CYFRA-21-1, A CYTOKERATIN SUBUNIT-19 FRAGMENT, IN BRONCHOALVEOLAR LAVAGE FLUID FROM PATIENTS WITH INTERSTITIAL LUNG-DISEASE

1. It has been suggested that CYFRA21-1, a cytokeratin subunit 19 frag ment, is potentially useful for diagnosis and monitoring of lung carci noma. However, serum levels of CYFRA21-1 are also increased in a high proportion of patients with interstitial lung disease. In this study w e measured CYFRA21-1 levels in bronchoalveolar lavage fluid from 10 no rmal subjects, 18 patients with idiopathic pulmonary fibrosis and 14 p atients with sarcoidosis, and determined whether any relationship exis ts between CYFRA21-1 levels in bronchoalveolar lavage fluid and clinic al parameters. 2. CYFRA21-1 levels in bronchoalveolar lavage fluid wer e significantly higher in patients with sarcoidosis (mean value 8.3 ng /ml, P < 0.01) and idiopathic pulmonary fibrosis (42.5 ng/ml, P < 0.00 5) than in normal controls (1.0 ng/ml), Moreover, higher CYFRA21-1 lev els in bronchoalveolar lavage fluid were found in sarcoidosis patients in radiological stage 2 or 3 than in those in stage 1, In patients wi th idiopathic pulmonary fibrosis, there was a significant correlation between CYFRA21-1 levels, and percentage of inflammatory cells in bron choalveolar lavage fluid (r = 0.56, P < 0.05) and the magnitude of the alveolar - arterial oxygen pressure difference [P(A-a)O-2] gradient ( r = 0.66, P < 0.01). 3. Serial bronchoalveolar lavage samples were obt ained from six patients with clinically active pneumonitis after they had undergone systemic corticosteroid therapy. CYFRA21-1 levels were s ignificantly lower after these patients exhibited clinical improvement (P < 0.05). 4. These findings suggest that the level of CYFRA21-1 in bronchoalveolar lavage fluid is a useful marker for the clinical diagn osis of pneumonitis, and is also adequate for the evaluation of diseas e activity, especially over the course of treatment.