Lipid composition of sputum from patients with asthma and patients with cystic fibrosis.

Lipids from the sputum of patients with asthma and with cystic fibrosis were isolated and characterized. In both cases, lipids constituted approximately 30% of the dry material. Phosphatidlycholine was the most abundant lipid, Significant amounts of phosphatidylethanolamine and phosphatidylglycerol were present. Hexosyl ceramides, sphingomyelin, phosphatidylinositol, lysophosphatidylcholine, and lysophosphatidylethanolamine were present as minor lipid components. Apperciable quantities of neutral lipids were present, of which triglycerides and cholesterol were the main constituents. Phosphatidylcholine, sphingomyelin, and phosphatidylgycerol were highly saturated. Large amounts of phosphatidylcholine containing mostly palmitic acid, particularly in the asthmatic sputum, suggest htat this highly saturated. Large amounts of phosphatidylcholine containing mostly palmitic acid, particularly in the asthmatic sputum, suggests that this highly saturated phospholipid is synthesized in the upper airways for reasons other than its beneficial surface-active properties in the alveoli.