[Bone marrow culture in aplastic anemia and preleukemias]

After incubation of bone marrow cells obtained from normal subjects and patients with pancytopenia in the double layer agar culture (Robinson-Pike), the clusters of different size and the colonies were counted on days 2, 3, 5, 7 and 10. Aplastic anemia and two types of preleukemia could be distinguished by a different growth pattern. A high incidence of small clusters (4-12 cells) was found in patients with aplastic anemia on days 2 and 3, whereas these aggregates were markedly reduced in preleukemia of type B. In preleukemia of type A an excessive number of small clusters was obtained. The morphology of cells in clusters and colonies was studied by cytochemical staining and electronmicroscopy. In preleukemia marked defects of maturation were demonstrable in the cells.