European Journal of Immunology / IL31 transgenic mice show reduced allergeninduced lung inflammation

Interleukin31 (IL31) is a Th2 cellderived cytokine that has been closely linked to pruritic skin inflammation. More recently, enhanced IL31 serum levels have also been observed in patients with allergic rhinitis and allergic asthma. Therefore, the main aim of this study was to unravel the contribution of IL31 to allergeninduced lung inflammation. We analyzed lung inflammation in response to the timothy grass (Phleum pratense) pollen allergen Phl p 5 in C57BL/6 wildtype (wt) mice, IL31 transgenic (IL31tg) mice, and IL31 receptor alphadeficient animals (IL31RA/). IL31 and IL31RA levels were monitored by qRTPCR. Cellular infiltrate in bronchoalveolar lavage fluid (BALF) and lung tissue inflammation, mucus production as well as epithelial thickness were measured by flow cytometry and histomorphology. While allergen challenge induced IL31RA expression in lung tissue of wt and IL31tg mice, high IL31 expression was exclusively observed in lung tissue of IL31tg mice. Upon Phl p 5 challenge, IL31tg mice showed reduced numbers of leukocytes and eosinophils in BALF and lung tissue as well as diminished mucin expression and less pronounced epithelial thickening compared to IL31RA/ or wt animals. These findings suggest that the IL31/IL31RA axis may regulate local, allergeninduced inflammation in the lungs. (VLID)5807765