A microchip has been successfully used to identify allergic sensitisation in horses.
The development by an international study team of the allergen microchip array – a tiny test panel rather than the kind designed for inserting in a horse’s neck for identification – is described in the journal Allergy.
“Our best friends are more like us than we perhaps thought – even in terms of their immune system,” says the lead author of the study, Erika Jensen-Jarolim.
The study showed that horses develop an antibody reaction by producing immunoglobulin E – similar to the IgE profile in humans.
IgE is an antibody primarily intended to defend against parasites, but is also responsible for allergies. It 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 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 Bermuda grass.
“Buckwheat is often used as a high-protein pseudo-cereal in horse treats and horse muesli,” explains Jensen-Jarolim.
“The reaction to pollen from flat-leaved Bermuda grass, in particular, is explained by the fact that, when horses are grazing, they have their noses right down to the ground.”
Their custom-designed allergen microarray was able to check for 131 allergens. Blood from 51 horses from Europe or Japan were tested for specific IgE reactivity.
These included horse patients who were diagnosed for eczema due to insect bite hypersensitivity, chronic coughing, recurrent airway obstruction and urticaria or were clinically asymptomatic.
The researchers found that 72.5% of the horses responded to buckwheat.
They now intend to collaborate with Uwe Berger and his team from the Medical University of Vienna’s Pollen Monitoring Service to investigate the plants found in paddocks.
This will first require 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,” says Jensen-Jarolim.
The allergen chip is already being successfully used for diagnosing allergies in humans and is now available for horses as well.
Similar tests are being developed for dogs too – 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.
Jensen-Jarolim has dual affiliation, both to the Medical University of Vienna’s Institute of Pathophysiology and Allergy Research and to the inter-university Messerli Research Institute.
Molecular allergen profiling in horses by microarray reveals Fag e 2 from buckwheat as a frequent sensitizer.
L. Einhorn, G. Hofstetter, S. Brandt, E. K. Hainisch, I. Fukuda, K. Kusano, A. Scheynius, I. Mittermann, Y. Resch-Marat, S. Vrtala, R. Valenta, E. Marti, C. Rhyner, R. Crameri, R. Satoh, R. Teshima, A. Tanaka, H. Sato, H. Matsuda, I. Pali-Schöll, E. Jensen-Jarolim.
https://doi.org/10.1111/all.13417 Allergy, January 2018.