Kinetics of indium-111-labeled leukemic cells in patients with acute nonlymphocytic leukemia.

The distribution within the body of autologous leukemic cells labeled with indium-111 oxine was studied in seven patients with acute nonlymphocytic leukemia. The leukemic blood cells initially entered the spleen and liver, and the major site of localization was the former rather than the latter. The majority of the leukemic cells had not left the spleen and liver within 48 hr. Liver radioactivity fell transitorily up to the third hr after the initial rise. The clearance curve of radioactivity from the blood showed a plateau or the appearance of a "hump" from 1 to 5 hr after injection of labeled leukemic cells. These results might reflect recirculation of a portion of the leukemic cells between these organs and the bloodstream. In a patient with acute monoblastic leukemia. OKM1 monoclonal-antibody-treated monoblasts showed the lowest recovery into the blood and a greater increase of liver than splenic radioactivity at 30 min after injection. These results suggest the removal of damaged cells by the cytotoxic effects of antibody mediated by reticuloendothelial clearance mainly of the liver and others. In one patient with acute promyelocytic leukemia, leukemic cells accumulated in both kidneys, indicating the possible infiltration of these cells. Since indium-111 oxine stays firmly attached to the cells in spite of the possibility of radiation damaged in a long-term survey, it seems an ideal label for studying leukemic cell kinetics.