Improvement of clinical and immunological parameters after allergen‐specific immunotherapy in atopic dermatitis

Abstract Background Allergen immunotherapy (AIT) is considered a curative treatment in some atopic diseases, but in AD contradictory clinical results exist and the action of AIT has not been elucidated. In the literature, there is no evidence for parallel investigations of permeability barrier, cutaneous and blood immune responses after AIT in AD. Objectives The objective was to investigate immune parameters in the blood and skin and to detect clinical and barrier changes after AIT in AD. Methods Mild‐to‐moderate AD patients ( n = 14) with concomitant allergic rhinitis to house dust mites were selected. All patients received topical treatment, while eight patients were randomly selected for adjuvant AIT also. At baseline and after 6 months, clinical, barrier and immunological investigations (serum and skin tests) were performed. In selected patients, biopsies from atopy patch tests (APTs) were analysed by immunohistochemistry for AD‐relevant immune cells and mediators. Results In the adjuvant AIT group, clinical parameters and barrier functions improved significantly. Blood immune parameters displayed no significant changes. Post‐AIT APT became negative in all patients in the AIT group, but remained positive in the non‐AIT group. Cutaneous dendritic cell and T‐cell recruitment decreased significantly after allergen challenge in the AIT group, but no significant changes in skin or serum immunoglobulin E levels or prick test (SPT) reactivity were detected. Conclusions Allergen immunotherapy is a beneficial adjuvant treatment for sensitized AD patients. AIT improves not only clinical symptoms, but also permeability barrier functions. The effect of AIT on sensitization should be detected by APT, not by SPT.