Proinflammatory cytokines: measurement in nasal secretion and induction of adhesion receptor expression

We recently demonstrated that interleukin (IL)-1 beta, tumor necrosis factor (TNF)-alpha, IL-6 and IL-8 can be found in nasal secretions from allergic rhinitis patients under artificial and natural conditions. By ELISA measurements, significantly elevated baseline levels for IL-1 beta, IL-6 and IL-8 were found in seasonal allergic compared to control subjects. Within the first 2 h after nasal allergen challenge, IL-1 beta and TNF are secreted, whereas IL-6 and IL-8 showed a slow increase over 6-8 h. All cytokine levels returned to baseline within 24 h after exposure. Repeated measurements at 4-week intervals in perennial allergic rhinitis subjects (n = 27) showed significant correlations between IL-1 and IL-8, IL-6 and IL-8 and IL-6 and the symptom score (visual analogue scale). The IL-1 receptor antagonist IL-1ra was found in great molar excess in the secretions and correlated significantly with IL-8, but not IL-1 beta. In an in vitro assay using fresh nasal mucosa of grass-pollen-allergic subjects, we were able to demonstrate a strong and rapid induction of E-selectin adhesion receptor expression on endothelial cells by allergen, IL-1 beta and TNF. The adhesion receptor expression was markedly inhibited by soluble IL-1 receptors, sTNF-R and IL-1ra. These data indicate a key role for inflammatory cytokines in the regulation of allergic inflammation.