Suppressive effect of deferoxamine on the growth of Pneumocystis carinii in vitro.

The effects of the iron chelator deferoxamine on the growth of rat-derived Pneumocystis carinii in culture with human embryonic lung fibroblasts were studied. Growth inhibition was calculated by comparison of trophozoite numbers in replicate samples of supernatant of treated and untreated samples. Deferoxamine, in concentrations safely achievable in humans (5-15 micrograms/ml, corresponding to 7.6-22.8 microM), reproducibly suppressed P. carinii growth in a dose-dependent manner. The suppressive effect was reversed by prior iron saturation of the deferoxamine. Since the utility of current therapeutic agents for P. carinii disease is limited by toxicity and incomplete efficacy, the role of iron chelation as an adjunct to anti-Pneumocystis chemotherapy merits further investigation.