[Experience in administration low dose all-trans retinoic acid for a child with acute promyelocytic leukemia]

Ten year old boy with acute promyelocytic leukemia (APL) was treated with all-trans retinoic acid (ATRA). Immediately after the oral administration of ATRA (nine mg/m2 three times a day), DIC was controlled, and complete remission was achieved at day 39. The patient received ATRA therapy for 47 days, and then followed by conventional chemotherapy. Plasma ATRA level after 90 minutes of drug administration was 84.6 ng/ml. The superoxide generating activity of neutrophils in the bone marrow and peripheral blood was measured by chemiluminescence. The phagocytic function of neutrophils was markedly reduced in the ATRA-induced remission period, and was normal in the chemotherapy-induced remission. APL could be induced complete remission by three divided small doses of ATRA, and the ATRA-induced differentiated neutrophils might have lower phagocytic function.