Pathogenesis and Classification of Paracocidioidomycosis: New Insights From Old Good Stuff

Abstract

Different classifications of paracoccidioidomycosis emerged since its discovery in 1908, culminating in the proposition of a simplified and consensual one in 1987. However, by revisiting these classifications, case reports, or case series from which the authors based their own, we found many patients who did not fit in either the 1987 classification or in the correspondent natural history/pathogenesis view. In this report, the concepts of paracoccidioidomycosis infection, primary pulmonary paracoccidioidomycosis (PP-PCM), and other subclinical forms of PCM are reassessed. A classification is proposed to encompass all these subtle but distinct outcomes. I suggest a continuum between the PP-PCM and the overt chronic form of disease, and not the current view of quiescent foci, frozen in time and suddenly reactivated for unknown reasons. Failure to fully resolve the infection in its initial stages is a conceivable hypothesis for the chronic form. The proposed clinical classification might offer new insights to better characterize and manage PCM patients.

Keywords: classification; immune response; paracocidioidomycosis; pathogenesis; subclinical infection.

Figure 1.

Schematic view of the natural history/pathogenesis of the Paracoccidioides-host interaction, highlighting the main clinical outcomes (in bold). The number in parenthesis indicates an estimated frequency of the outcome from the total of individuals infected in endemic areas. Individuals infected in endemic areas usually represent 10% to 60% of the local population. A/SAF, acute/subacute form; AIDS, acquired immune deficiency syndrome; CF, chronic form; CNS, central nervous system; PP-PCM, primary pulmonary paracoccidioidomycosis;