The effects of histamine, antihistamines, isoproterenol and theophylline on the Fc and complement receptor functions of polymorphonuclear leukocytes in asthmatic children.

The effects of histamine, antihistamines, isoproterenol and theophylline on the expressions of Fc and complement (C') receptors on the polymorphonuclear leukocytes (PMN's) were studied in 40 asthmatic children. Histamine in concentrations of 10(-13) to 10(-3), isoproterenol in 10(-5) to 10(-3) and theophylline in 5 X 10(-6) to 10(-4) were all capable of causing a dose-related suppression of Fc and C' receptor functions of PMN's. Either diphenhydramine or cimetidine alone could partially block the histamine-induced suppressive effect but combination of H1 and H2 receptor antagonists were required for complete abolishment.