Role of antitumor activity of alveolar macrophages in lung cancer patients.

The purpose of this study is to clarify the significance of antitumor activity of alveolar macrophages (AM) in lung cancer patients. AM from tumor-bearing and non-tumor-bearing segments were obtained separately by the lavage of bronchoalveolar tracts of resected lungs of 74 patients with primary lung cancer. Cytostatic activity (CTS) of AM obtained from non-tumor-bearing segments was stable in spite of enlargement of tumor size or progression of N factor. In contrast, CTS of AM obtained from tumor-bearing segments may be augmented at Stage II as compared with Stage I, and suppressed with an advance of stage from II through IV, although the number of Stage II patients was as small as three. Moreover, CTS of AM from tumor-bearing segments was suppressed in N2 as compared with N0 or N1, and also it was suppressed as compared with that of AM from non-tumor-bearing segments in N2 disease. CTS of AM from smokers was suppressed as compared with that of nonsmokers in both tumor-bearing and non-tumor-bearing segments. These results suggest that lung cancer cells or their products may suppress antitumor activity of AM in the tumor-bearing segments at advanced stages, and cigarette smoking is a suppressive factor on antitumor activity of AM.