Comparison of seven Blastomyces dermatitidis antigens for the detection of antibodies in humans with occupationally acquired blastomycosis.

Yeast phase lysate antigens, prepared from seven isolates of Blastomyces dermatitidis (dogs, T-58, M-98; human, Le; soil, S; sea lion, SL; polar bear, PB; cat, C) were assayed by enzyme-linked immunosorbent assay (ELISA) to detect antibodies in human sera. The sera were from individuals potentially exposed to B. dermatitidis while working on a prairie dog relocation project in Colorado. All antigens exhibited greatest reactivity with three specimens in two separate assays. Absorbance values ranged from 0.370 (M-98) to 0.427 (LE) (Trial 1) and from 0.579 (M-98) to 0.714 (PB) (Trial 2) with serum 2; from 0.368 (C) to 0.453 (LE) (Trial 1) and from 0.565 (SL) to 0.694 (S) (Trial 2) with serum 3 and from 0.392 (M-98) to 0.506 (LE) (Trial 1) and from 0.557 (SL) to 0.758 (T-58) (Trial 2) with serum 6. The greatest reactivity was observed with sera from two persons (2 and 3 from the same individual and serum 6) who became ill with symptoms of pulmonary disease and sought medical care. Both patients were subsequently diagnosed with blastomycosis by microscopic and culture methods. The study indicated that all of the lysate antigens, regardless of source, could be used to reliably diagnose blastomycosis.