Functionally aberrant dendritic cell subsets and expression of DC-SIGN differentiate acute from chronic HBV infection.

BACKGROUND: Dendritic cells (DCs) promote pathogen recognition, uptake and presentation of antigen through DC-specific intercellular adhesion molecule 3-grabbing non-integrin (DC-SIGN) and toll-like receptors (TLRs). AIMS AND OBJECTIVES: We aimed to study temporal changes in DCs, TLRs and DC-SIGN during acute viral hepatitis B (AVHB) infection and compare them to chronic (CHB) and to investigate the earliest time point of activated pathogen recognition receptors in hepatitis B viral infection. METHODS: We measured the frequencies of circulating myeloid (mDC) and plasmacytoid (pDC) dendritic cells and IFN-α production along with the expression of DC-SIGN and Toll Like Receptors (TLR's) in HBV patients at different time points. Also investigated in healthy volunteers, the dynamic changes in TLRs expression after receiving hepatitis B vaccine. RESULTS: On follow-up of AVHB patients, we found the mDC population was significantly higher at week 4 and 6 (p < 0.02, 0.01), whereas the pDC population was unchanged at week 6 compared with week 0. Whereas frequencies of mDCs and pDCs were found to be elevated in AVHB and CHB patients than HC (p < 0.00 and 0.01, respectively) but was comparable among AVHB vs CHB. The DCs in CHB patients were functionally impaired with significantly low IFN-α production and low DCSIGN expression (p < 0.04 and 0.00, respectively). Even after stimulation by TLR agonists, no change was found in IFN-α production in CHB patients. MyD88 and IL-6, IFN-α mRNA levels were also found down-regulated. Interestingly, on follow-up after HBV vaccine, TLRs expression was found high at day 3 after vaccination. DISCUSSION: The initial events of immune activation might be responsible for modulating immune response. These novel observations would pave the way for the development of antiviral strategies for chronic HBV infection.

Circulating Tregs correlate with viral load reduction in chronic HBV-treated patients with tenofovir disoproxil fumarate.

Limited response to current hepatitis B virus (HBV) drugs is possibly due to inadequate host cytotoxic cellular responses. Circulating Tregs have been shown to be associated with chronicity of HBV infection, but their profile during antiviral therapy has not been studied. We analyzed the frequency and effect of Tregs on cellular immune responses against HBV in 35 chronic hepatitis B eAg-ve and eAg+ve patients treated with tenofovir 300 mg/day. Frequency of Tregs and their modulatory role in cytokine-secreting cells were determined after stimulation with HBsAg or HBcAg in the absence or presence of Tregs and after blockage of PD-1/PDL-1 in peripheral blood mononuclear cells (PBMCs). Prior to therapy, eAg-ve patients had lower HBV DNA levels, reduced CD8 T cells, increased Tregs, and T cells expressing PD1. After 12 weeks of therapy, >2 log HBV viral reduction was observed in both groups, along with an increase frequencies of CD8 T cells in eAg-ve patients and increased expression of chemokine receptors/Toll-like receptors in both groups. PD-1 expression on CD8 cells in PBMCs was decreased in both groups during therapy but not on Tregs. In eAg-ve group, sustained increase of Tregs was observed till week 12, which declined at week 24. In both groups, after 24 weeks, depletion of CD4(+)CD25(+) Tregs from PBMCs enhanced HBV-specific T cell responses, and blockage of PD-1/PDL1 pathway did enhance pro-inflammatory cytokine production in eAg+ve patients but not in eAg-ve. We conclude that Tregs induced by HBV replication in vivo are expanded in eAg-ve patients more. Reduction in HBV DNA by tenofovir partially restored adaptive immune responses and also reduced the Tregs. Blockage of PD-1/PDL1, enhanced cytokine production in eAg+ve patients but not in eAg-ve, suggests that distinctly different immunologic mechanisms are involved in eAg+ve and eAg-ve patients.

Impaired antigen processing and presentation machinery is associated with immunotolerant state in chronic hepatitis B virus infection.

