Elevated level of soluble interleukin-2 receptor in bronchoalveolar lavage fluid from sarcoidosis patients

Pulmonary sarcoidosis is a granulomatous disorder of unknown cause, characterized by an accumulation of active T lymphocytes in the lung. We measured the levels of soluble interleukin-2 receptor (IL-2R) in bronchoalveolar lavage fluid (BALF) of patients with active pulmonary sarcoidosis and normal subjects by a sensitive enzyme-linked immunosorbent assay. Soluble IL-2R was detectable in BALF from 6 of 11 patients with sarcoidosis but in only 1 of 8 normal control subjects, the mean levels of IL-2R in BALF of the two groups being 2.8 +/- 0.9 U/ml and 0.1 +/- 0.1 U/ml, respectively (p less than 0.01). A slight correlation was found between the soluble IL-2R level and the number of CD4-positive cells. Sarcoidosis patients were classified by radiographical staging. Soluble IL-2R was not detectable in the BALF of any stage I patients, but was found in the BALF of 6 of the 7 stage II and stage III patients. These results suggest that in the clinical management of patients with sarcoidosis, measurement of soluble IL-2R in BALF is useful for evaluating the activity of the lung disease is sarcoidosis.