Distribution of the HLA class I allele in chronic hepatitis C and its association with serum ALT level in chronic hepatitis C

Frequency of the Main Human Leukocyte Antigen A, B, DR, and DQ Loci Known to Be Associated with the Clearance or Persistence of Hepatitis C Virus Infection in a Healthy Population from the Southern Region of Morocco: A Preliminary Study

Hepatitis C Virus (HCV) infection represents a significant global health challenge, with its natural course largely influenced by the host's immune response. Human Leukocyte Antigen (HLA) molecules, particularly HLA class I and II, play a crucial role in the adaptive immune response against HCV. The polymorphism of HLA molecules contributes to the variability in immune response, affecting the outcomes of HCV infection. This study aims to investigate the frequency of HLA A, B, DR, and DQ alleles known to be associated with HCV clearance or persistence in a healthy Moroccan population. Conducted at the University Hospital Center Mohammed VI, Marrakech, this study spanned from 2015 to 2022 and included 703 healthy Moroccan individuals. HLA class I and II typing was performed using complement-dependent cytotoxicity and polymerase chain reaction-based methodologies. The results revealed the distinct patterns of HLA-A, B, DRB1, and DQB1 alleles in the Moroccan population. Notably, alleles linked to favorable HCV outcomes, such as HLA-DQB1*0301, DQB1*0501, and DRB1*1101, were more prevalent. Conversely, alleles associated with increased HCV susceptibility and persistence, such as HLA-DQB1*02 and DRB1*03, were also prominent. Gender-specific variations in allele frequencies were observed, providing insights into genetic influences on HCV infection outcomes. The findings align with global trends in HLA allele associations with HCV infection outcomes. The study emphasizes the role of host genetics in HCV infection, highlighting the need for further research in the Moroccan community, including HCV-infected individuals. The prevalence of certain HLA alleles, both protective and susceptibility-linked, underscores the potential for a national HLA data bank in Morocco.

Role of Some Predominant Host Immunomodulators' Single Nucleotide Polymorphisms in Severity of Hepatitis B Virus and Hepatitis C Virus Infection

Hepatitis B and C infections can be either acute or chronic. The chronic infection can culminate in liver cirrhosis and hepatocellular carcinoma. Influence of the host genetic makeup on conversion of acute to chronic infection, development of cirrhosis, and hepatocellular carcinoma is an interesting area of research. Variability in different immune system genes may account for such differences in the outcome of infection. This article discusses single nucleotide polymorphisms in different host immunomodulator genes that have been frequently reported to influence the outcome of infection and severity of disease. The genetic variability could be utilized for the prediction of disease outcome and treatment responses.

The host HLA-A*02 allele is associated with the response to pegylated interferon and ribavirin in patients with chronic hepatitis C virus infection

Human leukocyte antigen (HLA) alleles are associated with both the progression of chronic hepatitis C (CHC) and the sustained virological response (SVR) to antiviral therapy. HLA-A*02 is the most common HLA allele in people of European/Caucasian descent and the Chinese and Japanese population. Therefore, we investigated whether HLA-A*02 expression is associated with disease outcome in Chinese CHC patients. Three hundred thirty-one treatment-naïve CHC patients were recruited in this study. The expression of HLA-A*02 was tested by FACS and LABType SSO assays. All patients were treated weekly with pegylated interferon plus ribavirin (PEG-IFN/RBV) according to a standard protocol. Virological response was assessed by TaqMan assay at the 4th, 12th, 24th, and 48th week of therapy, and again at the 24th week post-therapy. By the end of the study, 293 CHC patients, including 144 HLA-A*02-positive patients and 149 HLA-A*02-negative patients, were evaluable for analysis. There were no statistical differences in clinicopathological parameters between HLA-A*02-positive and negative patients before antiviral therapy (P > 0.05). The HLA-A*02-positive patients had a higher rapid virological response (RVR, 74.3 % versus 62.4 %, P = 0.03) and SVR (78.5 % versus 64.4 %, P = 0.01) and a lower relapse rate (4.2 % versus 11.9 %, P = 0.03) than HLA-A*02-negative patients. Multivariable logistic regression analysis showed that HLA-A*02 expression, liver fibrosis stages <S3, HCV genotype 2a, IL-28B rs8099917 TT, and RVR were independent predictive factors of SVR (P < 0.05). Host HLA-A*02 allele expression is associated with SVR, highlighting the importance of considering HLA-A*02 as a predictor of the response to PEG-IFN/RBV treatment in the Chinese population with CHC.

