A novel humanized anti-IgE antibody is disclosed. The antibody is capable of binding to free IgE, membrane-bound IgE on B lymphocytes, IgE bound by CD23, but not to IgE bound by high-affinity IgE.Fc receptor on mast cells. The present invention relates to the treatment of IgE-mediated diseases, including allergic asthma, allergic rhinitis, atopic dermatitis, food allergy, chronic spontaneous (idiopathic) urticaria, chronic rhinosinusitis, systemic mastocytosis, cutaneous mastocytosis, allergic bronchopulmonary aspergillosis, recurrent idiopathic angioedema, and eosinophil-associated gastrointestinal disorder by administering the anti-IgE antibody of the present invention.
