Paracoccidioidomycosis is a systemic granulomatous disease caused by
the dimorphic fungus Paracoccidioides brasiliensis. It is the
most prevalent systemic mycosis of Latin America and 80% of the
reported cases are from Brazil. Because of the great number of
neutrophils found in the P. brasiliensis granuloma, studies
have been done to evaluate the role of these cells during the
development of the infection. Scanning and transmission electron
microscopy of thin sections showed that the neutrophils ingest yeast
cells through a typical phagocytic process with the formation of
pseudopodes. The pseudopodes even disrupt the connection established
between the mother and the bud cells. Neutrophils also associate to
each other, forming a kind of extracellular vacuole where large yeast
cells are encapsulated. Cytochemical studies showed that once P.
brasiliensis attaches to the neutrophil surface, it triggers a
respiratory burst with release of oxygen-derived products. Attachment
also triggers neutrophils' degranulation, with release of
endogenous peroxidase localized in cytoplasmic granules. Together,
these processes lead to killing of both ingested and extracellular
P. brasiliensis.