Immunotherapy of allergic diseases first called desensitization or hyposensitization is based on the introduction by parenteral administration or perhaps also by mouth of the allergens which has been considered to be responsible by the clinical symptoms. Immunotherapy partially corrects the imbalance of immune response decreasing IgE response and increasing the production of IgG1 and IgG4 antibodies either by direct effect or by an effect on specific T helpers and T suppressors subsets.