cirrhosis risk stratification models for patients with active CHB. Such individual predictive models for CHB are plagued by an inherent limitation of discriminatory power that clearly indicates the need for their improvement. In this article, we highlight genetic association studies in CHB that identified HLA and cytokine genetic susceptibility loci to CHB. We advance the position that translating CHB genetic susceptibility loci into polygenic risk scores will be a welcome addendum to the current arsenal of CHB outcome predictive models. We conclude with comments on hurdles that future research efforts should address within the research enclave of CHB and advocate for increased genetic data representation from sub-Saharan Africa.

Human genetic susceptibility to hepatitis B virus infection

Hepatitis B virus (HBV) infection is still a serious health threat worldwide. The outcomes of HBV infection consist of spontaneous HBV clearance and chronic HBV infection. Multiple factors contribute to the disparity of HBV infection outcomes, including host factors, viral factors and environmental factors. The present review comprehends the current researches mainly focusing on the relationships between genetic determinants, including single nucleotide polymorphisms (SNPs) and haplotypes, and susceptibility of HBV infection, namely chronic (persistent) HBV infection and HBV clearance. A number of determinants in the chromosomes, including mutations in human leukocyte antigens (HLAs), cytokines genes, toll-like receptors (TLRs), and other genes are related to the human susceptibility to HBV infection. Among the above variants, some of those in HLAs have been studied and replicated in multiple-ethnic populations and came to consistent conclusions, while some others are novel and need to be evaluated further.

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.

Association of NOD2 and IFNG single nucleotide polymorphisms with leprosy in the Amazon ethnic admixed population

Leprosy is a chronic infectious disease, caused by Mycobacterium leprae, which affects skin and peripheral nerves. Polymorphisms in genes associated with autophagy, metabolism, innate and adaptive immunity confer susceptibility to leprosy. However, these associations need to be confirmed through independent replication studies in different ethnicities. The population from Amazon state (northern Brazil) is admixed and it contains the highest proportion of Native American genetic ancestry in Brazil. We conducted a case-control study for leprosy in which we tested fourteen previously associated SNPs in key immune response regulating genes: TLR1 (rs4833095), NOD2 (rs751271, rs8057341), TNF (rs1800629), IL10 (rs1800871), CCDC122/LACC1 (rs4942254), PACRG/PRKN (rs9356058, rs1040079), IFNG (rs2430561), IL6 (rs2069845), LRRK2 (rs7298930, rs3761863), IL23R (rs76418789) and TYK2 (rs55882956). Genotyping was carried out by allelic discrimination in 967 controls and 412 leprosy patients. Association with susceptibility was assessed by logistic regression analyses adjusted for the following covariates: gender, age and ancestry. Genetic ancestry was similar in case and control groups. Statistically significant results were only found for IFNG and NOD2. The rs8057341 polymorphism within NOD2 was identified as significant for the AA genotype (OR = 0.56; 95% CI, 0.37-0.84; P = 0.005) and borderline for the A allele (OR = 0.76; 95% CI, 0.58-1.00; P = 0.053) and carrier (OR = 0.76; 95% CI, 0.58-1.00; P = 0.051). The rs2430561 SNP in IFNG was associated with disease susceptibility for the AT genotype (OR = 1.40; 95% CI, 1.06-1.85; P = 0.018) and carrier (OR = 1.44; 95% CI, 1.10-1.88; P = 0.008). We confirmed that NOD2 and IFNG are major players in immunity against M.leprae in the Amazon ethnic admixed population.

Host Genetic Determinants of Hepatitis B Virus Infection

Chronic hepatitis B virus (HBV) infection is still a major health problem worldwide. Recently, a great number of genetic studies based on single nucleotide polymorphisms (SNPs) and genome-wide association studies have been performed to search for host determinants of the development of chronic HBV infection, clinical outcomes, therapeutic efficacy, and responses to hepatitis B vaccines, with a focus on human leukocyte antigens (HLA), cytokine genes, and toll-like receptors. In addition to SNPs, gene insertions/deletions and copy number variants are associated with infection. However, conflicting results have been obtained. In the present review, we summarize the current state of research on host genetic factors and chronic HBV infection, its clinical type, therapies, and hepatitis B vaccine responses and classify published results according to their reliability. The potential roles of host genetic determinants of chronic HBV infection identified in these studies and their clinical significance are discussed. In particular, HLAs were relevant for HBV infection and pathogenesis. Finally, we highlight the need for additional studies with large sample sizes, well-matched study designs, appropriate statistical methods, and validation in multiple populations to improve the treatment of HBV infection.

