IFN-gamma activates superoxide anion production in blood monocytes from allergic asthmatic patients.

Background : Peripheral blood monocytes may participate in allergic diseases by releasing inflammatory mediators. We have recently shown enhancement of nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) oxidase activity in adherent human peripheral blood monocytes from allergic patients when immunoglobulin E (IgE) binds to its low affinity receptor. Interferon-gamma (IFN-γ), a monocyte-activating lymphokine, has been shown to prime monocytes for superoxide anion release. Objective : We hypothesized that IFN-γ could directly activate blood monocyte superoxide anion release and evaluated its modulatory effect on IgE-induced superoxide anion release from those cells. Methods : Seven patients with allergic asthma, 6 patients with allergic rhinitis, and five nonallergic controls were studied. We measured superoxide anion release from their blood monocytes using a chemiluminescence assay. Cells were either nonstimulated, or stimulated for 30 minutes with IFN-γ and/or serum IgE. Results : We found that IFN-γ stimulated superoxide anion production and decreased the IgE-induced superoxide anion production after 30 minutes of IFN-γ preincubation only in blood monocytes from patients with allergic asthma. Conclusions : These data suggest that IFN-γ receptors may be increased and/or coupled to NADPH oxidase in allergic asthmatic patients.