Produção e padronização dos antígenos de Paracoccidioides brasiliensis (Pb), Histoplasma capsulatum (Hc) e Aspergillus fumigatus (Af) para uso no imunodiagnóstico: comparação entre as técnicas de imunodifusão e imunoeletroosmoforese

Abstract

Soluble antigens (Ag) from Paracoccidioides brasiliensis, Histoplasma capsulatum and Aspergillus fumigatus were prepared and standardized by double immunodiffusion (DID) and immunoelectroosmophoresis (IEOP). No difference in sensitivity was observed between the two techniques; 100% of standard patient sera were positive with P. brasiliensis and A. fumigatus Ag and 83.3% were positive with H. capsulatum Ag. The specificity of the tests was verified testing 96 sera from patients with paracoccidioidomycosis, histoplasmosis, systemic candidiasis, sporotrichosis, tuberculosis, lung cancer, visceral or cutaneous leishmaniasis and 18 sera from healthy individuals. All the three antigens were 100% specific with the DID (using the identification pattern indicated by the confluence of test serum with standard serum precipitin lines as a positive criterium). However in the IEOP, the specificity varied with each Ag. Positive reactions with P. brasiliensis Ag were observed in 16.7% of histoplasmosis sera and in 10% of cutaneous leishmaniasis sera. On the other hand 31.8% of paracoccidioidomycosis and 10% of cutaneous leishmaniasis sera reacted with H. capsulatum Ag. The high sensitivity and specificity of the DID test, its easy reproducibility and low cost, led us to consider it highly appropriate as a routine procedure for the screening of patients with respiratory infections.

Paracoccidioidomycosis: an update

“…It is simple to perform and also highly reliable (53,103,105). In studies measuring the sensitivity and specificity of the immunodiffusion test, values of 89 and 91% for the former and 100% for the latter parameter have been established; as a consequence, the positive predictive value of this test is 100% (58,87).…”

“…In general, the titers are lower than those obtained with the CF test; nonetheless, the simplicity of the test is an advantage for small laboratories (261) ( Table 5). Counterimmunoelectrophoresis has also been employed by several investigators (13,53,77,105); its sensitivity is the same as or even slightly superior to that of immunodiffusion (87). Another variation of the precipitation test, immunoelectrophoretic procedures, has also been standardized but is used for research more than for diagnostic purposes (76,323,326,329).…”

Paracoccidioidomycosis: an update.

“…Agar gel immunodiffusion has demonstrated its versatility as both a screening test and a diagnostic test (6,106,164,196,214,260). It is simple to perform and also highly reliable (53,103,105). In studies measuring the sensitivity and specificity of the immunodiffusion test, values of 89 and 91% for the former and 100% for the latter parameter have been established; as a consequence, the positive predictive value of this test is 100% (58,87).…”

“…In general, the titers are lower than those obtained with the CF test; nonetheless, the simplicity of the test is an advantage for small laboratories (261) ( Table 5). Counterimmunoelectrophoresis has also been employed by several investigators (13,53,77,105); its sensitivity is the same as or even slightly superior to that of immunodiffusion (87). Another variation of the precipitation test, immunoelectrophoretic procedures, has also been standardized but is used for research more than for diagnostic purposes (76,323,326,329 Agglutination.…”

Sensitive immunoradiometric assay for the detection of Paracoccidioides brasiliensis antigens in human sera

“…This technique was used to assess the antigenicity of the fungous extract, to test the antiserum produced, and to study the antigenic relationship between cellular and metabolic P. brasiliensis preparations. All the antigens used were positive in DID against their homologous sera and negative against their heterologous sera using an already described criterion (5,6). Polyclonal IgG from rabbits and from paracoccidioidomycosis patients were found to react with both cellular and metabolic P. brasiliensis antigens.…”