Table 16.1.

Diagnosis and BAL

Diagnosis	BAL features
Alveolar hemorrhage	Macroscopically bloody
	Increased intensity from fraction to fraction
	Free red blood cells
	Hemosiderin-laden macrophages
	Fragmented red blood cells in the alveolar macrophages
	≥20% siderophages
Alveolar proteinosis	Milky fluid, PAS  +  acellular corpuscles
	Foamy alveolar macrophages
	Large amounts of amorphous debris, weak PAS+
Cigarette smoking	Three- to fivefold increase of size of alveolar macrophages
	Inclusion bodies (cytoplasmic inclusion of tar products, lipids, lipofuscin)
Eosinophilic pneumonia	Eosinophils >25%
Hypersensitivity pneumonitis	Lymphocytosis >25%
	Highest lymphocyte count
	CD4/CD8 ratio decreased, but variable too
Infection	Infectious organisms by stains or cultures
Langerhans’ cell histiocytosis	CD1a  +  or Langerin  +  Langerhans’ cells >5%
	Typical smoker’s changings
Lipoid pneumonia	Oily material
	Lipid-laden alveolar macrophages
Malignant infiltrations	Malignant cells
Pneumoconiosis	Dust particles in alveolar macrophages
	Birefringent material in alveolar macrophages
Asbestosis	Increased asbestos body count
Sarcoidosis	Lymphocytosis >25%, but milder
	Moderate lymphocyte count only
	CD4/CD8 ratio >3.5 (in the absence of mixed cellular pattern)