Serological Cross-Reactivity of Various Aspergillus spp. with Aspergillus fumigatus: A Diagnostic Blind Spot

Introduction: Aspergillus fumigatus is the most common airborne allergen of the Aspergillus family. However, allergies to Aspergillus spp. are increasing, and subsequently, allergies to Aspergillus species other than fumigatus are also on the rise. Commercial diagnostic tools are still limited to Aspergillus fumigatus. Hence, there is a need for improved tests. We decided to investigate the correlation between serological sensitization to A. fumigatus and other Aspergillus species. Methods: Hundred and seven patients with positive skin prick tests to A. fumigatus were included in this study. Immunoglobulin E (IgE) concentrations against A. fumigatus, A. terreus, A. niger, A. flavus, and A. versicolor were measured from specimens by fluorescent enzyme-linked immunoassays. Results: Patients showed considerably higher IgE concentrations against A. fumigatus (6.00 +/- 15.05 kUA/L) than A. versicolor (0.30 +/- 1.01 kUA/L), A. niger (0.62 +/- 1.59 kUA/L), A. terreus (0.45 +/- 1.12 kUA/L), or A. flavus (0.41 +/- 0.97 kUA/L). Regression analysis yielded weak positive correlations for all Aspergillus spp., but low r(2) values and heteroscedastic distribution indicate an overall poor fit of the calculated models. Conclusion: Serological sensitization against A. fumigatus does not correlate with sensitization against other Aspergillus spp. To detect sensitization against these, other diagnostic tools like a skin prick test solution of different Aspergillus spp. are needed.