Lipid composition and viscosity of parotid saliva in Sjögren syndrome in man.

Extraction of the dialysed and lyophilized saliva of patients with this syndrome by chloroform-methanol yielded 15.9 +/- 2.4 mg of lipid/100 ml of secretion, a level 2-times higher than in normal individuals. The saliva of such patients also had 3-times more glycolipid and 20-times more phospholipid than normal, but differences in the content of neutral lipids were less apparent. The neutral lipids, however, had higher proportions of glycerides, and lower proportions of cholesterol and cholesteryl esters than normal. Viscosity measurements, made with a cone/plate viscometer at shear rates between 1.15 and 230 s-1, revealed similarities between the saliva of normal individuals and Sjögren's syndrome.