Immunohistologic Diagnosis of Systemic Mycoses: an Update

Fluorescent antibody, immunoperoxidase and gold-silver staining methods for the rapid and accurate diagnosis of systemic mycotic infections are currently performed in a few specialized laboratories. These methods have proved applicable to formalin-fixed, paraffin-embedded tissues, and are reliable for identifying therein antigens of infectious dimorphic, monomorphic filamentous, and yeast-like fungal pathogens, i.e., Aspergillus spp., Blastomyces dermatitidis, Candida spp., Coccidioides immitis, Cryptococcus neoformans, Fusarium spp., Histoplasma capsulatum, Paracoccidioides brasiliensis, Pseudallescheria boydii, and Sporothrix schenckii. Most of the available reagents are derived from multiple adsorbed polyclonal antisera. However, problems occur in the production of uniform and standardized species- or genus- specific antibodies. Monoclonal antibodies, although promising, have to date not eliminated these problems. Immunohistologic methods will become more routinely used in clinical laboratories as these problems are resolved and more sensitive and specific reagents become commercially available.