Cytokine mRNA expression in the bronchoalveolar lavage cells from horses affected by different equine asthma subtypes.
Authors: Lo Feudo Chiara Maria, Stucchi Luca, Bazzocchi Chiara, Consiglio Anna Lange, Comazzi Stefano, Cozzi Maria Cristina, Gusmara Claudia, Gaspari Giulia, Cialini Chiara, Bizzotto Davide, Dellacà Raffaele, Ferrucci Francesco
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Cytokine Expression and Equine Asthma Phenotypes Understanding the immunological drivers of equine asthma (EA) remains challenging despite its prevalence in clinical practice, prompting researchers to investigate cytokine expression patterns in bronchoalveolar lavage fluid (BALF) across different disease subtypes. Lo Feudo and colleagues examined mRNA expression of five key cytokines (IL-1β, IL-2, IFN-γ, IL-4, and IL-17A) in BALF cells from 14 horses with EA and one healthy control, correlating expression profiles with BALF leukocyte populations and objective lung function measurements. Key findings revealed distinct immune pathways: IL-1β expression tracked closely with airway neutrophilia and expiratory resistance (r=0.76), whilst IL-4 was significantly elevated in mixed granulocytic compared to neutrophilic EA and showed inverse relationships with lung mechanics parameters; additionally, both IL-4 and IL-17A correlated inversely with expiratory reactance, suggesting protective or compensatory roles during airway obstruction. These results confirm that EA involves multiple overlapping immune mechanisms—innate responses coupled with neutrophilic inflammation, Th2-mediated mast cell activation, and Th17 pathways—rather than a single aetiologic process, implying that diagnostic and therapeutic strategies targeting EA may require phenotype-specific approaches rather than one-size-fits-all protocols. For practitioners, this research highlights the value of BALF cytology in stratifying horses into immunologically distinct categories, potentially guiding targeted anti-inflammatory treatment selection and prognostic expectations.
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Practical Takeaways
- •Cytokine profiling in BALF may help differentiate EA subtypes and guide targeted immunomodulatory therapies
- •Elevated IL-1β and neutrophils correlate with increased airway resistance, suggesting innate immunity as a key driver in some EA cases
- •IL-4 elevation in mixed granulocytic EA and its inverse correlation with airway reactance suggests Th2-mediated responses may have distinct functional consequences than pure neutrophilic inflammation
Key Findings
- •IL-1β expression positively correlated with BALF neutrophil count (r=0.56, p=0.038) and expiratory resistance (r=0.76, p=0.047)
- •IL-4 was significantly higher in mixed granulocytic EA compared to neutrophilic EA (p=0.008) and inversely correlated with expiratory reactance (r=-0.93, p=0.003)
- •IFN-γ was correlated with BALF mast cells (r=0.58, p=0.029) and IL-17A inversely correlated with expiratory reactance (r=-0.92, p=0.009)
- •Multiple immune responses including innate, Th2, and Th17 are involved in equine asthma pathogenesis with distinct phenotypes