Eradication of hepatitis C virus could improve immunological status and pyoderma gangrenosum-like lesions

Hepatitis C virus (HCV) can affect immune cells and induce various kinds of immune-related diseases including pyoderma gangrenosum. We experienced a difficult-to-treat case of pyoderma gangrenosum-like lesions in a patient with HCV infection. The patient was treated with pegylated interferon (PEG IFN)-α-2b and ribavirin (RBV) therapy and achieved a sustained virological response. Before the eradication of HCV, the frequency of T-helper 17 cells was remarkably high in comparison to chronic hepatitis C patients without extrahepatic immune-related diseases. Moreover, we could detect negative and positive strand-specific HCV RNA in the CD19(+) B lymphocytes and CD4(+) T lymphocytes. However, after the eradication of HCV, the immunological status became normal and the pyoderma gangrenosum-like lesions became stable without immunosuppressive therapy. Here, we report a sequential immunological analysis during PEG IFN/RBV therapy and the beneficial effect of HCV eradication in difficult-to-treat pyoderma gangrenosum-like lesions.

Host genetics in immune-mediated hepatitis C virus clearance

Upon infection with hepatitis C virus (HCV), only few patients spontaneously clear the virus, while most patients develop chronic HCV infection. The host innate and adaptive immune response is believed to be the key determinant of viral clearance or persistence. Several host factors have been demonstrated to influence the efficiency of the antiviral immune response, including IL-28B polymorphisms, inhibitory natural killer cell receptors, as well as HLA class I and II alleles presenting viral antigens to CD8(+) and CD4(+) T cells. The understanding of the respective mechanisms is essential for the development of successful vaccination strategies against HCV.

The relation of HLA genotype to hepatitis C viral load and markers of liver fibrosis in HIV-infected and HIV-uninfected women

BACKGROUND

Human leukocyte antigen (HLA) class I and II genotype is associated with clearance of hepatitis C virus (HCV) infection, but little is known regarding its relation with HCV viral load or risk of liver disease in patients with persistent HCV infection.

METHODS

High-resolution HLA class I and II genotyping was conducted in a prospective cohort of 519 human immunodeficiency virus (HIV)-seropositive and 100 HIV-seronegative women with persistent HCV infection. The end points were baseline HCV viral load and 2 noninvasive indexes of liver disease, fibrosis-4 (FIB-4), and the aspartate aminotransferase to platelet ratio index (APRI), measured at baseline and prospectively.

RESULTS

DQB1*0301 was associated with low baseline HCV load (β = -.4; 95% confidence interval [CI], -.6 to -.3; P < .00001), as well as with low odds of FIB-4-defined (odds ratio [OR], .5; 95% CI, .2-.9; P = .02) and APRI-defined liver fibrosis (OR, .5; 95% CI, .3-1.0; P = .06) at baseline and/or during follow-up. Most additional associations with HCV viral load also involved HLA class II alleles. Additional associations with FIB-4 and APRI primarily involved class I alleles, for example, the relation of B*1503 with APRI-defined fibrosis had an OR of 2.0 (95% CI, 1.0-3.7; P = .04).

CONCLUSIONS

HLA genotype may influence HCV viral load and risk of liver disease, including DQB1*0301, which was associated with HCV clearance in prior studies.

