Decreased antibody-dependent cellular cytotoxicity in preleukemic syndromes

In a previous report we showed decreased antibody-dependent cellular cytotoxicity (ADCC) activity of both leukemic and non-leukemic cells in human acute leukemia. In our present study, ADCC against tumor target cells was evaluated in 13 patients with preleukemic syndromes. ADCC was found to be significantly decreased in aplastic anemia, sideroblastic anemia, paroxysmal nocturnal hemoglobinuria and pure red cell aplasia, suggesting that impairment of immune defence capacity may precede the development of leukemia in man.