445:
Modulation of IgE and IgG4 with Dietary Treatment of Eosinophilic Esophagitis and Peanut Allergy
Sunday, March 4, 2018
South Hall A2 (Convention Center)
Elizabeth Erwin, MD, Alexander J Schuyler, B.S., Julia A. Cronin, MD, Patrice G Kruszewski, Lisa J. Workman, BA, Scott P. Commins, MD PhD, Thomas A.E. Platts-Mills, MD PhD FAAAAI
RATIONALE: Peanut allergy is thought to have a distinct immune response from eosinophilic esophagitis (EoE). We compared changes in IgE and IgG4 antibodies during cow’s milk elimination (CME) in EoE and in peanut allergy (PA) during peanut oral immunotherapy (OIT).

METHODS: At baseline and after treatment, we measured total IgE and IgG4 as well as specific IgE to milk, peanut, egg, wheat, and soy and IgG4 to peanut extract and milk and peanut components in 13 EoE patients on CME and 19 children receiving peanut OIT. We also measured specific IgG4 to egg components in EoE.

RESULTS: At baseline 54% of EoE patients and 89% with PA had specific IgE to >1 food (p=0.06). In PA compared to EoE, geometric mean titers (GMT) of specific IgE were higher to peanut (p<0.001) and soy (p=0.001) but similar to other foods. In PA with peanut avoidance, total IgG4 was similar to EoE patients consuming milk (p=0.53) with higher specific IgG4 to peanut (p=0.029) and lower specific IgG4 to milk (p=0.007). After 6-8 weeks of CME, GMT of IgG4 to milk (p<0.001) and egg (p=0.003) decreased in EoE. After OIT, GMT of IgG4 to peanut increased (p<0.001), and milk specific IgG4 also increased (p=0.016). Overall, total IgG4 decreased in EoE with CME (p=0.033) but increased in some PA patients during OIT.

CONCLUSIONS: In both conditions, IgE and IgG4 to multiple foods were detected. With food introduction, IgG4 increased and with food removal IgG4 decreased; however modulation of antibody levels with diet changes did not seem food specific.