Association between fungal detection and inflammatory
response
A significant positive association was found between fungal detection by
culture in BALF and a high tracheal mucus score, as well as with a high
percentage of neutrophils in BALF. When present (>10%) the
magnitude of neutrophilic response was however not significantly
associated with the prevalence of mold in BALF. Tracheal mucus
accumulation and neutrophil proportions are evidence of airway
inflammation, but without specific cause.5
Fungal exposure and its association with SA have frequently been
documented,8,43,44 but studies examining fungal
association with MA are still scarce. One study found that horses with
fungal elements observed in TW cytology had twice the odds of having IAD
than horses without fungi.10 There is also little
information to date concerning the association between antigenic
triggers and specific MA phenotypes.45 Neutrophilic
airway inflammation in BALF of racing Thoroughbreds has been correlated
with both respirable dust and endotoxin exposure, while mast cell
inflammation in BALF has been associated with β-glucan
exposure.9 Interestingly, our results tend to
demonstrate the lack of association between fungal detection in the
airways and non-neutrophilic forms (mast-cell and eosinophilic) of
pulmonary inflammation. These elements suggest that fungal detection in
the airways is not linked to a specific immune response.