DIAGNOSIS OF SYSTEMIC CANDIDIASIS BY ENZYME-IMMUNOASSAY DETECTION OF SPECIFIC ANTIBODIES TO MYCELIAL PHASE CELL-WALL AND CYTOPLASMIC CANDIDAL ANTIGENS

Diagnosis of systemic Candida infections was attempted by the use of a n enzyme-linked immunosorbent assay (EIA) to detect IgG antibodies tow ards cell wall-bound and cytoplasmic candidal antigens. Cell wall anti gens were sequentially solubilized by treatment of germinated blastoco nidia of Candida albicans (ATCC 26555 strain) with beta-mercaptoethano l (beta ME extract) and digestion with Zymolyase 20T, a beta-glucanase preparation (Zymolyase extract). Protoplasts obtained after treatment with Zymolyase were osmotically lysed (cytoplasmic antigens). Sera we re obtained from patients with systemic (n = 28) and superficial (n = 46) candidiasis. Control sera were obtained from normal healthy indivi duals (n = 31) and from hospitalized patients at low (n = 36) and at h igh (n = 13) risk of developing systemic candidiasis yet showing no sy mptoms of candidal infection. Detection of antibodies in crude sera sa mples by EIA using all of these antigenic extracts was highly specific (98-100%), but sensitivity of the method was low (3.5-17.8%). However , adsorption of sera with latex microspheres coated with purified Cand ida mannan in order to selectively remove antimannan antibodies prior to EIA improved the diagnostic efficiency of this test. Improvement wa s particularly noticeable when the beta ME extract was used as antigen ic preparation, yielding a sensitivity of 89.2% and a specificity of 9 8.6%.