Am. J. Respir. Crit. Care Med., Vol 152, No. 1, 07 1995, 360-366.
Ultrastructural features of alveolitis in sarcoidosis
T Takemura, Y Hiraga, M Oomichi, M Oritsu, O Akiyama, Y Matsui, Y Eishi and R Mikami
Department of Pathology, Japanese Red Cross Medical Center, Tokyo.
Seventy-nine specimens of lung parenchyma from 61 patients with sarcoidosis
were examined ultrastructurally with a focus on alveolitis, and they were
compared with specimens of hypersensitivity pneumonitis (HP) and the
percentage of lymphocytes in bronchoalveolar lavage fluid (BALF).
Lymphocytes and monocytes were frequently observed in the capillary lumina,
and these cells and macrophages were found in the interstitium of the
alveolar walls in the specimens with alveolitis of sarcoidosis and HP.
Increases in the percentage of lymphocytes in BALF correlated with the
degree of alveolitis. Swelling and bleb formation of the endothelium of
alveolar capillaries and changes in the capillary basement membrane were
commonly found and were significantly increased in the specimens with
alveolitis. The frequency of bleb formation was significantly higher in
alveolitis of sarcoidosis than in that of HP. However, the changes in
alveolar epithelium were not significant in sarcoidosis. Microvascular
changes in alveolitis are not specific for sarcoidosis, but they are
observed in other interstitial lung diseases. These alterations may play an
important role in the development of pulmonary sarcoidosis.
