T-lymphocyte subsets and immunoglobulin concentrations in bronchoalveolar lavage of patients with sarcoidosis and high and low intensity alveolitis.

Reproducible volumes of bronchoalveolar lavage (BAL) fluid were recovered from 19 patients with pulmonary sarcoidosis and from 6 control subjects using a standardized technique. Studies of cell surface markers showed that BAL from 9 patients contained more than 8 X 10(6) helper T-cells. These patients were classified as having high intensity alveolitis, whereas in 10 patients with lower cell counts, low intensity alveolitis was diagnosed. Activated helper T-cells coexpressing Leu-3a and Ia-antigens were significantly more numerous in BAL from patients with high intensity alveolitis than in BAL from the other patients and the control subjects. Concentrations of IgM, IgA, and IgG, but not of albumin were markedly increased in BAL from patients with high intensity alveolitis when compared with the other subjects. In BAL from both patient and control groups, numbers of helper T-cells and particularly of activated helper T-cells were correlated with immunoglobulin concentrations. In 4 patients with high intensity alveolitis, prednisone-induced and spontaneous clinical improvement were paralleled by a decrease in helper and activated helper T-cells and in immunoglobulin concentrations in BAL, indicating conversion of high to low intensity disease. No change was observed in 4 patients with low intensity alveolitis.