Association of interleukin-18 gene polymorphisms with hepatitis B virus clearance

Correlation of IL-10 and IL18 with the development of liver cirrhosis associated with hepatitis B virus infection: A systematic review

BACKGROUND

Patients who have been infected with the Hepatitis B virus (HBV) are susceptible to developing liver cirrhosis (LC) and hepatocellular carcinoma (HCC). The objective of this systematic review was to comprehensively scrutinize the existing evidence concerning the association between host genetic polymorphisms and HBV-associated LC.

METHODS

We searched databases of PubMed, Scopus, and Web of Science for relevant articles published from building databases to 25 October 2023.

RESULT

We detected 104 relevant articles, relating to 84 individuals genes. Nine genes had the strong evidence of correlation, including IL-10, IL-18, IL-1B, TGF- β, TLR3, STAT4, IL-1RN, Tim3, and IFN receptors. A positive correlation was found for 33 genes but this data had not yet been replicated, 11 genes had limited or mixed evidence of a correlation, and 34 genes indicated no correlation. IL-10 and IL-18 had the most evidence of correlation. There was a notable amount of diversity in both the design and method of studies and data quality.

CONCLUSION

IL-10 and IL-18 had the most evidence of correlation. There was a notable amount of diversity in both the design and method of studies and data quality. It is of necessary to take into account the fundamental mechanism behind these associations and discern those that are confounded by the coexistence of other LC/HCC risk factors and response to therapy. These results are expected to guide future studies on the genetic susceptibility of HBV-related LC/HCC.

Efficacy and Safety of Antiviral Therapy for Immune-tolerant Hepatitis B Viral Infection in Children: A Systematic Review and Meta-analysis

BACKGROUND

Chronic hepatitis B virus (HBV) infection burden in children remains a pressing public health concern. Whether antiviral therapy should be administered to children with HBV in the immune-tolerant phase remains controversial. We performed a meta-analysis to evaluate antiviral therapy efficacy and safety in children with immune-tolerant hepatitis B (ITHB).

METHODS

A search was conducted in multiple databases (PubMed, Embase, Cochrane, Web of Science, CBM, CNKI and Wanfang Data) to identify clinical trials examining antiviral therapy efficacy and safety in children (1-18 years) with ITHB viral infection from inception to February 2023. Outcomes were calculated separately for controlled and single-arm studies.

RESULTS

Nine trials (442 patients), including 2 randomized controlled trials (RCTs), 3 non-RCTs and 4 single-arm studies, were included in this meta-analysis. In the RCTs, antiviral therapy group exhibited greater rates of HBsAg loss [risk ratio (RR) = 6.11, 95% confidence interval (CI): 1.67-22.31, P Z-test = 0.006], HBsAg serologic response (RR = 5.29, 95% CI: 1.47-19.07, P Z-test = 0.011) and HBeAg loss (RR = 3.00, 95% CI: 1.35-6.66, P Z-test = 0.007) compared with the control group at the end of follow-up. In single-arm studies, the pooled incidences of HBsAg loss, HBeAg loss and HBsAg seroconversion were 24% (95% CI: -0.1% to 48%), 24% (95% CI: -0.1% to 48%) and 24% (95% CI: -5% to 52%), respectively.

CONCLUSION

Current evidence suggests the effectiveness of antiviral therapy in children with HBV infection in the immune-tolerant stage, with few serious adverse events. Due to the limited quality and number of included studies, more high-quality studies are required to validate our findings.

Changes in serum hepatitis B surface and e antigen, interferon-inducible protein 10, and aminotransferase levels during combination therapy of immune-tolerant chronic hepatitis B

BACKGROUND AND AIMS

Treatment of immune-tolerant (IT) children and adults with combined peginterferon alfa-2a and entecavir results in a decline in serum HBeAg and HBsAg concentrations but rarely results in loss of HBeAg or sustained off-treatment response. Factors associated with declines in these viral antigens during treatment remain unexplored.

APPROACH AND RESULTS

We investigated the pattern of virologic and biochemical response in 86 participants (59 children, 27 adults) by serial quantitative measurement of HBsAg (qHBsAg), quantitative HBeAg (qHBeAg), HBV RNA, interferon-inducible protein (IP-10), IL-18, and alanine aminotransferase (ALT). Each individual had previously been treated with 8 weeks of entecavir followed by 40 weeks of combined peginteferon and entecavir. We defined the interrelationships between these parameters and virologic response measured as nadir declines from baseline for HBeAg and HBsAg. The patterns of HBsAg and HBeAg decline were similar in pediatric and adult participants. Higher levels of IP-10 were observed during treatment in participants with greater ALT elevations and greater reductions of qHBsAg and qHBeAg. Individuals with peak ALT values exceeding three times the upper limit of normal were significantly more likely to have >1 log10 decline in both viral antigens. HBV DNA became undetectable in 21 of 86 (24%) and HBV RNA in 4 of 77 (5%) during therapy, but both markers remained negative only in those who became HBsAg negative, all of whom also had ALT elevations.

CONCLUSIONS

Induction of IP-10 during peginterferon treatment in adults and children in the IT phase of chronic HBV infection is associated with ALT elevations and decline in viral antigens, suggesting a degree of interferon-inducible viral control.

