Deficiency of salivary PAF in edentulous individuals

PAF, a potent phospholipid mediator of inflammation, is present in normal human, mixed saliva. However, the anatomic origin of PAF is not known. In this study, PAF levels in mixed saliva of edentulous subjects were estimated in comparison to that of dentate individuals. PAF activity was assessed in bioassay and expressed relative to the activity of known amounts of authentic PAF, 1-O-hexadecyl-2-acetyl-sn-glycero-3-phosphocholine (AGEPC). PAF was not detected in the saliva of 60% of the edentulous subjects; moreover, when present, the PAF levels were significantly less (635 +/- 82 AGEPC fmole equivalents/ml saliva, mean +/- SEM, n = 6) than in dentate subjects (5568 +/- 1135 AGEPC fmole equivalents/ml saliva, n = 27). Of relevance, the numbers of polymorphonuclear leukocytes in the mixed saliva samples of edentulous subjects were markedly reduced when compared to those of normal subjects. These findings suggest that salivary PAF most likely originates from the crevicular space, and derives from inflammatory cells within the gingival and/or periodontal tissues.