Detecting local immunoglobulin E from mucosal brush biopsy of the inferior turbinates using microarray analysis

Background It has been previously demonstrated that local, antigen-specific immunoglobulin E (IgE) can be detected using a standard in vitro assay of lysed epithelial cells in saline, harvested via nasal mucosal brush biopsy (MBB). However, compared to surgical biopsy or serum, smaller amounts of IgE are harvested using MBB, making detection much more difficult. Microarray analysis (MA) requires less IgE for detection, making this an attractive option for MBB. The goals of this study were to compare MA to a standard IgE assay for detecting antigen-specific IgE from MBB and to test the association between the presence of multiple positive components on MA with specific IgE on standard assay and skin-prick testing (SPT) grade. Methods MBB samples from 18 allergic rhinitis patients, which were previously tested for antigen-specific IgE to common airborne allergens using a standard IgE assay, underwent MA for antigen-specific IgE to multiple components of airborne and food allergens. Fisher's exact probability testing was used to measure the strength of association between the 2 testing modalities for Timothy grass, ragweed, cat, Alternaria, and D. farinae. Results MA correlated very highly with standard assay (p < 0.0001) and 50% of positive antigens on MA detected multiple components to that antigen. The presence of multiple components was not associated with specific IgE levels on standard assay or SPT grade. Conclusion This is the first demonstration that antigen-specific IgE in saline samples can be measured using MA. The ability of MA to measure smaller amounts of IgE, with similar accuracy, may give it a potential advantage for MBB analysis in the future.