Clinical, roentgenologic, functional and broncho-alveolar lavage features of lung involvement in primary Sjögren's syndrome were assessed in a retrospective study of 35 cases. Diffuse interstitial patterns on chest radiography were present in six patients and alveolar patterns were suggestive of lymphoid interstitial pneumonitis or pseudolymphoma in two. Acute and febrile onset mimicked infectious pneumonitis in three patients when dyspnea was the most common clinical feature in others. Patients with primary Sjögren's syndrome and pulmonary disease were older (65 vs 56 years) (P = 0.025), have more frequently extra-glandular manifestations (P = 0.03), keratoconjunctivis sicca (P = 0.018) and biological perturbations (hypergammaglobulinemia (P = 0.03), antinuclear antibodies (P = 0.01) than those without lung involvement. Low diffusion capacity was present in seven patients associated twice to small airways obstruction. Bronchoalveolar lavage revealed in all cases an increased total cells count (mean: 6.96 10(5)/mm3) and a lymphocytic alveolitis (range: 11 to 66%; mean: 38%) associated with an elevated percentage of alveolar neutrophils in four patients. A low CD4/CD8 ratio was related to a pejorative issue. Treatment consisted in corticotherapy combined with oral cyclophosphamide in case of pseudolymphoma.