[A case of pulmonary sarcoidosis with CD8 positive cell dominant alveolitis].

A 55-year-old woman was admitted for examination of bilateral hilar lymphadenopathy. Serum angiotensin converting enzyme was not elevated, but gallium-scan revealed an increased uptake in both lung hilus. The percentage of lymphocytes in the bronchoalveolar lavage fluid (BALF) was elevated (28.9%), and the proportion of OKIa1 positive cells was also elevated (50.5%). However, the ratio of cluster differentiation (CD) 4/8 was inverted at 0.5. Microscopic examination of the mediastinal lymph nodes revealed epithelioid cell granulomas without ceasation, and a diagnosis of sarcoidosis was made. Immunohistochemical examination of the lymph nodes showed predominancy of CD8 positive cells. Patients with pulmonary sarcoidosis having a low CD4/8 ratio in BALF are extremely rare in the early stage of sarcoidosis. The inverted CD4/8 ratio was of interest in regard to the pathogenesis of sarcoidosis.