Current information on the immunologic status of occult hepatitis B infection

New sights of low dose IL-2: Restoration of immune homeostasis for viral infection

Viral infection poses a significant threat to human health. In addition to the damage caused by viral replication, the immune response it triggers often leads to more serious adverse consequences. After the occurrence of viral infection, in addition to the adverse consequences of infection, chronic infections can also lead to virus-related autoimmune diseases and tumours. At the same time, the immune response triggered by viral infection is complex, and dysregulated immune response may lead to the occurrence of immune pathology and macrophage activation syndrome. In addition, it may cause secondary immune suppression, especially in patients with compromised immune system, which could lead to the occurrence of secondary infections by other pathogens. This can often result in more severe clinical outcomes. Therefore, regarding the treatment of viral infections, restoring the balance of the immune system is crucial in addition to specific antiviral medications. In recent years, scientists have made an interesting finding that low dose IL-2 (ld-IL-2) could potentially have a crucial function in regulating the immune system and reducing the chances of infection, especially viral infection. Ld-IL-2 exerts immune regulatory effects in different types of viral infections by modulating CD4+ T subsets, CD8+ T cells, natural killer cells, and so on. Our review summarised the role of IL-2 or IL-2 complexes in viral infections. Ld-IL-2 may be an effective strategy for enhancing host antiviral immunity and preventing infection from becoming chronic; additionally, the appropriate use of it can help prevent excessive inflammatory response after infection. In the long term, it may reduce the occurrence of infection-related autoimmune diseases and tumours by promoting the restoration of early immune homeostasis. Furthermore, we have also summarised the application of ld-IL-2 in the context of autoimmune diseases combined with viral infections; it may be a safe and effective strategy for restoring immune homeostasis without compromising the antiviral immune response. In conclusion, focusing on the role of ld-IL-2 in viral infections may provide a new perspective for regulating immune responses following viral infections and improving prognosis.

The roles played by IL-10, IL-23 and IL-17A in term delivery

BACKGROUND

The immune system significantly participates in the development of the successful delivery process. The roles played by cytokine molecules in the induction of term delivery are yet to be clarified. The aim of this project was to explore the serum levels of interleukin-10 (IL-10), IL-17A, and IL-23 in the mothers with term and prolonged pregnancy and their infants.

MATERIALS AND METHODS

In this study, 60 samples were collected from either mothers with term and prolonged pregnancy or their infants, collectively 240 samples. Serum levels of IL-10, IL-17A and IL-23 were explored using enzyme linked immunosorbent assay (ELISA) technique.

RESULTS

IL-10 serum levels significantly decreased in the neonates with prolonged pregnancy when compared to their mothers. Serum levels of IL-23 were increased either in term or prolonged pregnancy neonates when compared to their corresponded mothers. Serum levels of IL-10 and IL-23 significantly decreased and increased, respectively, in the female in comparison to male in the prolonged pregnancy neonates. IL-10 also significantly decreased in the term mothers who had higher gravidity.

CONCLUSION

Although, IL-17A does not play a key role in the delivery mechanism, IL-10 and IL-23 may be considered as potential factors in the modulation of term delivery.

Cytokine profile during occult hepatitis B virus infection in chronic hepatitis C patients

Background

The hepatitis B virus (HBV) is one of the leading causes of acute, chronic and occult hepatitis (OBI) representing a serious public health threat. Cytokines are known to be important chemical mediators that regulate the differentiation, proliferation and function of immune cells. Accumulating evidence indicate that the inadequate immune responses are responsible for HBV persistency. The aim of this study were to investigate the cytokines IFN-γ, TNF-α, IL-2, IL-4, IL-6, IL-10 and IL-17A in patients with OBI and verify if there is an association between the levels of these cytokines with the determination of clinical courses during HBV occult infection.

Methods

114 patients with chronic hepatitis C were investigated through serological and molecular tests, the OBI coinfected patients were subjected to the test for cytokines using the commercial human CBA kit. As controls, ten healthy donors with no history of liver disease and 10 chronic HBV monoinfected patients of similar age to OBI patients were selected.

Results

Among 114 HCV patients investigated, 11 individuals had occult hepatitis B. The levels of cytokines were heterogeneous between the groups, most of the cytokines showed higher levels of production detection among OBI/HCV individuals when compared to control group and HBV monoinfected pacients. We found a high level of IL-17A in the HBV monoinfected group, high levels of TNF-α, IL-10, IL-6, IL-4 and IL-2 in OBI/HCV patients.

