No abstract

Recent studies have shown that a single nucleotide polymorphism upstream of the interleukin (IL)-28B gene plays a major role in predicting therapeutic response in HCV-infected patients treated with pegylated interferon-alpha (IFN)/ribavirin. We sought to investigate the mechanism of the IL28B polymorphism, specifically as it relates to early HCV viral kinetics (VK), IFN pharmacokinetics (PK), IFN pharmacodynamics (PD), and gene expression profiles. Two prospective cohorts (HIV/HCV co-infected and HCV mono-infected) completing treatment with IFN/ribavirin were enrolled. Patients (N=88; 44 HIV/HCV and 44 HCV) were genotyped at the polymorphic site rs12979860. In the HIV/HCV cohort frequent serum sampling was completed for HCV RNA and IFN-levels. DNA microarray of PBMCs and individual expression of interferon stimulated genes (ISGs) were quantified on IFN-therapy. The IL28B favorable (CC) genotype was associated with improved therapeutic response compared to unfavorable (CT/TT) genotypes. Patients with favorable genotype had greater first and second phase VK (P=0.004 and P=0.036, respectively), IFN maximum anti-viral efficiency (P=0.007) and infected cell death loss (P=0.009) compared to unfavorable genotypes. Functional annotation analysis of DNA microarray data was consistent with depressed innate immune function, particularly of NK cells, from patients with unfavorable genotypes (P<0.004). Induction of innate immunity genes was also lower in unfavorable genotype. ISG expression at baseline and induction with IFN was independent of IL28B genotype. Conclusions Carriers of the IL28B favorable genotype were more likely to have superior innate immune response to IFN-therapy compared to unfavorable genotypes, this suggests the unfavorable genotype has aberrant baseline induction of innate immune response pathways resulting in impaired virologic response. IL28B genotype is associated with more rapid viral kinetics and improved treatment response outcomes independent of ISG expression.

OBJECTIVES:CD4+ regulatory T cells (Tregs) seem to have a key role in persistence of hepatitis B virus (HBV) infection. Notch and transforming growth factor (TGF-β) signaling independently help in the differentiation and regulation of CD4+T cells, including T-helper (TH) 1, TH2, and Tregs. Whether, the two pathways have modulatory role on different stages of HBV infection and severity of liver disease is not clear. We investigated Notch and TGF-β families' gene expression in peripheral blood and intrahepatic lymphocytes in patients with different stages of chronic HBV (CHB) infection.METHODS:Peripheral blood mononuclear cells (PBMCs), CD4+, and CD8+ T cells were isolated from patients with acute HBV (AVH-B, n=15), CHB (n=16), and controls (HC, n=10). In addition to PBMCs, intrahepatic lymphocytes were obtained from liver biopsies from CHB (n=12), cirrhosis (n=12), hepatocellular carcinoma (HCC, n=5), and healthy livers (n=5). Notch family (Notch1–4, Hes1, Jag1, and NF-kβ) and TGF-β family gene expressions were studied by real-time PCR, flow cytometry, and immunohistochemistry.RESULTS:Relative expression of Notch signaling target genes, Hes1 and NF-kβ, was higher in the total PBMCs of AVH-B and CHB patients than that in HC patients (Log relative quantification (RQ); 1.1 AVH-B vs. 0.3 HC, 1.3 CHB vs. 0.3 HC; P=0.02). CD8+ T cells showed upregulated expression of Hes1 and Notch1 (P=0.02 and 0.01, respectively) in AVH-B than in CHB patients. Also, in AVH-B patients, HBV-specific CD8+ T-cell proliferation (5.74% vs. 2.7%) and TGF-β signaling activity were higher. All Notch receptors and ligands were upregulated in the PBMCs in CHB infection (CHB vs. cirrhosis, P=0.001; CHB vs. HCC, P=0.023; and cirrhosis vs. HCC, P=NS). Intrahepatic expression of Notch1 and FoxP3 were significantly higher in cirrhotics and HCCs, and further blockage of Notch signaling reduced the FoxP3 expression. Array data of TGF-β family showed increased TGF-β3, TGF-α, SMAD3, SMAD4, SMAD6, and GDF9 expression on intrahepatic lymphocytes in cirrhotic and HCC patients compared with CHB.CONCLUSIONS:Our findings suggest that there is a complementary association between Notch1 and Hes1 in CD8+T cells during AVH-B infection. On development of CHB infection, repression of the Notch receptors mediates the regulation of immune response in patients, who progress to cirrhosis and HCC. Finally, HBV infection drives increased Notch1, TGF-β, and FoxP3 expression on intrahepatic T cells in cirrhosis, resulting in fibrogenesis and disease progression.