Presentation: Comparison of Cut-Off Values and Probability Curves for Egg Specific IgE in Diagnosis of Egg Allergy in Young Children ( World Allergy Congress)

Thursday, 15 October 2015

Hall D1 Foyer (Floor 3) (Coex Convention Center)

Kanae Furuya, RD , Allergy Center and Department of Clinical Research, Mie National Hospital, Tsu, Japan

Takahiro Ito, MD , Allergy Center and Department of Clinical Research, Mie National Hospital, Tsu, Japan

Yu Kuwahara, MD , Allergy Center and Department of Clinical Research, Mie National Hospital, Tsu, Japan

Junya Hirayama, MD , Allergy Center and Department of Clinical Research, Mie National Hospital, Tsu, Japan

Keigo Kainuma, MD , Allergy Center and Department of Clinical Research, Mie National Hospital, Tsu, Japan

Mizuho Nagao, MD, PhD , Allergy Center and Department of Clinical Research, Mie National Hospital, Tsu, Japan

Takao Fujisawa, MD, PhD , Allergy Center and Department of Clinical Research, Mie National Hospital, Tsu, Japan

Background: Numerous food specific IgE (sIgE) cut-off values and probability curves for OFC outcomes have been reported using the ImmunoCAP (CAP) assay, whereas, limited studies are available using the IMMULITE^® 2000 3gAllergy™ (3g), a sIgE assay with an extended measurement range. In order to establish interpretation criteria for 3g, we prospectively analyzed the relationships between egg OFC outcomes and sIgE values using 3g and CAP for two specific needs: 1) diagnosis of egg allergy in infants who had never eaten eggs because of documented egg sensitization (group A), and 2) diagnosis of tolerance to egg in preschool children who had eliminated eggs due to confirmed egg allergy (group B).

Methods: A multicenter prospective observation study was performed and 433 children were enrolled, comprising of groups A (n = 220; 1 year old) and B (n = 213; 2-6 years old). OFC was performed with cooked egg powder for all the participants and with raw egg powder for patients who passed the initial cooked egg challenge. sIgE values to egg white (EW) and ovomucoid (OM) were measured by 3g and CAP. The relationship between the sIgE and OFC outcomes was analyzed using ROC and logistic regression analyses. Fitted predicted probability curves (PCs) were plotted using logistic regression.

Results: Out of 433 children, 243 (56%) passed cooked egg challenge. From the subset of 243 who passed the challenge, 113 children were given the raw egg challenge. Out of these 113 children, 55 (49%) passed the challenge. The two sIgE tests in the cooked egg challenge group showed similar performance, with area under the curve (AUC) of 0.791 and 0.778 in group A, 0.848 and 0.828 in group B, for OM sIgE with 3g and CAP, respectively. However, 3g showed higher cut-off values than CAP, at 21.5 IU_A/L and 3.1 U_A/L in group A and 45.4 IU_A/L and 9.0 U_A/L in group B, respectively. The PCs of EW and OM sIgE by 3g showed a wider distribution of data across the x-axis (sIgE values) and y-axis (probability) in comparison to CAP. In the raw egg challenge group, EW sIgE tests showed similar performance with AUCs at 0.678 and 0.671 in group A and 0.771 and 0.751 in group B with 3g and CAP, respectively. However, PCs for raw egg challenge showed significantly larger 95% confident intervals than those for cooked egg challenge.

Conclusion: Overall results from 3g demonstrated similar but slightly better performance than CAP in predicting the OFC outcomes.

2077 Comparison of Cut-Off Values and Probability Curves for Egg Specific IgE in Diagnosis of Egg Allergy in Young Children