Passive antibody transfer on human leukocytes: application to small animal allergy diagnosis by flow cytometry

Animal allergy diagnosis is based mainly on clinical history, skin tests and, at least for dogs, specific IgE antibodies. The quality of anti-canine IgE antibodies is variable and monoclonal antibodies have been recently characterized. The allergen panel tested in humans and in dogs is similar except for flea and for Staphylococcus. Allergen-induced basophil activation may be measured by the release of mediators such as histamine and leukotriene C4 and by the expression of the CD63 marker on basophil membrane. This latter method is based on the flow cytometric analysis of leukocyte suspensions after double anti-IgE FITC, anti-CD63 PE labelling of human basophils, and has been validated for aero-allergens, food allergens, venoms and several drugs for human allergy diagnosis. After having demonstrated that, in the dog, anaphylactic anti- bodies were capable of binding to human basophil high-affinity receptors for IgE, we went up a flow cytometric method for animal allergy diagnosis based on passive sensitization of human basophils. Prelim- inary results obtained by this method for allergens such as house dust mite or pollen were very encouraging. This method is faster and less expensive than the methods based on mediator release but is still dependent on the availability of fresh human leukocytes. This method may represent a new sensitive and specific method for animal allergy diagnosis.