Allergen immunotherapy in people, dogs, cats and horses – differences, similarities and research needs.

Allergen immunotherapy (AIT) is a common treatment for allergies in humans and can also be effective in dogs, cats, and horses. This article analyzes how these treatments work in different species, indicates where more research is needed, and looks at how AIT could be further improved.

Allergen Immunotherapy: An Overview

• Allergen immunotherapy (AIT), which entails exposing patients to gradually larger doses of an allergen, was first successfully used in humans in 1911. Nowadays, it is widely used to treat a variety of allergies, including allergic asthma, rhinitis, insect venom hypersensitivity, atopic dermatitis, and recently, food allergies.
• A few different AIT protocols exist, such as subcutaneous (under the skin), epicutaneous (on the skin), intralymphatic (into the lymphatic system), oral, and sublingual (under the tongue) methods.
• In animals, the most data about AIT exists for dogs. The principles behind these treatments are fairly similar to those used in humans, involving the initiation of a regulatory response and the production of “blocking” IgG antibodies.

AIT in Different Animal Species

• The majority of animals studied for AIT effectiveness are dogs where subcutaneous AIT is recognized as a treatment for atopic dermatitis, a chronic inflammatory skin disease.
• While subcutaneous immunotherapy is also used to treat atopic dermatitis in cats, there is not as much data available on its efficacy. Evidence does suggest that AIT can successfully treat feline asthma, though.
• Research on horses indicates varied success with AIT for insect hypersensitivity. However, there are promising results from pilot studies that used recombinant antigens of biting midges (Culicoides spp.) to prevent insect hypersensitivity.

The Future of AIT

• Therapies are constantly being refined, and this includes allergen immunotherapies. Currently, researchers are looking at how they can optimize these treatments using allergoids (modified allergens), peptide immunotherapy, recombinant allergens (genetically engineered), and new adjuvants (substances that enhance the body’s immune response).
• By investigating different types of allergen administration and new adjuvants, it is hoped that the compliance and efficacy of this treatment modality can be improved.