Long-term treatment with GM-CSF in patients with chronic lymphocytic leukemia and recurrent neutropenic infections

In this prospective study we evaluated the multiple effects of long-term GM-CSF therapy on blood counts, granulocyte functions and disease progression in patients with chronic lymphocytic leukemia (CLL) with chronic neutropenia and recurrent bacterial infections. The treatment duration varied from 2 to 12 weeks. The neutrophil count was raised in all patients, by the median of 6.6-fold. The neutrophil level of 1.0 x 10(9)/l was usually reached after two weeks. The initial dose of GM-CSF was 5 microg/kg/day, and 1-7 microg/kg/day was required to maintain the neutrophil level above 1.0 x 10(9)/l. Granulocyte functions, i.e. chemiluminescence (CL), random migration, and fMLP-stimulated chemotaxis were initially depressed in all patients when compared to healthy controls. GM-CSF enhanced significantly CL even when given at small doses (less than 1 microg/kg/day), even lower than the dose required to promote granulopoiesis. We conclude that GM-CSF is effective in improving CLL associated chronic neutropenia and also enhances impaired granulocyte chemiluminescence. Thus, GM-CSF could be helpful for giving chemotherapy without neutropenic delays and for prophylaxis of infectious complications in CLL patients.