Analy Salles de Azevedo Melo1, Daniel Wagner de Castro Lima Santos1, Soraia Lopes Lima1, Anderson Messias Rodrigues2, Zoilo Pires de Camargo3, Malcolm Finkelman4, Arnaldo Lopes Colombo1. 1. Laboratório Especial de Micologia, Departamento de Medicina, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brasil. 2. Laboratório de Patógenos Fúngicos Emergentes, Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil. 3. Laboratório de Micologia Médica, Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil. 4. Associates of Cape Cod, Clinical Development Department, Research Laboratory, Falmouth, MA, USA.
Abstract
BACKGROUND: Paracoccidioidomycosis (PCM) is highly prevalent in Latin America, but no commercial system is available for diagnosing this endemic mycosis. OBJECTIVES: To check the performance of (1 → 3)-β-D-glucan assay (BDG) for diagnosing PCM in 29 patients with proven fungal disease and compared with double immunodiffusion assay for detecting anti-Paracoccidioides antibodies. PATIENTS AND METHODS: We selected 52 serum samples sequentially obtained from 29 patients with active PCM (12 chronic and 17 acute form). Samples were collected at baseline, and for 16 patients, additional serum levels were obtained after 3 and 6 months of antifungal treatment. Detection of BDG in serum was performed by using the Fungitell® assay. For the double immunodiffusion assay, Paracoccidioides exoantigen was used in latex agglutination tests to detect serum anti-Paracoccidioides antibodies. RESULTS: Despite exhibiting good sensitivity in the diagnosis of patients with PCM, we failed to demonstrate any correlation between the postdiagnosis kinetic profile of BDG serum levels and clinical response to antifungal therapy. This finding may be related to the maintenance of quiescent foci of fungal infection in several organs and tissues, a phenomenon that has been previously reported by other authors and helps to understand why so many relapses are documented in patients treated for short periods of time. Finally, we did not find any correlation between BDG quantification and specific anti-P brasiliensis antibodies serum titres in patients with PCM. CONCLUSIONS: In conclusion, BDG is detected in serum samples of most patients with PCM but is probably not useful for predicting clinical response to antifungal therapy.
BACKGROUND:Paracoccidioidomycosis (PCM) is highly prevalent in Latin America, but no commercial system is available for diagnosing this endemic mycosis. OBJECTIVES: To check the performance of (1 → 3)-β-D-glucan assay (BDG) for diagnosing PCM in 29 patients with proven fungal disease and compared with double immunodiffusion assay for detecting anti-Paracoccidioides antibodies. PATIENTS AND METHODS: We selected 52 serum samples sequentially obtained from 29 patients with active PCM (12 chronic and 17 acute form). Samples were collected at baseline, and for 16 patients, additional serum levels were obtained after 3 and 6 months of antifungal treatment. Detection of BDG in serum was performed by using the Fungitell® assay. For the double immunodiffusion assay, Paracoccidioides exoantigen was used in latex agglutination tests to detect serum anti-Paracoccidioides antibodies. RESULTS: Despite exhibiting good sensitivity in the diagnosis of patients with PCM, we failed to demonstrate any correlation between the postdiagnosis kinetic profile of BDG serum levels and clinical response to antifungal therapy. This finding may be related to the maintenance of quiescent foci of fungal infection in several organs and tissues, a phenomenon that has been previously reported by other authors and helps to understand why so many relapses are documented in patients treated for short periods of time. Finally, we did not find any correlation between BDG quantification and specific anti-P brasiliensis antibodies serum titres in patients with PCM. CONCLUSIONS: In conclusion, BDG is detected in serum samples of most patients with PCM but is probably not useful for predicting clinical response to antifungal therapy.