Conclusion

These cytokines could be involved in the persistence of HBV DNA in hepatocytes triggers a constant immune response, inducing continuous liver inflammation, which can accelerate liver damage and favor the development of liver cirrhosis in other chronic liver diseases.

Role of maternal interleukin-8 (IL-8) in normal-term birth in the human

Cytokines are the main factors involved in the normal functions of the placenta and delivery process. The aim of this project was to compare serum levels of interleukin-8 (IL-8), IL-6, tumour necrosis factor α (TNF-α) and transforming growth factor β (TGF-β) in term and prolonged-pregnancy mothers and their neonates. This study was performed on 240 participants including 60 term and prolonged-pregnancy neonates and their corresponding mothers. Serum levels of IL-8, IL-6, TNF-α and TGF-β were evaluated by the enzyme-linked immunosorbent assay technique. The results revealed that IL-8 serum levels were significantly lower in the prolonged-pregnancy mothers and their neonates when compared with term mothers and their neonates. Data analysis also revealed a negative correlation between TGF-β and age of prolonged-pregnancy mothers. A poor positive correlation between IL-6 and head circumference of term neonates was also observed. IL-8 may play crucial roles in the process of on-time delivery and age may significantly affect TGF-β production in prolonged-pregnancy mothers. Pro-inflammatory cytokines, such as IL-6, can also be considered as main factors involved in fetal growth.

Chronic Hepatitis B Virus Infection Associated with Increased Colorectal Cancer Risk in Taiwanese Population

Chronic hepatitis B virus (HBV) infections and colorectal cancer (CRC) are prevalent in Taiwan. We carried out a population-based case-control study to assess the association between HBV infection and CRC risk. Using the National Health Insurance Research Database of Taiwan, we identified 69,478 newly diagnosed patients with CRC from 2005 to 2011. We further randomly selected 69,478 age- and gender-matched controls without CRC from the same database. Odds ratios (ORs) were calculated to evaluate the association between chronic HBV infection and CRC using a logistic regression analysis. HBV infection was found to be associated with the risk of CRC (OR = 1.27, 95% confidence interval (CI) = 1.20–1.33). This relationship was similar in men and women. Age-specific analysis revealed that the CRC risk associated with HBV decreased with age. The adjusted ORs for patients aged <55, 55–64, and 65–74 years were 1.63 (95% CI = 1.48–1.79), 1.24 (95% CI = 1.13–1.37), and 1.02 (95% = 0.92–1.13), respectively. In conclusion, this study suggests that chronic HBV infection is significantly associated with an increased risk of CRC. Monitoring the risk of CRC development in young patients with HBV infection is crucial.

Correlation between Hepatitis B Virus Infection and Colorectal Neoplasia

Background: Data about the association between hepatitis virus infection and colorectal neoplasia (CRN) are extremely limited. We examined the association between hepatitis B virus (HBV) and hepatitis C virus (HCV) infection with the risk of CRN. Methods: A cross-sectional study was performed on asymptomatic examinees who underwent a colonoscopy and serologic testing for hepatitis B surface antigen (HBsAg) and hepatitis C antibody (HCV Ab) between 2004 and 2015. Results: Of 155,674 participants who underwent serologic testing for HBsAg, 5476 (3.5%) were positive for HBsAg. The mean age of the study participants was 41.1 ± 9.1 years. The prevalence of CRN was higher in the HBsAg (+) than in HBsAg (-) participants (16.9% vs. 15.6%, p = 0.009). Even after adjusting for confounders, HBsAg positivity was correlated with an increased risk of CRN (odds ratio (OR), 1.10; 95% confidence interval (CI), 1.01–1.19; p = 0.025). Of 155,180 participants who underwent serologic testing for HCV Ab, only 240 (0.15%) were positive for HCV Ab. The prevalence of CRN was higher in HCV Ab (+) than in HCV Ab (-) participants (22.9% vs. 15.6%, p = 0.002). However, the association disappeared after adjusting for confounders (OR, 1.04; 95% CI, 0.72–1.50; p = 0.839). Conclusions: HBV infection was independently correlated with an increased risk of CRN. Our results indicate the possibility that HBV infection may contribute to colorectal carcinogenesis. Screening colonoscopy may have to be recommended more thoroughly for HBV-infected 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.

