De novo sensitization during subcutaneous allergen specific immunotherapy - an analysis of 51 cases of SCIT and 33 symptomatically treated controls

Since the beneficial implementation of allergen specific subcutaneous immunotherapy (SCIT), there are only a few studies on the risk of SCIT-induced neosensitizations. In 51 patients, we retrospectively analyzed sIgE and sIgG patterns by a multiplex ELISA as well as demographic and clinical features before and after SCIT. 33 allergic patients, who only received symptomatic treatment, served as controls. In 12 of 51 SCIT-treated patients (24%), we found new sIgE against allergen components of the allergen source treated by SCIT; eight of them were adults. Among controls, no adult patient showed neosensitization to components of the primarily affected allergen source. Only two children of the control group were affected by neosensitization, which was limited to major allergen components and rarely accompanied by sIgG. In the SCIT-treated group, neosensitization affected major and minor allergen components, and was accompanied by a strong induction of sIgG against major components. A clear clinical predictor of neosensitization during SCIT was not found. Comparing symptom scores, patients seem to profit more from SCIT, if neosensitization remained absent. Patients undergoing SCIT might carry an enhanced risk of neosensitization towards formerly unrecognized allergen components. According to anamnestic data, these neosensitizations might be of clinical relevance - supporting attempts towards personalized recombinant vaccines.