Clinical utility of Jug r 1-specific IgE in diagnosis of walnut allergy

Abstract

 Objective : We investigated the clinical utility of analyzing Jug r 1-specific IgE antibodies in diagnosis of walnut allergy.

 Methods : Participants with suspected walnut allergy based on a positive walnut extract-specific IgE test were enrolled from 8 facilities. Specific IgE to walnut extract, Jug r 1 and Jug r 3 were tested using ImmunoCAP. We analyzed diagnostic value of these tests using Receiver operating characteristic (ROC) analysis.

 Results : Of 144 patients (median age 6 years) 98 were regarded as walnut allergy and 46 were regarded as non-walnut allergy. The specific IgE levels to walnut extract and Jug r 1 showed significantly higher in allergic group than tolerant group. ROC analysis showed area under the curve values for specific IgE to Jug r 1, walnut extract and Jug r 3 of 0.858, 0.787 and 0.284, respectively. A positive predictive value of 95% for Jug r 1-specific IgE was obtained at 0.98 U_A/mL. The corresponding sensitivity was 78.6% and the specificity was 91.3%.

 Conclusion : Jug r 1-specific IgE testing is a valuable marker for diagnosis of walnut allergy in patients suspected walnut allergy.