Platelet activation in patients with alcoholic liver disease.

OBJECTIVE To elucidate the mechanisms of thrombocytopenia in alcoholic liver diseases, we investigated activation status of platelets in patients with alcoholic fatty liver (Al-FL), alcoholic liver cirrhosis (Al-LC) or hepatitis-C liver cirrhosis C (C-LC). METHODS Platelet activation was evaluated by flow cytometry using monoclonal antibodies against P-selectin (CD62P) and the fibrinogen receptor (PAC-1), both specific for platelet activation, and anti-CD61 antibody for the presence of microparticles (PMP) in seven patients with Al-FL, thirteen patients with Al-LC and, as a non-alcoholic liver disease control, nine patients with C-LC. As a normal control, seventeen healthy subjects without liver dysfunction were also evaluated. RESULTS Compared with the healthy controls, the platelet count was significantly decreased in patients with alcoholic liver diseases or C-LC. Ten days after discontinuation of alcohol intake, the platelet count was significantly higher in both the Al-FL and Al-LC groups than that measured on admission. There was an inverse correlation between the platelet count and PMP, a marker of platelet activation. The Al-FL, Al-LC and C-LC groups showed significantly higher percentages of platelets positive for CD62P than the healthy controls. The PAC-1 positivity was increased only in the C-LC group. PMP were significantly increased in the Al-FL, Al-LC and C-LC groups compared to that in the healthy group. In the Al-LC group, PMP were significantly decreased 10 days after discontinuation of alcohol intake from that measured on admission. CONCLUSION Patients with alcoholic liver diseases have increased platelet activation, which may contribute to the occurrence of thrombocytopenia. The formation of PMP might be one of the important factors of thrombocytopenia in alcoholic liver diseases.