Clinical impact of HLA DR B1 genotypes in chronic hepatitis C virus infection

HLA Class II-DRB1 Alleles with Hepatitis C Virus Infection Outcome in Egypt: A Multicentre Family-based Study

INTRODUCTION AND AIM

Hepatitis C virus (HCV) infection is a global medical problem. HLA -DRB1 alleles have an important role in immune response against HCV. The aim of this study is to clarify the contribution of HLA -DRB1 alleles in HCV susceptibility in a multicentre family-based study.

MATERIAL AND METHODS

A total of 162 Egyptian families were recruited in this study with a total of 951 individuals (255 with chronic hepatitis C (CHC), 588 persons in the control group(-ve household contact to HCV) and 108 persons who spontaneously cleared the virus (SVC). All subjects were genotyped for HLA -DRB1 alleles by SSP-PCR and sequence based typing (SBT) methods.

RESULTS

The carriage of alleles 3:01:01 and 13:01:01 were highly significant in CHC when compared to that of control and SVC groups [OR of 3 family = 5.1289, PC (Bonferroni correction ) = 0.0002 and 5.9847, PC = 0.0001 and OR of 13 family = 4.6860, PC = 0.0002 and OR = 6.5987, PC = 0.0001 respectively]. While DRB1*040501, DRB1*040101, DRB1*7:01:01 and DRB1*110101 alleles were more frequent in SVC group than CHC patients (OR = 0.4052, PC = 0.03, OR: OR = 0.0916,PC = 0.0006, OR = 0.1833,PC = 0.0006 and OR = 0.4061, PC = 0.0001 respectively).

CONCLUSIONS

It was concluded that among the Egyptian families, HLA-DRB1*030101, and DRB1*130101 alleles associated with the risk of progression to CHC infection, while DRB1*040101, DRB1*040501, DRB1*7:01:01and DRB1*110101 act as protective alleles against HCV infection.

HLA-DRB1 and susceptibility to kidney allograft rejection in Southern Iranian patients

Kidney transplantation is the best treatment option for the patients with end-stage renal disease. Viral infections and genetic factors such as HLA-II antigens may affect the kidney transplant outcome. The compatibility of HLA-DRB1 molecules in the survival of kidney transplant is important. Also, the correlation between these molecules and viral infections is significant. The current study investigates the allele frequency of HLA-DRB1 in 41 recipient kidney transplant and 203 normal healthy controls by polymerase chain reaction using sequence specific primers. Moreover the relation between HLA-DRB1 allelic groups and hepatitis B, hepatitis C and cytomegalovirus viral infections was also studied. However statistical analysis of the allele frequencies didn't show any significant association between HLA-DRB1 allelic group distributions or sharing and susceptibility to acute kidney transplant rejection (P > 0.05). Comparing the allele frequencies between HLA-DRB1*14 and DRB1*04 allelic showed a significant difference in controls and patients (P = 0.03 and P = 0.05 respectively). The results of the present study also showed a significant association between possession of HLA-DRB1*07 allele in kidney transplant recipients and hepatitis C virus infection (P = 0.009). In conclusion however the results of the present study did not showed relation between HLA-DRB1 allele's frequencies or sharing and kidney transplantation outcome, the results indicated that HLA-DRB1 alleles may susceptible individuals to renal disease or play a role in susceptibility to viral infection in kidney transplant patients.

