Atopy--the genetic predisposition to produce allergen-specific IgE is one of the most important predisposing factors for the development of asthma and other allergic diseases. Because of pivotal place of IgE in early and late phase e of allergic responses the introduction of anti-IgE antibodies to therapy provides a novel and promising approach to treatment of asthma and other IgE-dependent diseases. The administration of anti-IgE reduces circulating IgE levels to less than 1% of the baseline value and down-regulates the expression of basophil IgE receptors. Anti-IgE antibody rhuMAb E25 (omalizumab) improved asthma symptoms, reduced the rates of exacerbations and allowed for the reduction of corticosteroids and rescue medication doses. Anti-IgE therapy is safe and well tolerated.