Recovery from pulmonary edema requires clearance of both liquid and protein from the alveolar space. Passive mechanisms are important for protein clearance in the first few days after alveolar flooding, but cellular mechanisms appear to increase in importance after two to three days. Protein degradation increases and more alveolar protein is associated with alveolar macrophages. Alveolar macrophages take up soluble and insoluble forms of albumin from the alveolar space more avidly than other cell types (Hastings RH et al. Cellular uptake of albumin from lungs of anesthetized rabbits. Am J Physiol: Lung Cell Molec Physiol 13:L453-L462, 1995).
References about alveolar liquid and protein clearance