Impacts of Interleukin-18 Polymorphisms on the Incidence of Delayed-Onset Cytomegalovirus Infection in a Cohort of Kidney Transplant Recipients

Background

The incidence of cytomegalovirus (CMV) infection in solid organ transplant recipients may be reduced by antiviral prophylaxis, but this strategy may lead to delayed-onset CMV infection. The proinflammatory cytokine interleukin (IL)-18 plays a major role in viral host defense responses. This study examines the impacts of 2 single-nucleotide polymorphisms (SNPs) in the promoter region of the IL-18 gene, -607C/A (rs1946518) and -137G/C (rs187238), on the incidence of delayed-onset CMV infection in patients undergoing kidney transplant.

Methods

This retrospective study analyzed 2 IL-18 SNPs in consecutive adult kidney transplant recipients using real-time polymerase chain reaction with TaqMan probes. Participants were enrolled over the period 2005–2013 and stratified according to their IL-18 SNP genotype. The concordance index (Harrell’s c-index) was used as a measure of the discriminatory power of the predictive models constructed with bootstrapping to correct for optimistic bias.

Results

Seven hundred nine patients received transplants in the study period, and 498 met selection criteria. Cytomegalovirus infection and disease incidence were 38% and 7.5%, respectively. In multivariate competing risk regression models, carriers of the -607C/-137G haplotype who received prophylaxis showed a higher incidence of CMV replication after antiviral agent discontinuation (hazard ratio = 2.42 [95% confidence interval, 1.11–5.26]; P = .026), whereas CMV disease was not observed in those given prophylaxis who were noncarriers of this polymorphism (P = .009).

Conclusions

Our findings suggest that the -607C/-137G IL-18 haplotype is associated with a higher incidence of postprophylaxis CMV replication. The prior identification of this polymorphism could help select alternative measures to prevent delayed-onset CMV infection in these patients.

IL-18 and IL-1β Gene Polymorphisms: The Plausible Risk Factors for Chronic Hepatitis B

Chronic inflammation is the main risk factor for induction of liver cirrhosis and also hepatocellular carcinoma in chronic hepatitis B (CHB) patients. Although our knowledge is growing regarding molecular mechanisms of immune responses against viruses, the main mechanisms that lead to the progression of chronic inflammation and then CHB are yet to be clarified. IL-18 and IL-1β are the members of the IL-1 family and produced in the cytoplasm of a wide range of immune and nonimmune cells and activated by inflammasome pathways. The cytokines play key roles in the pathologies of CHB. IL-18 and IL-1β productions are altered in CHB patients. It has been hypothesized that the polymorphisms within IL-18 and IL-1β genes may be the main reasons for the induction of chronic inflammation in CHB patients. This review article discusses the related investigations regarding the main correlation between the polymorphisms within IL-18 and IL-1β genes and CHB pathogenesis.

Associations of human leukocyte antigen and interleukin-18 gene polymorphisms with viral load in patients with hepatitis B infection

This study aimed to assess the associations of human leukocyte antigen (HLA)-DR and interleukin (IL)-18 gene polymorphisms with hepatitis B virus (HBV).Clinical data were retrospectively reviewed between December 2006 and December 2015 at Xiangyang Central Hospital. HBV patients were assigned to the high and low viral load groups, respectively, according to HBV copies. HLA-DRB1*03 polymorphisms and IL-18 polymorphisms were detected by sequence-specific primer-polymerase chain reaction (PCR-SSP) and PCR-ligase detection reaction (PCR-LDR), respectively. T cell subgroups were identified by flow cytometry, and IL-18, IL-12, interferon-γ (IFN-γ), IL-4, and IL-10 expression levels were assessed by ELISA. A total of 630 subjects were included in the analysis.Compared with healthy controls, the chronic HBV group showed significantly lower IL-18 (P < .001), IL-12 (P < .001), and IFN-γ (P < .001) expression levels, and markedly increased IL-4 (P < .001) and IL-10 (P < .001) amounts. Th2 cytokine expression was high in HLA-DRB1*03 positive (+) HBV patients, with low Th1 cytokine levels. The ratios of CD4+/CD8+ and Th1/Th2 cells decreased with increasing HBV DNA levels. The chronic HBV group showed a relatively high frequency of -137G in the IL-18 gene, while IL-18 expression was low in homozygous GG genotype individuals.Polymorphisms in the HLA-DRB1*03 and IL-18 genes are associated with viral load in HBV. HLA-DRB1 and IL-18 gene polymorphisms are involved in the regulation of the Th1/Th2 balance and expression of relevant cytokines that influence immune responses in HBV.

Hepatitis B vaccine non response: A predictor of latent autoimmunity?

Unresponsiveness to Hepatitis B virus (HBV) vaccine has been associated with interleukins involved with Th1 functioning including Interleukin-8 (IL-18) and Interferon-γ (IFN-γ). IL-18 and IFN-γ have also been implicated in the onset of different types of immune-mediate inflammatory conditions such as Type 1 Diabetes (T1D), Celiac disease (CD), rheumatoid arthritis (RA), obesity and systemic lupus erythematosus (SLE). Taking into account that HBV vaccination is provided in the 1st year of life worldwide, I propose that all babies should be tested for anti-HBs response after completion of the vaccine series. And I suggest that children with undetectable anti-HBs titers after recommended immunization schedule as well as the additional booster doses should be followed up over time because they may be at risk of developing a number of autoimmune disorders. In this light, the non-responsiveness to HBV vaccine might be a predictor of latent autoimmunity. For that reason, research studies are needed in order to verify the existence of potential IL-18 and IFN-γ gene polymorphisms to utilize as biomarkers of latent autoimmunity. As a final point, administration of neutralizing antibodies against IFN-γ and/or IL-18 might represent a future target for immune-modulatory therapeutic approach to halt or even reverse autoimmune phenomena.