Dysfunction of Immune Systems and Host Genetic Factors in Hepatitis C Virus Infection with Persistent Normal ALT

Patients with chronic hepatitis C (CHC) virus infection who have persistently normal alanine aminotransferase levels (PNALT) have mild inflammation and fibrosis in comparison to those with elevated ALT levels. The cellular immune responses to HCV are mainly responsible for viral clearance and the disease pathogenesis during infection. However, since the innate and adaptive immune systems are suppressed by various kinds of mechanisms in CHC patients, the immunopathogenesis of CHC patients with PNALT is still unclear. In this review, we summarize the representative reports about the immune suppression in CHC to better understand the immunopathogenesis of PNALT. Then, we summarize and speculate on the immunological aspects of PNALT including innate and adaptive immune systems and genetic polymorphisms of HLA and cytokines.

Association of human leucocyte antigen Class I (HLA-A and HLA-B) with chronic hepatitis C virus infection in Egyptian patients

Egypt has the highest prevalence of hepatitis C virus (HCV) in the world, ranging from 6% to 28% with an average of approximately 13.8% in the general population. It has been reported that human leucocyte antigen (HLA) alleles are associated with the outcome of HCV infection, but this associations showed ethnic and geographical differences. The objective of this study is to investigate the association between the frequencies of HLA Class I and chronic HCV infection in Egyptian patients and to find out whether there is a relation between certain HLA Class I antigens and HCV viral load, degree of fibrosis, activity and alanine aminotransferase (ALT) level. A case control study was conducted on 100 patients with chronic HCV infection and 150 healthy controls. HLA-A and HLA-B typing by complement-dependent micro-lympho-cytotoxicity assay was performed for both groups. HLA-A11 antigen was significantly increased in patients with chronic HCV infection versus controls (OR 3.98; 95% CI = 1.85-8.89; P = 0.001; and Pc = 0.021). HLA-B12, HLA-B13, HLA-B17 and HLA-B40 were higher in patients, and HLA-A32 and HLA-B14 were higher in controls, although the significance was lost after correction for multiple testing. HLA-A9 was significantly associated with low viral load (P = 0.008, Pc = 0.048). The results of this work implicate that HLA-A11 antigen may influence chronic HCV infection and may play a role in viral persistence. Different HLA Class I antigens are not associated with degree of liver fibrosis, grades of activity or level of ALT. However, HLA-A9 is associated with low HCV viral load in chronic HCV Egyptian patients.

HLA-class II alleles in Egyptian patients with hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is linked to environmental, dietary, and life style factors. Its incidence and distribution vary widely among ethnic groups, sex, and geographic regions. HBV and HCV Infection, liver cirrhosis, male gender, and old age are important risk factors of HCC. Variability in outcome following exposure, and the clustering of HCC within families raise the possibility that genetic factors are also involved in susceptibility to HCC. The Major Histocompatibility Complex (MHC) plays a key role in anti-virus and tumor defense. HLA polymorphism is implicated in conferring genetic susceptibility to a large number of immune-mediated diseases, including some cancers. The association between HLA class II antigen and HCC in different ethnic populations that has been reported is controversial. Therefore, the aim of this work was to study the association between HLA class II-DRB1 and DQB1 polymorphism and HCC in Egyptian patients and to investigate their role as risk factors for the development of HCC.

METHODS

HLA-class II (DRB1 and DQB1) typing was done by SSP for 100 subjects; 50 patients suffering from HCC (45 males and 5 females) with age range 40-64 years (51.16 years (y) +/- 6.16); and 50 normal healthy control subjects.

RESULTS

1. A significantly increased frequency of DRB1*04, and DQB1 *02 in HCC patients versus control group (p = 0.016, and 0.032, respectively) was found; 2. A significantly decreased frequency of DQB1*06 (p = 0.032) was found; 3. A significantly increased frequency of DRB1*07 (odds ratio (OR) = 4.929) was found; and 4. A significantly decreased frequency of DRB1*15 (OR = 0.316) was seen. In conclusion, while some alleles are significantly associated with HCC (DRB1*04, DQB1*02) and others are not associated (DQB1*06); therefore, it can be concluded that the DRB1*04 and DQB1*02 alleles might be risk factors for the occurrence of HCC (OR = 4.373 and 3.807, respectively), and DQB1*06 may be a protective allele (OR = 0.259).

