DETECTION OF CANDIDAL ANTIGENS IN AUTOIMMUNE POLYGLANDULAR SYNDROME TYPE-I

Autoimmune polyglandular syndrome type I (APS I) is associated with ch ronic mucocutaneous candidiasis. To characterize the antibody response s in this subgroup of Candida albicans infections, we screened a candi dal cDNA expression library with patient sera and found four cDNA clon es encoding the immunopositive proteins enolase, heat shock protein 90 , pyruvate kinase, and alcohol dehydrogenase. The reactivity to these antigens was studied further by immunoprecipitation assays with in vit ro-transcribed and -translated proteins. Analysis of sera from 44 APS I patients showed that the highest antibody reactivity was found with enolase (80% of patients reactive), but significant serological respon ses were also found with heat shock protein 90 (67%), pyruvate kinase (62.5%), and alcohol dehydrogenase (64%). Overall, 95.5% of patients h ad detectable antibodies to at least one of these proteins. The cDNAs of enolase and heat shock protein 90 were also expressed in Escherichi a coli and studied by immunoblotting. Again, 84% of sera reacted with enolase, whereas 44% of sera reacted with heat shock protein 90. A goo d correlation between the two methods was found for both enolase (r = 0.86; n = 58; P < 0.001) and heat shock protein 90 (r = 0.71; n = 56; P < 0.001). Our results indicate that the four abundant candidal prote ins are the major antigens and can be used as accurate markers of cand idiasis in APS I patients. The immunoprecipitation assay described her e is particularly useful for the rapid analysis of a large number of s amples.