Elevated pre-treatment IL-18 level is associated with HBeAg seroconversion in HIV-HBV coinfection

BACKGROUND

In HBV-infected patients, hepatitis B e antigen (HBeAg) seroconversion is associated with better outcomes. Interleukin-18 (IL-18) controls hepatitis B replication in a mouse model. However, its role in treatment response in HIV-HBV-coinfected patients is unknown.

METHODS

We enrolled 35 treatment-naive, HBeAg-positive, HIV-HBV-coinfected patients. HBV DNA, HIV RNA, CD4⁺ T-cell count, HBV surface antigen (HBsAg) quantification (qHBsAg), HBeAg quantification (qHBeAg) and IL-18 levels were measured prior to, at 24 and 48 weeks of HBV-active combination antiretroviral therapy (cART). Multivariate Poisson regression models with robust standard errors were used to determine factors associated with HBeAg seroconversion.

RESULTS

Twenty-one patients received tenofovir (TDF) + lamivudine (3TC) based cART while 14 patients received 3TC-based cART. After 48 weeks of treatment, 10 patients experienced HBeAg seroconversion. Compared with non-seroconverters, seroconverters had higher median HIV RNA (5.22 versus 4.58 log copies/ml; P=0.030), lower median qHBsAg (3.97 versus 4.76 log IU/ml; P=0.011), lower median qHBeAg (1.61 versus 3.01 log PEIU/ml; P=0.004) and marginally higher median IL-18 (2.70 versus 2.53 log pg/ml; P=0.068) prior to ART. In the multivariate regression, higher baseline IL-18 (adjusted relative risk [aRR] 2.99 per 1 log pg/ml increase; P=0.035), high HIV RNA (aRR 1.84 per 1 log copies/ml; P=0.029) and low qHBeAg (aRR 0.71 per 1 log PEIU/ml; P=0.029) were significantly associated with HBeAg seroconversion.

CONCLUSIONS

In HIV-HBV-coinfected patients with HBeAg positivity, higher IL-18 levels, HIV RNA load, as well as low qHBeAg prior to cART were associated with HBeAg seroconversion.

Genetic polymorphisms -137 (rs187238) and -607 (rs1946518) in the interleukin-18 promoter may not be associated with development of hepatocellular carcinoma

This study meta-analyzed the literature on possible association of polymorphisms -137 (rs187238) and -607 (rs1946518) in the interleukin-18 (IL-18) promoter with risk of hepatocellular carcinoma (HCC). The analysis included 8 case-control studies on the -137 polymorphism (1,318 cases, 2,254 controls) and 7 case-control studies on the -607 polymorphism (1,262 cases, 1,696 controls). None of the five genetic models suggested a significant association between the -137 polymorphism and HCC risk: allelic model, OR 0.99, 95% CI 0.74-1.34, P = 0.97; recessive model, OR 0.98, 95% CI 0.65-1.46, P = 0.91; dominant model, OR 1.35, 95% CI 0.73-2.52, P = 0.34; homozygous model, OR 0.99, 95% CI 0.65-1.49, P = 0.95; heterozygous model, OR 0.99, 95% CI 0.66-1.48, P = 0.94. Similar results were obtained in subgroup analyses of Asian patients, Chinese patients, or patients with hepatitis B virus (HBV)-related HCC. Similar results were also obtained for the -607 polymorphism across the entire study population as well as in the three subgroups. The available evidence suggests no significant association of the -137 or -607 polymorphisms with risk of HCC in general or specifically of HBV-related HCC. These conclusions should be verified in large, well-designed studies.

Role of IL-18 Gene Promoter Polymorphisms, Serum IL-18 Levels, and Risk of Hepatitis B Virus-related Liver Disease in the Guangxi Zhuang Population: a Retrospective Case-Control Study

BACKGROUND

The aim of this study was to assess the relationship between IL-18 gene polymorphisms and HBV-related diseases and whether these polymorphisms influence its expression in the Guangxi Zhuang population.

MATERIALS AND METHODS

We enrolled 129 chronic HBV infected (CHB) patients, 86 HBV-related liver cirrhosis (LC) patients and 160 healthy controls in our study. Polymerase chain reaction-restriction fragment length polymorphism methods were used to detect IL-18 gene -607C/A, -137G/C polymorphisms, and an ELISA kit was employed to determine serum IL-18 levels.

RESULTS

No correlation was found between the -607C/A polymorphism and risk of HBV-related disease. For the -137G/C polymorphism, the GC genotype and C allele were associated with a significantly lower risk of CHB (95%CI: 0.32-0.95, p=0.034 and 95%CI: 0.35-0.91, p=0.018) and HBV-related LC (95%CI: 0.24-0.89, p=0.022 and 95%CI: 0.28-0.90, p=0.021). A similar decreased risk was also found with the A-607C-137 haplotype. With respect to IL-18 expression, it was significantly lower in both patient groups, but no association was noted between the two polymorphisms in the IL-18 gene and its expression.

