Component-resolved IgE profiles in Austrian patients with a convincing history of peanut allergy

Peanut allergy develops after primary sensitization to peanut allergens and/or IgE cross-sensitization with homologous allergens from various plants. Therefore, heterogeneous patterns of sensitization to individual peanut allergens are observed in different countries. The aim of this study was to examine the IgE sensitization patterns of Austrian peanut-allergic patients.

Sera from 65 peanut-allergic patients and 20 peanut-tolerant atopics were obtained in four Austrian allergy clinics. Sensitization patterns against peanut allergens Ara h 1-3, 6, 8 and 9 were identified by ImmunoCAP and ImmunoCAP ISAC.

Austrian peanut-allergic patients were sensitized to Ara h 2 and 6 (71%), followed by Ara h 1 (62%), Ara h 8 (45%), Ara h 3 (35%) and Ara h 9 (11%). All sera containing Ara h 2-specific IgE were also positive for Ara h 6, with Ara h 6-specific IgE levels significantly (p < 0.05) higher compared with Ara h 2. Twelve percent displayed IgE reactivity exclusively to Ara h 8. Peanut extract and Ara h 8 showed low diagnostic specificities of 25 and 10%, respectively. The other peanut allergens showed 100% specificity. Diagnostic sensitivities determined by ImmunoCAP ISAC and ImmunoCAP were highly similar for Ara h 2, 3 and 8.

The majority of symptomatic peanut-allergic patients are sensitized to Ara h 2 and Ara h 6. In peanut-symptomatic patients with additional birch pollen allergy, other peanut allergens, especially Ara h 8, should be tested when IgE reactivity to Ara h 2 is absent.