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Medline ® Abstract for Reference 76

of 'Clinical manifestations and diagnosis of oral allergy syndrome (pollen-food allergy syndrome)'

Efficacy of birch-pollen immunotherapy on cross-reactive food allergy confirmed by skin tests and double-blind food challenges.
Bolhaar ST, Tiemessen MM, Zuidmeer L, van Leeuwen A, Hoffmann-Sommergruber K, Bruijnzeel-Koomen CA, Taams LS, Knol EF, van Hoffen E, van Ree R, Knulst AC
Clin Exp Allergy. 2004;34(5):761.
BACKGROUND: The effect of birch-pollen immunotherapy (IT) on cross-reactive food allergies is controversial.
OBJECTIVE: The aim of this study was to investigate the effect of birch-pollen IT on apple allergy and to evaluate recombinant allergens and double-blind placebo-controlled food challenges (DBPCFCs) as monitoring tools.
METHODS: Twenty-five adult birch-pollen- and apple-allergic patients were randomly divided into two groups, either receiving birch-pollen IT or symptomatic drugs only. IgE and IgG4 antibodies against birch pollen, apple, natural Bet v 1 and Mal d 1 were measured. In addition, skin prick tests (SPT) were performed using recombinant Bet v 1 (rBet v 1) and Mal d 1 (rMal d 1). Clinical outcome was evaluated by DBPCFC. CD4(+)CD25(+) regulatory T cells (Tregs) were isolated from peripheral blood and tested in functional assays.
RESULTS: Birch-pollen IT resulted in a significant decrease of SPT reactivity for rBet v 1 (30-fold) and rMal d 1 (10-fold) already after 3 months. IgG4 antibodies were potently induced against Bet v 1, displaying cross-reactivity to Mal d 1. Visual analogue scale scores decreased>10-fold in 9/13 patients of the IT group, with three patients converting to negative. In the control group, no decrease was observed. Birch-pollen IT did not lead to detectable changes in the number or function of the CD4(+)CD25(+) Tregs.
CONCLUSIONS: This trial supports the claims that birch-pollen IT also decreases allergy to foods containing Bet v 1-homologous allergens. Recombinant allergens and DBPCFCs have proven to be useful tools for monitoring the effect of birch-pollen IT on linked food allergies.
Department of Dermatology/Allergology, University Medical Center Utrecht, Utrecht, The Netherlands. S.Bolhaar@azu.nl