High expression of ubiquitin carboxyl-terminal hydrolase 22 is associated with poor prognosis in hepatitis B virus-associated liver cancer

Deubiquitinating enzymes regulate protein activity and cell homeostasis by removing ubiquitin moieties from various substrates. Ubiquitin carboxyl-terminal hydrolase 22 (USP22) is a member of the deubiquitinating protease family and is associated with the development of several tumor types. A previous study demonstrated that USP22 is highly expressed in liver cancer, and its high expression is associated with resistance to chemotherapy. However, the role of USP22 in hepatitis B virus (HBV)-associated liver cancer has not yet been elucidated. The current study demonstrated that USP22 was highly expressed in the tissues of patients with HBV-associated liver cancer, and its high expression was associated with clinicopathological characteristics, including tumor size, clinical stage and prognosis. Further results indicated that USP22 may regulate the proliferative and apoptotic abilities of HepG2.2.15 cells. Additionally, investigation into the underlying mechanism, using small interfering RNA, revealed that the downregulation of USP22 inhibited proliferation and promoted apoptosis though the phosphoinositide 3-kinase/protein kinase B signaling pathway. Therefore, USP22 has the potential to be used as an independent predictor of patient prognosis, as well as a therapeutic target for the treatment of HBV-associated liver cancer.

IFNG +874 A/T is associated with acute lymphoblastic leukemia in Mexican Mestizos

Acute lymphoblastic leukemia (ALL), the most common type of cancer in children worldwide, has one of the highest incidence rates in Mexico. It is a multifactorial disease and different cytokine single nucleotide polymorphisms (SNP), have been associated with ALL expression. Few studies have been published analyzing IFNG +874 T/A and IL2 -330 G/T in this type of leukemia. These SNPs are involved in high or low expression, and are central to cellular immunity, influencing greatly tumor growth. The purpose of this work was to explore the association of IFNG +874 A/T (rs2430561) and IL2 -330 G/T (rs2069762) SNPs with ALL susceptibility and/or protection in 488 Mexican Mestizos patients, as compared to 950 Mexican Mestizo healthy controls. The results demonstrated that IFNG +874 T allele (pc = 0.00004, OR = 0.673) and the TT genotype (pc = 0.00015, OR = 0.349), protect against ALL expression with no specific gender association; however, the TT homozygote genotype (vs. TA+AA) seems more protective in males (pc = 0.00683). IL2 -330 G/T does not contribute to the development of ALL. In healthy Mexicans, the most common genotypes for IL2 and IFNG, are the low cytokine producers, suggesting that the genetic background in this ethnic group, may be partly responsible for the high incidence of ALL. These results show for the first time in Mexicans, the relevant role that IFNG SNP has in the genetic etiology of ALL. Thus, a large group of patients belonging to different ethnicities will be very helpful to study in order to demonstrate if these SNPs contribute to the genetic etiology of ALL, as shown here in Mexican Mestizos.

Polymorphism of IFN-γ +874T/A associated with production of IFN-γ affects human papillomavirus susceptibility in rural women from Luohe, Henan, China

Purpose

In this paper, the association between polymorphisms of IFN-γ +874T/A (rs2430561), IFN-γR1 −56 T/C (rs2234711), IFN-γR1 +95 C/T (rs7749390), and IFN-γR1 −611A/G (rs 1327474) and human papillomavirus (HPV) susceptibility was investigated in rural women from Luohe, Henan, China.

Patients and methods

A total of 520 rural women were enrolled from Luohe, including 260 with HPV infection and mild dysplasia or less and 260 without HPV infection. Single-nucleotide polymorphisms (SNPs) of IFN-γ +874T/A, IFN-γR1 −56 T/C, IFN-γR1 +95 C/T and IFN-γR1 −611A/G were genotyped using TaqMan Pre-Designed SNP Genotyping Assays. Serum IFN-γ levels were measured using Human IFN-γ Quantikine ELISA Kit. Multivariate logistic regression analysis was performed to identify the SNPs associated with HPV susceptibility. Serum IFN-γ levels were compared between different genotypes.

