Alexander Behnke, Franziska Trudzinski, Quoc Thai Dinh and Sebastian Fähndrich
Background: T helper (Th)17/22 cells may play a role in allergic asthma. Recent findings showed increased mRNA expression for IL-22 in peripheral blood mononuclear cells (PBMC) from patients with asthma. Thereby, the role of the natural antagonist of IL-22, IL-22 binding protein (IL-22 BP), a soluble receptor for IL-22, remains to be elucidated. In this study, we investigate the expression of mRNA for IL-22 BP in individuals with asthma. Methods: We assessed the effect of allergen inhalation challenge on mRNA-expression for IL-22 and IL-22 BP, and IL-22 receptor in mononuclear cells of the broncheoalveolar fluid (BALF) from individuals with allergic asthmatic. Furthermore, in vitro we investigated mRNA expression for IL-22 and IL-22 BP, and IL 22 receptor after costimulation of peripheral blood mononuclear cells (PBMC) from individuals with asthma and normal controls with Th2 cytokines IL-4, IL-9, and GM-CSF in a time-dependent manner. Results: The expression of mRNA for IL-22-BP in PBMCs from healthy controls and individuals with asthma could be found after co-stimulation with IL-4 after a minimum of 12 hours, which hold on for 96 hours. The expression of mRNA for IL-22 BP in subjects with atopic asthma was discovered in mononuclear cells of the BALF after segmental allergen inhalation challenge. Our findings suggest a possible role for IL-22 BP in allergen-induced airway responses.