AUGMENTATION OF APOPTOSIS IN BRONCHIAL EXUDED RAT EOSINOPHILS BY CYCLOSPORINE-A

The effect of cyclosporin A on apoptosis in eosinophils was examined t o clarify the inhibitory mechanisms of cyclosporin A on allergen-induc ed eosinophilia in the airway. Eosinophils in bronchoalveolar lavage f luid from sensitized rats after inhaling an allergen were used. More t han 50% of the eosinophil that died spontaneously by apoptosis within 24 hour incubation in RPMI 1640 medium contained 10% fetal calf serum. The addition of cyclosporin A or dexamethasone significantly enhanced the eosinophils apoptosis at concentrations of more than 0.1 mu M. Ap optosis in eosinophils was considerably suppressed in the presence of culture super natant of activated splenocytes as a source of various c ytokines. Even in the presence of culture supernatant of activated spl enocytes, cyclosporin A or dexamethasone facilitated apoptosis in eosi nophil,. These results suggest that apoptotic death of activated eosin ophils is augmented with cyclosporin A and that accelerated apoptosis in eosinophils of the airway may account for the inhibitory effect of cyclosporin A on eosinophilia. (C) 1996 Academic Press, Inc.