Evaluation of specific IgE to the recombinant group 2 mite allergens Lep d2 and Tyr p 2 in the pharmacia CAP system

Background: Several recombinant allergens have been shown to be potentially useful for diagnosis of IgE-mediated allergy, but only a few recombinant a llergens are at present commercially available in serological assays for de tection of specific IgE. The aim of this study was to evaluate the IgE bind ing to the recombinant major dust mite allergens rLep d 2 and rTyr p 2 and compare it with the IgE binding to the commercial mite extracts Lepidoglyph us destructor and Tyrophagus putrescentiae in the Pharmacia PAST CAP System . Methods: The recombinant allergens rLep d 2 and rTyr p 2 were immobilised on ImmunoCAPs, and sera from 461 Swedish farmers who are frequently expose d to mites were analysed for specific IgE antibodies. Immunoblotting was pe rformed to evaluate discrepancies between the results obtained with the rec ombinant and the commercial CAP assays, Results: The IgE values of each rec ombinant assay significantly correlated with the IgE values of the correspo nding commercial CAP assay. The sensitivity of the rLep d 2 assay was 73.3% and that of the rTyr p 2 assay, 60.5% of that provided by the commercial L . destructor and T. putrescentiae assays. Two subjects out of 416, who test ed negative in the commercial L, destructor assay, were positive to rLep d 2, The corresponding figures for rTyr p 2 and the T. putrescentiae extract were 5/418. The possibility that these subjects were sensitised to L. destr uctor and T. putrescentiae could not be excluded. Conclusion: The data sugg est that it may be possible to use rLep d 2 and rTyr p 2 on ImmunoCAPs to d etect and quantify IgE antibodies to these, the major allergens of L. destr uctor and T: putrescentiae. It appears likely that the addition of just a f ew more recombinant L. destructor and T. putrescentiae allergens in the CAP assay will be sufficient for in vitro diagnosis of IgE mediated allergy to L. destructor and T. putrescentiae.