[Utility of the allerport® HRT in the diagnosis of hen's egg allergy: a pediatric multicenter challenge study].

Purpose This study aimed to evaluate the utility of the Allerport® HRT in the diagnosis of hen's egg allergy. Method We enrolled 51 subjects who underwent the Allerport® HRT before an oral food challenge (OFC) consisting of heated egg. Blood samples were collected within three months prior to OFC to measure histamine release (HR) and specific IgE antibody titers. We examined whether the Allerport® HRT was useful as a means of diagnosing hen's egg allergy and predicting severity of induced symptoms. Of 51 subjects, three whose OFC results were not valid**1** and 13 who were classified as "low responders" to the Allerport® HRT (%HR due to anti-IgE below 20%) were excluded. Of the remaining 35 subjects (average age: 4 years), 23 showed positive reactions to the OFC. Quantities of histamine released in spontaneous HR and egg white (EW)- and ovomucoid (OVM)-induced HR were significantly higher in patients with positive reactions. In our receiver operating characteristic analysis, the area under the curve for %HR against 6 ng/ml of EW was 0.9601 and that against 3 ng/ml of OVM was 0.9022. The cutoff value was 15.0% for EW and 3.7% for OVM. The sensitivity was 95.7% for EW and 91.3% for OVM, and the specificity was 83.3% for EW and 58.3% for OVM. %HR correlated well with the severity of induced symptoms in the OFC. Conclusion Allerport® HRT is useful for the diagnosis of hen's egg allergy, and may also aid in predicting the severity of induced symptoms.