IL28B alleles associated with poor hepatitis C virus (HCV) clearance protect against inflammation and fibrosis in patients infected with non-1 HCV genotypes

Genetic polymorphisms near IL28B are associated with spontaneous and treatment-induced clearance of hepatitis C virus (HCV), two processes that require the appropriate activation of the host immune responses. Intrahepatic inflammation is believed to mirror such activation, but its relationship with IL28B polymorphisms has yet to be fully appreciated. We analyzed the association of IL28B polymorphisms with histological and follow-up features in 2335 chronically HCV-infected Caucasian patients. Assessable phenotypes before any antiviral treatment included necroinflammatory activity (n = 1,098), fibrosis (n = 1,527), fibrosis progression rate (n = 1,312), and hepatocellular carcinoma development (n = 1,915). Associations of alleles with the phenotypes were evaluated by univariate analysis and multivariate logistic regression, accounting for all relevant covariates. The rare G allele at IL28B marker rs8099917-previously shown to be at risk of treatment failure-was associated with lower activity (P = 0.04), lower fibrosis (P = 0.02) with a trend toward lower fibrosis progression rate (P = 0.06). When stratified according to HCV genotype, most significant associations were observed in patients infected with non-1 genotypes (P = 0.003 for activity, P = 0.001 for fibrosis, and P = 0.02 for fibrosis progression rate), where the odds ratio of having necroinflammation or rapid fibrosis progression for patients with IL28B genotypes TG or GG versus TT were 0.48 (95% confidence intervals 0.30-0.78) and 0.56 (0.35-0.92), respectively. IL28B polymorphisms were not predictive of the development of hepatocellular carcinoma. CONCLUSION: In chronic hepatitis C, IL28B variants associated with poor response to interferon therapy may predict slower fibrosis progression, especially in patients infected with non-1 HCV genotypes.     

Hepatocyte polarization is essential for the productive entry of the hepatitis B virus

Human hepatitis B virus (HBV) is characterized by a high species specificity and a distinct liver tropism. Within the liver, HBV replication occurs in differentiated and polarized hepatocytes. Accordingly, the in vitro HBV infection of primary human hepatocytes (PHHs) and the human hepatoma cell line, HepaRG, is restricted to differentiated, hepatocyte-like cells. Though preparations of PHH contain up to 100% hepatic cells, cultures of differentiated HepaRG cells are a mixture of hepatocyte-like and biliary-like epithelial cells. We used PHH and HepaRG cells and compared the influence of virus inoculation dose, cell differentiation, and polarization on productive HBV infection. At multiplicities of genome equivalents (mge) >8,000, almost 100% of PHHs could be infected. In contrast, only a subset of HepaRG cells stained positive for HBcAg at comparable or even higher mge. Infection predominantly occurred at the edges of islands of hepatocyte-like HepaRG cells. This indicates a limited accessibility of the HBV receptor, possibly as a result of its polar sorting. Multidrug resistance protein 2 (MRP2), a marker selectively transported to the apical (i.e., canalicular) cell membrane, revealed two polarization phenotypes of HepaRG cells. HBV infection within the islands of hepatocyte-like HepaRG cells preferentially occurred in cells that resemble PHH, exhibiting canalicular structures. However, disruption of cell-cell junctions allowed the additional infection of cells that do not display a PHH-like polarization. CONCLUSION: HBV enters hepatocytes via the basolateral membrane. This model, at least partially, explains the difference of PHH and HepaRG cells in infection efficacy, provides insights into natural HBV infection, and establishes a basis for optimization of the HepaRG infection system.     

Clinical relevance of RET variants G691S, L769L, S836S and S904S to sporadic medullary thyroid cancer

Background Based on reports of higher frequencies among patients with sporadic medullary thyroid cancer (MTC) relative to external controls, the RET (REarranged during Transfection) variants G691S, L767L, S836S and S904S have been considered disease modifiers, suggesting greater lifetime risks of MTC. Other studies, employing different external controls, failed to confirm this association. Using a complementary approach, this study aimed at exploring differences in clinico‐pathological characteristics among patients with sporadic MTC carrying no (wildtype), one (heterozygotes) or both (homozygotes) homologue RET variants in the germline, with wildtype cases acting as internal controls. Methods Included in this investigation were 150 patients with complete genetic information on G691S, L769L, S836S and S904S RET alleles operated on for sporadic MTC at a tertiary referral centre. Results Not one statistically significant dose–response relationship was identified between any RET variant (wildtype vs RET heterozygotes vs homologue RET homozygotes) and patient age at MTC diagnosis, gender, primary tumour size, extrathyroidal extension, numbers of involved and removed lymph nodes, or distant metastasis. L769L and S836S homozygotes, unlike G691S and S904S homozygotes, were either rare or absent, limiting the analyses to comparisons of heterozygosity versus wildtype. On time‐to‐event analysis, G691S, L769L, S836S or S904S carriers and noncarriers developed MTC at similar rates. Conclusions In carriers and noncarriers of the RET variants G691S, L767L, S836S and S904S, sporadic MTC appeared clinically and pathologically indistinguishable. This observation, along with the inconclusive evidence of previous association studies, calls for larger longitudinal association studies with age‐ and sex‐matched external controls and additional functional studies of RET biology.     

Th17 and non-Th17 interleukin-17-expressing cells in chronic lymphocytic leukemia: delineation, distribution, and clinical relevance

Background

The levels and clinical relevance of Th17 cells and other interleukin-17-producing cells have not been analyzed in chronic lymphocytic leukemia. The objective of this study was to quantify blood and tissue levels of Th17 and other interleukin-17-producing cells in patients with this disease and correlate blood levels with clinical outcome.

Design and Methods

Intracellular interleukin-17A was assessed in blood and splenic mononuclear cells from patients with chronic lymphocytic leukemia and healthy subjects using flow cytometry. Interleukin-17A-producing cells were analyzed in formalin-fixed, paraffin-embedded spleen and lymph node sections using immunohistochemistry and immunofluorescence.

Results

The absolute numbers of Th17 cells in peripheral blood mononuclear cells and the percentages of Th17 cells in spleen cell suspensions were higher in patients with chronic lymphocytic leukemia than in healthy subjects; in six out of eight paired chronic lymphocytic leukemia blood and spleen sample comparisons, Th17 cells were enriched in spleen suspensions. Circulating Th17 levels correlated with better prognostic markers and longer overall survival of the patients. Two “non-Th17” interleukin-17-expressing cells were identified in chronic lymphocytic leukemia spleens: proliferating cells of the granulocytic lineage and mature mast cells. Granulocytes and mast cells in normal spleens did not express interleukin-17. Conversely, both chronic lymphocytic leukemia and healthy lymph nodes contained similar numbers of interleukin-17+ mast cells as well as Th17 cells.

Conclusions

Th17 cells are elevated in chronic lymphocytic leukemia patients with better prognostic markers and correlate with longer survival. Furthermore, non-Th17 interleukin-17A-expressing cells exist in chronic lymphocytic leukemia spleens as maturing granulocytes and mature mast cells, suggesting that the microenvironmental milieu in leukemic spleens promotes the recruitment and/or expansion of Th17 and other IL-17-expressing cells. The pathophysiology of Th17 and non-Th17-interleukin-producing cells in chronic lymphocytic leukemia and their distributions and roles in this disease merit further study.