Oral birch pollen immunotherapy with apples: Results of a phase II clinical pilot study

Abstract

BackgroundSeventy percent of patients suffering from birch pollen allergy (BPA) develop a pollen‐related food allergy (prFA), especially to apples, due to a clinically relevant cross‐reactivity between the major allergen in birch Bet v 1 and Mal d 1 in apples. Therefore allergen‐specific immunotherapy with fresh apples (AITA) could be a promising natural treatment of both BPA and prFA.ObjectiveTo assess the clinical efficacy of immunotherapy by daily apple consumption for patients with BPA and prFA.MethodsA daily defined increasing amount of selected cultivars (Red Moon®, Pink Lady®, Topaz, Golden Delicious) was continuously consumed by 16 patients (12 female; median age; 50; range, 23–68 years), leading to increased intake of allergen over a period of at least 8 months. Specific IgE and IgG4 to Bet v 1 and Mal d 1, conjunctival and oral provocation tests, skin reactivity, and the average daily rhinoconjunctivitis combined symptom and medication score (CSMS) were measured during the peak birch pollen season.ResultsAfter 8 months of therapy, patients showed increased tolerance to apples (p < .001) and a decreased skin reactivity to apples. Oral allergy syndrome to other birch prFA than apple also decreased (p < .05). Moreover, daily rhinoconjunctivitis CSMS declined by 34% (p < .001), as did conjunctival reactivity to birch pollen extract by 27% (p < .01), while specific IgG4 to Mal d 1 and Bet v 1 increased (p < .01).