KL-6, a mucinous glycoprotein, as an indicator of chronic lung disease of the newborn.

KL-6 is a mucinous glycoprotein that is preferentially expressed by alveolar type 2 cells. Plasma KL-6 was higher in infants with chronic lung disease (n = 12) than in infants without chronic lung disease (n = 14) on day 0-1, 10, and 30 (P =.04). KL-6 correlated with the alveolar-arterial oxygen tension difference on day 10 and day 30. Plasma KL-6 may be useful as an early marker of chronic lung disease and an indicator of severity.