Skin test-active substance prepared from culture filtrate of Fonsecaea pedrosoi

Ethanol-precipitated substance (EP) was prepared from culture filtrate of Fonsecaea pedrosoi. EP was separated into two components by passing through a Sephadex G-50 column; the faster passing component was referred to as EP-1, the slower as EP-2. EP-1 and EP-2 were evaluated as an antigen for detecting cutaneous delayed hypersensitivity in patients with chromomycosis. EP-1 elicited positive delayed skin reactions in all of 8 patients with chromomycosis, of which 7 caused by F. pedrosoi and one by Exophiala jeunselmei. Healthy subjects, patients with sporotrichosis and patients with tinea barbae failed to react to EP-1. These results indicate that EP-1 is a useful tool for detecting cutaneous delayed hypersensitivity in patients with chromomycosis caused by F. pedrosoi. It was found that precipitin test using EP-1 as an antigen had little diagnostic value in chromomycosis. EP-2 did not show antigenic activity in both skin and precipitin reactions.