Cross-Reactive Carbohydrate Determinant (CCD) Binding in Seasonal Allergy Tests in Dogs
Allergen specific immunglobulin E (IgE) in allergic patients is measured with the purpose of identifying the allergen(s) the pet is sensitized to. In humans some patient sera IgE has been shown to be directed against cross-reactive carbohydrate determinants (CCDs) that occur on many plant allergens. Extremely positive results in seasonal allergy tests are an indication that IgE is binding not only to proteins, but that IgE against CCDs have also been formed.
The aim of this study was to determine if dogs in which IgE against all seasonal single allergens tested also had concomitant IgE against CCDs.
Sera from dogs for seasonal allergen-specific IgE analysis were used. Animals in which IgE against all seasonal allergens were detected were chosen for further study (n=29 dogs). An Fe-Epsilon-receptor test (CHO test) was used to measure CCDs in dog sera. If this test was positive we repeated the test for seasonal allergens with a blocking solution that blocked the CCD reaction.
All of the chosen samples were also positive for CCD with positive CHO tests. In all cases, repeating the allergy test for pollen with a blocking solution still showed positive results.
The identification of CCDs is indicated in extreme positive seasonal allergy test results. This study shows that the CHO test is helpful in proving that IgE antibodies against CCD occur. Blocking this binding is helpful for the selection of allergens for the immunotherapy in order to avoid the inclusion of false allergens. We present a rapid and inexpensive method.