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

Abstract

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