Allergens in dog extracts: Implication for diagnosis and treatment

Background Five to ten percent of the population in affluent countries are allergic to dog. Diagnosis and treatment is based on allergen extracts from natural sources where composition and concentration are poorly defined. Objective We aimed to quantify six dog allergens (Can f 1‐6) in commercial skin prick test (SPT) solutions and to determine individual allergen profiles in dogs. Method The allergen content of SPT solutions from five vendors and allergen source material from three anatomical sites were analyzed. Fur and saliva samples were collected from a mixed population of 120 dogs. Can f 1‐6 were quantified by inhibition ELISA using purified recombinant or natural allergens and polyclonal or monoclonal antibodies. Allergenicity was analyzed by basophil activation test. Results Extensive variation in allergen composition was observed in commercial SPT vials resulting in a patient‐dependent ability to activate basophils. Extract heterogeneity depended on collection site and allergen composition in individual dogs and source materials. Can f 2 and Can f 6 exhibited low levels in fur and SPT solutions, whereas Can f 4, which was the dominating allergen in fur samples, did not display similar high proportions in SPT solutions. Can f 3 varied most among SPT solutions. Conclusion There is a great variation of dog allergens in natural extracts raising questions of source, sampling, processing and ultimately of standardization and minimum allergen levels for accurate diagnosis and treatment. Raw material for dog allergen extracts comes from dogs with various allergen profiles. Commercial dog allergen extracts vary in allergen content. Successful diagnosis and treatment of a dog allergic patient depends on the extract used for diagnosis/treatment and on the IgE profile of the patient.