Immunological response to cell-free antigens of Paracoccidioides brasiliensis: relationship with clinical forms of paracoccidioidomycosis.

Sera from patients with the acute (AF) and chronic (CF) forms of paracoccidioidomycosis (PCM) were tested against Paracoccidioides brasiliensis cell-free antigens by Western blot (immunoblot). The CFA preparation contained components ranging in molecular mass from 18 to 102 kDa. The immunoglobulin G (IgG) reactivity profiles were similar for patients with both forms of the disease, and the 43-kDa component was recognized by 100% of the sera. IgM antibodies from the AF- and the CF-PCM sera recognized 21 and 20 components, respectively, the AF-PCM sera reacting preferentially with components with molecular masses above 50 kDa. None of the AF-PCM sera (IgM) reacted with the 43-kDa component, and only 10% of the CF-PCM sera recognized this molecule. The IgA response was more significant in the CF-PCM group than in the AF-PCM group, and the 43- and 74-kDa components were the most reactive ones (about 40% each). Our results showed that the cell-free antigen preparation is very appropriate for the immunoblotting analysis of PCM sera, and they also showed that the detection of IgG anti-gp43 is the best marker for the diagnosis and the following up of patients with the acute or the chronic form of the disease.