Host genetic factors and antiviral immune responses to hepatitis C virus

Human genome variations explain some of the heterogeneity in the immune response to antigenic stimuli. Such differences in response to hepatitis C virus (HCV) antigens can account for the ability of the immune response to clear HCV after an acute infection or to develop more rapidly progressive liver disease. Several studies have examined polymorphisms in several candidate immune-response genes for their relation to these HCV outcomes. Results of some of these studies complement knowledge gained from immunology studies, and others offer new insights into HCV biology. This review summarizes published studies on variation in immune-response genes and HCV outcomes.

Associations between the human MHC and sustained virologic response in the treatment of chronic hepatitis C virus infection

The human major histocompatability complex (MHC) genes encode the human leukocyte antigens, which are important in antigen presentation and regulation of CD8+ and CD4+ T cells. Response to therapies in hepatitis C virus (HCV) infection is highly variable (30-80%) and lower response rates have been reported among African Americans (AA; approximately 30%) compared to Caucasian Americans (CA; approximately 50%) infected with genotype-1 viruses. We evaluated whether MHC gene variants were associated with response to therapy and racial differences in AA and CA sustained virologic response (SVR) rates. We genotyped alleles at 8 MHC loci: 3 class I (A, B and C) and 5 class II (DRB1, DQA1, DQB1, DPA1 and DPB1) loci in 373 individuals (179 AA and 194 CA) with genotype-1 HCV infections, who were treated with peginterferon-alpha-2a and ribavirin. We observed carriage of A(*)02 (RR=1.33(1.08-1.64); P=0.008), B(*)58 (RR=1.84(1.24-2.73); P=0.002) and DPB1(*)1701 (RR=1.57(1.09-2.26); P=0.015) to be associated with SVR after adjustment for other predictors of response. In analysis of AA and CA subgroups separately, we observed potential, though not statistically significant, differences in these MHC associations. Variation in the immunogenetic background of HCV-infected individuals might account for some observed variation in viral-specific immunity and courses of disease. In this regard, future studies examining broader patient populations are warranted.

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.

Dynamics of immature subsets of dendritic cells during antiviral therapy in HLA-A24-positive chronic hepatitis C patients

BACKGROUND

The cellular immune response is important in chronic hepatitis C (CHC). To better understand its mechanism, we examined dendritic cells (DCs) and hepatitis C virus (HCV)-specific cytotoxic T cells (CTLs), which are thought to contribute to liver injury and viral clearance.

METHODS

CHC patients received 24 weeks of interferon-alpha-based antiviral therapy. We analyzed time-sequential frequencies of peripheral DCs, classified as myeloid DCs (mDCs) or plasmacytoid DCs (pDCs), together with peptide major histocompatibility class I tetramers, epitope specific for HCV core 129-137 (t*24/c129) or HCV NS3 1296-1304 (t*24/ns1294), directly ex vivo.

RESULTS

The mDC and pDC populations changed in parallel (P < 0.05), showing a significant transient decrease at weeks 12 and 16 during the therapy, and then recovering. However, neither of the tetramer results showed a direct correlation with the kinetics of peripheral DCs.

CONCLUSIONS

There is an apparent effect of antiviral therapy or a subsequent reduction of HCV on host immunity, but the effect may not include the induction of CTLs in CHC.

