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

This research studies the concentrations of allergen-specific IgE in the blood of horses suffering from RAO, a common respiratory issue, and compares it with healthy horses. It found that RAO horses had a higher concentration of specific IgE, particularly for the mite Tyrophagus putrescentia.

Research Context and Objective

• The study is based on the premise that equine recurrent airway obstruction (RAO), also known as ‘heaves’, is a prevalent respiratory problem in older horses. Symptoms tend to lessen when the horses are kept in dust-free environments or pastures for an extended period.
• While the mechanics of RAO involve a complex range of factors –including environmental, immunologic, infectious, and genetic elements – this study focuses on the immunologic basis of the disease, which is currently not well-understood.
• The primary objective of the study was to scrutinize and compare the levels of allergen-specific IgE (Immunoglobulin E) found in the serum of horses diagnosed with RAO and healthy horses.

Methodology

• A total of 14 adult Polish Konik horses, kept in a consistent environment, were selected for the study. They were categorically split into two groups – one group consisting of seven healthy horses (control group) and the other group consisting of seven RAO-affected horses (study group).
• Each horse underwent a medical and lab assessment, endoscopic examination, and bronchoalveolar lavage (BAL), a procedure to examine the lower airways of the lungs.
• The horses’ serum was then tested against allergens from nine types of molds and three types of mites using the Heska Allercept assay, a diagnostic test.

Results

• The serum tests exhibited a statistically notable difference in IgE concentrations between the two groups.
• The RAO horses had significantly higher IgE concentrations against mites, specifically Tyrophagus putrescentia, which was most strongly associated with RAO in this study.
• There was, however, no significant difference in IgE concentrations against molds between the two groups.

Conclusion

• Based on these findings, the researchers concluded that an increase in the concentration of mite-specific IgE, particularly against Tyrophagus putrescentia, is significantly associated with RAO.