H1-antihistamines and oxidative burst of professional phagocytes.

We analysed and compared the effect of five H1-antihistamines on stimulated oxidative burst at extra- and intracellular level of isolated and stimulated human polymorphonuclear leukocytes. Oxidative burst of isolated human neutrophils was studied by means of luminol and isoluminol enhanced chemiluminescence. The following rank order of potency for H1-antihistamines to decrease chemiluminescence was evaluated extracellularly: dithiaden> loratadine> chlorpheniramine> brompheniramine> pheniramine and at intracellular site: loratadine> dithiaden. H1-antihistamines differ substantially according to their chemical structure in suppressing oxidative burst both at extra- and intracellular site of isolated stimulated human neutrophils.