Localisation of oncostatin M receptors (OSMR) in human airways by immunohistochemistry: Altered pattern of distribution in asthma

Oncostatin M (OSM) is a member of the IL-6 family of cytokines and to date has been demonstrated to be released by activated T-cells and macrophages. OSM is a potent inducer of epithelial anti-proteinases as well as tissue inhibitor of metalloproteinases, suggesting an anti-proteolytic function. However, the distribution of OSMR in human airways is unknown. We hypothesised that due to these effects, OSMR would be present in human airway epithelium and that the expression and pattern of OSMR distribution would be upregulated in asthma. Methods: Transverse sections (n=3) of large airways were obtained at autopsy from cases of fatal asthma (FA, n=7) and from non-smoking controls (con, n=4). Sections were stained for OSMR using a specific polyclonal antibody (provided by Immunex, Seattle, WA). Positive staining for OSMR was scored semi-quantitatively for intensity (0-4) and distribution (0-4) in the epithelium (epi), basement membrane (bm), smooth muscle (asm), sub-mucosal glands (smg), vasculature (bv), mononuclear (mono) and multinuclear cells (poly) Results: The mean ±S.D. scoring intensity is shown below. epi bm asm smg bv mono, poly FA T3±1.3# T5±1.6 2.8±1.8# 1.4±0.7 1.9±1~5~ 2.0±12~ 0.3±1.1 Con 0.6±1.2 1.4±1.6 1.1±1.8 1.2±1.8 1.3+1.8 1.6±1.5 0.3±1.1 #P<0.01 vs con. The distribution of staining score showed similar trends. Conclusion: These results show for the first time that OSMR are present in human airways and that the pattern of expression is altered in asthma. The distribution of staining suggests that OSM may play an important role in airway inflammation associated with asthma.