Immunologic studies of alveolar macrophages from patients with metastatic renal cell carcinoma

Alveolar macrophage function in patients with renal carcinoma, a disease characterized by frequent pulmonary metastases, has not been examined. The purpose of this study was to evaluate tumoricidal responses of alveolar macrophages in renal carcinoma to determine if such activity is compromised. Alveolar macrophages and/or blood monocytes were obtained from 26 normal volunteers and 16 patients with renal carcinoma. Tumoricidal activity of alveolar macrophages and monocytes was assessed against 3H-thymidine-labeled tumor target cells. Patient alveolar macrophages and monocytes exposed to lipopolysaccharide (LPS) or recombinant interferon-gamma expressed tumoricidal activity comparable to those in normal subjects. Activated alveolar macrophages recognized and lysed neoplastic cells (including allogenic renal carcinoma cells), but not nonneoplastic cells. Alveolar macrophage and monocyte tumoricidal responses of patients with pulmonary metastases were not different from those of patients with metastases to other sites. These results indicate that alveolar macrophages from patients with renal carcinoma with or without pulmonary metastases are not compromised in vitro, but respond to immunomodulators with enhanced tumoricidal activity in the same fashion as do alveolar macrophages from normal volunteers.