Nodular endobronchial sarcoidosis: a study comparing blood and lung lymphocytes.

Patients with active sarcoidosis have a depression in systemic cell-mediated immunity manifested by lymphopenia, a reduction in circulating T cells, and impaired responses of these cells to polyclonal mitogens and recall antigens. Studies of bronchoalveolar cells (BA) have disclosed characteristic changes in lymphocyte populations that are opposite to what is found in peripheral blood. Since previous lavage studies have not specifically addressed endobronchial disease, we present results of peripheral blood (PB) and BA lymphocyte studies in a patient with acute pulmonary sarcoidosis who had gross endobronchial nodules. The lymphocytosis in the BA air space of this patient was greatly increased compared with patients with newly diagnosed sarcoidosis but no overt endobronchial disease. Cell surface markers, morphology, and in vitro proliferative response indicated that the BA lymphocytes were stimulated and more reactive than PB lymphocytes, suggesting a local immune inflammatory response. Bronchial biopsy specimens showed mononuclear cell infiltration of the epithelium overlying the inflammatory nodules. The biopsy examination and great increase in lymphocytes recovered from the airways suggest that the bronchi were a source of the BA lymphocytes. Since clinically inapparent bronchial involvement is frequent in sarcoidosis, inflamed bronchi may also be a source of BA lymphocytes in the absence of conspicuous endobronchial nodules.