Gly m 5/Gly m 8 fusion component for diagnosing soybean allergy
Monday, March 5, 2018
South Hall A2 (Convention Center)
Nobuyuki Maruyama, PhD, Sakura Sato, MD, Cerrone Cabanos, PhD, Akira Tanaka, Komei Ito, MD PhD, Motohiro Ebisawa, MD PhD FAAAAI
RATIONALE: Soybean is a major food allergen in children. Component-resolved diagnostics (CRD) has improved the accuracy of diagnosing immunoglobulin E (IgE)-mediated food allergies. We aimed to develop a novel component for the diagnosis of soybean allergy using recombinant technology.

METHODS: Pediatric patients with suspected soybean allergy (n = 91) were enrolled, and symptomatic (n = 40) and asymptomatic (n = 51) cases were divided through oral food challenge (OFC) testing. Specific IgE (sIgE) antibodies to each recombinant allergen component were analyzed by enzyme-linked immunosorbent assay, and the diagnostic performances of the components were assessed by area under the receiver operating characteristic (ROC) curves (AUC).

RESULTS: Among the components listed in WHO/IUIS Allergen Nomenclature Subcommittee, Gly m 8 (2S albumin) showed the highest AUC (0.706). A combination of Gly m 8 and α' subunit of Gly m 5 (vicilin), improved the diagnostic performance of the single components. Moreover, the N-terminal extension region of α' subunit of Gly m 5, which has low cross-reactivity among the vicilins, showed higher diagnostic performance (AUC 0.695) than the full-length α' subunit of Gly m 5 (AUC 0.613). Based on these findings, we developed a fusion protein of Gly m 8 plus the extension region of α' subunit of Gly m 5; this fusion protein was very efficient for diagnosing soybean allergy (AUC 0.801).

CONCLUSIONS: sIgE antibody levels to the fusion protein of allergen components had a higher accuracy for diagnosing soybean allergy than any single allergen component.