IntroductionCellular immune responses are thought to play a key role in the pathogenesis of hepatitis C virus (HCV)-related liver damage. Recently, increasing attention has been drawn towards components of the innate immune system to HCV, including natural killer (NK) cells. The present work was designed to study peripheral blood and intrahepatic NK cells in patients with chronic hepatitis C in relation to disease activity and severity of hepatic fibrosis.MethodsFifteen patients with untreated chronic hepatitis C (CHC) and 12 healthy subjects were included in the current study. The NK and NKT cells in fresh whole blood samples were identified using two-colour flow cytometry as CD3-CD56+ and CD3+CD56 cells, respectively, and the results were expressed as percentages of the total lymphocyte count. Liver biopsies were taken from all patients and the specimens were evaluated as regards the histological activity grade and fibrosis stage according to METAVIR scoring system and for the presence and grade of steatosis. Immunohistochemical staining was done using antibodies against CD56 and smooth muscle actin (SMA) for detection of intrahepatic NK cells and activated hepatic stellate cells (HSCs), respectively. A semi-quantitative method was used to score the intensity of immunostaining.ResultsThe percentages of CD3-CD56+ NK cells and CD3+CD56+ NKT cells in peripheral blood showed significant decreases in patients with CHC compared with healthy subjects (p<0.01) and was positively correlated with the intensity of intrahepatic NK cells (p=0.001). The CD56+ NK cell infiltrate was found to be absent or minimal in about 70% of the liver biopsies of patients with CHC. Patients presented with chronic fatigue showed significantly lower percentages of circulating NK and NKT cells and intensity of intrahepatic NK cells than patients who were asymptomatic (p<0.05). The percentages of peripheral blood NK cells and NKT cells and the intensity of intrahepatic NK cells showed significant inverse correlations with serum HCV RNA levels, steatosis grade, METAVIR fibrosis stage and intensity of activated HSCs (p<0.05) and statistically insignificant correlations with serum levels of aminotransferases and the histological activity grade (p>0.05).ConclusionThe deficiency of peripheral blood and intrahepatic NK cells in patients with chronic hepatitis C may provide a mechanism for immune suppression resulting in viral persistence, disease chronicity and progression of hepatic fibrosis. Restoration of the NK cell population may be one of the potential manipulations for resolution of HCV infection and for therapeutic modulation of hepatofibrogenesis.

IntroductionHepatitis C virus (HCV) is a major risk factor for development of hepatocellular carcinoma (HCC), however, the mechanism of hepatocarcinogenesis in HCV infection is still undefined. Heat shock protein (HSP) 27 is a ubiquitous chaperone molecule induced in cells exposed to different stress conditions, including carcinogenesis. It also has potent anti-apoptotic properties through inhibition of caspase-3 activation. Therefore, the aim of the present work was to study the expression of HSP27 and caspase-3 in HCV-related HCCs in relation to tumour progression.MethodsTwenty cirrhotic patients with HCV-related HCC were enrolled in the study. The severity of liver disease was assessed according to the Model for End Stage Liver Disease (MELD) score. Serum levels of α-fetoprotein (AFP) were measured by enzyme immunoassay kit. The tumour stage was classified using the scoring system proposed by the Cancer of the Liver Italian Program (CLIP). Histological grading of tumour s was performed according to the Edmondson and Steiner's criteria and the surrounding liver tissue was examined for the presence of cirrhosis and steatosis. Expression of HSP27 and caspase-3 was studied in HCC and adjacent non-neoplastic liver tissues by immunohistochemistry and the staining intensity of the tumour was designated as “negative/low expression” or “high expression” if <25% and >25% of cells were positively-stained, respectively.ResultsHCV-related HCCs showed a significant increase in HSP27 expression and a significant decrease in caspase-3 expression as compared with adjacent non-neoplastic liver tissues (p=0.029 and p=0.040, respectively). The expression of HSP27 showed an inverse correlation with caspase-3 expression in HCC tissues (r=−0.691, p=0.001). High HSP27 expression and negative/low caspase-3 expression in HCCs were associated with significant increases in serum levels of aminotransferases, HCV RNA and AFP, MELD score, tumour size, tumour stage, histological tumour grade, body mass index and the presence of steatosis in the surrounding liver tissue (P<0.05). No relationship was found between expression of HSP27 and caspase-3 in HCCs and age, gender, apparent duration of HCV infection, and tumour encapsulation, multiplicity, location and lymphocyte infiltration (P>0.05).ConclusionHSP27 plays an important role in the pathogenesis and progression of HCC in HCV infection through inhibition of caspase-3 mediated cell apoptosis and may serve as a potentially useful therapeutic target.