Serum concentrations of allergen-specific IgE in horses with equine recurrent airway obstruction and healthy controls assessed by ELISA

Background: Equine recurrent airway obstruction (RAO), also known as heaves, is one of the most common respiratory problems in older horses. When RAO-affected horses stay pastured or in a dust-free environment for a prolonged time, clinical signs as well as airway inflammation wane. A number of environmental, immunologic, infectious, and genetic factors play an important role in the pathogenesis of RAO, and the immunologic basis of this disease is still poorly understood.

Objectives: The aim of this study was to investigate the concentrations of allergen-specific IgE in the serum of horses suffering from RAO and healthy controls.

Material and methods: The study included a group of 14 adult Polish Konik horses, kept in a standardized environment, and divided into 2 groups: 7 horses which did not have any respiratory problems comprised the control group and 7 horses with a history of RAO constituted the study group. A clinical and laboratory evaluation, endoscopic examination, and bronchoalveolar lavage (BAL) were performed in all horses. Sera of all horses were tested against allergens from 9 molds and 3 mites using the Heska Allercept assay.

Results: In the serologic tests, a statistically significant difference between both groups was found for specific IgE against mites, wherein Tyrophagus putrescentia correlated most clearly with RAO. There was no difference between groups for IgE specific against molds.

Conclusion: On the basis of our observations and results, we conclude that RAO is associated with increased serum concentrations of specific serum IgE against mites, in particular T putrescentia.