Terbinafine induces the PMNL priming effect and enhances in vitro PMNL fungicidal activity against Candida albicans blastospores.
Terbinafine, a new antifungal drug of the allylamine category, has been shown not to interfere with some polymorphonuclear leucocyte (PMNL) functions such as chemotaxis and chemiluminescence. The aim of the present study was to elucidate the effects of terbinafine on PMNL respiratory burst activation and killing of Candida albicans blastospores by PMNLs at the biochemical and ultrastructural level by means of scanning electron microscopy (SEM). Terbinafine is shown to enhance the respiratory burst and superoxide anion release in human PMNLs stimulated by phorbol esters or chemotactic peptides, and to have a priming effect on PMNL functions. Moreover, in our experiments we found that terbinafine does not interfere with PMNL killing of C. albicans blastospores but, in fact, at the concentration found in tissues after oral administration, slightly increases it. As PMNLs play a key role in the early stages of fungal infections we suggest that in vivo terbinafine induces priming of PMNLs, and that this effect is related to enhanced candidacidal activity independent of direct drug damage to fungal particles.