The airways of LPI lungs with PAP contain high levels of protein, dying cells and has low bioavailability of SP-D. (A) BCA assay results showing the protein concentrations of the BALF in each collectin vial (left lung). Protein concentration gradually decreased with subsequent lavages. No noticeable changes in protein concentrations occur after about 10 washes with 100 ml saline each. (B) Protein concentrations determined by BCA assay on the samples present in the first collection vial of four lavages conducted on separate occasions. BAL1, left lung; BAL2-4, right lung. Control sample was obtained from a diagnostic BAL from a patient with bronchitis. (C) Trypan blue exclusion assay showing the dead cells present in the BALF. Values represent the % of dead cells present in the total cells isolated from the BALF. (D) Western blot for SP-D. Initial lavage samples contained slowly migrating SP-D (smear). Later samples show multiple SP-D bands with lower molecular weights suggestive of degraded SP-D fragments. (E and F) LPI lung surfactant contains altered atypical tubular myelin with circular lattice. TEM analysis was performed on lipid pellet isolated from 10,000 × g centrifugation of cell-free LPI BALF. (E) High abundance of amorphous electron dense lipid-droplet like material (arrow) and some classical SP-A-mediated tubular myelin structures with square lattice-like structures are seen (arrowhead). (F) Large numbers of atypical tubular myelin structures with circular lattices and a central electron dense dot are also detected (~90 nm diameter; arrows). Bar, 100 nm (E and F).