Non–IgE-Mediated Gastrointestinal Food Allergies: Distinct Differences in Clinical Phenotype Between Western Countries and Japan

Non-IgE-mediated gastrointestinal food allergies, including food-protein-induced enterocolitis, enteropathy, proctocolitis and allergic eosinophilic gastroenteritis, seem to be increasing in several regions in the world. However, unlike the case of IgE-mediated food allergy, development of diagnostic laboratory tests and our understanding of the immunological mechanisms involved in non-IgE-mediated gastrointestinal food allergies lag. Although the clinical entities in Western countries have been well established, the clinical phenotypes might differ somewhat among the human races and geographical regions. In Japan, non-IgE-mediated gastrointestinal food allergies have increased sharply since the late 1990s, and clinicians have sometimes experienced confusion because of differences in the clinical phenotypes from those seen in Western countries. Aiming to solve this problem, we performed clinical research and determined a useful method for dividing patients into four clusters with distinctive clinical symptoms. We are confident this method will help in diagnosing and treating these patients. We also tried to clarify the differences between these patients in Japan and Western countries.