Measurement of T cell subsets in bronchoalveolar lavage fluid for diagnosis of pulmonary sarcoidosis

Pulmonary sarcoidosis is characterized by the accumulation in the lower respiratory tract of large numbers of activated CD4 T cells and elevated ratio of CD4/CD8 in bronchoalveolar lavage fluid (BALF). To study the value of CD4/CD8 ratio in BALF in the diagnosis of pulmonary sarcoidosis, we measured T cell subsets in BALF of patients with pulmonary sarcoidosis. The CD4/CD8 ratio in the patients (7.5 +/- 4.3) was significantly higher than that of the controls (2.1 +/- 0.7). The sensitivity and specificity of CD4/CD8 ratio in BALF for the diagnosis of sarcoidosis were 86% and 100%, respectively. We found that the CD4/CD8 ratio in BALF plays an important role in the diagnosis of pulmonary sarcoidosis. The analysis of CD4 in BALF may be useful in assessing the activity of sarcoidosis. The measurement of the CD4/CD8 ratio may be used to determine prognosis of pulmonary sarcoidosis.