Effect of misoprostol on the secretion of histamine from basophils of whole blood

Background: Misoprostol (MSP), the synthetic prostaglandin E1 (PGE1) analog , possesses multifunctional features, including modulating some inflammator y aspects of immune and allergic disorders. Objectives: To investigate the effect of MSP on histamine release (HR) from basophils of whole blood using anti-IgE, specific allergens, and calcium i onophore. Methods: The study was performed using the automated glass fiber- based whole blood leukocyte histamine release test (LHRT). Results: Very low concentrations of MSP produced a marked inhibition of HR induced with anti-IgE. Maximum inhibition was observed at 10(-9) M. It was also shown that the levels of HR inhibition with MSP varied at different in cubation times. The greatest inhibition of HR was noted at 1 to 2 hours of incubation at MSP concentrations of 10(-8) and 10(-9) M, respectively. Incu bation of blood from allergic patients at the optimal MSP concentration and optimal elapsed time (2 hours) resulted in significant reductions of aller gen-specific HR induced by both Timothy pollen grass allergen and D.pteroni ssinus. Incubation of blood with varying concentrations of MSP and subseque nt stimulation with calcium ionophore A23187 also inhibited HR from basophi ls. In the latter case, the most effective concentrations of MSP ranged fro m 10(-8) to 10(-6) M. Conclusions: This study demonstrated that MSP can inhibit basophil HR indic ating a potentially beneficial role of PGE1 analogs as pharmacotherapy for allergic diseases.