778:
Clinical utility of basophil activation test in diagnosis of fish allergy
Monday, March 5, 2018
South Hall A2 (Convention Center)
Ryo Imakiire, MD, Tomoki Hattori, MD, Keigo Kainuma, MD, Reiko Tokuda, MD, Keiko Kameda, MD, Naofumi Suzuki, MD, Yu Kuwabara, MD, Taiga Kobori, MD, Mizuho Nagao, MD, PhD, Takao Fujisawa, MD FAAAAI
RATIONALE: The rising consumption of fish, due to its nutritional value, has led to an increase in fish allergy. There is, however, no reliable predictive marker for diagnosis of fish allergy except for time-consuming oral food challenge (OFC). It has been reported that results of specific IgE (sIgE) and skin prick test do not correlate well with a clinically significant allergy. Diagnostic value of basophil activation test (BAT) has been reported in various food allergy, but not in fish allergy.

METHODS: We performed retrospective analysis of 55 patients who were suspected of fish allergy. Diagnosis of allergy to each kind of fish was made by positive OFC or immediate induced symptoms after eating a specific fish. Negative fish allergy was based on negative OFC or regular eating of a specific fish. Whole blood was incubated with various kinds of fish extracts and induced expression CD203c on basophils was analyzed by a flow cytometry. ImmunoCAP sIgE to each kind of fish was also measured. Predictive performance of the two tests for fish allergy was evaluated using receiver-operating characteristic (ROC) analysis.

RESULTS: Area under the curve (AUC) for BAT was higher than sIgE; tuna: 0.94 vs. 0.62, salmon: 0.90 vs. 0.74, mackerel: 0.90 vs. 0.69, respectively. AUC for BAT in diagnosis of flounder, red snapper, yellowtail and bonito allergies, for which sIgE test was not available, was also high at 0.91, 0.87, 0.81 and 0.80, respectively.

CONCLUSIONS: BAT using CD203c expression may a reliable method to predict fish allergy.