BACKGROUND AND AIMS: The mechanism of hepatitis B virus (HBV)-specific T cell hyporesponsiveness in hepatitis Be antigen (HBeAg)-positive subjects is not well understood. Inefficient antigen processing and transport to major histocompatibility complex class I molecules, namely due to low molecular weight protein (LMP) 2 and 7 and transporter associated with antigen processing (TAP) 1 and 2 genes could be playing a role. PATIENTS AND METHODS: Forty patients with chronic hepatitis B (CHB) infection, hepatitis B surface antigen, and HBeAg positive; 26 with raised (Gr. I) and 14 with persistently normal ALT levels (Gr. II) and 11 healthy controls (Gr. III) were studied. Total RNA was isolated from peripheral blood mononuclear cells and mRNA expression of TAP1, TAP2, LMP2, and LMP7 genes was analyzed by semi-quantitative reverse transcriptase-polymerase chain reaction method. Gamma interferon (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) levels were quantified by enzyme-linked immunosorbent assay (ELISA) using log-log and linear graphs, respectively. RESULTS: Group II CHB patients had significantly lower mRNA expression for TAP1 (p = 0.003) and LMP2 (p = 0.002) genes as compared to Gr. I patients. The mRNA expression of TAP2 and LMP7 genes was comparable between the groups. However, expression of TAP1 (p = 0.02), TAP2 (p = 0.035), and LMP2 (p = 0.041) was found to be significantly higher in Gr. III subjects compared to Gr. I and Gr. II patients. In Gr. I and II, the IFN-gamma {s54.2{9.4-165} pg/ml), (59.5{28.5-110} pg/ml)}, and TNF-alpha {12.0 (8.0-23.2)},{10.8(6.2-20.8)} pg/ml levels were comparable but were significantly (p = 0.00,0.004, respectively) higher than Gr. III subjects. CONCLUSIONS: Low expression of TAP1 and LMP2 suggests an important role of these genes in defective viral antigen processing in immune tolerant state of CHB patients. Higher IFN-gamma and TNF-alpha production in CHB are probably enough to potentiate liver injury but not enough to clear the chronic HBV infection. These novel observations could pave way for new therapeutic strategies for immune restoration in CHB infected patients.

Natural history of hepatic fibrosis progression in chronic hepatitis C virus infection in India.

BACKGROUND AND AIM: The rate of fibrosis progression per year can predict the time for the development of cirrhosis in chronic hepatitis C (CHC). We assessed the rate of fibrosis progression and the predictors of disease severity in Indian CHC patients. METHODS: Of the 355 treatment-naïve, histologically-proven CHC patients, the precise duration of infection (from the time of exposure to HCV until liver biopsy) could be determined in 213 patients (age = 41.6 +/- 14.7 years, male : female = 139 : 74, genotype 3 = 75%). The rate of fibrosis progression per year was calculated. The correlation of the advanced degree of fibrosis and age, duration of infection, age at the onset of infection, sex, mode of infection, hepatitis C virus (HCV) genotype, histological activity index (HAI), and the presence of diabetes mellitus were studied. RESULTS: The median rate of fibrosis progression per year was 0.25 (0.0-1.5) fibrosis units. The fibrosis progression rate was higher in patients who acquired infection at > 30 years of age, those < 30 years (0.33 vs 0.15; P < 0.001), and those who acquired HCV infection with a history of blood transfusion than with other modes of transmission (0.25 vs 0.19; P = 0.04). The median time to progress to cirrhosis was 16 years. The multivariate analysis found that the HAI score (odds ratio [OR]= 14.03; P < 0.001) and the duration of infection > 10 years (OR = 4.83; P < 0.001) correlated with severe liver disease (fibrosis > or = 3). CONCLUSION: The median rate of fibrosis progression per year in Indian CHC patients is 0.25 fibrosis units. A higher HAI and longer duration of infection are associated with a significant risk of advanced liver disease, and merit early therapeutic interventions.

Risk factors analysis for hepatocellular carcinoma in patients with and without cirrhosis: a case-control study of 213 hepatocellular carcinoma patients from India.

AIM: To assess the role of hepatitis B virus (HBV), hepatitis C virus (HCV) and alcohol intake as risk factors for hepatocellular carcinoma (HCC) in the presence or absence of cirrhosis in Indian population. METHODS: A total of 213 patients with HCC and 254 control subjects not affected with hepatic diseases or neoplasm were recruited. Odds ratios (ORs) were estimated for each risk factor and synergism among various risk factors was also studied. RESULTS: The ORs and 95% confidence intervals (CI) of HCC were 48.02 (25.06-91.98) for any HBV marker, 38.98 (19.55-77.71) for HBsAg positivity, 12.34 (2.84-53.61) for HBsAg negative and antibody positive (either of anti-HBe or total anti-HBc), 5.45 (2.02-14.71) for anti-HCV positive and HCV RNA positive, and 2.83 (1.51-5.28) for heavy alcohol use. No significant risk increase was evident for subjects who were anti-HCV positive and HCV RNA negative. Synergism between alcohol and HCV infection in causing HCC was found, but not between alcohol and HBV. Overall, conclusive evidence of the presence or absence of cirrhosis was reached in 189 (88.73%) HCC patients; cirrhosis was present in 137 (72.48%) of them. ORs with 95% CI of HCC in the presence and absence of cirrhosis, respectively, for HBV were as follows: (i) 48.90 (24.61-97.19) and 35.03 (15.59-78.66) for any HBV marker; (ii) 39.88 (19.41-81.97) and 24.40 (10.60-56.18) for HBsAg positivity; and (iii) 12.10 (2.67-54.88) and 19.60 (3.94-97.39) for HBsAg negativity and antibody positivity. Significantly increased risk was found among cirrhotic patients for anti-HCV positivity and HCV RNA positivity [OR = 7.53 (2.73-20.78)] and for heavy alcohol use [OR = 3.32 (1.70-6.47)]; however, in the absence of cirrhosis, no significant risk increase was evident for subjects who were anti-HCV positive and HCV RNA positive [OR = 0.97 (0.11-8.54)], or who had history of heavy alcohol use [OR = 1.58 (0.55-4.53)]. CONCLUSIONS: Infection with HBV and HCV are the major risk factors for the development of HCC in Indian patients. Presence of HBV antibodies even in the absence of HBsAg conferred increased risk for HCC in the presence or absence of cirrhosis. Anti-HCV positivity in the absence of HCV RNA conferred no increased risk. HCV RNA positivity and heavy alcohol use significantly increased the risk of HCC among cirrhotic patients, but not non-cirrhotic patients.