Results

The polymorphism of IFN-γ +874T/A was associated with HPV susceptibility and +874A carriers had an increased risk. Moreover, the odds ratio was higher in +874 AA carriers than in +874 AT carriers (1.672 vs 2.874). Serum IFN-γ levels were highest in IFN-γ +874 TT carriers, intermediate in AT carriers, and lowest in AA carriers (2.86±1.14 vs 1.57±0.79 vs 0.41±0.22 pg/mL, all P<0.05).

Conclusion

The polymorphism of IFN-γ +874T/A was associated with HPV susceptibility in rural women from Luohe, Henan, China, and +874A carriers had an increased risk. The possible mechanism was that +874A carriers had a low production of IFN-γ.

Population genetic evidence for positive and purifying selection acting at the human IFN-γ locus in Africa

Despite its critical role in the defense against microbial infection and tumor development, little is known about the range of nucleotide and haplotype variation at IFN-γ, or the evolutionary forces that have shaped patterns of diversity at this locus. To address this gap in knowledge, we examined sequence data from the IFN-γ gene in 1461 individuals from 15 worldwide populations. Our analyses uncovered novel patterns of variation in distinct African populations, including an excess of high frequency-derived alleles, unusually long haplotype structure surrounding the IFN-γ gene, and a "star-like" genealogy of African-specific haplotypes carrying variants previously associated with infectious disease. We also inferred a deep time to coalescence of variation at IFN-γ (~ 0.8 million years ago) and ancient ages for common polymorphisms predating the evolution of modern humans. Taken together, these results are congruent with a model of positive selection on standing variation in African populations. Furthermore, we inferred that common variants in intron 3 of IFN-γ are the likely targets of selection. In addition, we observed a paucity of non-synonymous substitutions relative to synonymous changes in the exons of IFN-γ in African and non-African populations, suggestive of strong purifying selection. Therefore, we contend that positive and purifying selection have influenced levels of diversity in different regions of IFN-γ, implying that these distinct genic regions are, or have been, functionally important. Overall, this study provides additional insights into the evolutionary events that have contributed to the frequency and distribution of alleles having a role in human health and disease.

Association of interferon gamma gene polymorphism and susceptibility to hepatitis C virus infection in Egyptian patients: A multicenter, family-based study

BACKGROUND AND AIM

Polymorphisms in some genes may influence the persistence of hepatitis C virus (HCV) infection, clinical outcome, HCV replication, and liver damage. This study was conducted to investigate the role of the interferon gamma (IFN-γ) gene at (+874 T/A, -764 G/C, -179 C/A) single-nucleotide polymorphisms (SNPs) and its receptor (IFN-γR2) at (rs 2786067 A/C) SNP in the susceptibility of Egyptian families to HCV infection with high-resolution techniques.

METHODS

In total, 517 Egyptian families, with 2246 subjects, were recruited to this study from the Upper and Lower Egypt governorates and were classified into three groups: 1034 patients with chronic hepatitis C virus, 108 subjects with spontaneous virus clearance (SVC), and 1104 subjects as a healthy control group. All subjects were genotyped for (+874 T/A, rs2430561, -764 G/C, rs2069707, -179 C/A, rs2069709, and rs 27860067, A/C) SNPs of the IFN-γ gene using the allelic discrimination real-time polymerase chain reaction technique and were confirmed using sequence-based typing.

RESULTS

The carriage of T allele of (+874) IFN-γ is a risky allele and was significantly higher in chronic hepatitis C more than other two groups (odds ratio [OR]: 2.6646, P < 0.0002). On the other hand, the C allele of (-764, rs2069707) is a protective allele and was higher in SVC than the other two groups (OR: 0.2709, P < 0.0001). However, both (-179 C/A, rs 2069709) and (rs 27860067, A/C) SNPs are not polymorphic enough to be studied in the Egyptian population.

CONCLUSIONS

HCV infection is associated with the T allele of (+874 rs2430561), while SVC of HCV is associated with the C allele of (-764, rs2069707) of the IFN-γ gene.

