Reactivity of antibodies from patients with acute and chronic paracoccidioidomycosis to a high molecular mass antigen from Paracoccidioides brasiliensis

Yeast forms of Paracoccidioides brasiliensis produce polydispersed high molecular mass (h‐MM) antigens. We investigated the antibodies to an h‐MM antigen from P. brasiliensis by immunoblotting and ELISA in sera from paracoccidioidomycosis (PCM) patients. IgG from the sera of chronic PCM patients was able to recognize the h‐MM antigen at a higher frequency in the cell‐free antigen (CFA) (8/13) than in the somatic antigen (SA) (2/13), as assessed by immunoblotting. The CFA was fractionated by Sephadex G‐200 chromatography, and fraction 17 (F17) with the h‐MM antigen of approximately 366 kDa was used in ELISA to analyze specific levels of IgG and IgE. Patients with the chronic form showed significantly higher levels of IgG (P0.05) to F17 by ELISA, compared to patients with the acute form or to healthy donors. In conclusion, CFA is better than SA as a source of the P. brasiliensis h‐MM antigen. This study reveals a new characteristic to differentiate between the acute and chronic forms of PCM, by demonstrating a higher level of seric IgG to h‐MM antigen in chronic compared to acute PCM patients. J. Clin. Lab. Anal. 19:199–204, 2005. © 2005 Wiley‐Liss, Inc.