In vivo potentiation of polymorphonuclear leukocyte function by ciprofloxacin.

Ciprofloxacin was administered to 10 healthy volunteers at a dose of 250 mg orally. Serum and polymorphonuclear leukocytes (PMNLs) were obtained from all subjects before the administration of the drug and 12 hours after the administration. In addition serum was obtained from all subjects at 24 and 48 hours after ciprofloxacin administration. All sera and PMNLs were used for the chemotactic, phagocytic and killing determinations of the PMNLs. The results demonstrated that serum obtained 12 hours after the administration of ciprofloxacin potentiates PMNL chemotactic activity (chemotactic index (CI) = 33.0 +/- 4.2 microns (means +/- S.D.)) as compared to the chemotactic activity generated by serum obtained prior to administration of the drug, CI = 20.4 +/- 4.4 microns (p < 0.01). Serum obtained 24 and 48 hours after ciprofloxacin administration did not stimulate PMNL function. The administration of ciprofloxacin did not have any direct influence on the PMNLs in terms of their chemotactic response. Furthermore, serum obtained after the administration of ciprofloxacin markedly enhanced PMNL phagocytosis and killing of all organisms tested. Ciprofloxacin also acted directly on the PMNLs and increased their bactericidal activity. These results demonstrate that ciprofloxacin potentiates PMNL function in vivo which may be of potential clinical benefit.