INCREASED PERIPHERAL-BLOOD NORMAL MYELOID PROGENITOR CELLS (CFU-GM) IN CHRONIC LYMPHOCYTIC-LEUKEMIA - A PERSPECTIVE FOR AUTOLOGOUS PERIPHERAL-BLOOD STEM-CELL TRANSPLANTATION

We assayed granulocyte-macrophage committed progenitor cells (CFU-GM) in the peripheral blood of 34 patients with chronic lymphocytic ;leuke mia (CLL) and 12 normal individuals. The patients were divided into se parate groups on the basis of previous therapy (i.e. analysis performe d at diagnosis, during and after chemotherapy) and clinical features o f the disease (i.e. disease stage, pattern of bone marrow infiltration , peripheral blood lymphocytosis). The mean CFU-GM colony count of the patients was 30 times higher than that of the controls (206.4 +/- 197 .8 (SD) CFU-GM per 5 x 10(5) cells plated versus 6.5 +/- 3.6). There w as no statistical difference in the numbers of circulating CFU-GM betw een the patients studied at diagnosis (257 +/- 215.4 CFU-GM/5 x 10(5) cells) and those studied during (117.6 +/- 169.2 CFU-GM/5 x 10(5) cell s) or after chemotherapy (207.5 +/- 105.9 CFU-GM/5 x 10(5) cells), alt hough a trend towards a higher recovery of myeloid progenitors was obs erved as a function of time elapsing from the last treatment. In addit ion, we found no significant difference in the in vitro CFU-GM growth of patients grouped according to their disease stage, pattern of bone marrow infiltration and degree of peripheral blood lymphocytosis. In c onclusion, our data indicate that intensification with peripheral bloo d stem cell support may be feasible in C-LL, since progenitor cells of myeloid-monocytic series are markedly increased in the peripheral blo od of these patients. Moreover, it is possible to extend this kind of therapy to patients who have undergone previous extensive chemotherapy and who might have persisting bone marrow infiltration.