An allergen microchip developed at the Medical University of Vienna (MedUni) in Austria can be used to identify allergic sensitization in horses. This is the main finding of an international study recently published in the journal Allergy.

"Our best friends are more like us than we perhaps thought — even in terms of their immune system," explained lead author of the study Erika Jensen-Jarolim, who has dual affiliation to both MedUni Vienna's Institute of Pathophysiology & Allergy Research and the inter-university Messerli Research Institute of Vienna University of Veterinary Medicine, the Medical University of Vienna and the University of Vienna.

The study showed that horses develop an antibody reaction by producing immunoglobulin E (IgE) — similar to the IgE profile in people. IgE is an antibody primarily intended to defend against parasites, but it is also responsible for allergies and is an important biomarker for the early detection of allergies. Even in the case of horses, a single drop of blood is enough to test for allergies using the allergen microchip, the announcement said.

The international study consortium headed up by Jensen-Jarolim, also comprising researchers from Germany, Switzerland and Japan, was able to identify a strong IgE immune system reaction, particularly to buckwheat but also to alder pollen and bermudagrass (also called "dogtooth grass" in German), which is becoming increasingly widespread in Austria.

"Buckwheat is often used as a high-protein pseudo-cereal in horse treats and horse muesli," Jensen-Jarolim explained. "The reaction to pollen from flat-leaved bermudagrass, in particular, is explained by the fact that, when horses are grazing, they have their noses right down to the ground. In collaboration with Uwe Berger and his team from MedUni Vienna's Pollen Monitoring Service, we now intend to investigate the flora found in paddocks."

This requires a clinical investigation to ascertain whether and to what extent these allergens are linked to the allergic reactions commonly found in horses, such as coughs, colic and skin problems. "However, just like the IgE test in human allergy sufferers, our results are, at any rate, a strong indication of the direction to take in further diagnostic investigations," Jensen-Jarolim said.

The allergen chip is already being used successfully for diagnosing allergies in people and is now available for horses as well. Similar tests are currently being developed for dogs, and these study findings should be available in the near future.

Affected horses could then be put on an elimination diet that totally avoids any suspected allergens to see whether their symptoms improve.