The Clinical Utility of Recombinant Component Testing for Nut Allergy in Doha, Qatar

Component resolved diagnosis is a useful adjunct to allergen-specific IgE testing in diagnosis of food allergy. Here we report the results of the first year of component testing for hazelnut and peanut allergy in Qatar. The Laboratory Information System was interrogated to identify all Allergy clinic patients tested for the hazelnut recombinant panel (cora1, cora8, cora9, cora14) and/or peanut recombinant panel (arah1, arah2, arah3, arah8, arah9) since September 2018. Samples were tested using the ImmunoCap assay on the Phadia 250 analyser (Phadia AB, Uppsala, Sweden). The most common individual hazelnut components were cora9 (93.1%) and cora14 (54.8%). The most common pattern was for presence of antibodies to both cora9 and cora14, present in 63/173 (36.4%). Only 11/177 patients were cora1 positive (6.2%), all of whom also had positive results for at least one of cora8,9,14. The most common peanut components were arah1 (58.2%), arah2 (57.2%), and arah3 (46.1%). While 14/244 patients were arah8 positive (5.7%), all these patients also had positive results for at least one of arah1-3. With respect to arah9, 75/245 were positive (30.6%), with 16/75 positive for arah9 alone (21.3%). The most common hazelnut components were cora9 and cora14, hazelnut storage proteins, and the most frequent peanut components were arah1-3, indicating primary sensitization. Despite a mixed population including native Qatari’s and ex-patriates, no patients with isolated cora1 or arah8 (PR-10) antibodies were found, suggesting cross-reactive hazelnut or peanut allergy were extremely rare in our clinic.