Background The nasal mucosa is the initial site in the upper airway of host defence against antigenic challenge in the form of airborne allergens, irritants, toxins and infectious agents, and yet little is known about nasal mucosal cytokine expression and function. We hypothesized that IL-2 might play a role in immunocompetence of the upper airway.
Methods IL-2 immunoreactivity was measured by ELISA in nasal secretions and by Western blot. Immunohistochemistry and electron microscopy were performed on turbinated tissue. mRNA for IL-2 was evaluated by RTPCR and Southern hybridization.
Results IL-2 immunoreactivity was demonstrated by Western blot and quantitated by an enzyme immunoassay. Immunohistochemical and electron microscopy analysis of turbinate tissue revealed interstitial staining for IL-2. By RTPCR, IL-2 message was evident in 5/5 atopies and 5/5 non-atopics. IL-2 message was expressed in all subjects by Southern hybridization to an internal probe after PCR.
Conclusion This study has demonstrated constitutive expression of IL-2 protein and mRNA in the upper airway of heallhy individuals. The further characterization of cytokines in the upper airway could provide useful insights into immune regulation at the mucosal level.