Human leukocyte antigen class II alleles (DQB1 and DRB1) as predictors for response to interferon therapy in HCV genotype 4

Human leukocyte antigens class II play an important role in immune response against HCV. We investigated whether HLA class II alleles influence susceptibility to HCV infection and response to interferon therapy. HLA-DRB1 and -DQB1 loci were genotyped using PCR-SSO Luminex technology. According to our regimen, 41 (66%) of patients achieved sustained virological response to combined treatment of IFN and ribavirin. Frequencies of DQB1∗0313 allele and DRB1∗04-DRB1∗11, DQB1∗0204-DQB1∗0313, DQB1∗0309-DQB1∗0313, and DQB1∗0313-DQB1∗0319 haplotypes were significantly more frequent in nonresponders than in responders. In contrast, DQB1∗02, DQB1∗06, DRB1∗13, and DRB1∗15 alleles were significantly more frequent in responders than in nonresponders. Similarly, DRB1∗1301, DRB1∗1361, and DRB1∗1369 alleles and DRB1∗1301-DRB1∗1328, DRB1∗1301-DRB1∗1361, DRB1∗1301-DRB1∗1369, DRB1∗1328-DRB1∗1361, and DRB1∗1328-DRB1∗1369 haplotypes were significantly found only in responders. Some alleles and linkages showed significantly different distributions between patient and healthy groups. These alleles may be used as predictors for response to treatment or to susceptibility to HCV infection in the Egyptian population.

The association of HLA class II DR B1 alleles with HCV infection in Egyptian children

BACKGROUND AND STUDY AIMS

Human leucocyte antigens (HLA) class II appear to play an important role in the individual's immune response to viral infection. The aim of this study is to assess the relationship between HLA class II antigens with the clinical, laboratory and histopathological state of the liver in Egyptian children and adolescents with chronic hepatitis C virus (HCV) infection.

PATIENTS AND METHODS

The study included 46 chronically infected HCV children and adolescents without - hepatitis B virus (HBV) nor human immunodeficiency virus - (HIV). Their mean age was 10.4±4.23years (3-17). HLA-DRB typing was done by polymerase chain reaction (PCR) for the patients and 20 control subjects. Biochemical and haematological parameters were assessed as well as a liver biopsy was taken from the included patients.

RESULTS

The most frequent alleles demonstrated among patients were DRB1∗03, DRB1∗04 and DRB1∗13 (45.6%, 39.1% and 26.1%), respectively. Analysis of DRB1 frequencies between patients and control revealed that DRB1*15 is significantly reduced among patients when compared with the control group (p<0.01). Patients possessing the allele DRB1*03 had significantly reduced platelet count (p=0.03), and this allele was presented to a greater extent in patients with minimal grade of inflammation. Patients with DRB1*04 had significantly low serum albumin (p=0.04) and patients with DRB1*13 had significantly high serum aspartate aminotransferase (AST) levels (p=0.05).

CONCLUSION

In Egyptian HCV-infected children, special HLA patterns were found; HLA DRB1*03 was present in nearly half of the patients, while the frequency of HLA DRB1*15 was significantly reduced among the cases in comparison to the control subjects.

Evolution of hepatitis C virus infection under host factor influence in an ethnically complex population

BACKGROUND

The ethnic influence makes it difficult to reach a consensual definition of host-dependent genetic factors controlling the hepatitis C virus (HCV) disease course.

AIMS

To investigate, in an ethnically complex Brazilian population, whether human leucocyte antigen (HLA) molecules are associated with susceptibility to HCV infection, self-limiting viral clearance and predisposition to chronic disease.

METHODS

One hundred and four HCV-antibody-positive patients (stratified into groups with spontaneous viral clearance and chronic HCV infection) and 166 healthy controls were submitted to HLA genotyping.

RESULTS

Two strong associations were observed between the susceptibility to HCV infection and DRB3 [odds ratio (OR), 4.03; 95% confidence interval (CI), 2.40-6.77; P(c)=0.0000041] and DQB1*02 (OR, 1.72; 95% CI, 1.05-2.84; P=0.041), and between the spontaneous viral clearance and DRB1*01 (OR, 4.59; 95% CI, 1.70-12.41; P=0.003) and DQB1*03 (OR, 2.83; 95% CI, 1.14-7.02; P=0.029). No evidence was observed regarding the epidemiology or viral genotype influence on the disease course.

