Component-resolved diagnostics can be useful for identifying hazelnut allergy in Japanese children

Cor a 9 and Cor a 14 are effective markers for predicting hazelnut allergy. However, there have been no reports on the component-resolved diagnostics (CRD) of hazelnut allergy using an oral food challenge (OFC) for diagnosis in Asia. We hypothesized that CRD would improve the accuracy of diagnosing hazelnut allergies in Japanese children.

We recruited 91 subjects (median age: 7.3 years) who were sensitized to hazelnuts and had performed a hazelnut OFC at the National Hospital Organization Sagamihara National Hospital between 2006 and 2017. All subjects were classified as allergic or asymptomatic to 3 g of hazelnuts. The sIgE levels (hazelnut/Cor a 1/Cor a 8/Cor a 9/Cor a 14/alder pollen) were measured using ImmunoCAP. We aimed to determine the predictive factors of hazelnut allergy.

Nine subjects (10%) were allergic to ≤3 g of hazelnuts. Levels of sIgE for Cor a 9 in hazelnut-allergic subjects were significantly higher than those in asymptomatic subjects (4.47 vs. 0.76 kU_A/L, p = 0.039). Levels of sIgE to alder pollen and Cor a 1 in hazelnut-allergic subjects were significantly lower than those in asymptomatic subjects (<0.10 vs 13.0 kU_A/L, p = 0.004; <0.10 vs 5.03 kU_A/L, p = 0.025). The area under the receiver operating characteristics curve for hazelnut/alder/Cor a 1/Cor a 9 was 0.55/0.78/0.72/0.71, respectively, with p = 0.651/0.006/0.029/0.040, respectively.

The findings of a high sIgE level for Cor a 9 and a low sIgE level for Cor a 1 can improve the diagnostic accuracy to better identify Japanese children sensitized to hazelnuts.