Kinetics of indium-111 chloride in chronic myelogenous leukaemia

Indium-111 (111In) bound to transferrin incorporates transferrin receptors which emerge onto the cell membrane of leukaemic cells that have entered into the proliferative status. This study was undertaken to evaluate the kinetics of 111In chloride by counting blood cell radioactivity in five cases of chronic myelogenous leukaemia (CML). Leucocyte radioactivities reached a peak on the third to ninth day after 111In injection. In one case of mild leucocytosis in the early stage of the chronic phase, leucocyte activity was less than 14% of whole blood cell activity throughout the 14 day period. In two cases in the progressive stage of the chronic phase, and in two cases of blast crisis, 44 to 98% of whole blood cell activity at 48 h after 111In injection was occupied by the leucocyte fraction. Platelet radioactivities revealed maximum counts of only 0.1 to 0.4% of the injected dose on the sixth to tenth day. Accordingly, conventional marrow scintigraphy 48 h after 111In chloride injection seems to depict distribution of myelopoiesis rather than erythropoiesis in the progressive stage of the chronic phase and blast crisis in CML in addition to phagocytosis of 111In colloid by reticuloendothelial system.