CONCLUSIONS

Our study indicated that the -137C allele in the IL-18 gene may be a protective factor for HBV-related disease, and serum IL-18 level may be inversely associated with CHB and HBV-related LC.

IL18 Gene Variants Influence the Susceptibility to Chagas Disease

Chagas disease is a parasitic disorder caused by the infection with the flagellated protozoan Trypanosoma cruzi. According to the World Health Organization, more than six million people are currently infected in endemic regions. Genetic factors have been proposed to influence predisposition to infection and development of severe clinical phenotypes like chronic Chagas cardiomyopathy (CCC). Interleukin 18 (IL18) encodes a proinflammatory cytokine that has been proposed to be involved in controlling T. cruzi infection. In this study, we analyzed the possible role of six IL18 gene variants (rs5744258, rs360722, rs2043055, rs187238, rs1946518 and rs360719), which cover most of the variation within the locus, in the susceptibility to infection by T. cruzi and/or CCC. In total, 1,171 individuals from a Colombian region endemic for Chagas disease, classified as seronegative (n = 595), seropositive asymptomatic (n = 175) and CCC (n = 401), were genotyped using TaqMan probes. Significant associations with T. cruzi infection were observed when comparing seronegative and seropositive individuals for rs187238 (P = 2.18E-03, OR = 0.77), rs360719 (P = 1.49E-03, OR = 0.76), rs2043055 (P = 2.52E-03, OR = 1.29), and rs1946518 (P = 0.0162, OR = 1.22). However, dependence analyses suggested that the association was mainly driven by the polymorphism rs360719. This variant is located within the promoter region of the IL18 gene, and it has been described that it creates a binding site for the transcription factor OCT-1 affecting IL-18 expression levels. In addition, no evidence of association was observed between any of the analyzed IL18 gene polymorphisms and the development of CCC. In summary, our data suggest that genetic variation within the promoter region of IL18 is directly involved in the susceptibility to infection by T. cruzi, which provides novel insight into disease pathophysiology and adds new perspectives to achieve a more effective disease control.

Antiviral activity of various interferons and pro-inflammatory cytokines in non-transformed cultured hepatocytes infected with hepatitis B virus

In HBV-infected patients, therapies with nucleoside analogues or IFNα remain ineffective in eradicating the infection. Our aim was to re-analyze the anti-HBV activity of a large panel of IFNs and cytokines in vitro using non-transformed cultured hepatocytes infected with HBV, to identify new immune-therapeutic options. HepaRG cells and primary human hepatocytes were infected with HBV and, when infection was established, treated with various concentrations of different IFNs or inflammatory cytokines. Viral parameters were evaluated by quantifying HBV nucleic acids by qPCR and Southern Blot, and secreted HBV antigens were evaluated using ELISA. The cytokines tested were type-I IFNs, IFNγ, type-III IFNs, TNFα, IL-6, IL-1β, IL-18 as well as nucleos(t)ide analogues tenofovir and ribavirin. Cytokines and drugs, with the exception of IL-18 and ribavirin, exhibited a suppressive effect on HBV replication at least as strong as, but often stronger than, IFNα. The cytokine presenting the highest effect on HBV DNA was IL-1β, which exerted its inhibition within picomolar range. Importantly, we noticed differential effects on other parameters (HBV RNA, HBeAg, HBsAg) between both IFNs and inflammatory cytokines, thus suggesting different mechanisms of action. The combination of IL-1β and already used therapies, i.e. IFNα or tenofovir, demonstrated a stronger or similar anti-HBV activity. IL-1β was found to have a very potent antiviral effect against HBV in vitro. HBV was previously shown to promptly inhibit IL-1β production in Kupffer cells. Strategies aiming at unlocking this inhibition and restoring local production of IL-1β may help to further inhibit HBV replication in vivo.

Association between IFN-γ genetic polymorphisms and susceptibility to hepatitis B virus infection: A meta-analysis

BACKGROUND

Hepatitis B virus (HBV) infection has become a global health burden because of its contagious mode of transmission and the resultant long-term liver damage.

AIM

To investigate how the polymorphisms of the IFN-γ gene, particularly the IFN-γ +874T/A (rs2430561) single nucleotide polymorphism (SNP), influence susceptibility to HBV infection.

SUBJECTS AND METHODS

Relevant articles were identified by a comprehensive literature search covering the following computerised bibliographic databases. Eleven independent case-control studies were ultimately selected for the current meta-analysis, comprising a total of 1527 HBV cases and 1467 healthy subjects.

RESULTS

The results in the current meta-analysis showed that carriers of the IFN-γ A allele were more likely to develop HBV infection than those without in all five genetic models (all p < 0.05). According to the ethnicity-based sub-group analysis, a significant difference of the IFN-γ rs2430561 T > A polymorphism was detected associated with the increased risk of HBV infection in Asians and European-derived populations in the majority of the groups.

CONCLUSIONS

The results implicate a possible relationship between the IFN-γ rs2430561 T > A polymorphism and the risk of HBV infection. Therefore, IFN-γ genetic polymorphisms might be important in determining an individual's susceptibility to HBV infection.