Inflammasomes and their roles in the pathogenesis of viral hepatitis and their related complications: An updated systematic review

Inflammasomes are a set of innate receptors which are the responsible molecules for activation of pro-interleukin (IL)-1β and IL-18 and induction of inflammation. Due to the key roles of the inflammasomes in the induction of inflammation, it has been hypothesized that the molecules may be the main parts of immune responses against viral infections and the tissue damage. Because some cases of viral hepatitis infections, including hepatitis B and C, are diagnosed as chronic and may be associated with various complications such as liver cirrhosis and hepatocellular carcinoma (HCC), several studies focused on the roles played by the inflammation on the pathogenesis of viral hepatitis. Based on the roles played by inflammasomes in induction of inflammation, it has been hypothesized that inflammasomes may be the main parts of the puzzle of the viral hepatitis complications. This article reviews the roles of the inflammasomes in the pathogenesis of hepatitis B and C viral infections and their complications, liver cirrhosis, and HCC.

Hepatitis B Virus Infection Is Independently Associated With Advanced Colorectal Adenoma

BACKGROUND

Studies on the association of chronic hepatitis B virus (HBV) infection with colonic neoplasm are rare. We aimed to investigate the association between chronic HBV infection and the development of colonic adenoma.

MATERIALS AND METHODS

One hundred thirty-three patients with chronic HBV infection who underwent colonoscopic examination, were enrolled. A healthy HBV-uninfected group was matched with the HBV group. Those with a previous history of colorectal cancer, inflammatory bowel diseases or colorectal surgery were excluded from both HBV and HBV-uninfected groups. Clinical information and data on age, sex, body mass index, smoking, alcohol consumption and comorbidities were obtained. Advanced adenoma was defined as tubular adenoma ≥10mm, or adenoma with a villous component or high-grade dysplasia.

RESULTS

The HBV group had a higher rate of colorectal adenoma and advanced adenoma than the HBV-uninfected group. Patients in the HBV group had larger colorectal polyps than those in the HBV-uninfected group. In the chi square test, HBV DNA positivity was significantly associated with colorectal adenoma (P < 0.001) and advanced adenoma (P = 0.007). HBV infection (odds ratio [OR] = 23.961, 95% CI: 9.400-61.076), diabetes mellitus (OR = 2.633, 95% CI: 1.071-6.473) and age (OR = 1.057, 95% CI: 1.020-1.095) were significantly associated with advanced adenoma in the multivariable logistic regression analysis. Multivariable logistic regression analysis within the HBV group revealed that HBV DNA (OR = 1.236, 95% CI: 1.029-1.485) was associated with advanced adenoma.

CONCLUSIONS

HBV DNA in patients with HBV infection and HBV infection are independently associated with advanced colorectal adenoma development.

Innate immunity related pathogen recognition receptors and chronic hepatitis B infection

Innate immunity consists of several kinds of pathogen recognition receptors (PRRs), which participate in the recognition of pathogens and consequently activation of innate immune system against pathogens. Recently, several investigations reported that PRRs may also play key roles in the induction/stimulation of immune system related complications in microbial infections. Hepatitis B virus (HBV), as the main cause of viral hepatitis in human, can induce several clinical forms of hepatitis B and also might be associated with hepatic complications such as cirrhosis and hepatocellular carcinoma (HCC). Based on the important roles of PRRs in the eradication of microbial infections including viral infections and their related complications, it appears that the molecules may be a main part of immune responses against viral infections including HBV and participate in the HBV related complications. Thus, this review article has brought together information regarding the roles of PRRs in immunity against HBV and its complications.

IL-2 and polyoma BK virus infection; A systematic review article

It has been demonstrated that IL-2 plays a dual role in induction/suppression of immune responses via activation of conventional and regulatory T lymphocytes, respectively. IL-2 contacts complete IL-2 receptor (IL-2R) which contains CD25 (α chain) on the antigen specific activated T helper and cytotoxic lymphocytes and also T regulatory cells. Additionally, previous investigations revealed that polyoma BK virus (PBK) reactivation and induction of PBK associated nephropathy (PBKAN) is a main complication following renal transplantation. Based on the important dual roles played by IL-2 in the immune responses, it may be hypothesized that IL-2/IL-2R interaction could be considered a potential mechanism against/toward PBK reactivation and also PBKAN. Accordingly, the aim of the current review article is to determine the roles of IL-2 IL-2/IL-2R interaction in PBK reactivation and PBKAN complications.

