The effect of growth hormone and IGF-I on clonogenic growth of hematopoietic cells in leukemic patients during active disease and during remission--a preliminary report.

The number of survivors of childhood leukemia treated with growth hormone for growth retardation is increasing. The debate about the direct or indirect relationship of GH and insulin-like growth factor I (IGF-I) to the occurrence or recurrence of malignancy, especially in the case of GH therapy in patients with leukemia, is still unresolved. We, therefore, studied the effect of GH and IGF-I on bone marrow of patients with acute leukemia (ALL and AML) in diagnosis and recurrence and in chronic leukemia patients (CML) in remission. GH increased blast colony numbers by a mean of 68% and 77% at GH concentrations of 250 and 300 ng/ml, respectively. IGF-I increased blast colony numbers in ALL patients by 50, 93 and 105%, and in AML patients by 33, 58 and 65%, at IGF-I concentrations of 0.05, 0.25 and 0.5 ng/ml, respectively. In 3 CML patients in remission a granulocyte-macrophage colony forming assay did not reveal stimulation of peripheral blood blast colony formation by GH or IGF-I. Our in vitro data (as previously reported) suggest that GH and IGF-I may promote blast cell proliferation, and the supplemental administration of these peptides in leukemia patients in remission must be carefully monitored for early relapse. Additional studies on bone marrow cells of leukemic patients in remission are needed in order to examine the effects of GH and IGF-I on these cells.