We initiated this study to determine the cellular composition and T-lymphocyte subpopulations of fluid from bronchoalveolar lavage from 15 patients with primary Sjögren's syndrome (1SS), six patients with secondary Sjögren's syndrome associated with primary biliary cirrhosis (2SS-PBC), eight patients with secondary Sjögren's syndrome associated with collagen-vascular diseases (2SS-CVD), and 12 normal subjects. All were nonsmokers who were free of clinical pulmonary symptoms and had normal findings on chest roentgenograms. Lymphocyte subsets were identified by mouse monoclonal antibodies that were specific for T-cells, helper/inducer, and suppressor/cytotoxic (namely, OKT3, OKT4, and OKT8). Patients with 1SS, patients with 2SS-PBC, and patients with 2SS-CVD had a significantly increased percentage of lymphocytes in fluid from bronchoalveolar lavage (respectively, 21.6 +/- 3.7 percent, 24.3 +/- 6.1 percent, and 25.6 +/- 3.9 percent) compared with the normal value of control subjects (9.9 +/- 1.5 percent). In addition, two of the 15 patients with 1SS and five of the eight patients with 2SS-CVD demonstrated an increased percentage of alveolar neutrophils. The predominant T-cell subset in patients with 1SS was T4+, and the mean T4:T8 ratio was normal. The percentage of T4+ cells was increased in patients with 2 SS-PBC, resulting in an increased T4:T8 ratio. In contrast, patients with 2 SS-CVD demonstrated a markedly increased percentage of T8+ cells, reflected by a shift in the T4:T8 ratio which was inverted. Patients with Sjögren's syndrome and with neutrophilia on bronchoalveolar lavage had a marked expansion of the T8+ lymphocyte subpopulation, where as patients with Sjögren's syndrome and with pure lymphocytosis on bronchoalveolar lavage showed predominantly T4+ cells. In addition, we found a strong positive correlation between the number of neutrophils and the number of T8+ cells in bronchoalveolar lavage from patients with Sjögren's syndrome (r = 0.74; p less than 0.05). Until the functional activities of OKT4+ and OKT8+ cells are better defined, the role that these cells play in the pathogenesis of pulmonary disease in Sjögren's syndrome remains unclear.