Reversal by cimetidine of histamine-induced inhibition of true chemotaxis in neutrophil polymorphonuclears.

The effects of histamine and cimetidine on neutrophil locomotion were studied in vitro in experimental conditions able to dissociate random from truly directional motility. Histamine 10(-4) mol/l inhibited the true chemotactic response. Cimetidine was able to reverse the histamine-induced inhibition of true chemotaxis. Since histamine-induced inhibition of neutrophil chemotaxis may play a role in allergic patients with repeated infections, and since cimetidine has been shown to enhance cell-mediated immunity in vivo, often impaired in such cases, the use of cimetidine is suggested for the prevention of recurrences in these patients.