The link between TLR7 signaling and hepatitis B virus infection

Toll-Like Receptors (TLRs) play crucial roles in recognition and induction of appropriate immune responses against viral infections, including hepatitis B. TLR7 detects intracellular viral single strand RNA which leads to the activation of several pro-inflammatory transcription factors via the MYD88 dependent pathway. Patients with prolonged infectious forms of hepatitis B, including active and inactive chronic forms, are unable to clear HBV from hepatocytes completely. It is believed that the differences in genetic and immunological parameters of the patients and clearance subjects, who successfully clear HBV infections, are the main factors responsible for allowing the long term infections to persist. It appears that defective expression of TLR7 may result in impaired immune responses against HBV. The aim of this review is to address the recent information regarding the crucial roles played by TLR7 in hepatitis B infection and also the main mechanisms used by HBV to escape from recognition by TLR7 in prolonged HBV infected patients. Considering that chronic hepatitis B infection is not yet curable, it could be possible to activate TLR7-related immunological pathways as a therapy directed towards persistent HBV infection. Hence, another aim of this study is to present recent developments of TLR7 agonists as a therapeutic strategy for chronic hepatitis B.

Are RIG-1 and MDA5 Expressions Associated with Chronic HBV Infection?

Melanoma differentiation-associated protein 5 (MDA5) and retinoic acid-inducible gene 1 (RIG-1) as the pattern recognition receptors play important roles in viral mRNA recognition. Chronic HBV-infected (CHB) patients are unable to properly respond to hepatitis B virus (HBV). Therefore, the aim of the present study was to evaluate the mRNA levels of MDA5 and RIG-1 in the peripheral blood immune cells of CHB patients in comparison to healthy controls. In this cross-sectional study, the mRNA levels of MDA5 and RIG-1 were examined in 60 CHB patients and 60 healthy controls using the real-time polymerase chain reaction (PCR) technique. Our results showed that mRNA levels of MDA5 and RIG-1 were significantly decreased and increased, respectively, in CHB patients when compared to healthy controls. Our results also revealed that mRNA levels of MDA5 and RIG-1 were not altered among CHB patients with various states of e-antigen of hepatitis B and HBV-DNA viral loads. According to the results presented here, it may be concluded that downregulation of MDA5 may be a responsible mechanism from several reasons, which leads to HBV persistence in CHB patients.

Establishing the link between hepatitis B virus infection and colorectal adenoma

BACKGROUND

Chronic hepatitis B (CHB) infection has been associated with malignancy, most notably hepatocellular carcinoma. Previous research has shown that hepatitis C is associated with increased colorectal adenomas and neoplasia. Currently, there are no studies on the association of CHB and colorectal adenomas. We aimed to identify a possible link between CHB and colorectal adenoma.

METHODS

A retrospective chart review was performed on 588 consecutive patients undergoing screening or diagnostic colonoscopy that were previously screened or diagnosed with hepatitis B. Comparisons between categorical variables were analyzed with Chi Square test and t-test for continuous variables. Unconditional logistic regression was used to generate age-, gender-and race-adjusted odds ratios and their 95% confidence intervals (CI) comparing medication users with non-users. Statistical analyses were performed with SAS 9.3 software.

RESULTS

A total of 487 patients were analyzed in the control group vs. 71 in the hepatitis B group. The adenoma detection rate was 23.9% in hepatitis B vs. 15.9% in the non-hepatitis B group for all cause colonoscopy; however this did not reach statistical significance. There was a significantly higher number of adenomas present in the distal colon compared to control (OR =2.16; 95% CI, 1.06-4.43; P=0.04). There were no significant findings between hepatitis B infection with size, multiplicity or presence of proximal adenomas. There was a significant difference noted in regards to smoking history, BMI and age between two groups.

CONCLUSIONS

Although the adenoma detection rate was higher in hepatitis B population vs. the non-hepatitis B group this did not reach statistical significance. However, we did find an association between CHB infection and the presence of distal colorectal adenomas. Larger prospective studies are needed to strengthen our findings along with future studies examining hepatitis B virus (HBV) and mechanisms inducing colorectal carcinogenesis.

Significant roles played by IL-10 in Chlamydia infections

Chlamydia species are obligate intracellular parasites which cause usually asymptomatic genital tract infections and also are associated with several complications. Previous studies demonstrated that immune responses to Chlamydia species are different and the diseases will be limited to some cases. Additionally, Chlamydia species are able to modulate immune responses via regulating expression of some immune system molecules including cytokines. IL-10, as the main anti-inflammatory cytokine, plays important roles in the induction of immune-tolerance against self-antigen and also immune-homeostasis after microbe elimination. Furthermore, it has been documented that ectopic expression of IL-10 is associated with several chronic infectious diseases. Therefore, it can be hypothesized that changes in the regulation of this cytokine can be associated with infection with several species of Chlamydia and their associated complications. This review collected the recent information regarding the association and relationship of IL-10 with Chlamydia infections. Another aim of this review article is to address recent data regarding the association of genetic variations (polymorphisms) of IL-10 and Chlamydia infections.

