Capture enzyme-linked immunosorbent assay to detect specific immunoglobulin E in sera of patients with paracoccidioidomycosis.

Paracoccidioidomycosis (PCM) is the most frequent systemic mycosis in South America. The disease is characterized by a polyclonal activation of B cells, resulting in hyperimmunoglobulinemia. The production of immunoglobulin (Ig) E in deep mycosis has been related to the severity of the disease. However, the detection of specific IgE in sera of patients is difficult because of the competition with the IgG. We compared a capture and an indirect enzyme-linked immunosorbent assay (ELISA) technique to detect Paracoccidioides brasiliensis IgE. We found that the capture ELISA presented higher performance and lower background values than the indirect assay, resulting in a significant quantitative discrimination between sera from patients with the 2 major clinical forms of PCM. Patients with the juvenile form presented significantly higher levels of P. brasiliensis IgE, as compared with patients with the adult form. The capture ELISA was used in the follow-up of patients receiving treatment, showing that the levels of specific IgE decreased as the patient's clinical conditions improved.