Temporal dynamics of inflammatory cytokines/chemokines during sofosbuvir and ribavirin therapy for genotype 2 and 3 hepatitis C infection

The analysis of inflammatory cytokines and chemokines produced during hepatitis C virus (HCV) infection has advanced our understanding of viral-host interactions and identified predictors of treatment response. Administration of interferons (IFNs) made it difficult to interpret biomarkers of immune activation during treatment. Direct-acting antiviral (DAA) regimens without IFN are now being used to treat HCV with excellent efficacy. To gain insight into HCV-host interactions occurring before, during, and after HCV treatment, we performed a case-control study that measured serial plasma levels of IFN-γ-inducible protein 10 (IP-10), monocyte chemoattractant protein 1 (MCP-1), macrophage inflammatory protein 1 beta (MIP-1β), and interleukin-18 (IL-18) in 131 patients with chronic HCV treated with sofosbuvir (SOF) plus ribavirin (RBV). A linear regression analysis using baseline factors identified strong positive associations between elevated alanine aminotransferase and pretreatment IP-10 and between the presence of cirrhosis and elevated pretreatment IL-18. Mean IP-10, MCP-1, MIP-1β, and IL-18 levels all decline on therapy, but display different dynamics late in treatment and after cessation of therapy. On treatment, IP-10 and MIP-1β levels were significantly higher in individuals who achieved sustained virological response (SVR). Logistic regression analyses examining treatment response in all patients demonstrated significant associations between higher baseline MIP-1β levels and smaller decreases in MIP-1β early in treatment and SVR. Higher early MIP-1β levels were also significantly associated with SVR in subsets of patients with cirrhosis and individuals with genotype 3 (GT3) infection, two factors associated with decreased responsiveness to treatment.

CONCLUSION

Changes in IP-10 levels mirror HCV RNA, suggesting that IP-10 is an indicator of innate immune viral recognition. MIP-1β levels remain elevated in GT2/3 patients who achieved SVR, suggesting differential immune activation in those who respond to SOF/RBV therapy and a potential role in predicting treatment responses.

Relationship between cytokine gene polymorphisms and chronic hepatitis B virus infection

Hepatitis B virus (HBV) infection is still a public health problem worldwide, being endemic in some parts of the world. It can lead to serious liver diseases such as chronic hepatitis, cirrhosis, and hepatocellular cancer. The differences in host immune response can be one of the reasons for the various clinical presentations of HBV infection. Polymorphisms of genes encoding the proinflammatory and antiinflammatory cytokines, which are responsible for regulation of the immune response, can affect the clinical presentation of the infection. Particularly, the polymorphisms of the genes encoding cytokines such as interleukin (IL)-1, IL-6, IL-8, IL-10, IL-18, IL-28B, interferon-γ, tumor necrosis factor-α, tumor growth factor-β1, and regulatory molecules like vitamin D receptor and chemokine receptor 5 can be responsible for different clinical presentations of HBV infections. The genomic information about cytokines and other mediators can be important for determining high-risk people for developing chronic hepatitis or hepatocellular cancer and may be used to plan treatment and preventive approaches for these people. In this review, the current knowledge in the literature on the association between cytokine/regulatory molecule gene polymorphisms and clinical course of chronic HBV infection is summarized, and the clinical implementations and future prospects regarding this knowledge are discussed.

Association of polymorphisms in interleukin-18 and interleukin-28B genes with outcomes of hepatitis B virus infections: a meta-analysis

Several polymorphisms in the interleukin-18 (IL-18) and nterleukin-28B (IL-28B) genes have been reported to influence hepatitis B virus (HBV) infection. However, the published findings have been conflicting. We conducted meta-analyses of randomized, controlled trials to address the association of IL-18 or IL-28B polymorphisms and the outcomes of HBV infection. Weipu, Wanfang, CNKI, MEDLINE, PubMed, EMBASE, and Cochrane Library databases were employed to search for citations using the MeSH terms as "interleukin-18"/"interleukin-28B" AND "HBV" AND "gene" AND "polymorphism" without any restriction in language and publication year. Meta-analysis was conducted by RevMan 5.0 software. The results showed that the IL28B rs8099917 AA genotype (AA vs AC + CC: odds ratio (OR) = 0.63, 95 % confidence interval (CI) = 0.46-0.87) was associated with a decreased risk of hepatocellular carcinoma (HCC). Carriage of IL28B rs12979860 CC genotype was associated with an increased risk for developing liver cirrhosis among patients with HBV infection (CC vs CT + TT: OR = 1.39, 95 % CI = 1.04-1.85). Further well-designed large studies are warranted to confirm the mechanisms by which these are involved in these outcomes of HBV infection.

