Some of cells attracted in by chemotactic signals released by mast cells include eosinophils and macrophages. these cells release a variety of toxic proteins, such as major basic protein. this protein damages the respiratory epithelium causing structural changes (epithelial desquamation). also release various growth factors that cause hyperplasia's seen in asthmatic respiratory epithelium and signalling molecules that can sensitise the epithelium to further allergen challenges.