Objective: To study the treatment of experimental metastatic lung carcinoma by intratracheal injection of IL-l8 gene recombinant adenovirus. Methods: (1)The mouse IL-18 mRNA was detected by RT-PCR, and the concentration of IL-18 and associated cytokines in lung lavages and blood were determined by ELISA at different time points after intratracheal injection of IL-18 recombinant adenovirus. (2)The lung metastasis nodes, mouse survival periods and survival rates were evaluated. NK activity and CTL activity were determined by 51Cr 4 h release method. Results: (1) IL-18 mRNA was detectable in lung tissue 6 h after intratracheal use of IL-18 recombinant adenovirus. and the concentration of IL-18 in lung lavage was higher than that in peripheral blood. Neither IL-18 mRNA nor IL-18 was detectable in control group. (2) Intratracheal use of IL-18 recombinant adenovirus resulted in increased CTL and NK activity, longer survival time and higher survival rates compared with the control group, showing significant therapeutic effect on expermental lung metastasis. Conclusion: Intratracheal use of adenovirus vector containing IL- 18 gene has therapeutic effect on the lung metastasis, denoting that gene therapy of lung diseases could be applied through airway directly with recombinant adenovirus. Objective: To study the treatment of experimental metastatic lung carcinoma by intratracheal injection of IL-l8 gene recombinant adenovirus. Methods: (1) The mouse IL-18 mRNA was detected by RT-PCR, and the concentration of IL-18 and associated cytokines In lung lavages and blood were determined by ELISA at different time points after intratracheal injection of IL-18 recombinant adenovirus. (2)The lung metastasis nodes, mouse survival periods and survival rates were evaluated. NK activity and CTL activity were determined by 51Cr 4 h release method. Results: (1) IL-18 mRNA was detectable in lung tissue 6 h after intratracheal use of IL-18 recombinant adenovirus. and the concentration of IL-18 in lung lavage was higher than that in peripheral blood. Neither IL -18 mRNA nor IL-18 was detectable in control group. (2) Intratracheal use of IL-18 recombinant adenovirus resulted in increased CTL and NK activity, longer survival time and higher survival rates compared with with control group, show Ing significant therapeutic effect on expermental lung metastasis. Conclusion: Intratracheal use of adenovirus vector containing IL-18 gene has therapeutic effect on the lung metastasis, denoting that gene therapy of lung diseases could be applied through airway directly with recombinant adenovirus.