We examined leukocyte counts and ex vivo cytokine response of whole blood to lipopolysaccharide (LPS) or lipoteichoic acid (LTA) in patients under low-dose molgramostim therapy. Patients were injected subcutaneously daily for ten days with 1 microg/kg (n=9) or 2 microg/kg (n=14) molgramostim. Leukocytosis was observed in all patients, but only the eosinophil fraction was significantly increased in relation to other leukocyte populations. Ex vivo IFN-gamma release was decreased and IL-10 and IL-1ra secretion were increased in response to LPS or LTA. Thus, in non-neutropenic patients, leukocytosis can already be initiated by low doses of molgramostim. The ex vivo cytokine data suggest that these doses prime blood towards a systemic anti-inflammatory response.Copyright 2000 Academic Press.