The predictive value of in-vitro techniques in acute non-lymphocytic leukemia

Bone marrow aspirates obtained from 27 patients with acute non-lymphocytic leukemia (ANLL) was cultured at the time of presentation, during remission and at relapse. Growth patterns were assessed throughout the patient's clinical course. The percentage of Ia-positive progenitor cells was assayed by a complement-dependent cytotoxicity assay. The percentage of cells in S phase was measured by a tritiated thymidine suicide index. Growth patterns of leukemic bone marrow samples at presentation showed varied numbers of clusters but only rare colonies. This was not predictive of clinical course. Growth patterns of bone marrow in complete remission from ANLL often had depressed colony numbers. However, some patients in remission had bone marrow growth patterns that approached or reached normal colony numbers, suggesting elimination of residual leukemia. The percentage of cells that expressed Ia antigen at presentation, during remission and at relapse varied widely and was not predictive of long-term remission or early relapse. The percentage of cells in S phase was also highly variable and not predictive of clinical course. At presentation the S-phase percentage correlated with the percentage of cells expressing Ia antigen. However, there was no such correlation during remission.