Activation of human blood neutrophils and monocytes for enhanced release of toxic oxygen radicals may take place after priming with several cytokines including hematopoietic growth factors. The potential impact of human immunodeficiency virus (HIV) on this response and the relative potency of various cytokines remains unclear. Blood neutrophils and monocytes were isolated from 25 HIV outpatients with variable immunodeficiency. Oxidative burst response upon stimulation with N-formyl-methionyl-leucyl-phenylalanine was assessed in neutrophils after priming with granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF) and interferon-gamma (IFN-g), and in monocytes after priming with GM-CSF and IFN-g. Monocyte oxidative burst responses were not changed in patients or controls. In contrast, following priming with IFN-g, GM-CSF or medium (but not G-CSF) the neutrophils in HIV patients with CD4 counts > 200 x 10(9)/L exhibited a significantly higher chemiluminescence response than was seen in healthy age-matched controls, whereas the response in patients with lower CD4 counts was not different from controls. At comparable concentrations, GM-CSF induced a significantly higher priming than G-CSF and IFN-g. A significant positive correlation between CD4 counts and priming activity of GM-CSF and IFN-g on neutrophils was observed. We conclude that neutrophils in HIV infection have a normal or enhanced response to the oxidative metabolism priming activity of hematopoietic growth factors in vitro, whereas priming effect on monocytes was not seen.