TLR9: an important molecule in the fight against hepatitis B virus

Hepatitis B virus (HBV) is the most prevalent infectious agent that can induce severe liver disease. Patients infected with long-term HBV, including chronic, asymptomatic and occult forms, cannot clear HBV from infected hepatocytes completely. It is not clear why some people can clear the infection while others cannot. Furthermore, the main mechanisms responsible for progression of the infections are not fully understood. It has been hypothesised that differences in genetic and immunological parameters between patients and subjects who successfully clear HBV infections are responsible for inducing the long-term forms of the infection. Previous investigations showed that Toll-like receptors (TLRs) play important roles in immune responses, especially innate immunity, against viral infections, including hepatitis B. TLR9 detects intracellular viral dsDNA, which results in the activation of an immune response against HBV. However, defects in this system may result in an attenuated response ultimately leading to long-term HBV infections. Targeting the defects in TLR9 or reactivating the downstream pathways that are normally switched on by TLR9 in response to HBV infection is a new approach to the treatment of long-term HBV infection. However, the pathways and defects seen in patients with long-term HBV need to be thoroughly explored before therapeutics can be applied in the clinical setting. Furthermore, the apparently multigenic nature of long-term HBV infection suggests that treatment of patients may need to be personalised.

Genetic characterization and genotyping of hepatitis B virus (HBV) isolates from donors with an occult HBV infection

BACKGROUND AND OBJECTIVES

Screening of Thai blood donors has resulted in the detection of donors with an occult HBV infection (OBI), where HBsAg is undetectable, but hepatitis B virus (HBV) DNA is present in serum in low concentrations. This study was designed to determine whether the occurrence of OBI in donors was linked to the HBV genotype and possibly to mutations in the surface (S) and core (C) gene regions.

MATERIALS AND METHODS

Mutations in the S and C gene regions in 48 Thai donors with OBI were mapped by sequencing. Genotyping was determined with the INNO-LiPA test and by phylogenetic analysis of sequences from the S and C genes.

RESULTS

The majority of OBI samples were genotype C (81·3%) with 6·3% of samples being genotype B. In addition, two genotype I isolates were identified. Mutations in the S region (100%) were found especially in loop 1 of the major hydrophilic loop (MHL) at positions I110L, T114S, T126I and S113T, whereas mutations in the C region (65%) were within the basal core promoter region (position A1762T/G1764A) and precore region (position G1896A).

CONCLUSION

The majority of OBI samples were HBV genotype C, although genotype I, which is newly emerging in Thailand, was also detected. The study demonstrated that OBI was probably not associated with a particular HBV genotype or with certain mutations in the S and C gene regions. However, mutations in the C gene region which could potentially impair viral replication and HBsAg production and potentially lead to OBI were identified.

Toll-like receptor 4 and hepatitis B infection: molecular mechanisms and pathogenesis

Hepatitis B virus (HBV) infection mainly causes liver disease, including inflammation, cirrhosis, and hepatocellular carcinoma (HCC). It has been documented that prolonged hepatitis B-infected patients are unable to clear HBV from hepatocytes completely. Previous investigations have suggested that various genetic and immunologic parameters may be responsible for the induction of prolonged infection forms. Toll-like receptors (TLRs), as members of pathogen recognition receptors (PRRs), play critical roles in the recognition of viruses and the induction of appropriate immune responses. Thus, TLRs may be considered as essential sensors for the recognition of HBV and the induction of immune responses against this virus. It has been documented that TLR4 plays key roles in the detection of several microbial pathogen-associated molecular pattern molecules, including bacterial lipopolysaccharide (LPS), as well as endogenous ligands (damage-associated molecular pattern molecules) and subsequently activates pro-inflammatory transcription factors in either MYD88 or TRIF dependent pathways. Previous investigations have proposed that TLR4 might be involved in appropriate immune responses against HBV. Therefore, the aim of this review is to present the recent data regarding the important roles of TLR4 in HBV recognition and regulation of immune responses against this virus, and also its roles in the pathogenesis of cirrhosis and HCC as complications of prolonged hepatitis B infections.

Intensity of HLA-A2 Expression Significantly Decreased in Occult Hepatitis B Infection

Background:

Occult hepatitis B infected (OBI) patients cannot eradicate hepatitis B virus (HBV)-DNA from their liver and peripheral blood, completely.

