Platelet activation in patients with chronic hepatitis C

To elucidate the mechanisms of thrombocytopenia in chronic hepatitis C (CHC), we investigated platelet activation in patients with chronic viral liver diseases. Platelet activation was evaluated with flow cytometry in twenty-five patients with chronic viral hepatitis and 11 patients with liver cirrhosis of viral etiology. Liver biopsies were carried out in all patients. The platelet counts decreased significantly in patients with CHC and in patients with liver cirrhosis compared to controls, but not in patients with chronic hepatitis B (CHB). Patients with CHC had a significantly higher percentage of platelets positive for activation-dependent monoclonal antibodies (MoAbs), and also had a higher percentage of platelet microparticles (PMP), a marker of platelet activation, than patients with CHB. There was a significant correlation between the percentage of PMP and the levels of liver fibrosis markers, such as serum hyaluronate and N-terminal propeptide of type III procollagen (P-III-P), in CHC, suggesting the relationship between platelet activation and liver fibrosis. Platelet activation was markedly enhanced in CHC patients with high histological scores of liver fibrosis. Patients with CHC have increased platelet activation, which may contribute to the occurrence of thrombocytopenia in CHC. Liver fibrosis may play a role in activation of platelets in CHC.