Inflammatory cells in equine summer eczema and asthma

Background

Summer eczema is caused by an allergy to the saliva of biting insects, especially midges. The disease often causes severe discomfort in the form of chronic and intensely itchy eczema, which can also lead to open wounds that become infected. In severe cases, summer eczema can even lead to the horse having to be euthanised for ethical reasons. Asthma is another chronic allergic disease affecting horses. In severe asthma, the horse may experience marked respiratory distress and chronic coughing, while mild forms of asthma mainly cause reduced performance. Current treatment options for both summer eczema and asthma in horses are very limited, which is a major challenge for veterinarians and owners alike.

About the project

In one part of the study, we will investigate immune cells in the skin of horses with summer eczema. We will use ‘single cell’ RNA sequencing to identify the gene expression of individual cells. With this method, we can obtain very comprehensive information about the composition of different cell types in the skin. In addition, by comparing normal and inflamed skin, we can identify new types of cells and variations in gene expression that may affect the inflammatory process in the skin. This gives us a more detailed picture of the damaging mechanisms that contribute to the disease. With this increased knowledge, new and more effective treatments can be developed in the longer term. The findings from the study may also be relevant to allergic eczema in humans as they are similar to equine summer eczema.

Mast cells are immune cells that contribute in several ways to chronic allergic diseases in humans, but their role in horses is unclear. An important goal of the study is therefore to characterise equine mast cells under normal and allergic conditions. We will purify mast cells from the respiratory tract, lung and skin using a new method that we have developed in a previous project. The normal gene expression of mast cells in the skin and lung will be analysed using a quantitative RNA sequencing method. The function of the purified mast cells will be studied by measuring their response to activation by allergen and other stimuli. This will allow us to identify the unique properties of horse mast cells. This type of knowledge can form the basis for new targeted therapies in equine allergic disease.