Complement in fungal infections and complement evasion strategies

Abstract

Fungal infections are of particular importance in modern medicine. This is mainly due to an optimised iatrogenic immunosuppression, which, for example, enables a longer survival of organ transplantation recipients, or due to better treatment options for chronic infections or neoplastic diseases. These improved therapeutic approaches will keep more patients for longer periods in immunocompromised states, where they are in particular susceptible to fungal infections. As a consequence, invasive fungal infections are on the march. Therefore a deeper understanding of the interaction between the various fungi and the host's innate and adaptive immune defence system is warranted. This understanding is the essential prerequisite for a successful therapeutic approach. The present article reviews the current knowledge of the role of complement, as a central part of innate immunity, its activation by fungi, and its role as a fine tuner of adaptive immunity in the fungus-induced pathogeneses on the one hand, and the strategies of the fungi to evade complement attack on the other hand, with particular emphasis on candidiasis, aspergillosis, cryptococcosis, blastomycosis, histoplasmosis, paracoccidioidomycosis, and Malassezia-associated skin diseases