EVIDENCE FOR AN IMMUNOLOGICAL PATHOGENESIS OF THROMBOCYTOPENIA IN CHRONIC LIVER-DISEASE

Objectives: To elucidate the role of platelet-associated IgG (PA-IgG) in the mechanism of thrombocytopenia associated with chronic liver dis ease. Methods: Platelet count in blood, PA-IgG, and scintigraphic sple en/liver ratio as a marker of splenomegaly was examined in 214 individ uals, including 16 controls showing nonspecific reactive change in liv er biopsy and 198 patients with chronic liver disease. Results: The me an blood platelet count decreased significantly according to severity of liver disease, from control to liver cirrhosis. PA-IgG levels incre ased significantly in relation to severity of liver disease, as did sp leen/liver ratio. In chronic hepatitis or liver cirrhosis, an inverse correlation was found between platelet counts and PA-IgG levels. An in verse correlation was also observed between platelet count and spleen/ river ratio in liver cirrhosis. The splenic embolization resulted in a significant rise in platelet count and a significant fall in PA-IgG i n the 14 cirrhotic patients. Conclusions: These results may give suppo rt to evidence for an immunological mechanism mediated by PA-IgG for t he thrombocytopenia occurring in chronic liver disease. In the case of liver cirrhosis, this mechanism would act in addition to platelet poo ling in the spleen on thrombocytopenia. PA-IgG may also have an import ant role in thrombocytopenia associated with chronic hepatitis, in whi ch splenic platelet pooling is less marked.