Objectives:

The main aim of this study was to investigate the rate of HLA-A2 expression on peripheral blood mononuclear cells (PBMCs) of patients with OBI.

Materials and Methods:

In this experimental study, intensity of HLA-A2 was measured on the PBMCs of 57 OBI patients and 100 HBsAg-/anti-HBc+/HBV-DNA samples were enrolled as controls; measurements were performed using the flow cytometry technique.

Results:

Flow cytometric analysis indicated that 19 (33.3%) OBI patients and 28 (28%) controls expressed HLA-A2 antigen on their PBMCs. There was no significant difference between the two groups regarding the rate of individuals expressing HLA-A2 antigen. Statistical analyses showed that the intensity of HLA-A2 expression significantly decreased in OBI patients (3.58 ± 0.1) in comparison to healthy controls (4.21 ± 0.25; P < 0.001).

Conclusions:

According to these results it can be concluded that decreased intensity of HLA-A2 on the PBMCs of OBI patients may lead to resistance of HBV in the patients.

Occult HBV infection: a faceless enemy in liver cancer development

The hepatitis B virus (HBV) represents a worldwide public health problem; the virus is present in one third of the global population. However, this rate may in fact be higher due to occult hepatitis B virus infection (OBI). This condition is characterized by the presence of the viral genome in the liver of individuals sero-negative for the virus surface antigen (HBsAg). The causes of the absence of HBsAg in serum are unknown, however, mutations have been identified that produce variants not recognized by current immunoassays. Epigenetic and immunological host mechanisms also appear to be involved in HBsAg suppression. Current evidence suggests that OBI maintains its carcinogenic potential, favoring the progression of fibrosis and cirrhosis of the liver. In common with open HBV infection, OBI can contribute to the establishment of hepatocellular carcinoma. Epidemiological data regarding the global prevalence of OBI vary due to the use of detection methods of different sensitivity and specificity. In Latin America, which is considered an area of low prevalence for HBV, diagnostic screening methods using gene amplification tests for confirmation of OBI are not conducted. This prevents determination of the actual prevalence of OBI, highlighting the need for the implementation of cutting edge technology in epidemiological surveillance systems.

IL-17A in hepatitis B infection: friend or foe?

Hepatitis B virus (HBV) is one of the most prevalent and infectious agents that leads to liver disease in humans. Five clinical forms of HBV infection exist, including fulminant, acute, chronic, asymptomatic and occult. The chronic, asymptomatic and occult forms are long-term infections that can lead to hepatocellular carcinoma (HCC) and liver cirrhosis. The mechanisms responsible for progression of these forms of the infection to HCC and liver cirrhosis are not yet clearly understood or characterised. However, genetic and immunological parameters may play important roles in the disease. IL-17A is an important cytokine involved in early immune responses against fungal and bacterial infections, but its role in the response against viral infections is yet to be fully clarified. The crucial roles of IL-17A in the pathogenesis of autoimmune and destructive immune-related diseases have been documented and may provide insights into its functions during hepatitis infection. Therefore, the aim of this review was to address the recent information regarding the status and association of IL-17A during hepatitis B infection and its related disorders, including HCC and liver cirrhosis.

Is the CCR5 Δ 32 mutation associated with immune system-related diseases?

Hypersensitivity and autoimmunity are the main features of immune system-related diseases such as type 2 diabetes (T2D), multiple sclerosis (MS), and asthma. It has been established that chemokines play key roles in the activation and regulation of immune cell migration which is important in the pathogenesis of the diseases mentioned. CC chemokines receptor 5 or CCR5 is a receptor for RANTES, MIP-1α, and MIP-1β and is expressed by several immune cells including NK cells, T lymphocytes, and macrophages. It plays key roles in the regulation of migration and activation of the immune cells during immune responses against microbe and self-antigens during autoimmunity and hypersensitivity disorders. Therefore, any alteration in the sequence of CCR5 gene or in its expression could be associated with immune system-related diseases. Previous studies revealed that a 32-base pair deletion (Δ 32) in exon 1 of the CCR5 gene led to downregulation of the gene. Previous studies demonstrated that not only CCR5 expression was altered in autoimmune and hypersensitivity disorders, but also that the mutation is associated with the diseases. This review addresses the recent information regarding the association of the CCR5 Δ 32 mutation in immune-related diseases including T2D with and without nephropathy, MS, and asthma. Based on the collected data, it seems that the CCR5 Δ 32 mutation can be considered as a risk factor for MS, but not asthma and T2D with and without nephropathy.

Can Toll-Like Receptor (TLR) 2 be considered as a new target for immunotherapy against hepatitis B infection?

