Justification for IgE as a therapeutic target in chronic spontaneous urticaria

Monoclonal anti-IgE antibodies (omalizumab) are able to induce clinically significant benefits in patients with severe chronic spontaneous urticaria (CS). Those results led clinicians and investigators to reconsider a possible pathogenic role not previously supported for IgE and its receptors in this disease, and to investigate additional approaches for understanding its pathogenesis. IgE antibodies to unknown environmental allergens able to trigger chronic urticaria are not generally regarded as the etiologic factor for the disease. Other proposed mechanisms for the production of wheals and angioedema in CSU include IgG autoantibodies and CD4-positive T cells directed to the high-affinity IgE receptor, autoantibodies to IgE itself, IgE autoantibodies directed to thyroid and nuclear autoantigens, highly cytokinergic IgE, and histamine-releasing factors able to bind to IgE and cause mast cell activation. It is expected that a better knowledge on the mechanisms leading to CSU and the clarification of the immunological effects of anti-IgE will provide novel therapies for this frequent condition.