Differences in allergen‐specific basophil activation and T cell proliferation in atopic dermatitis patients with comorbid allergic rhinoconjunctivitis treated with a monoclonal anti‐IL‐4Rα antibody or allergen‐specific immunotherapy

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.