Tumor necrosis factor-alpha protein concentrations in bronchoalveolar lavage fluid from healthy horses and horses with severe equine asthma

The objective of this study was to determine if TNF-alpha protein concentration differs in bronchoalveolar lavage fluid (BALF) obtained from healthy horses, horses with naturally occurring exacerbations of severe equine asthma and horses in remission from severe equine asthma. Tumor necrosis factor-alpha (TNF- alpha) protein concentrations were determined in BALF by commercial equine ELISA. Horses with naturally occurring exacerbation of severe equine asthma were found to have significantly lower BALF TNF-alpha protein concentrations than healthy horses (p = 0.0026). There was no significant difference in BALF TNF-alpha concentration between horses in exacerbation and remission from disease, but there was a decrease in median TNF-alpha concentration between healthy horses and horses with clinical exacerbation of severe equine asthma. These findings suggest, that similar to human asthma, the role of TNF-alpha in chronic lower airway inflammation of horses may differ between disease phenotypes and disease state. Furthermore, the method with which TNF-alpha is measured (mRNA expression vs. protein concentration) may affect results when studying the role of TNF-alpha in horses with severe equine asthma.