特発性血小板減少性紫斑病の経過中に発症したEvans症候群の一例

Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC)と溶血機序

抄録

A 21-year-old male patient was admitted because of acute onset of generalized purpura and thrombocytopenia (0.2×10⁴/cmm) in Dec., 1977, and treated with prednisolone (PSL) under the diagnosis of idiopathic thrombocytopenic purpura. In Sept., 1979, he noticed jaundice and general malaise. Marked anemia and mild splenomegaly were demonstrated. Examinations of peripheral blood showed normocytic anemia (Hb 5.2 g/dl), leukocytosis (10,700/cmm), thrombocytopenia (6.1×10⁴/cmm), and reticnlocytosis (12.2%). Hemolytic anemia was confirmed by other laboratory data, such as indirect bilirubin, serum LDH, serum iron, and myelogram. Both direct and indirect antiglobulin test were positive, and anti-erythrocyte antibody in his serum was confirmed as IgG. Treatment with large dosage of PSL (100 mg/day) was started. Anemia and then thrombocytopenia were gradually improved.
Antibody-dependent cell-mediated cytotoxicity (ADCC) of human peripheral leukocytes (PBL) was investigated by using ⁵¹Cr-labelled human erythrocytes sensitized with the patients serum. It was concluded that ADCC of PBL in this case was not participated in the mechanism of hemolysis, because neither cytotoxic nor phagocytic activity of PBL was demonstrated against target erythrocytes.