Methods: Pb from asthmatic (taking only inhaled bronchodilators), untreated AR and AD patients, and non allergic non asthmatic controls was collected. Leukocyte fraction was isolated and stained using Abs against CD48 and the specific markers for each cell type (T cells, B cells, neutrophils, monocytes, eosinophils, basophils and NK cells). Results were analyzed by FACS. sCD48 was detected using a specific ELISA.
Results: mCD48 expression in asthmatics was significantly increased on eosinophils as compared with healthy donors (p<0.001). Importantly this enhanced expression was also found to be significant on neutrophils (p<0.015) and monocytes (p<0.05) although at a lower extent. Interestingly on both AR and AD derived cells, CD48 expression was decreased in comparison to the control group. In the asthmatic group sCD48 levels were also significantly elevated (p<0.006 and 2 folds higher) as compared with the control, AR and AD groups. We also found that sCD48 can down regulate eosinophil activation carried out by heat killed S.aureusby significantly reducing the release of IL-8 (p<0.005).
Conclusions: Our results suggest that both the mCD48 and sCD48 may serve as novel biomarkers for asthma. sCD48 may regulate the allergic response and provide a new potential target for the suppression of asthma. Further research must be done in order to evaluate CD48 expression and release throughout the course of the different forms of asthma and its expression and function in the airways.