T-cell subsets in sarcoidosis: an immunocytochemical investigation of blood, bronchoalveolar lavage fluid, and prescalenic lymph nodes from eight patients.

T-lymphocyte subsets in peripheral blood, bronchoalveolar lavage fluid, and prescalenic lymph nodes from eight patients with sarcoidosis were evaluated with monoclonal antibodies. Both in lung and lymph nodes significant increases in helper T cells were demonstrated, except in patients with stage III pulmonary disease or with unaffected lymph nodes. A good statistical correlation was observed between the activity of the disease (expressed by an increased ratio of helper to suppressor/cytotoxic T cells) in bronchoalveolar fluid and in lymph node cell suspensions from each patient. A three-step immunoperoxidase staining reaction, performed on lymph node frozen sections, showed a prevalence of helper T cells both inside and around the granulomas. These findings confirm that sarcoidosis is characterized by increased activity of cell-mediated immunity in its different localizations.