DETECTION OF SPECIFIC ANTIBODIES IN HUMAN BLASTOMYCOSIS BY ENZYME-IMMUNOASSAY

Serologic tests for the diagnosis of blastomycosis have had inadequate sensitivity, but results are improved with enzyme immunoassay (ELA) w ith A-antigen of Blastomyces dermatitidis. The Premier Blastomyces EIA kit (Meridian Diagnostics Inc, Cincinnati, Ohio) detected antibody ag ainst the B dermatitidis A-antigen in sera from 104 of 125 patients (8 3%) with culture-proven blastomycosis. Semiquantitative index values ( positivity multiplied by the dilution) ranged from 1.0 to 423.3; the d egree of positivity correlated with disease activity. Immunodiffusion bands were infrequently detected, with positive specimens from only 19 (21%) of 92 patients with blastomycosis. In 8 of 24 patients with his toplasmosis, 24 of 51 specimens (47%) were positive for Blastomyces an tibody by EIA; index values were lower, with a mean of 3.8 versus 24.3 for sera from patients with blastomycosis. Only I of 13 patients with other fungal infections had positive results with EIA. This EIA syste m provided better sensitivity than previously available commercial sys tems for serodiagnosis of blastomycosis.