RELIABILITY OF BRONCHOALVEOLAR LAVAGE FLUID LYMPHOCYTES COUNT AND BLOOD NEOPTERIN LEVELS AS INFLAMMATORY MARKERS IN SARCOIDOSIS

Background: Sarcoidosis is an inflammatory granulomatous disease of unknown origin. Lungs and thoracic lymph nodes are most frequently affected. To assess inflammatory process activity, disease activity criteria are to be identified. In clinical practice, bronchoalveolar lavage (BAL) fluid lymphocytes count and blood neopterin levels are commonly used for the monitoring of inflammatory activity in sarcoidosis, though, reliability of the methods may be inadequate. Aim: To assess reliability of BAL fluid lymphocytes count and blood neopterin levels as inflammatory markers in pulmonary sarcoidosis. Materials and methods: BAL fluid lymphocytes counts and blood neopterin levels were measured in 111 patients with pulmonary sarcoidosis. 39 patients had stage I sarcoidosis on chest radiographs, 57 patients had stage II, 15 patients had stage III sarcoidosis. In 28 patients, BAL fluid was sampled from different segments of the lung to compare lymphocytes counts. The results were paralleled with pulmonary function tests, radiographic stage and lung parenchyma changes in computed tomography. Results: Lymphocytes counts in BAL fluid correlated with blood neopterin levels (r=0.26, p=0.027), forced vital capacity value (r=-0.24, p=0.04), and did not correlate with sarcoidosis radiographic stage. In 43% of patients, relative lymphocyte counts in BAL fluid samples from different parts of the lung varied significantly (from 5 to 23%). Normal neopterin levels were detected in 40% of patients with active inflammation. Conclusion: Non-uniform pattern of pulmonary inflammation results in variable lymphocytes counts in BAL fluid samples from different parts of the lung. BAL fluid lymphocytes counts and blood neopterin levels should not be used for reliable monitoring of inflammation in sarcoidosis.