Association of the interleukin-12 polymorphic variants with the development of antibodies to surface antigen of hepatitis B virus in hemodialysis patients in response to vaccination or infection

Cytokines, involved in the T-helper 1 system, play a role in the regulation of hepatitis B virus (HBV) clearance and the immune response to HBV antigens during natural infection or planned vaccination. Our aim was to examine whether the polymorphic variants of IL-12 are equally associated with development of antibodies to HBV surface antigen (anti-HBs) in hemodialysis (HD) patients in the case of HBV vaccination or HBV infection. The IL-12A rs568408 and IL-12B rs3212227 polymorphisms were analyzed in relation to anti-HBs development in 602 HD patients with negative antibodies to HBV core antigen (anti-HBc) who were hepatitis B vaccinated (group I) as well as in 237 anti-HBc positive HD patients who were infected with HBV in the past (group II). In group I, 199 patients did not develop an anti-HBs titre >10 IU/L (subgroup Ia), whereas in group II, 55 patients did not develop an anti-HBs titre >10 IU/L (subgroup IIa). Patients of groups I and II that developed an anti-HBs >10 IU/L were included into subgroups Ib and IIb, respectively. In hepatitis B vaccinated HD patients, development of a protective anti-HBs titre was positively associated with vintage of renal replacement therapy (RRT), chronic glomerulonephritis as a cause of RRT, and GA rs 568408 IL-12A (OR 1.6, 95 % CI 1.0-2.5, P = 0.035), but a frequency distribution of this genotype between responders and non-responders was not significant when the Bonferroni correction was applied. In HBV infected HD patients, anti-HBs development was positively associated with AC rs3212227 IL-12B (OR 8.0, 95 % CI 2.6-24.9, P < 0.001), whereas HBsAg positivity, AA rs3212227 IL-12B (OR 0.3, 95 % CI 0.1-0.7, P = 0.007), and CC rs3212227 IL-12B (OR 0.1, 95 % CI 0.03-0.6, P = 0.011) were negative predictors of positive anti-HBs phenotype. When the Bonferroni correction was applied, if appropriate, these associations remained significant. In HD patients, the studied IL-12 polymorphic variants seem to be associated with the anti-HBs phenotype (a) with borderline significance for IL-12A in hepatitis B vaccinated patients, and (b) significantly for IL-12B in patients who underwent natural HBV infection.

Association between Interferon-Inducible Protein 6 (IFI6) Polymorphisms and Hepatitis B Virus Clearance

CD8+ T cells are key factors mediating hepatitis B virus (HBV) clearance. However, these cells are killed through HBV-induced apoptosis during the antigen-presenting period in HBV-induced chronic liver disease (CLD) patients. Interferon-inducible protein 6 (IFI6) delays type I interferon-induced apoptosis in cells. We hypothesized that single nucleotide polymorphisms (SNPs) in the IFI6 could affect the chronicity of CLD. The present study included a discovery stage, in which 195 CLD patients, including chronic hepatitis B (HEP) and cirrhosis patients and 107 spontaneous recovery (SR) controls, were analyzed. The genotype distributions of rs2808426 (C > T) and rs10902662 (C > T) were significantly different between the SR and HEP groups (odds ratio [OR], 6.60; 95% confidence interval [CI], 1.64 to 26.52, p = 0.008 for both SNPs) and between the SR and CLD groups (OR, 4.38; 95% CI, 1.25 to 15.26; p = 0.021 and OR, 4.12; 95% CI, 1.18 to 14.44; p = 0.027, respectively). The distribution of diplotypes that contained these SNPs was significantly different between the SR and HEP groups (OR, 6.58; 95% CI, 1.63 to 25.59; p = 0.008 and OR, 0.15; 95% CI, 0.04 to 0.61; p = 0.008, respectively) and between the SR and CLD groups (OR, 4.38; 95% CI, 1.25 to 15.26; p = 0.021 and OR, 4.12; 95% CI, 1.18 to 14.44; p = 0.027, respectively). We were unable to replicate the association shown by secondary enrolled samples. A large-scale validation study should be performed to confirm the association between IFI6 and HBV clearance.

Antibodies to hepatitis B virus surface antigen and interleukin 12 and interleukin 18 gene polymorphisms in hemodialysis patients

BACKGROUND

The interleukin (IL)18 rs360719 CC genotype is associated with the development of antibodies to hepatitis B virus surface antigen (anti-HBs) in hemodialysis (HD) patients. IL18 shares biological properties with IL12 in promoting the T-hepler 1 (Th1) system. We studied whether polymorphisms in the IL12A 3` untranslated region (UTR) and IL12B 3`UTR may contribute to anti-HBs development (titre ≥ 10 IU/L) in HD patients either individually or jointly with the IL18 polymorphism.

METHODS

In 518 HD patients and 240 controls the IL12A rs568408 3'UTR G > A polymorphism was genotyped by high-resolution melting curve analysis. Polymerase chain reaction restriction fragment length polymorphism was used to detect the IL12B rs3212227 3'UTR A > C and IL18 -1297 T > C rs360719 polymorphisms. The associations between the IL12A, IL12B and IL18 genotypes and the risk of impaired anti-HBs development were estimated by computing the odds ratios and their 95% confidence intervals using logistic regression analysis.

RESULTS

In the logistic regression analysis, the higher frequency of rs360719 CC individually (2.9% in 207 patients without anti-HBs development vs 8.0% in 311 patients with anti-HBs development, p = 0.009) and of rs360719 CC combined with rs568408 GG (p = 0.048), rs568408 GA (p = 0.035), rs568408 GG/AA (p = 0.034) or rs3212227 AA (p = 0.046) was associated with an increased chance for the development of anti-HBs in HD patients. Patients bearing both rs568408 AA and rs360719 TT had a 10.9-fold or 8.9-fold lower chance, respectively, to develop anti-HBs compared with those carrying any other genotype (p = 0.005) or those who had both wild-type rs568408 GG and rs360719 TT (p = 0.011). Carriers of both rs3212227 CC and rs360719 TC had a 4.6-fold lower chance for anti-HBs development than carriers of any other genotype (p = 0.042).

