Figure 1.
Mechanisms of mast cell activation in chronic spontaneous urticaria. Type I autoimmunity is characterized by diverse antigens such as thyroperoxidase (TPO) crosslinking IgE autoantibodies. Type IIb autoimmunity is based on IgG autoantibodies against IgE or FcԑRI. Both autoimmune mechanisms lead to a degranulation of mast cells.