An antibody reactivity-based assay for diagnosis of invasive candidiasis using protein array

The increased incidence of invasive candidiasis and of patients at risk requires early diagnosis and treatment to improve prognosis and survival. The aim of this study was to set up a ten-protein array-based immunoassay to assess the IgG antibody responses against ten well-known immunogenic C. albicans proteins (Bgl2, Eno1, Pgk1, Pdc11, Fba1, Adh1, Als3, Hwp1, Hsp90 and Grp2) in 51 patients with invasive candidiasis (IC) and in 38 culture-negative controls (non-IC). Antibody levels were higher against Bgl2, Eno1, Pgk1, Als3, Hwp1 and Grp2, than against Adh1, Pdc11, Fba1 and Hsp90, irrespectively of the patient group considered. Moreover, the IgG levels against Bgl2, Eno1, Pgk1 and Grp2 were significantly higher in IC than in non-IC patients. Furthermore, the ROC curves generated by the analysis of the antibody responses against Bgl2, Grp2 and Pgk1 displayed AUC values above 0.7, thus discriminating IC and non-IC patients. According to these results, the employment of the microarray immunoassay (a rapid, sensitive and multiparametric system), in parallel with conventional diagnostics, can help to spot IC patients. This ultimately will allow to initiate an early, focused and optimized antifungal therapy.