Blood sample collection
Blood samples from FPIES patients were collected at symptomatic and asymptomatic stages. Samples were collected when the four patients not undergoing the OFC test presented to the hospital due to vomiting within 3 hours after onset or vomited after the intake of causative foods during hospitalization. For the three patients undergoing OFC, samples were collected just after vomiting during the test. The asymptotic samples were collected from patients without any symptoms such as vomiting or bloody stool. For the evaluation of the cytokine profile, samples were collected at several time points (Patient No. 6: before OFC and 3, 6, and 24 hours after the beginning of OFC; Patient No. 7: before OFC and 0.5, 1, 1.5, 2, and 48 hours after the beginning of OFC; FPIES-resolved control: before OFC and 3, 6, and 24 hours after the beginning of OFC). In the OFC of Patient No. 3, samples were collected only immediately after vomiting. The FPIES-resolved control is an 11-month-old boy whose symptoms were induced by egg yolk.
The blood samples of patients with infectious enterocolitis and anaphylaxis were collected at the time of presentation to the emergency department of the hospital. Samples were centrifuged at 1,400 × gfor 5 min, and serum was collected and stored at -25 °C.