Development of a sensitive, colorometric microarray assay for allergen-responsive human IgE.

With the existence of several thousand unique human allergens, a multiplex format, such as protein microarrays, is an attractive option for allergy screening. To determine the feasibility and sensitivity of using an enzyme-based, colorimetric protein microarray assay, three common allergens (mold, dust-mite, grass) were arrayed and added sera assayed for responsive human IgE. Normal, low positive, and negative control samples were assayed to determine optimal reaction parameters. Sensitivity of the assay (in international units, IU) was determined by constructing a standard curve using World Health Organization (WHO) standards. The system described here can reliably detect allergen-specific IgE below 0.35 IU, the current WHO standard cutoff. By taking advantage of the sensitivity of enzyme-linked immunosorbent assays (ELISAs) and the multiplex format of microarrays, we have achieved a high throughput system, capable of screening patients for allergen-susceptibility with optimal sensitivity.