RESUMEN
Apple allergy is common in patients allergic to birch pollen, and this is defined as 'birch-apple syndrome'. Allergens responsible for cross-reactivity belong to the pathogenesis-related-10 family, and high homology in the amino acid sequences of the major allergens Bet v 1 from birch and Mal d 1 from apple has been demonstrated. Here we review the literature on the treatment of birch-apple syndrome by allergen immunotherapy. The only allergen immunotherapy method available thus far is based on the administration of birch-pollen extracts, through the subcutaneous or sublingual route, to induce tolerance to Bet v1 and to the homologous allergen Mal d 1. However, the studies performed thus far show modest efficacy, and thus other methods of immunotherapy should be investigated.
Asunto(s)
Antígenos de Plantas/inmunología , Antígenos de Plantas/uso terapéutico , Desensibilización Inmunológica/métodos , Hipersensibilidad a los Alimentos/terapia , Proteínas de Plantas/uso terapéutico , Rinitis Alérgica Estacional/terapia , Betula/inmunología , Reacciones Cruzadas , Hipersensibilidad a los Alimentos/inmunología , Humanos , Tolerancia Inmunológica , Malus/inmunología , Proteínas de Plantas/inmunología , Polen/inmunología , Síndrome , Resultado del TratamientoRESUMEN
BACKGROUND: The most common pollen-fruit cross-reaction is the birch-apple syndrome. Allergen immunotherapy (IT) is clearly effective for birch allergy, but its efficacy on apple allergy is controversial. We performed a randomized study on patients with birch-apple syndrome to evaluate the outcome of subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT). METHODS: Forty patients underwent IT with a birch extract (Staloral; Stallergenes, Antony, France), 20 by SCIT and 20 by SLIT. After 1 year of treatment, 15 patients (8 for SCIT and 7 for SLIT) accepted to undergo an oral apple challenge. Measurements of specific IgE to Bet v 1 and Mal d 1 and related allergens Api g 1 and Dau c 1 were obtained in 10 patients, at baseline and after IT. RESULTS: Two of 8 SCIT-treated patients (25%) and 1 of 7 SLIT-treated patients (14.2%) developed complete tolerance to apple. In the remaining patients, an increase in the provocative dose was found in 3 of the SCIT-treated (37.5%) and 2 of the SLIT-treated patients (28.6%). Changes in the levels of specific IgE to Mal d 1 were unrelated to clinical results. CONCLUSIONS: These findings suggest that different doses of birch extract may be needed in different patients to improve the associated apple allergy and that a finer diagnostic work-up in selecting patients with birch-apple syndrome who are candidates to respond to birch pollen IT also concerning apple allergy is required.