Participation of T regulatory cells in equine recurrent airway obstruction.

This research article delves into the role of T regulatory cells in the progression of equine recurrent airway obstruction (RAO), a prevalent immune-related disease in horses. Researchers used flow cytometry to observe changes in peripheral blood and bronchoalveolar lavage fluid cells, before and after the horses were exposed to mouldy hay, a common RAO inducer. The findings highlighted an increased count of specific cell populations, CD4+, Foxp3+ and CD4+, CD25(high), in horses with RAO, which may suggest their influence in mitigating the disease.

Research Goals and Methodology

• The primary objective of this research was to gain a comprehensive understanding of the pathogenesis of RAO. Specifically, they aimed to investigate the role of T regulatory cells bearing specific markers such as CD4, CD25 and Foxp3, in relation to RAO.
• To carry out the study, mononuclear cells were collected from peripheral blood (PB) and bronchoalveolar lavage fluid (BALF) obtained from horses. This was done both prior to and following exposure to mouldy hay, known for provoking RAO symptoms.
• The collected cells were stained with fluorescing antibodies for ease of analysis and then studied using flow cytometry, a technique for counting and examining microscopic particles, like cells.

Key Findings

• The researchers found an increase in the percentage of CD4+, Foxp3+ cells in peripheral blood and bronchoalveolar lavage fluid harvested from RAO affected horses.
• The proportion of CD4+, CD25(high) cells substantially increased in the bronchoalveolar lavage fluid of RAO positive horses compared to the baseline, with no changes observed in the peripheral blood compartment.
• The number of CD4+, CD25(high), Foxp3+ cells in bronchoalveolar lavage fluid rose in diseased horses compared to those in remission, indicating that these cells could be involved in the resolution or cessation of immune-triggered bronchial inflammation.
• It was also noted that when the percentage of CD4, Foxp3 positive cells were compared with the percentage of CD4+, CD25(high) cells, the numbers were very similar, regardless if the horse was exposed to antigen or not.

Conclusions and Implications

• These findings suggest that RAO horses show increased accumulation of T cells with regulatory markers in their airways, which potentially modulate the course of the disease.
• This research advances our understanding of the role of T regulatory cells in equine recurrent airway obstruction, potentially leading to improved interventions and treatments for this widespread equine ailment.