SERUM LEVELS OF GRANULOCYTE-MACROPHAGE COLONY-STIMULATING FACTOR AND GRANULOCYTE-COLONY-STIMULATING FACTOR IN TREATED PATIENTS WITH CHRONIC MYELOGENOUS LEUKEMIA IN CHRONIC PHASE

Background. Despite the fact that granulocyte-macrophage colony-stimulating factor (GMCSF) and granulocyte colony-stimulating factor (G-CSF) are increasingly used in clinical practice, little is known of their endogenous production, especially in myeloproliferative disorders such as chronic myelogenous leukemia (CML). Methods. In order to define serum levels of GM-CSF and G-CSF in subjects affected by CML, the sera of 17 patients with CML in chronic phase treated either with hydroxyurea or interferon-alpha were tested by specific enzyme immunoassays. Fifteen age- and sex-matched healthy volunteers were used as normal controls. Results. Eight out of the 17 patients (44%) with CML showed detectable (> 3 pg/mL) serum levels of GM-CSF (range 3.9-55 pg/mL). Detectable levels (> 50 pg/mL) of G-CSF were observed in 9 of these patients (52%) (range 150-2,830 pg/mL). On the contrary, among the normal controls only one had detectable GM-CSF concentrations, and none had detectable G-CSF concentrations. The highest concentrations of both GM-CSF and G-CSF were seen in patients with the highest white blood cell counts, although a linear correlation between the levels of these growth factors and the number of circulating leukocytes was not demonstrated. Conclusions. Our data indicate that significant amounts of both endogenous GM-CSF and G-CSF are detectable in the serum of a substantial percentage of patients with CML in chronic phase. The pathophysiological meaning of this finding remains to be determined.