CIRCULATING CANDIDA ANTIGENS AND ANTIBODIES - USEFUL MARKERS OF CANDIDEMIA

To investigate the utility of the 48-kDa antigen from Candida albicans in its commercial form (Directigen; Becton Dickinson) and three other serodiagnostic methods (detection of one antigen by Pastorex Candida [Sanofi Diagnostics Pasteur] and detection of immunoglobulin G [IgG] a nd IgM antibodies to C. albicans blastoconidia [bioMerieux]) for diagn osis of invasive Candida infection, we conducted a prospective clinica l trial among 10 patients with candidemia (group 1), 30 patients colon ized by C. albicans (group 2), 20 patients with bacteremia (group 3), and 20 subjects without clinical or microbiological evidence of infect ion. The Directigen system was positive for at least one serum sample each from eight patients in group 1. In groups 2, 3, and 4, it was pos itive for only three patients. There was no reaction to the Pastorex s ystem in any of the patients infected with or colonized by C. albicans or in the non-Candida-carrying controls. The IgG antibody concentrati on oscillated between 100 and 800 (mean, 510 +/- 268) IU/ml for the pa tients in group 1. In this group, eight patients had IgG antibody leve ls of >400 IU/ml. The percentages of persons with IgG antibody levels of >400 IU/ml in groups 2, 3, and 4 were 43.3, 0, and 0, respectively. Specific IgM antibody was present in all group 1 patients but not in those in groups 2, 3, and 4. The sensitivity and specificity of the Di rectigen test were 65 and 97.1%, respectively. For the Pastorex test, the sensitivity was 0%. The sensitivity of IgG antibodies was 80%, wit h a specificity of 81.4%, while the IgM antibodies were 100% specific and sensitive. Both the positive and negative predictive values of spe cific IgM antibodies appeared to be superior to those of the other thr ee tests.