When comparing healthy controls with asthmatic subjects (Fig 8), differential expression was observed in MUC5AC (p < 0.000001), FOXJ1 (p < 0.000001), NOTCH2 (p = 0.003), MUC5B (p < 0.000001), IL-6 (p < 0.000001) and IL-8 (p = 0.000009) (multiple Unpaired t-tests), suggesting that these markers may be used in the diagnosis of equine asthma using the nasal brush technique. This evidence concerns the gene CXCL8 and asthma.