Lung involvement in rheumatoid factor-negative arthritis.

Bronchoalveolar lavage (BAL) was performed on 13 asymptomatic patients with sero (rheumatoid factor)-negative arthritis (SNA); (6 with peripheral psoriatic arthritis, 2 with axial psoriatic arthritis, 3 with ankylosing spondylitis, 2 with sacroiliitis). BAL revealed a significant decrease of neutrophil granulocytes and an increase of B-lymphocytes in patients with SNA in comparison with 64 patiénts with rheumatoid arthritis (RA; 24 seronegative, 39 seropositive) and 15 healthy controls. Patients with SNA and RA had a significant increase of lymphocytes, especially T, T-helper and activated cells. In addition patients with RA had a significant increase of natural killer cells and a lower percentage of alveolar macrophages and T-suppressor cells. Transbronchial biopsy was performed on 9 patients with SNA and on 59 patients with RA. Abnormal histologic features of lung tissue were observed in 4 out of 9 patients with SNA (2 with fibrosis, 1 with follicular lymphoid hyperplasia, 1 with desquamative interstitial pneumonitis). The abnormal lung histology in RA patients was more pronounced, however, the differences between SNA and RA were not significant. The data from BAL and histology suggest, that the pulmonary involvement in SNA and RA is caused by an unspecified immunologic process.