High prevalence of IgE antibodies among blood donors in Sweden and Norway

Background: Reactions after a blood transfusion could be allergic because of passive transfer of immunoglobulin E (IgE) antibodies from allergic donors. Aims of t he study: To compare spectrum and prevalence of IgE antibodies in blood donors from Sweden and Norway. Methods: Using the ImmunoCAP method, serum samples from 1002 blood donors from Sweden and 500 from Norway were analysed for IgE antibodies to common inhalant and food allergens and allergens common in a hospital environment, such as penicilloyl G and latex. Results: As many as 23.6-27.3% of the donors had IgE antibodies to at least one of the 14 allergens tested. Of these 6.8-16.7% had extremely high concentrations, i.e. > 35 kU(A)/l corresponding to 100 times the cut-off for a positive allergy test. Most donors were sensitized to pollens, dander and mite but several had very high levels of IgE antibodies to penicilloyl G, latex and peanut. The pattern of sensitizing allergens differed between Sweden and Norway. Conclusions: High serum levels of IgE antibodies to various allergens are common among blood donors and the degree of sensitization and spectrum of involved allergen varies between geographical regions. Present routines to identify IgE sensitized, potential risk, donors are not satisfactory; the sensitivity of selection procedures is about 25%.