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Biochemical and immunological analysis of mould skin prick test solution: current status of standardization
Author(s) -
Kespohl S.,
Maryska S.,
Zahradnik E.,
Sander I.,
Brüning T.,
RaulfHeimsoth M.
Publication year - 2013
Publication title -
clinical and experimental allergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.462
H-Index - 154
eISSN - 1365-2222
pISSN - 0954-7894
DOI - 10.1111/cea.12186
Subject(s) - immunoglobulin e , aspergillus fumigatus , antigen , aspergillus versicolor , alternaria alternata , immunology , sensitization , population , allergen , biology , aspergillus , microbiology and biotechnology , allergy , medicine , antibody , horticulture , environmental health
Summary Background Sensitization prevalence to moulds reached from less than 10% in the general population to more than 25% in atopic and/or asthmatic subjects. To diagnose I g E ‐mediated mould sensitization, skin prick test ( SPT ) and specific I g E ( sIgE ) measurement are recommended. However, concordance of SPT and sIgE results is often less than 50% and standardization of the extracts is required to achieve reliable test results. Objective The aim of our study was to analyse mould SPT solutions ( SPT s) with respect to quantity and quality of protein, antigen and human I g E ‐binding content as a prerequisite for further in vivo studies. Methods Commercial SPT s of A lternaria alternata, A spergillus fumigatus, C ladosporium herbarum and P enicillium chrysogenum from six manufacturers as well as two in‐house extracts from A spergillus versicolor were investigated. Protein‐, antigen‐ and I g E ‐binding contents were quantified by B radford assay, sandwich ELISA and I g E ‐ I mmuno CAP ‐inhibition tests. Protein composition and I g E and I g G binding were analysed by SDS ‐ PAGE and immunoblotting, respectively. Results Median protein concentrations were similar in all mould SPT extracts (90–110 μg/mL). In contrast, antigen contents and I g E ‐binding capacity showed a high variability with median antigen values from 4 to 118 μg/mL and I g E inhibition results between 30 to 95%. Whereas almost all SPT s of A. alternata and A. versicolor showed complete sIgE inhibition with mean values > 80%, only three extracts for A. fumi gatus, two extracts for C. herbarum and none of the tested extracts for P. chrysogenum exceeded 50% sIgE reduction. Quantitative amounts of protein, antigenic and I g E ‐binding structures were not comparable with the quality of the corresponding protein or immunoblot pattern, with the exception of A. alternata SPT s. Conclusions and Clinical Relevance Commercially available mould SPT extracts showed high variability raising the question of comparability and reliability of SPT results. Possible consequences for diagnostic test outcome will be investigated in the next step.