Increasing the predictive value positive of the precipitin test for the diagnosis of deep-seated candidiasis

Three hundred fifty human sera were tested by double immunodiffusion, crossed-line electrophoresis, and crossed immuno-affinoelectrophoresis with a concanavalin A intermediate gel for precipitating antibodies to antigens present in cytoplasmic extracts of Candida albicans. Sera from 48 of 287 hospitalized patients at risk of invasive candidiasis contained precipitating antibodies to Candida antigens. Of these 48 sera, 27 had precipitating antibodies only to cell-wall antigens present in the cytoplasmic extract, and 21 sera had precipitating antibodies to both cytoplasmic and cell-wall antigens. The latter sera came from patients who were 2.5 times as likely to have deep-seated candidiasis as those patients with precipitins exclusively to cell-wall antigens. Sera from seven of 22 patients with vaginal candidiasis and 10 of 41 patients with other fungal infections had precipitating antibodies to C. albicans cell-wall antigens; only two of these sera also contained precipitating antibodies to the cytoplasmic antigens. Crossed immunoaffinoelectrophoresis with concanavalin A reduced the number of false-positive results and increased the predictive value positive of the precipitin test for deep-seated candidiasis from 31% to 71%.