The kinetics of allergen-induced eotaxin level in nasal lavage fluid - Itskey role in eosinophil recruitment in nasal mucosa

Eotaxin (CCL11) is a potent eosinophil chemoattractant belonging to the C-C chemokine. To evaluate the role of eotaxin in eosinophilic inflammation in nasal mucosa, we investigated the levels of eosinophil chemoattractants in nasal lavage fluids obtained after antigen challenge, compared with eosino phil counts and eosinophil protein X (EPX) levels. In subjects with allergi c rhinitis, allergen challenge led to parallel increases in eosinophil coun ts, levels of EPX, and eotaxin concentrations in nasal lavage fluid. The le vels of eotaxin in lavage samples showed strong correlation with savage lev els of eosinophil counts and EPX. Normal subjects had few, if any, eosinoph ils and EPX as well as the measured parameters in their nasal lavage fluids before and after antigen challenge. In our experiments of eosinophil endot helial transmigration (TEM) assay using the nasal microvascular endothelial cells, eotaxin showed the most potent effect among various eosinophil chem oattractants. In addition, treatment of eosinophils with anti-CCR-3 mAb sig nificantly blocked eosinophil TEM induced by homogenate of nasal mucosa. Th ese results indicate that eotaxin has an important role in eosinophil-depen dent inflammation in nasal mucosa and suggest that blocking eotaxin or CCR- 3 might be useful for new therapeutic tools of allergic rhinitis.