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Higher immunoglobulin E antibody levels to recombinant Fel d 1 in cat‐allergic children with asthma compared with rhinoconjunctivitis
Author(s) -
Grönlund H.,
Adédoyin J.,
Reininger R.,
Varga E.M.,
Zach M.,
Fredriksson M.,
Kronqvist M.,
Szepfalusi Z.,
Spitzauer S.,
Grönneberg R.,
Valenta R.,
Hedlin G.,
Van Hage M.
Publication year - 2008
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/j.1365-2222.2008.03003.x
Subject(s) - immunoglobulin e , medicine , asthma , immunology , allergy , odds ratio , antibody
Summary Background Current diagnosis of allergy and asthma to cat is confirmed using cat dander extract (CDE). We have previously engineered a recombinant major cat allergen, rFel d 1, with properties identical to the natural molecule. Objective The aim of the study was to evaluate IgE and IgG4 antibodies to rFel d 1 among sera from cat‐allergic children and adults suffering from asthma and/or rhinoconjunctivitis (RC) in populations from Sweden and Austria. Methods Cat‐allergic children and adults from Sweden ( n =27 and 31, respectively) and Austria ( n =41 and 41) with RC and/or asthma were selected. Sera were tested for IgE and IgG4 antibodies to CDE and rFel d 1 by CAP, and IgE to rFel d 1 by ELISA. Healthy subjects and non‐cat‐allergic patients ( n =75) were included as controls. Results There was a high correlation between IgE responses to rFel d 1 and CDE among the 140 patients ( r s =0.85, P <0.001); however, measured levels to rFel d 1 were on average 30% higher ( P <0.0001). Ninety‐eight percent of patients and none of the controls showed IgE to rFel d 1 and there was a threefold increased risk of asthma for half of the children with the highest IgE levels [odds ratio 3.23; 95% confidence interval (CI), 1.19–8.79] by ELISA. IgE responses to rFel d 1 among children with asthma were higher (median 19.4 kU/L) compared with children with RC (median 6.6 kU/L, P <0.05) and adults with asthma (median 3.0 kU/L, P <0.01). Furthermore, children with asthma displayed higher IgG4 levels than the asthmatic adults. Conclusion A single recombinant molecule, rFel d 1, is at least as sensitive for in vitro diagnostics of cat allergy as the current extract‐based test. Elevated IgE antibody levels to Fel d 1 are suggested to be a risk factor for asthma in cat‐allergic children.