Lipid transfer protein syndrome due to wild grape juice and various vegetables: A life-threatening food allergen

We report a 16-year-old Japanese male with mugwort pollinosis in whom ingestion of wild grape juice and various vegetables caused recurrent general urticaria, abdominal pain, dyspnea, and loss of consciousness. A skin prick test demonstrated positive reactions to a wide variety of both non-heated and heated vegetables and fruits such as wild grape, bell pepper, onion, Chinese cabbage, tomato, eggplant, and broccoli. The serum immunoglobulin E levels (ImmunoCAP ISAC^®) for Art v 3, Pla a 3, Pru p 3, and Jug r 3, which are lipid transfer protein (LTP) homologs, were positive but those for Bet v 1 and Bet v 2 were negative. We diagnosed the patient as having LTP syndrome, a condition in which additional factors such as exercise, non-steroidal anti-inflammatory drugs, or alcohol may trigger an allergic reaction. Wild grapes contain a large amount of salicylic acid, and in our patient ingestion of wild grape juice led to immediate loss of consciousness in the absence of exercise. This suggests that salicylic acid contained in fruits and vegetables may act as an important cofactor in LTP syndrome. Although sensitization to LTP is rarely reported in Asia, LTP are considered to be potentially life-threatening food allergens, and therefore warrant attention.