Enhanced superoxide generation by eosinophils from asthmatic children.

In 21 asthmatic children, aged 2-19 years, and 11 age-matched controls purified (purity greater than 75%) peripheral blood eosinophils and neutrophils (purity greater than 95%) were stimulated with phorbol myristate acetate (44 ng/ml) for 30 min at 37 degrees C. The superoxide generation was determined as well as the superoxide dismutase inhibitable cytochrome c reduction. Eosinophils obtained from asthmatic patients displayed a significantly higher O2- generation (p less than 0.01) when compared to neutrophils from the same patients or to eosinophils and neutrophils from healthy controls. Preincubation with human recombinant granulocyte macrophage colony stimulating factor for 30 min or platelet-activating factor for 10 min resulted in augmented O2- generation by eosinophils from control, but not from asthmatic children, indicating a possible in vivo priming of eosinophils in asthma.