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Conference paper, 2007

Relation of clinical score and mRNA cytokine IL-4, 5, 6 and 10 regulation in horses with elevated pulmonary mast cells

Pringle, John; Riihimäki, Miia; Lilliehöök, Inger; Raine, Amanda


Aims: To assess the relationship of bronchoalveolar lavage (BAL) mast cell elevations in horses to mRNA of the Th2 cytokines IL-4, IL-5 and the general proinflammatory IL-6 in BAL cells. Method Twelve young standardbred race horses were examined by BAL on 3 occasions at 6 month intervals. BAL cytology cells and real time PCR of BAL cells to mRNA IL-4, 5 and 6 were performed. Results were stratified according to same-horse samples, with low (< 3%) BAL mast cells versus high (> 5%) mast cells. Statistical comparisons of mRNA of cytokines IL-4, 5 and 6 in individual horses were performed using the Wilcoxon signed rank test. Significance was set at p=0.05. Results Seven of the horses were found to fit these criteria on two of the sampling occasions, having occasions of both low BAL mast cells, and markedly elevated BAL mast cells. There was no statistical difference in mRNA to IL-4, IL-5 or IL-6 when horses had low versus high BAL mast cells. However, BAL neutrophil percent appeared to be a confounding variable, as there was a trend for an inverse relationship to mast cell numbers. Due to low animal numbers this did not reach significance. Conclusions and Practical Significance: We were unable to detect a relationship of BAL mast cell to alterations in mRNA IL-4 or IL5 that could implicate classical Th2 allergic reaction, nor upregulation of more general inflammation related to IL-6 in horses with episodes of increased BAL mast cells. These findings contrast current theories that incriminate BAL mast cell elevations as being pathologic and contributing to inflammatory airway disease

Published in

Title: conference proceedings


British Equine Veterinary Association