THE POTENTIAL ROLE OF INTERLEUKIN-13 IN EOSINOPHILIC INFLAMMATION IN NASAL-MUCOSA

Background Recent studies have revealed that interleukin (IL)-13, as w ell as IL-4, causes de novo surface expression of vascular cell adhesi on molecule-1 (VCAM-1) on endothelial cells of the umbilical vein and accelerates selective eosinophil migration. However, its role in aller gic rhinitis remains to be clarified. Of particular interest is whethe r IL-13 upregulates VCAM-1 expression in human mucosal microvascular e ndothelial cells (HMMECs), to which eosinophils adhere in nasal mucosa . Methods To understand the potential role of IL-13 in eosinophilic in flammation in nasal mucosa, we examined the effects of IL-13 on the ad hesiveness between HMMECs and eosinophils. Results IL-13 increased VCA M-1 expression in HMMECs, the adhesiveness of endothelial cells to eos inophils, and the transendothelial migration. On the other hand, IL-13 decreased the adhesiveness of eosinophils to HMMECs, and, as a result , accelerated eosinophil infiltration. Those effects are more potent t han was those of IL-4. In addition, we also report that the amount of IL-13 in nasal mucosa was higher than that of IL-4. Conclusions These results strongly indicate that IL-13, as well as IL-4, may be importan t in eosinophilic inflammation in the nasal mucosa.