TCR-CXCR4 signaling stabilizes cytokine mRNA transcripts via a PREX1-Rac1 pathway: implications for CTCL

As with many immunopathologically driven diseases, the malignant T cells of cutaneous T-cell lymphomas (CTCLs), such as Sézary syndrome, display aberrant cytokine secretion patterns that contribute to pathology and disease progression. Targeting this disordered release of cytokines is complicated by the changing cytokine milieu that drives the phenotypic changes of CTCLs. Here, we characterize a novel signaling pathway that can be targeted to inhibit the secretion of cytokines by modulating either CXCR4 or CXCR4-mediated signaling. We demonstrate that upon ligation of the T-cell antigen receptor (TCR), the TCR associates with and transactivates CXCR4 via phosphorylation of S339-CXCR4 in order to activate a PREX1-Rac1-signaling pathway that stabilizes interleukin-2(IL-2), IL-4, and IL-10 messenger RNA (mRNA) transcripts. Pharmacologic inhibition of either TCR-CXCR4 complex formation or PREX1-Rac1 signaling in primary human T cells decreased mRNA stability and inhibited secretion of IL-2, IL-4, and IL-10. Applying this knowledge to Sézary syndrome, we demonstrate that targeting various aspects of this signaling pathway blocks both TCR-dependent and TCR-independent cytokine secretion from a Sézary syndrome-derived cell line and patient isolates. Together, these results identify multiple aspects of a novel TCR-CXCR4-signaling pathway that could be targeted to inhibit the aberrant cytokine secretion that drives the immunopathogenesis of Sézary syndrome and other immunopathological diseases.

Polymorphism of IFN-γ (+874 T/A) in Syrian patients with chronic hepatitis B

AIM

This study aimed to investigate the association of IFN- γ +874 (T/A) polymorphism with susceptibility to chronic HBV infection in the Syrian population.

BACKGROUND

Accumulating evidence indicate that the inadequate immune responses are responsible for HBV persistency. Therefore, polymorphisms in genes encoding the cytokines, which are responsible for regulation of the immune response, can affect the course and outcome of the infection. The IFN-γ +874 T/A polymorphism affects the expression of IFN-γ, which has been shown to be crucial to HBV clearance.

METHODS

In this case-control study, 140 samples were collected (70 healthy individuals, 70 chronic HBV patients), and genomic DNA was isolated. Sequencing and ARMS-PCR were performed to genotype the IFN-γ +874 T/A polymorphism.

RESULTS

Results of this study showed an association between IFN- γ +874 T/A polymorphism and the susceptibility to chronic HBV infection (P < 0.05). In addition, results showed that the AA genotype increased the risk of chronicity (OR = 3.05, 95% CI = 1.35 - 6.89), whereas the AT and TT genotypes reduced the risk of chronicity (OR = 0.33, 95% CI = 0.150 - 0.753).

CONCLUSION

Results of this study conclude that the IFN- γ +874 T/A polymorphism may be associated with the chronic HBV infection, according to the genetic model AA vs. AT&TT.

Role of superoxide dismutase in hepatitis B virus-related hepatocellular carcinoma

Background:

Reactive oxygen species (ROS) play important roles in hepatocarcinogenesis. Superoxide dismutase (SOD) is involved in the repair of ROS. Serum alpha-fetoprotein (AFP) is the “golden marker” for diagnosing hepatocellular carcinoma (HCC), and one major shortcoming of its use is that it is insensitive for the early detection of HCC. Therefore, we evaluated serum SOD levels and their association with AFP in hepatitis B virus (HBV)-related HCC.

Materials and Methods:

A total of 279 subjects were divided into three groups: 99 HBV patients with HCC, 73 HBV patients without HCC, and 107 sex- and age-matched healthy controls. Serum levels of SOD were assayed using colorimetry, while AFP levels were measured by electrochemiluminescence immunoassay.

Results:

A highly significant elevation was found in AFP in HBV-with HCC patients compared to HBV-without HCC patients and control subjects (P < 0.001). Alternatively, serum SOD levels were significantly decreased in patients with HCC compared to HBV patients without HCC and healthy controls (P < 0.001). Furthermore, serum SOD was negatively correlated with AFP (r = −0.505, P < 0.001) in HBV-with HCC patients.

Conclusion:

SOD and AFP might be simultaneously evaluated to improve the HCC detection rate.