KL-6 is a mucinous glycoprotein that is preferentially expressed by alveola
r 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 te
nsion difference on day 10 and day 30. Plasma KL-6 may be useful as an earl
y marker of chronic lung disease and an indicator of severity.