Initial investigation of molecular phenotypes of airway mast cells and cytokine profiles in equine asthma.
Authors: Woodrow Jane S, Hines Melissa, Sommardahl Carla, Flatland Bente, Lo Yancy, Wang Zhiping, Sheats Mary Katie, Lennon Elizabeth M
Journal: Frontiers in veterinary science
Summary
Equine asthma encompasses a spectrum of lower airway disease with chronic obstruction and inflammation, currently classified as mild-to-moderate (mEA) or severe (sEA), though cellular mechanisms may warrant further distinction. Woodrow and colleagues investigated mast cell protease expression and bronchoalveolar lavage fluid (BALF) cytokine profiles in healthy horses, mEA cases, and sEA cases, using quantitative PCR to measure airway mast cell phenotypes and multiplex immunoassay to quantify inflammatory mediators. Whilst mast cell protease expression patterns showed minimal variation across groups—with tryptase predominating over chymase—horses with severe asthma demonstrated significantly elevated TNF-α, CXCL-8 (IL-8), and IFN-γ in BALF supernatant, suggesting a distinctly pro-inflammatory milieu. Multivariate analysis revealed that healthy and mEA horses clustered together immunologically, with sEA separating primarily due to differences in BALF neutrophil and lymphocyte concentrations rather than mast cell phenotype. These findings support the notion that current asthma classifications may obscure important endotypic heterogeneity, particularly in severe cases, which could guide future exploration of targeted anti-inflammatory and immunomodulatory therapies tailored to individual cytokine signatures.
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Practical Takeaways
- •Cytokine profiling (particularly TNF-α, CXCL-8, and IFN-γ levels) may help differentiate severe asthma from milder disease and guide targeted anti-inflammatory therapy selection
- •Current clinical classification of equine asthma into mild-to-moderate versus severe categories is supported by distinct inflammatory endotypes, but further phenotypic subdivision may improve diagnostic and treatment precision
- •Future therapeutic development should focus on modulating elevated neutrophilic and lymphocytic airway inflammation in severe asthma rather than targeting mast cell proteases
Key Findings
- •Airway mast cells in horses primarily express tryptase with minimal chymase expression across all groups
- •Severe equine asthma is characterized by significantly elevated TNF-α, CXCL-8, and IFN-γ concentrations in bronchoalveolar lavage fluid
- •Healthy horses and mild-to-moderate asthma horses show overlapping immunological characteristics, while severe asthma separates as a distinct phenotype
- •Increased neutrophil and lymphocyte concentrations in severe asthma drive the primary immunological distinction between asthma severity groups