The Role of Specific Antibodies of Different Immunoglobulin Classes in the Rapid Diagnosis of Systemic Mycotic Infections

Abstract

Antibodies represent a major effector mechanism of the immunologic response. Many function to opsonize the tissue-form cells of pathogenic fungi for phagocytosis. IgA, IgE, IgG, and IgM class antibodies are known to react with fungal antigens. The most frequently detected specific antibodies are of the IgG class. These antibodies have both diagnostic and prognostic value. IgM-specific antibodies playa more restricted diagnostic role. They are particularly useful for the early detection of candidiasis, coccidioidomycosis, and histoplasmosis. Circulatory IgG and IgM antibodies are elicited by specific fungal antigens in individuals with such symptomatic systemic fungal infections as aspergillosis, blastomycosis, candidiasis, coccidioidomycosis, cryptococcosis, histoplasmosis, and paracoccidioidomycosis. These antibodies are detected by a variety of old and new serologic tests. They do not appear to playa major protective role in host immunity, in contrast to the T-lymphocytes, which are of paramount importance in protecting the host against systemic mycotic infections. I will appraise the value of these antibodies, describe their sequence of occurrence during the course of infection, and where possible, characterize the immunoglobulin classes associated with them.