Immunologic changes with allergen immunotherapy

During allergen immunotherapy, several consistent immunologic changes are observed. Allergen-specific Treg cells are generated, which express multiple suppressor factors, such as IL-10, TGF-beta, IL-10R, TGF-beta-R, CTLA4, PD1, HR2, FOXP3, and RUNX. Breg cells, producing IL-10 and IgG4 and expressing CD25 and CD71 on their surface, are also generated. Both Treg and Breg cells suppress allergen-specific effector Th2 cells. In addition, mast cell and basophil activity decreases, and Th2 and ILC2 responses are suppressed. Over time, allergen-specific IgG4 in the serum increases and allergen-specific IgE decreases.