The frequency of invasive fungal infections has risen dramatically in recent years, and early and accurate diagnosis of these infections is important for appropriate use of antifungal agents. The value of serological tests is apparent, but they suffer from disadvantages, such as being time-consuming and their inability to produce simultaneous results. Protein microarrays are a convenient technology that can be used to perform high-throughput antibody detection and enable the monitoring of different antibodies simultaneously. We constructed a low-density microarray using purified recombinant enolase (Eno) fructose-bisphosphate aldolase (Fba1) from Candida and thioredoxin reductase (TR) from Aspergillus fumigatus as immobilized antigens. Following optimization of microarray construction and serum testing, we investigated the sensitivity, repeatability, and stability of the assay using sera from patients with invasive Candida and/or Aspergillus infections and control subjects. Sera from patients with invasive candidiasis (IC) were subjected to low-density microarray assay for detection of two antibodies from Candida and one antibody from A. fumigatus. Our results indicated a sensitivity and specificity of 67.6% and 96.5% for anti-Eno and 64.8% and 90.3% for anti- Fba1 antibodies, respectively. The combined detection of anti-Eno and anti- Fba1 returned a sensitivity of 81%, and in invasive aspergillosis (IA) patients, the sensitivity and specificity of detection were 71.4% and 98.2%, respectively, for the anti-TR antibody. The low-density protein microarray assay developed in this study was capable of detecting three antibodies against two fungi simultaneously, demonstrating its potential value in diagnosing IC and IA.
Xiao Chen, Fang-qiu Li*, Chun-fang Ma, Li-ning Shi and Yu-an Hu