Lymphocyte stimulation test for diagnosing hen’s egg yolk–induced enterocolitis syndrome

BACKGROUND: There is currently little research into factors predicting the results of an initial diagnostic oral food challenge (OFC) test for food protein–induced enterocolitis syndrome (FPIES). OBJECTIVE: The present study aimed to identify predictors of the diagnosis of hen’s egg yolk-induced FPIES (HEY-FPIES). METHODS: The present monocentric study was performed at Tokyo Metropolitan Children’s Medical Center and included patients who underwent hen’s egg yolk OFC (HEY-OFC) between March 2018 and March 2023 to assess for HEY-FPIES. The baseline characteristics of the groups and HEY-OFC positivity or negativity were then compared. Univariate analysis was conducted by using the Mann-Whitney U test or Fisher exact test. Receiver operator characteristic analysis was used to create probability curves. RESULTS: In total, 35 patients were analyzed; of these, 17 were HEY-OFC–positive. No significant difference was observed between the HEY-OFC–positive and HEY-OFC–negative groups in terms of background factors except for the HEY-LST value, which was significantly higher in the HEY-LST group (P = .027). Receiver operator characteristic analysis demonstrated that the area under the curve for HEY-OFC positivity using the HEY-LST value was 0.719 (95% CI = 0.541-0.897). The statistically optimal cutoff value for the HEY-LST was 610%, which had a clinical sensitivity and specificity of 64.7% and 83.3%, respectively. CONCLUSIONS: The present study demonstrated that the HEY-LST may be a useful predictor of the result of an initial OFC for HEY-FPIES.