The major birch allergen Betulae verrucosa 1, (Bet v 1), belongs to the
proteinase 10 (PR-10) family of panallergens that are common to many
fruits, nuts and vegetables. A high proportion of birch-sensitised individuals
experience oral symptoms upon consumption of such foods. This has been
termed ‘oral allergy syndrome (OAS),’ or ‘pollen-food syndrome.’
Birch pollen specific immunotherapy (BP-SIT) can successfully treat birchsensitive
rhinitis; it has been postulated that BP-SIT might also reduce oral
allergy symptoms. Previous studies have been small and contradictory, using
differing methodology and primary outcome measures.
We designed a placebo controlled, double blind, randomised study aiming to
establish definitively whether BP-SIT can effectively treat the pollen-food
syndrome; outcome measures include open and double blind placebo
controlled food challenges (DBPCFC) after one and two years of treatment.
To date 22 patients have been enrolled, 18 have undergone assessment at
one year and ten at two years. Four patients are due to attend for final followup
in Autumn 2015. Eight patients have dropped out. Of the ten who have
completed the study: nine have an increased tolerance to fresh apple as
evaluated by open challenge. When assessed with DBPCFC, six patients
tolerated larger quantities of fresh apple at two years compared to baseline.
However, a total of eight patients were noted to have an apple threshold of
100g or more at baseline, despite reacting to only 20g during screening. The
clinical trial is on going and remains blinded; it is therefore impossible to
draw any firm conclusions regarding the efficacy of BP-SIT to treat OAS at
|Date of Award