The current literature describes pivotal mechanisms in which hepatitis B virus (HBV) induces liver diseases including inflammation, cirrhosis and hepatocellular carcinoma (HCC). It appears that differences in genetic and immunological parameters between patients and controls may be responsible for inducing the prolonged forms of the infection. Previous studies demonstrated that Toll-Like Receptors (TLRs) play key roles in viral recognition and inducing appropriate immune responses. Therefore, TLRs can be considered as key sensors for HBV recognition and subsequent induction of immune responses against this virus. It has also been shown that the TLR2 detects several microbial PAMPs either in its homodimer form or in a heterodimer with TLR1 or TLR6 and subsequently activates NF-κB in a MYD88 dependent manner. Therefore, defective TLR2 expression may result in impaired immune responses against HBV which is reported in long-term forms of hepatitis B. This review presents the recent data regarding the status and important roles played by TLR2 in HBV recognition and induction or suppression of immune responses against HBV as well as its roles in the pathogenesis of cirrhosis and HCC in prolonged hepatitis B forms.

NK cells in hepatitis B virus infection: a potent target for immunotherapy

Viruses, including hepatitis B virus (HBV), are the most prevalent and infectious agents that lead to liver disease in humans. Hepatocellular carcinoma (HCC) and cirrhosis of the liver are the most serious complications arising from prolonged forms of hepatitis B. Previous studies demonstrated that patients suffering from long-term HBV infections are unable to eradicate HBV from hepatocytes completely. The mechanisms responsible for progression of these forms of infection have not yet been clarified. However, it seems that there are differences in genetic and immunological parameters when comparing patients to subjects who successfully clear HBV infections, and these may represent the causes of long-term infection. Natural killer (NK) cells, the main innate immune cells that target viral infections, play important roles in the eradication of HBV from hepatocytes. NK cells carry several stimulatory and inhibitor receptors, and binding of receptors with their ligands results in activation and suppression of NK cells, respectively. The aim of this review is to address the recent information regarding NK cell phenotype, functions and modifications in hepatitis B. This review addresses the recent data regarding the roles of NK cells as novel targets for immunotherapies that target hepatitis B infection. It also discusses the potential to reduce the risk of HCC or cirrhosis of the liver by targeting NK cells.

CCR5 plays important roles in hepatitis B infection

In humans, hepatitis B virus (HBV) is the most prevalent and the main infectious agent that leads to liver disease. Previous investigations identified that long-term HBV-infected patients are unable to eradicate HBV completely from hepatocytes. The main mechanisms responsible for long-term forms of the infections are yet to be clarified. However, researchers believe that the differences in genetic and immunological parameters in the patients in comparison to subjects who successfully clear HBV infections may be the causes for long-term infection. Previous studies demonstrated that chemokines play important roles in the regulation of immune cell migration and activation, which is crucial for a comprehensive immune response against HBV. RANTES, MIP-1α, and MIP-1β are important CC chemokines which act through CC chemokines receptor 5 (CCR5). This receptor is expressed on several effector immune cells including NK cells, T lymphocytes, and macrophages, and plays a crucial role in the regulation of activation and migration of the immune cells during immune responses against viruses, including HBV. Therefore, alterations in its expression or functions could be associated with attenuated immune responses against HBV. In addition, previous studies identified that a 32 base pair deletion (Δ32) in exon 1, as well as three polymorphisms in the promoter region of the CCR5 gene results in downregulation of the molecule. Previous studies revealed that CCR5 expression was altered in hepatitis B but the role of the CCR5 Δ32 mutation and CCR5 promoter polymorphisms in this disease is controversial. This review addresses the recent information regarding the status of CCR5 expression on immune cells and the association of CCR5 promoter polymorphisms with HBV-infected patients.

Reduced expression of TRIF in chronic HBV infected Iranian patients

BACKGROUND AND AIMS

TRIF is one of the main intracellular adaptor proteins required for TLR3 and 4 signaling. Abnormal gene expression of TRIF may lead to abrogated immune responses against viral infections including hepatitis B infection. The aim of this study was to identify the mRNA levels of TRIF in PBMCs isolated from chronic HBV (CHB) infected patients.

MATERIAL AND METHODS

mRNA was isolated from 63 CHB patients and 60 healthy controls and transcript levels of TRIF were examined in parallel with beta-actin (as housekeeping gene) using Real-Time PCR techniques.

RESULTS

Our results demonstrated that expression of TRIF was significantly decreased in PBMCs isolated from CHB patients when compared to healthy controls.

