Cor a 14 Specific Ig E Best Distinguishes Between Hazelnut Allergic and Tolerant Patients

Rationale: Several hazelnut (HZNT) allergens have been identified to date including Cor a8 (LTP), Cor a9 (11S globulin) and Cor a14 (2S albumin). The aim of the study was to determine the importance of these allergens in component resolved diagnosis in HZNT allergic patients.

Methods: Forty-four children suspected to have fruit, nut and/or legume allergy were selected. Patients were classified as allergic if they had presented at least 2 reactions unequivocally related to HZNT ingestion in the last 2 years. Patients were defined as tolerant if they consumed HZNT on a regular basis. Clinical questionnaire, skin prick test (SPT), serum total and specific IgE and MIA-ISAC IgE (Thermo Fisher Scientific, Uppsala, Sweden) were performed.

Results: Sixteen patients (11 males) were defined as allergic and 28 (15 males) tolerant. HZNT-SPT wheal size (mm) (median 7.75;IQR:4-12 vs.2.5;  IQR:0-9.5,p=0.000) and HZNT-sIgE (kU/L) (median 14.45;IQR:1.98-370 vs. 0.82;IQR:0.02-14.3,p=0.000) were significantly greater in allergic than in tolerant children. Both positive Cor a9-sIgE and Cor a14-sIgE were significantly more frequent in allergic patients (75.00% vs. 14.28%,p=0.000 and 75.00% vs. 10.71%,p=0.000, respectively). Cor a9-sIgE values were significantly higher in allergic children whether by means of ImmunoCAP (median 4.38 kU/L; IQR:0.26-16 vs. 0.02 kU/L; IQR:0-0,21, p=0.000) or MIA-ISAC (median 0.14 ISU;IQR:0-2.2 vs. 0 ISU;IQR:0-0, p=0.000), as were Cor a14-sIgE values (median 4.97 kU/L;IQR:0.39-20.4 vs. 0.02 kU/L;IQR:0.01-0.09,p=0.000). This was not found for Cor a8. ROC curves were constructed for the three allergens showing Cor a14 the best diagnostic performance (AUC:0.925,95%CI:0.847-1,p=0.000).

Conclusions: Cor a14 is the best discriminating allergen in the diagnosis of HZNT allergic patients.