Histopathological changes of the lung were studied with transbronchial lung biopsy (TBLB) in 9 patients with definite or classical rheumatoid arthritis (RA). The patients were between 41 to 65 years old (the average age: 57.6 years old). Fibrosis was found in all specimens examined. A mild lymphocytic infiltration in alveolar septa in one case and infiltration of macrophages in alveolar spaces in 4 cases were found. In 4 out of these five cases, rheumatoid factor (RF) and CRP were positive and obstructive type of respiratory dysfuction was observed.