CONCLUSION

We could confirm with a highly admixed population the association of viral clearance with two allele groups (DRB1*01 and DQB1*03) previously reported in homogeneous populations. The identification of DRB1*01 and DQB1*03 involved with self-limiting hepatitis in different ethnic groups is a very important finding that will contribute to the current knowledge about HCV-host interaction and the development of therapeutic vaccines.

A comparative review of HLA associations with hepatitis B and C viral infections across global populations

Hepatitis B (HBV) and hepatitis C (HCV) viral infection or co-infection leads to risk of development of chronic infection, cirrhosis and hepatocellular carcinoma (HCC). Immigration and globalization have added to the challenges of public health concerns regarding chronic HBV and HCV infections worldwide. The aim of this study is to review existing global literature across ethnic populations on HBV and HCV related human leukocyte antigen (HLA) associations in relation to susceptibility, viral persistence and treatment. Extensive literature search was conducted to explore the HLA associations in HBV and HCV infections reported across global populations over the past decade to understand the knowledge status, weaknesses and strengths of this information in different ethnic populations. HLA DR13 is consistently associated with HBV clearance globally. HLADRB1*11/*12 alleles and DQB1*0301 are associated with HBV persistence but with HCV clearance worldwide. Consistent association of DRB1*03 and *07 is observed with HCV susceptibility and non-responsiveness to HBV vaccination across the population. HLA DR13 is protective for vertical HBV and HCV transmission in Chinese and Italian neonates, but different alleles are associated with their susceptibility in these populations. HLA class I molecule interactions with Killer cell immunoglobulin like receptors (KIR) of natural killer (NK) cells modulate HCV infection outcome via regulating immune regulatory cells and molecules. HLA associations with HBV vaccination, interferon therapy in HBV and HCV, and with extra hepatic manifestations of viral hepatitis are also discussed. Systematic studies in compliance with global regulatory standards are required to identify the HLA specific viral epitope, stage specific T cell populations interacting with different HLA alleles during disease progression and viral clearance of chronic HBV or HCV infections among different ethnic populations. These studies would facilitate stage specific therapeutic strategies for clearance of HBV and HCV infections or co-infections across global populations and aid in identification of HBV-HCV combined vaccine. HLA associations of chronic HBV or HCV development with confounding host factors including alcohol, drug abuse, insulin resistance, age and gender are lacking and warrant detailed investigation across global populations.

Immunology of hepatitis C virus infection

Hepatitis C virus (HCV) is known for its ability to establish persistent infection and cause chronic hepatitis in most infected individuals. The pathogenesis of hepatic injury and the precise mechanisms underlying viral persistence are unknown. Accumulating evidence indicates that successful elimination of HCV is associated with the induction and maintaining of strong helper T-cell and cytotoxic T-cell responses against multiple viral epitopes. In contrast, patients who develop chronic HCV infection are characterized by the lack of strong viral-specific helper T-cell responses. The failure to mount and maintain strong HCV-specific T-cell responses may be determined by the genetics, especially the major histocompatibility complex background, of the host. However, it is likely that other host and viral factors are also involved in determining the outcome of HCV infection. Available data suggest that HCV is not cytopathic to hepatocytes and that liver injury associated with chronic HCV infection is likely to be mediated by immune responses against HCV-infected hepatocytes. In addition to hepatitis, HCV infection may also cause breaching of immune tolerance, leading to autoimmune disorders. Although the lack of a small animal model and a tissue culture system has impeded research on hepatitis C virus (HCV) infection, recent studies in humans and chimpanzees have significantly enhanced our understanding of the interaction between HCV and the host's immune system. This review focuses on the most recent advances in our understanding of the immunology of HCV infection. In particular, the possible mechanisms of how HCV establishes chronic infection are discussed. The pathogenesis of liver injury, the immunogenetics of HCV infection, and the effect of HCV infection on host's immune function are also reviewed.