Eosinophils and their secretory proteins are important in necroinflammatory processes. In this study we surveyed eosinophilic infiltration of the liver in 176 liver biopsy specimens from patients with primary biliary cirrhosis. A considerable number of eosinophils were found in the portal tracts in 5 1 of these specimens (29%), whereas this finding occurred in only 2 of 50 (4%) specimens from patients with viral chronic active hepatitis. Eosinophilic infiltration of the portal tracts was focal. These eosinophils were immunohistochemically shown to contain the secreted form of eosinophilic cationic protein. Grades of eosinophilic infiltration of the portal tracts were higher in those livers with higher grades of lymphoplasmacytic infiltration, granulomas and florid duct lesion in the portal tracts, and they were lower in those livers with higher grades of bile duct disappearance and orcein-positive granuoles in hepatocytes. In the livers of patients with primary biliary cirrhosis, eosinophils were abundant around the damaged bile ducts, around the portal vein branches and at the marginal regions, and they were scattered in the portal tracts, whereas only the last pattern was seen in viral chronic active hepatitis. Peripheral blood eosinophils tended to be increased in primarybiliary cirrhosis patients with higher grades of eosinophilic infiltration of the portal tracts. Eosinophilic infiltration of the portal tracts may play a role in immunological injuries of the interlobular bile ducts in primary biliary cirrhosis. (HEPATOLOGY 1993; 17:206-212.) Eosinophils and their secretory proteins are known to play important roles in necroinflammatory processes in human beings, especially in hypersensitivity reactions
(1-4). Eosinophilic infiltration of the liver portal tracts is reported to occur in several kinds of hepatobiliary diseases, such as drug-induced hepatitis, autoimmune hepatitis, primary sclerosing cholangitis and human hepatic allograft rejection (5-10). The role of eosinophils as effector cells in liver tissue injury has recently been