Fig 3. Mechanism of immune changes after treatment with allergen immunotherapy.

During the course of AIT, several groups of cellular and molecular events take place. Within hours, there is a noted decrease in mast cells and basophil activity and degranulation leading to a decrease in type 1 skin test reactivity. Treg cells and their cytokines suppress Th2-type immune responses and help control the allergic diseases. During AIT, Breg cells are activated and suppress T cells and contribute to IgG4 synthesis, whereas Tregs suppress the allergic process by preventing and inhibiting inflammation in many different cell types.