Antiplatelet antibodies contribute to thrombocytopenia associated with chronic hepatitis C virus infection.

Thrombocytopenia is one of the most frequent hematological manifestations of hepatitis C virus (HCV) infection; which typically worsens with progression of the liver disease and can become a major clinical complication. Several mechanisms have been postulated to explain thrombocytopenia in HCV hepatic patients, including immune mechanisms. The aim of the present work is to investigate the role of immune mechanisms as a causative agent of thrombocytopenia in HCV hepatic patients. The study included 50 hepatic patients with HCV infection (30 with thrombocytopenia and 20 with normal platelets counts). Platelets associated glycoprotein specific antibodies were evaluated by flow cytometry and confirmed by quantitative monoclonal immobilization of platelet antibodies (MAIPA). The frequency of platelet associated immunoglobulin (PAIg) in thrombocytopenic HCV positive hepatic patients by FCM was 86.7, 83.3, 46.7 and 33.3% for total PAIg, PAIgG, PAIgM and PAIgA respectively. MAIPA found platelet specific antibodies in 26/30 (86.7%) of patients. The most likely target antigen for platelets antibodies were glycoprotein (GP) IIb/IIIa (30%), followed by GP IIIa (20.5), GP IIb (13.3%), GPIb (13.3%), then GPIa (10%). The platelets count was inversely correlated to the levels of platelets GP specific antibodies (r=-0.42, p=0.024), and significantly parallel to spleen size (p=0.024). Platelet associated glycoprotein specific antibodies represent a common mechanism inducing thrombocytopenia in patients with chronic HCV infections.