There is mounting evidence that successful allergen immunotherapy (SIT) functions through the induction of different subset of Treg including Foxp3 positive cells, therefore additional strategies to enhance this property are highly attractive. Since corticosteroids directly induce the development of an IL-10-synthesizing regulatory T-cell population (Tr1) and this effect can be greatly increased with vitamin D3 treatment we , we assumed that combine allergen immunotherapy with non-specific treatments such as glucocorticosteroids and vitamin D3 as well as montelukast sodium treatment might enhanced allergen tolerance induction and improved clinical effectiveness of allergen-specific immunotherapy, therefore we conducted the stud comparing the effect of glucocorticosteroid, glucocorticosteroid with vitamin D3 or montelukast sodium on early immunological and clinical effect of allergen-specific immunotherapy in asthmatic children.