Alterations in erythropoiesis preceding leukemia.

An attempt was made to study preleukemic changes in bone marrow cell proliferation. Seven patients with hypercellular marrows and aregenerative anemia were studied. Five of them could be followed to autopsy, several years after the kinetic studies; all died with a picture of leukemia. Total bone marrow cell numbers, erythroblast generation times, and erythrocyte production were estimated with 59Fe. Despite hypercellularity, the total erythroblast number was not significantly increased. Erythrocyte production and life span were both decreased, and erythroblast generation time were significantly longer than normal.