Leukemic cell colony formation in soft agar by bone marrow cells and peripheral blood cells from untreated acute leukemia patients.

An in vitro culture technique for colony formation of marrow cells and peripheral blood cells from untreated acute leukemia patients and from patients in relapse is described. The colonies from bone marrow cells of an untreated acute myelogenous leukemia (AML) patient were demonstrated to be of leukemic origin by cytogenetic analysis. Cells obtained from colonies of leukemic origin contained the human malignancy-associated nucleolar antigen (HMNA) as detected by indirect immunofluorescence. This nucleolar antigen was not present in marrow or peripheral blood cells or cells from colonies of marrow from hematologically normal individuals. Colonies could be grown from over 70% of the marrow and peripheral blood samples from untreated acute leukemia patients. The median number of colonies obtained was 75 per 10(5) marrow cells from patients with AML. In 1/3 of the cases an increased number of colonies could be grown from marrow cell suspensions kept in liquid culture for 5 days. This is indicative of the proliferative capacity of the colony forming cell population. This assay may be useful for detection of residual clonogenic leukemic cells in marrow and peripheral blood cell suspensions.