A patient with clinical features of acute hepatitis E viral infection and autoimmune hepatitis

Hepatitis E virus (HEV) is one of the major causative agents of acute hepatitis in many developing countries. Recent intensive examination has revealed the existence of non-imported cases in industrialized countries. The patient was a 25-year-old Japanese female with acute hepatitis. Laboratory test demonstrated positive anti-nuclear antibody (ANA), anti-smooth muscle antibody (ASMA) and high level of serum immunoglobulin G (IgG). The patient was negative for serum markers of hepatitis A, B or C virus infection. She demonstrated a clinical course similar to severe autoimmune hepatitis, including response to prednisolone therapy. After a few years, with the availability of tests for the serum antibodies to HEV, we examined the frozen stocked sera of the patient and found her exact diagnosis was acute hepatitis E. Although we could not detect HEV-RNA, which is positive only in limited period of acute phase, serum IgA and IgG antibodies to HEV were positive and the titer of IgA and IgG antibodies were declined with the time course. In conclusion, we must take into consideration of HEV infection for the diagnosis of acute cryptogenic hepatitis including autoimmune hepatitis. Further studies are feasible to understand the pathogenesis of liver injuries induced by HEV infections.

Interferon-gamma is produced by CD8 T cells in response to HLA-A24-restricted hepatitis C virus epitopes after sustained virus loss

Differences in cytotoxic T lymphocyte activity in hepatitis C virus infection may account for the outcome of interferon monotherapy. To investigate this hypothesis, we analysed the response of peripheral CD8(+) T cells that recognized epitopes presented by HLA-A*2402. We synthesized HLA/beta2-microglobulin/peptide complexes using two epitopes. Production of interferon-gamma by CD8(+) T cells in response to plastic-bound monomeric HLA/peptide complex was observed frequently in sustained virus responders (SVR) (n = 13) against all the peptides, NS31296-1304 (the percentage of responding patients, 61.5%) and core 129-137 (53.8%), while no interferon-gamma production was observed in non-responders (NR) (n = 13) for any of the peptides. Tetramer-staining showed the presence of CD8(+) T cells specific for all the peptides except NS31296-1304 in two SVR at the end of interferon monotherapy, although hardly any such cells were found in four NR. Specific killing was observed against peptides NS31296-1304 (3/4) and core 129-137 (1/4) in sustained responders but none in non-responders. These results suggest that the responses of cytotoxic T lymphocytes (CTLs) were induced during interferon therapy in these patients and that interferon-gamma production by CD8(+) T lymphocytes against HCV NS31296-1304 and core 129-137 are well maintained in patients with SVR compared with those with NR. These findings emphasize the importance of the CD8(+) T cell response in controlling HCV infection.

Recovery of functional cytotoxic T lymphocytes during lamivudine therapy by acquiring multi-specificity

To characterize cytotoxic T lymphocytes (CTLs) that appeared in circulation during lamivudine therapy, we analyzed HBV-specific CTLs using HLA-A24 tetramer and HBcAg-specific Th1 cells in patients receiving lamivudine therapy. Six patients (HLA-A24(+)) with chronic hepatitis B, six patients (HLA-A24(-)) with chronic hepatitis B, and six patients (HLA-A24(+)) with chronic hepatitis C were studied. In addition to known CTL epitopes (C117 and P756), three epitopes were confirmed as CTL epitopes (C23, S89, S226) by chromium release assay and by staining intracellular perforin. CTLs specific for P756 were most frequently found at pre-treatment. During lamivudine therapy, increase in the frequencies of HLA-tetramer(+) cells was found for C117, S89, and S226. Recovery of CTLs was observed earlier in patients with HBeAg(-)/anti-HBe(+) compared with those with HBeAg(+)/anti-HBe(-). HBcAg-specific Th1 cells did not increase significantly up to 8 weeks. T cell lines from patients with chronic hepatitis B had a lower level of proliferation (0- to 24.9-fold expansion by in vitro stimulation) and a higher ability to produce interferon-gamma (0-84% except for S89), while perforin-positive cells showed low frequencies (0-50% except for S89). In conclusion, these results suggest that lamivudine therapy induces mainly CTLs that were less frequent before the therapy. Since recovered CTLs maintained the ability to produce interferon-gamma in response to peptides, these CTLs apparently contribute to the efficacy of lamivudine therapy in patients with hepatitis B.