The hepatitis C virus NS5A protein and response to interferon alpha: mutational analyses in patients with chronic HCV genotype 3a infection from India.

The hepatitis C virus (HCV) non-structural (NS)5A protein is linked to interferon alpha resistance in vitro and higher numbers of NS5A amino acid (aa) variations in HCV 1a/b isolates are associated with virologic response to interferon alpha-based therapy in vivo. Here, we aimed to study NS5A aa variations in Indian patients undergoing interferon alpha/ribavirin treatment infected with HCV 3a. The NS5A region [aa 2194-2401, comprising interferon sensitivity determining region, protein kinase resource (PKR) binding domain, V3 region] was sequenced from pre-treatment sera of 24 patients with HCV 3a infection. Mean number and physicochemical properties of aa variations (conserved vs. non-conserved) were assessed. Additionally, published NS5A sequences [NS5A region (n = 61), PKR binding domain (n = 111)] of characterized HCV 3a isolates were analyzed. The mean number of NS5A aa variations was not correlated with treatment response in our cohort. When all available NS5A sequences were included, a higher number of non-conserved aa variations within PKR binding domain and an extended V3 region of NS5A was associated with virologic response (P = 0.004 and 0.05, respectively). Mutational analyses of a large number of NS5A sequences suggest, that a higher number of non-conserved aa variations within the PKR binding domain and the extended V3 region is correlated with virologic response in HCV 3a infected patients.

Hepatitis C virus genotype 3 predominates in North and Central India and is associated with significant histopathologic liver disease.

Hepatitis C virus (HCV) genotypes help to tailor the treatment response, but their influence on the disease severity and association with hepatic steatosis is not well understood. The prevalence of HCV genotypes and their correlation with the histopathological severity of liver disease and steatosis in Indian patients were studied. HCV-RNA and genotyping was carried out in 398 patients with chronic hepatitis C. Liver biopsy was available in 292 (73.4%) patients. The severity of liver disease was graded on the basis of the histological activity index and the stage of hepatic fibrosis. The patients were categorized as having mild (histological activity index < or =5 and/or fibrosis < or =2) or severe (histological activity index > or =6 and/or fibrosis > or =3) liver disease. Steatosis was graded in 106 patients as 0 (no steatosis), 1 (<33% of hepatocytes affected), 2 (33%-66% of hepatocytes affected), or 3 (>66% of hepatocytes affected). HCV genotype 3 was detected in 80.2% patients (3a:24.4%, 3b:3.3%, 3c:0.5%, 3a/3b:36.7%, and un-subtypable 3:15.3%), genotype 1 in 13.1% (1a:3%, 1b:5.5%, 1a/1b:0.3%, and un-subtypable 1:4.3%), genotype 4 in 3% patients (4a:1.5%, 4b:0.3%, 4a/4c:0.5%, and un-subtypable 4:0.8%), 2 in 2.5% and mixed genotypes (more than one genotype) in 1.3% of patients. The median histological activity index and fibrosis scores were: 5 and 2 in genotype 1; 4 and 2 in genotype 2; 5 and 2 in genotype 3; 7 and 3 in genotype 4; and 5 and 2 in mixed genotypes, respectively. Severe liver disease was present in 17 of 38 (45%) with genotype 1; in 1 of 3 (33%) with genotype 2; in 128 of 236 (54%) with genotype 3; 7 of 10 (70%) with genotype 4; and in 1 of 4 (25%) with mixed genotype. Hepatic steatosis grade > or =2 was found in 28.1% of genotype 3; 23.5% of genotype 1; 20% of genotype 4; and in none of genotype 2 and mixed genotypes. In conclusion, genotype 3 is the most prevalent genotype in patients with chronic hepatitis C in North and Central India and this is associated with significant hepatic steatosis and fibrosis.