We studied the possibility of IL-2 application in the complex treatment of the asthmatic patients. 18 patients, who received the Roncoleukin therapy («Biotech», St. Petersburg, Russia), and 16 patients of the control group with traditional anti-inflammatory and bronchodilative therapy were examined. The mild or moderate form of primary allergic bronchial asthma in the abating exacerbation or remission phase was diagnosed in all the cases. We fulfilled the bronchoscopy, immunoglobulin profile monitoring with calculation of permeability coefficients blood/lavage and relative coefficients of the secretion for immunoglobulins. We also evaluated spontaneous and induced by lypopolysaccharides TNF-α production by blood mononuclears. Our results showed good clinical acceptability of Roncoleukin in all examined patients, lack of allergic responses to the Roncoleukin administration, and considerable effectiveness of its application. We observed both clinical and lung function indexes (OFV1) improvement after Roncoleukin treatment in patients with bronchial asthma. Thus, we showed the possibility and advisability of the Roncoleukin insert in complex therapy of the asthmatic patients. (Med. Immunol., 2000. Vol. 2, N 3, pp 311-320)