Candidal infection of bone. Assessment of serologic tests in diagnosis and management.

In this case report, 30 sera from a 25-year-old heroin abuser with intervertebral candidosis were treated for the presence of anti-Candida albicans antibodies by agglutination, counterimmunoelectrophoresis, and indirect immunofluorescent assay. Sera were also adsorbed with heat-killed blastospores to remove antibodies against yeast-phase cells and tested by indirect immunofluorescent assay for anti-C. albicans germ tube antibodies (CAGTAs). Humoral responses to candidal 47-kD antigen were studied by immunoblotting in 23 unadsorbed sera. Anti-C. albicans antibodies were found in high titers by the three procedures but correlated poorly with the clinical evolution of the disease. CAGTAs were present from the beginning of the infection: Titers decreased in association with antifungal treatment and the patient's improvement, eventually becoming negative. Only class IgG antibodies to the 47-kD antigen were detected. These were present during the full course of the infection, failing to disappear at the end of the study. In this case, detection of CAGTAs appeared to be an important aid to diagnosis of the bony candidal infection, as they are detected early during the illness and seemed to have a prognostic significance.