Abstract
A passive hemagglutination inhibition assay was studied by using a hyperimmune serum from rabbits immunized with whole yeast cells (Candida albicans group A). This technique was effective at detecting small amounts of laboratory-prepared mannan or a whole-cell extract of C. albicans. Of 32 patients with documented disseminated candidiasis that were tested, 19 showed evidence of circulating antigen by passive hemagglutination inhibition. Three of these patients showed only partial, rather than complete, inhibition. Among 22 colonized patients, 4 showed partial inhibition, and none of 49 normal controls demonstrated inhibition. All of the sera were tested for antibody by agglutination, immunodiffusion, and passive hemagglutination. This last technique added increased sensitivity, but not specificity, to the standard tests already in use. Fourfold or greater titer rises by passive hemagglutination occurred in fewer than one-third of patients with invasive candidiasis and developed in more than one-half of patients who were colonized and did not require systemic anticandida therapy.