Subcutaneous Allergen Immunotherapy With Hypoallergenic Bet v 1 Compared to Conventional Extract: Poorer Blocking Antibody Capacity Dominated by <scp> IgG ₁ </scp> Instead of <scp> IgG ₄ </scp>

Preclinically established hypoallergenicity of BM41 did not result in a lower number of adverse events. The reduced induction of sIgG₄ by the fold variant in the course of the treatment was less efficient in blocking sIgE-mediated responses. This is the first study providing evidence that, instead of a Th1-favored IgG₁-dominated response, "modified Th2"-skewed IgG₄-dominated humoral responses are beneficial in AIT vaccine design.