Supplementary Figure 3

Diagram of changes in the surfactant subtype distribution in acute respiratory distress syndrome (ARDS). Under physiological conditions, some 80–90% of the extracellular surfactant material is in the large surfactant aggregate fraction, which has a high surfactant apoprotein B (SP-B) content and excellent surface activity (γmin; = minimum surface tension after 5 min of film oscillation). In inflammatory lung disease (as in severe pneumonia or ARDS), the small surfactant aggregates increase as SP-B and surface activity within the large-aggregate fraction decrease.