Comparison of serum mannan, arabinitol, and mannose in experimental disseminated candidiasis.

Concentrations of arabinitol, mannose, and mannan in serum have independently been reported to be elevated in patients with invasive candidiasis. These three marker substances were compared in a rabbit model. Twelve rabbits, immunosuppressed with cortisone, were infected intravenously with Candida albicans 3181A. Six uninfected control animals also received cortisone, and four rabbits were neither infected nor immunosuppressed. Blood samples, drawn from 2 days before to 14 days after infection, were assayed for serum mannan by sandwich enzyme immunoassay, antibodies to mannan by indirect enzyme immunoassay, arabinitol and mannose by gas-liquid chromatography, and serum creatinine. Serum mannan, negative before infection, peaked in all infected animals 4 days after infection (mean, 18 ng/ml) and decreased thereafter. Significant increases (2 standard deviations greater than mean in normals) in arabinitol, the arabinitol/creatinine ratio, and mannose were found in 12, 8, and 12 of the infected rabbits, respectively, but also in all 6 uninfected animals receiving cortisone. Only serum mannan was specific in this immunosuppressed rabbit model.