Purified Candida albicans proteinase in the serological diagnosis of systemic candidosis.

An inducible, exocellular proteinase enzyme, purified from culture filtrates of Candida albicans, was tested as an antigen for the detection of serum anti-Candida precipitins. The purified proteinase was a more specific antigen for the serological diagnosis of systemic candidosis than traditional cytoplasmic extracts of the fungus. Precipitin titers to purified proteinase exceeded 1:4 in 75% of serum samples from 12 patients with confirmed systemic Candida infection, in 23% of serum samples from 22 patients positive for Candida anticytoplasm antibodies but without corroborative diagnostic evidence of systemic candidosis, and in none of 28 serum samples from patients without either candidosis or anticytoplasm antibodies.