Effect of antimalarial drugs on human neutrophil chemotaxis in vitro.

The effect of several antimalarial drugs, commonly used for prophylaxis and therapy of human malaria, on polymorphonuclear leukocyte chemotaxis was studied. A modified, reversible Boyden chamber method was used. Various concentrations of each drug was mixed with neutrophils and incubated in the chambers for 2 1/2 hours. After the incubation period percent inhibition of chemotaxis was determined. It was shown that chloroquine, quinine, proguanil, and tetracycline at concentrations frequently obtained in clinical situations significantly inhibited chemotaxis of neutrophils towards casein. There was a direct correlation between increasing drug concentration and percent inhibition of chemotaxis. Drugs such as pyrimethamine and fansidar at any concentration tested had no effect on chemotaxis.