PLATELET-ACTIVATING-FACTOR-LIKE ACTIVITY IN EOSINOPHILS OBTAINED FROMASTHMATIC-PATIENTS

We investigated platelet-activating-factor (PAF)-like activity in eosi nophils obtained from patients with bronchial asthma and from nonasthm atic subjects. The eosinophils were stimulated with formyl-methionylle ucylphenylalanine (f-MLP) (10 mu M) for 15 minutes. PAF-like activity was detected via platelet aggregation using washed guinea pig platelet s. The PAF-like activity (mean +/- SD) released from asthmatic eosinop hils was 53 +/- 11% aggregation/10(7) cells in the supernatants and 83 +/- 15% aggregation/10(7) cells in the cells. PAF-like activity in no nasthmatic eosinophils stimulated with f-MLP was 8 +/- 4% aggregation/ 10(7) cells in the supernatants and 20 +/- 8% aggregation/10(7) cells in the cells. Our results demonstrate that PAF-like activity in asthma tic eosinophils is more pronounced than that in nonasthmatic eosinophi ls, suggesting that asthmatic eosinophils play a role in the developme nt of bronchial asthma through increased PAF-like activity.