[Interstitial pneumonia associated with collagen vascular diseases: histological findings, and cells in bronchoalveolar lavage fluid].

Collagen vascular diseases are systemic inflammatory disorders, and autoimmune abnormalities play an important role in their pathogenesis. The lungs are often involved and the manifestations can be quite heterogenous. Cases of interstitial pneumonia associated with collagen vascular disease must be distinguished from infection, malignancy, cardiac failure, and renal failure. The diversity of interstitial pneumonia can be seen in the results of computerized tomography and in cells found in bronchoalveolar lavage fluid (BALF). We examined the heterogeneity of interstitial pneumonia diagnosed by open lung biopsy, and evaluated the diagnostic accuracy of BALF cell findings by comparing then with results of histological studies. Three patterns of BALF cell findings were defined, and were used to study the heterogeneity of the interstitial pneumonia associated with collagen vascular diseases: sarcoidosis, usual interstitial pneumonia (UIP), and bronchiolitis obliterans organizing pneumonia (BOOP). In 36 patients with collagen vascular diseases, interstitial pneumonia was diagnosed by open lung biopsy: 15 patients had rheumatoid arthritis, 3 had systemic lupus erythematosus, 9 had systemic sclerosis, 6 had dermatomyositis/polymyositis, and 4 had Sjögren's syndrome. As disease controls, 78 patients with idiopathic pulmonary fibrosis and 12 with idiopathic BOOP diagnosed by open lung biopsy were used. BAL was done before the biopsy. In most patients, the interstitial pneumonia associated with systemic sclerosis was UIP and the BALF cell pattern was a UIP-pattern. In addition, BALF UIP-patterns were associated with histologic findings of UIP in samples obtained by open lung biopsy. In contrast, other collagen vascular diseases tended to be associated with a BALF BOOP-pattern, which included various histological findings. Thus, the BALF BOOP-pattern, is associated with BOOP, with cellular interstitial pneumonia, with lymphocytic interstitial pneumonia, and with UIP. The BALF sarcoidosis-pattern is rare in patients with interstitial pneumonia associated with collagen vascular diseases.