CONCLUSIONS

Based on the results reported here, it seems that CHB patients are unable to express appropriate levels of the TRIF gene, which may attenuate TLR3 and 4 signaling subsequent to HBV infection. Our results suggest a possible mechanism, which may explain why hepatitis B infection is stable in CHB patients.

Important roles played by TGF-β in hepatitis B infection

Hepatitis B virus (HBV) which includes, fulminant, acute, chronic, asymptomatic, and occult HBV infection is the most prevalent virus that leads to human liver diseases. Chronic, asymptomatic, and occult infection can induce further sever diseases such as hepatocellular carcinoma (HCC) and cirrhosis of the liver. The underlying mechanisms that allow progression of the prolonged forms of the infection and subsequent HCC or cirrhosis of the liver are yet to be clarified. However, many researchers have suggested that immunological and genetic parameters may play important roles in the etiology of hepatitis B. Transforming growth factor beta (TGF-β) is an important cytokine with dual regulatory functions in the immune system and in the responses against viral infections. However, the pathways and mechanisms controlling these are not fully understood. The crucial roles of TGF-β in the development of Th17 and T regulatory lymphocytes, the main cell types involved in autoimmunity and destructive immune related diseases, have been documented and this provides insights into TGF-β function during hepatitis infection and subsequent HCC and cirrhosis of the liver. Recent findings also confirm that TGF-β directly alters hepatocyte function during hepatitis B, hence, the aim of this review is to address the current data regarding the association and status of TGF-β with hepatitis B infection and its related disorders including HCC and cirrhosis of the liver.

Clinical significance of occult hepatitis B infection in progression of liver disease and carcinogenesis

Occult hepatitis B infection (OBI) is defined as long-lasting persistence of hepatitis B virus (HBV) DNA in the liver of patients with hepatitis B surface antigen (HBsAg)-negative status, with or without serological markers of previous exposure (antibodies to HBsAg and/or to hepatitis B core antigen). Over the past two decades, significant progress has been made in understanding OBI and its clinical implications. OBI as a cause of chronic liver disease in patients with HBsAg-negative status is becoming an important disease entity. In conditions of immunocompetence, OBI is inoffensive in itself and detection of HBV DNA in the liver does not always indicate active hepatitis. However, when other factors that cause liver damage, such as hepatitis C virus infection, obesity and alcohol abuse are present, the minimal lesions produced by the immunological response to OBI might worsen the clinical course of the underlying liver disease. Several lines of evidence suggest that OBI is associated with progression of liver fibrosis and the development of hepatocellular carcinoma in patients with chronic liver disease. The major interest in OBI is primarily associated with the growing, widely discussed evidence of its clinical impact. The aim of this review is to highlight recent data for OBI, with a major focus on disease progression or carcinogenesis in patients with chronic liver disease.

Is the IL-10 promoter polymorphism at position -592 associated with immune system-related diseases?

Immune responses are the main causes of immune system-related diseases such as hypersensitivities and autoimmunity. It has also been established that cytokines play key roles in the regulation of immune responses which have been shown to be important in the pathogenesis of the diseases. IL-10, the main anti-inflammatory cytokine, is produced by several immune cells such as T regulatory and Th2 lymphocytes, activated macrophages, B regulatory lymphocytes as well as other cell types. It plays a key role in the regulation of immune responses after microbe elimination (homeostasis) and against self-antigens to prevent hypersensitivity and autoimmune diseases, respectively. Studies showed that a single nucleotide polymorphism (SNP) at the -592 position of IL-10 is associated with its regulation of expression. This review addresses the recent information regarding the association of the polymorphism at position -592 of IL-10 with immune-related diseases including type 2 diabetes with and without nephropathy, multiple sclerosis, and asthma with an emphasize on Iranian patients.

High Serum Levels of TGF-β in Iranians With Chronic HBV Infection

BACKGROUND

The transforming growth factor-β (TGF-β) is an important cytokine with anti-inflammatory properties.

OBJECTIVES

The main purpose of this study was to compare the serum levels of TGF-β in a group of chronic HBV infected (CHB) patients as well as healthy individuals from South-East of Iran.

PATIENTS AND METHODS

Sixty patients with CHB as well as sixty healthy individuals were enrolled in the study. ELISA technique was applied to measure the serum levels of TGF-β in both groups.

RESULTS

Our results revealed that the serum levels of TGF-β were significantly increased in CHB patients in compare to healthy controls.

CONCLUSIONS

According to this result, it may be concluded that high serum levels of TGF-β may be a mechanism by which immune response against HBV is suppressed.