[KL-6 in patients with interstitial pneumonitis]

Levels of KL-6 are high in serum and in bronchoalveolar lavage fluid (BALF) from patients with interstitial pneumonitis. To examine the usefulness of the KL-6 level as a marker of disease activity in interstitial pneumonitis, KL-6 was measured in serum and in BALF from patients with this disease. Correlations between KL-6 levels and the number of cells in BALF and between KL-6 levels and pulmonary function were computed. Serum KL-6 levels were abnormally high and correlated with the number of lymphocytes in BALF in patients with interstitial pneumonitis. Furthermore, changes in serum KL-levels reflected clinical coursed in these patients. KL-6 levels in BALF were very high and correlated with the total number of cells, and with the numbers of lymphocytes, neutrophils, and eosinophils in BALF. KL-6 levels in serum and in BALF correlated significantly with %VC, %DLco, and %DLco/VA. These results suggest that KL-6 levels in serum and in BALF reflect the degree of alveolitis and of deterioration of pulmonary function in these patients, and that KL-6 is a useful indicator of disease activity in interstitial pneumonitis.