Evaluation of tests for antibody response in the follow-up of patients with acute and chronic forms of paracoccidioidomycosis.

Several serological tests have been used successfully in the diagnosis of paracoccidioidomycosis (PCM). In contrast, data about the use of these tests in the follow-up of PCM patients have been heterogeneous. In this study, serum samples from 43 PCM patients with different clinical forms were analysed by counter-immuno-electrophoresis (CIE), complement fixation (CF) and ELISA before treatment. With CIE and ELISA, the chronic unifocal form showed significantly lower antibody levels compared with chronic multifocal and acute forms. Acute form patients had significantly higher titres than patients with multifocal disease by CIE but not by ELISA. No significant differences were observed with CF. Twenty-seven of these patients were followed-up for 2 years and showed a decline in antibody levels by all three tests, paralleling clinical improvement. However, only patients with unifocal disease cleared their antibodies after 1 year of treatment as analysed by CF and ELISA and after 2 years by CIE, suggesting that these patients may need shorter courses of therapy. Patients with the other clinical form of the disease needed > or =2 years of therapy to clear their antibodies. Sera from a further five patients who presented with a relapse were analysed. At the time of relapse all showed increases in antibody levels by CIE and ELISA, but only three showed increases by CF tests. Therefore, CIE and ELISA demonstrated a better clinical correlation than CF, probably reflecting the fungal burden of PCM patients more accurately.