CONCLUSION

Development of anti-HBs in HD patients is associated with gene polymorphisms of interleukins involved in the Th1 system.

Association of GNLY genetic polymorphisms with chronic liver disease in a Korean population

Granulysin (GNLY) is found in cytotoxic granules of cytolytic T lymphocytes and natural killer (NK) cells, which are critical for hepatitis B virus (HBV) clearance. GNLY cytotoxicity plays an important role in the defense against viruses or intracellular bacteria. We hypothesized that genetic variation in the GNLY gene could affect the resistance of hosts against HBV infection. We compared the distribution frequencies of GNLY polymorphisms between an HBV-induced chronic liver disease (CLD) group and a spontaneous recovery (SR) control group to determine whether GNLY polymorphisms play a role in HBV clearance. A total of 117 patients in the SR group and 230 patients in the CLD group were enrolled. Samples derived from complex infections, including hepatitis C and human immunodeficiency virus, and those associated with insufficient clinical information (10 samples in SR and 24 samples in CLD) were excluded from the study. The final analysis included 107 SR and 206 CLD samples. DNA was extracted from peripheral blood, and GNLY genotypes were determined by the GoldenGate(®) method. The genotype distribution of the single-nucleotide polymorphisms (SNPs) rs2886767 (C>T), rs1561285 (G>C), and rs11127 (T>C) were significantly different between the SR and CLD groups in a recessive model (p<0.015). These three SNPs were in a complete linkage disequilibrium (LD) block. Diplotype distributions of haplotype (HT) 1 (C-G-T) and HT2 (T-C-C) were significantly different between the SR and CLD groups in a recessive model (p=0.025) and a dominant model (p=0.008). All p-values remained significant after multiple comparisons. GNLY polymorphism genotypes and diplotypes were associated with the chronicity of HBV. These data suggested that genetic variation of GNLY may be an important factor in HBV clearance through the CD8+ T or NK cell-mediated removal of HBV-infected cells from the host.

Interleukin-18 and interferon-gamma polymorphisms are implicated on proviral load and susceptibility to human T-lymphotropic virus type 1 infection

Interleukin-18 (IL-18) and interferon-gamma (IFN-γ) exert important functions in both innate and adaptive immune responses against intracellular pathogens and viruses. Previous studies suggested that host genetic factors, including cytokines gene polymorphisms, could be involved in the pathogenesis of human T-cell leukemia virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Thus, we analyzed -137C/G and -607A/C of the IL-18 promoter and +874T/A of the IFN-γ in DNA samples from 98 HTLV-1-infected individuals exhibiting or not clinical symptoms and 150 healthy control individuals. The IL-18 promoter -607CC genotype was significantly lower in HTLV-1 asymptomatic carriers (HAC) and HTLV-1-infected individuals (HAC + HAM/TSP) than healthy control group. In contrast, the -607AC genotype was significantly higher in HAC and HTLV-1-infected individuals group compared to the healthy control group. The -137G/-607A IL-18 haplotype was higher in infected group than healthy control group, and the -137C/-607C IL-18 haplotype was increased in the healthy control group compared to the others. Finally, the IFN-γ polymorphism analysis showed that the HTLV-1-infected individuals with +874AT genotype presented higher proviral load than +874AA genotype. These data indicate that the IL-18-607AC genotype and -137G/-607A haplotype could be a risk factor for HTLV-1 infection, whereas the protective effect could be conferred by -607CC genotype and -137C/-607C haplotype. Also, the IFN-γ could be implicated on the proviral load levels.

Molecular mechanisms underlying occult hepatitis B virus infection

Chronic hepatitis B virus (HBV) infection is a complex clinical entity frequently associated with cirrhosis and hepatocellular carcinoma (HCC). The persistence of HBV genomes in the absence of detectable surface antigenemia is termed occult HBV infection. Mutations in the surface gene rendering HBsAg undetectable by commercial assays and inhibition of HBV by suppression of viral replication and viral proteins represent two fundamentally different mechanisms that lead to occult HBV infections. The molecular mechanisms underlying occult HBV infections, including recently identified mechanisms associated with the suppression of HBV replication and inhibition of HBV proteins, are reviewed in detail. The availability of highly sensitive molecular methods has led to increased detection of occult HBV infections in various clinical settings. The clinical relevance of occult HBV infection and the utility of appropriate diagnostic methods to detect occult HBV infection are discussed. The need for specific guidelines on the diagnosis and management of occult HBV infection is being increasingly recognized; the aspects of mechanistic studies that warrant further investigation are discussed in the final section.

Molecular mechanisms underlying occult hepatitis B virus infection

Chronic hepatitis B virus (HBV) infection is a complex clinical entity frequently associated with cirrhosis and hepatocellular carcinoma (HCC). The persistence of HBV genomes in the absence of detectable surface antigenemia is termed occult HBV infection. Mutations in the surface gene rendering HBsAg undetectable by commercial assays and inhibition of HBV by suppression of viral replication and viral proteins represent two fundamentally different mechanisms that lead to occult HBV infections. The molecular mechanisms underlying occult HBV infections, including recently identified mechanisms associated with the suppression of HBV replication and inhibition of HBV proteins, are reviewed in detail. The availability of highly sensitive molecular methods has led to increased detection of occult HBV infections in various clinical settings. The clinical relevance of occult HBV infection and the utility of appropriate diagnostic methods to detect occult HBV infection are discussed. The need for specific guidelines on the diagnosis and management of occult HBV infection is being increasingly recognized; the aspects of mechanistic studies that warrant further investigation are discussed in the final section.

