Thank you for your inquiry.
As you can see from the abstract copied below, there is very significant cross-reactivity between oak pollen and birch pollen. Thus, I believe for the majority of patients one sees, immunotherapy with one of the two pollens will suffice. However, there are exceptions to this generalization, and unfortunately, because we do not have component testing available for separate allergens in these pollens, some patients with oral allergy syndrome may be responsive to one and not the other pollen.
The reason for this is that most of our studies relating cross-reactivity between oak and birch have looked for cross-reactivity between rBet v 1 and rBet v 2. As you know, these are major allergens responsible for both allergic respiratory tract symptoms and oral symptoms. Both pollens also contain profilin which can produce oral allergy symptoms as well. However, there are a number of other allergens in birch pollen which may not be in oak pollen. These include Bet v 3, 4, 5, 6, 7, and 11. I have not found any evidence in the literature that these have been looked for or found in oak pollen.
Thus, in summary, in the majority of instances, patients with allergic rhinitis and oral allergy syndrome (food-pollen syndrome), immunotherapy to the predominant allergen in your area (oak or birch) should suffice. But there may be exceptions to this rule, and I do not think it is possible at this time to tell you how often such exceptions occur.
If you have concern that you would be missing patients in this regard, you might consider testing with both pollens, and if both are positive, treating with both.
Thank you again for your inquiry and we hope this response is helpful to you.
The Journal of Allergy and Clinical Immunology
Volume 102, Issue 4 , Pages 579-591, October 1998
Background: Pollen from trees of the order Fagales are important allergen sources in most parts of the world. Clinical, immunochemical, and molecular biology studies indicate that they contain cross-reactive allergens. The major birch pollen allergen, Bet v 1, and birch profilin, Bet v 2, a highly cross-reactive allergen, have been cloned and expressed in Escherichia coli.
Objective: The purpose of this study was to demonstrate the presence of allergens in Fagales pollens that share IgE epitopes with recombinant Bet v 1 and Bet v 2 and to determine the percentage of birch, alder, hornbeam, hazel, and oak pollen–specific IgE that can be preabsorbed with rBet v 1 and rBet v 2 from 102 sera of different populations of subjects allergic to Fagales tree pollen.
Methods: The presence of rBet v 1– and rBet v 2–homologous allergens in tree pollen extracts was investigated by IgE immunoblot inhibition experiments, and the percentage of tree (birch, alder, hornbeam, hazel, and oak) pollen–specific IgE that was bound by a mixture of rBet v 1 and rBet v 2 was determined by RAST-based quantitative IgE inhibition experiments. The clinical significance of IgE antibody cross-reactivity was studied by skin prick testing with rBet v 1, rBet v 2, and Fagales pollen extracts.
Results: Natural birch, alder, hornbeam, hazel, and oak pollen contain allergens that share IgE epitopes with rBet v 1 and rBet v 2. A combination of rBet v 1 and rBet v 2 accounted for 82% of tree pollen–specific IgE on average. Most of the tree pollen–specific IgE was directed against rBet v 1.
Conclusion: rBet v 1 and rBet v 2 contain most of the Fagales pollen–specific IgE epitopes and may therefore substitute natural tree pollen extracts not only for diagnosis but also for patient-tailored immunotherapy of tree pollen allergy (J Allergy Clin Immunol 1998;102:579-91).
Phil Lieberman, M.D.