[Hemolytic anemia and thrombocytopenia associated with anti-omeprazole antibody].

An 80-year-old woman was admitted with anemia, jaundice and a bleeding tendency about 5 weeks after starting omeprazole. On admission, the hemoglobin was 6.4 g/dl, platelets 0.1 x 10(4)/microliter, leukocyte count 7,500/microliter, and reticulocyte count 325/1000. The total bilirubin was 1.9 mg/dl, indirect bilirubin 0.6 mg/dl, lactate dehydrogenase 572 IU/l, and haptoglobin < 10 mg/dl. Both the direct and the indirect Coombs' tests were positive. The platelet-associated IgG (PAIgG) was 1,100.0 ng/10(7) cells. A decrease in the complement value was observed. There was an increase in the number of megakaryocytes and erythroblasts in the marrow film. After omeprazole administration was halted, her hemoglobin and platelet levels gradually returned to normal. On the 27th hospital day, the direct Coombs' test was positive but the indirect Coombs' test became negative. The PAIgG value also returned to normal, and she was discharged on the 59th hospital day. The acute phase of the drug-induced lymphocyte stimulation test was negative, however, we detected the IgG antibody to omeprazole. In the recovery phase, the IgG value decreased. Forty days after discharge, the direct Coombs' test had become negative. This is apparently the first report of a patient with acute hemolytic anemia and thrombocytopenia due to omeprazole through an immune complex mechanism.