Increase of the soluble IL-4 receptor (IL-4sR) and positive correlation between IL-4sR and IgE in nasal fluids from school children with allergic rhinitis

Soluble cytokine receptors (SCR) can either act as inhibitors, by competiti vely inhibiting cytokines from binding to their membrane-bound receptors, o r as enhancers, by sewing as cytokine carriers. We have previously found th at the levels of the Th2 cytokines interleukin (1L)-4, IL-5, IL-6, and IL-1 0 were positively correlated to eosinophils and IgE in nasal fluids from 60 children with seasonal allergic rhinitis. In this study, nasal fluids were reexamined to analyze IL-4sR, IL-6sR, IL-1 beta, TNF-alpha, IL-1sR2, TNF-s R1, and TNFsR2 in relation to eosinophils, neutrophils, ECP, and IgE. In al lergic patients IL-4sR increased significantly during the pollen season, an d weak, but positive correlations with IgE and eosinophils were found (r = 0.45, P < 0.001 and r = 0.4 P < 0.001 respectively). By contrast, none of t he other SCR showed increases or correlations with IgE. However, positive c orrelations between IL1 beta, TNF-alpha, IL-6sR, IL-1sR2, TNF-sR1, TNF-sR2, and either neutrophils or ECP were found. Also, in healthy controls, these cytokines and their receptors were positively correlated to neutrophils or ECP. Thus, increased levels of the soluble IL-4 receptor, as well as IgE, were specifically associated with allergic rhinitis, whereas all other SCR correlated with either inflammatory cells or their products, in both allerg ic and healthy subjects. These results may suggest that SCR in vivo act as cytokine enhancers, rather than inhibitors.