Abstract
BACKGROUND: Atopic dermatitis (AD), a chronic inflammatory disorder, is often accompanied by allergic rhinoconjunctivitis (ARC) as a co-morbidity. The use of a monoclonal anti-IL-4Rα antibody has been effective in controlling moderate to severe AD symptoms. Allergen-specific immunotherapy (AIT) is widely used for the treatment of ARC and asthma. The effects of AIT on basophil reactivity/effector functions have already been examined and used as indicators of the treatment efficacy. However, it is unclear, how an anti-IL-4Rα antibody can influence allergen-specific immune responses of basophils and T cells of AD patients with comorbid ARC. OBJECTIVE: To investigate the effect of a monoclonal anti-IL-4Rα antibody on the in vitro allergic responses of basophils and T cells deriving from AD patients with comorbid ARC. METHODS: Blood samples of 32 AD patients were obtained before, after 4 and 16 weeks of an anti-IL-4Rα antibody therapy (300 mg subcutaneously/2 weeks; n = 21) or AIT (daily sublingual application; n = 11). Patients treated with an anti-IL-4Rα antibody were grouped according to their serum specific immunoglobulin E levels and ARC symptoms, while patients receiving an AIT were additionally grouped according to the allergen specificity of their AIT. Basophil activation test and T cell proliferation assays were undertaken after an in vitro allergen stimulation. RESULTS: A significant reduction of the immunoglobulin E levels and the allergen-specific T cell proliferation was observed in AD patients treated with an anti-IL-4Rα -antibody, while the allergen-specific basophil activation/sensitivity were found to be significantly increased. In patients receiving an AIT, the in vitro allergen-specific basophil activation and the T cell proliferation were found to be significantly decreased in response to seasonal allergens. CONCLUSIONS: An IL-4Rα blockade induced by a monoclonal anti-IL-4Rα antibody leads to an increased activity/sensitivity of early effector cells (such as basophils), in contrast to a decreasing reactivity observed under an AIT. The late-phase T cell reaction to allergens did not differ between the herein assessed treatments.