Quantitative effects of immunosuppression on bronchoalveolar cells

The use of immunosuppressive chemotherapy is associated with an increased incidence of pneumonia. An animal model is described in which drug-induced defects in pulmonary host defense may be evaluated. Guinea pigs receiving cyclophosphamide (15 mg/kg) plus cortisone acetate (100 mg/kg) daily for seven days developed leukopenia (1.5 X 10(3) cells/mm3), neutropenia (0.4 X 10(3)/mm3), and lymphocytopenia (0.7 X 10(3)/mm3) and also lost prior skin hypersensitivity to purified protein derivative. No animal bled or died unexpectedly during immunosuppression. Transtracheal bronchoalveolar lavage of normal and immunosuppressed animals revealed a significant decrease in the number of pulmonary alveolar macrophages during immunosuppressed periods. Cell viability, phagocytosis of latex particlex, and adherence to plastic surfaces were not decreased in immunosuppressed alveolar macrophages. This animal model should allow further studies of cellular and humoral pulmonary immune parameters during a variety of immunosuppressive drug regimens.