Copyright ERS Journals Ltd 1994 European Respiratory Journal

ABSTRACT: Previous work has demonstrated an increase in the production of granulocyte-macrophage colony-stimulating factor (GM-CSF) by monocytes derived from asthmatic individuals. We have suggested that monocytes and macrophages enhance airways inflammation by augmented cytokine production. We tested this hypothesis by measuring the production of GM-CSF and macrophage-derived cytokines, namely interleukin-1β (IL-1β), tumour necrosis factor-α (TNF-α) and interleukin-8 (IL-8), from unstimulated and lipopolysaccharide (LPS)-stimulated peripheral blood monocytes and alveolar macrophages in 31 asthmatic and 11 nor-mal, control subjects. The basal production of GM-CSF was four fold higher in the monocytes of asth-matic individuals, but there was no significant difference in the basal production of TNF-α, IL-1β and IL-8. After stimulation with LPS, asthmatic monocytes pro-duced twofold more GM-CSF and fourfold more IL-1β than the monocytes from control subjects. Unstimulated macrophages from asthmatic subjects produced sig-nificantly less GM-CSF and TNF-α than macrophages from controls, and ther