Relationship between interleukin 18 polymorphisms and susceptibility to chronic hepatitis B virus infection

AIM

To identify the relationship between the tagging single nucleotide polymorphism sites (tagSNPs) of the Interleukin-18 (IL-18) gene and genetic susceptibility to chronic hepatitis B virus infection in Chinese patients.

METHODS

Five hundred and one cases of chronic hepatitis B virus (HBV) infection and 301 HBV natural clearance controls were studied. Two tagSNPs in the IL-18 gene (rs1946518A/C and rs574424C/G) were genotyped by the Multiplex Snapshot technique. The genotype and allele frequencies were calculated and analyzed.

RESULTS

In the genotypes of rs1946518, the AA type was present at a higher frequency in the patients compared to those in the controls. Odds ratio (OR) of the AA genotype for the comparison with that of the AC and the CC genotype was 1.537 (95% confidence intervals (CI): 1.116-2.218, P = 0.009 < 0.025). In phenotypes, the allele C at rs1946518 was of a significantly lower frequency in the patients with chronic hepatitis B than that in the controls (P = 0.017 < 0.025). OR of the allele A for the comparison with that of the allele C was 1.279 (95% CI: 1.045-1.567). As for the rs574424 genotypes, no significant difference in this genotype distribution or in this allele frequency between the patients and the control subjects was observed. No significant difference in the haplotype frequencies between the patients with chronic hepatitis B and HBV natural clearance individuals was displayed.

CONCLUSION

The data suggest that genotype AA and the allele A of the IL-18 at position rs1946518 are closely associated with the resistance to chronic hepatitis B and may be the dangerous gene. However, no statistical association was found between polymorphisms of rs574424 for IL-18 and hepatitis B.

High plasma interleukin-18 levels mark the acute phase of hepatitis C virus infection

BACKGROUND

Proinflammatory cytokines play a critical role in antiviral immune responses. Large-scale genome studies have found correlations between single-nucleotide polymorphisms (SNPs) in the interleukin (IL) 18 promoter and spontaneous control of hepatitis C virus (HCV), suggesting a role in clearance.

METHODS

Plasma IL-18, IL-1β, IL-6, IL-8, IL-12, interferon-γ, tumor necrosis factor-α, alanine aminotransferase (ALT), and HCV RNA levels were assessed longitudinally in subjects with known dates of HCV acquisition and analyzed according to IL-18 SNPs and outcome, either spontaneous clearance (SC) (n = 13) or persistent infection (PI) (n = 25).

RESULTS

No significant change in plasma proinflammatory cytokine expression was observed with the exception of IL-18, which increased in every subject with initial detection of HCV RNA. In every SC subject, IL-18 returned to the preinfection baseline concomitant with HCV control. In PI subjects, IL-18 declined following the acute phase of infection but remained above the preinfection baseline throughout chronic infection and did not correlate with HCV RNA or ALT levels.

CONCLUSIONS

Plasma IL-18 was an early and the most reliably detected host response to HCV infection measured in blood. Reduced IL-18 production with transition to chronic infection without correlation with HCV RNA or ALT levels suggests modulation of the innate response with persistent infection.

Dual effects of interleukin-18: inhibiting hepatitis B virus replication in HepG2.2.15 cells and promoting hepatoma cells metastasis

Interleukin-18 (IL-18) has been reported to inhibit hepatitis B virus (HBV) replication in the liver of HBV transgenic mice; however, the molecular mechanism of its antiviral effect has not been fully understood. In the present study, it was shown that IL-18 and its receptors (IL-18R) were constitutively expressed in hepatoma cell lines HepG2 and HepG2.2.15 as well as normal liver cell line HL-7702. We demonstrated that IL-18 directly inhibited HBV replication in HepG2.2.15 cells via downregulating the activities of HBV core and X gene promoters. The suppressed HBV replication by IL-18 could be rescued by the administration of BAY11-7082, an inhibitor of transcription factor NF-κB. On the other hand, it was of interest that IL-18 promoted HepG2 cell metastasis and migration dose dependently in both wound-healing assays and Transwell assays. The underlying mechanism could be partially attributable to the increased activities of extracellular matrix metalloproteinase (MMP)-9, MMP-3, and MMP-2 by IL-18, which upregulated the mRNA levels of MMP-3 and MMP-9 in a NF-κB-dependent manner. Furthermore, it was confirmed that expression of IL-18/IL-18R and most MMPs were remarkably upregulated in hepatocellular carcinoma (HCC) liver cancer tissue specimens, suggesting that IL-18/IL-18R-triggered signaling pathway was closely related to HCC metastasis in vivo. Therefore, we revealed the dual effects of IL-18 in human hepatocytes: it not only inhibited HBV replication but also promoted hepatoma cells metastasis and migration. NF-κB played a critical role in both effects. Our work contributed to a deeper understanding of the biological function of IL-18 in human hepatocytes.