781:
Can urinary tetranor-PGDM, a metabolite from prostaglandin D2, be used as a reliable marker for evaluating the effectiveness of oral immunotherapies for children with food allergies?
Monday, March 5, 2018
South Hall A2 (Convention Center)
Shinichiro Inagaki, MD, PhD, Masami Narita, MD, PhD, Tatsuro Nakamura, DVM PhD, Takahisa Murata, DVM, PhD., Yukihiro Ohya, MD PhD
RATIONALE: Tetranor-PGDM is a metabolite of prostaglandin D2 that is secreted by mast cells. Previously, we reported that the concentration of urinary tetranor-PGDM at 4hours after the start of an oral food challenge (OFC) was associated with the severity grade of the immediate allergic reaction. The aim of this study was to verify the usefulness of urinary tetranor-PGDM as a predictor of the effectiveness of oral immunotherapies (OIT).

METHODS: Urine samples from 17 children undergoing OIT were collected at three points: 4hours after food intake at home for OIT, before OFC (baseline), and 4hours after OFC. All the patients continued to consume low doses of foods for more than 6months and did not experience any allergic reaction on the day of urine collection.

RESULTS: The results of OFC were negative for 8 patients and positive for 9 patients (ages 2-13). The ratios of the cumulative dose of food used for the OFC/daily intake dose of the food for OIT at home were similar between OFC-positive patients and OFC-negative patients, (28.4 and 22.5, respectively; P > 0.05). The mean difference in the tetranor-PGDM concentration between 4hours after food intake at home and the baseline concentration in OFC-positive patients was significantly higher than that in OFC-negative patients (0.95 vs. 0.16 ng/mg CRE, P < 0.05).

CONCLUSIONS: The urinary tetranor-PGDM concentration at 4hours after food intake at home in patients receiving OIT can be used to predict the results of OIT as verified using OFC by detecting the subclinical activation states of mast cells during OIT.