Factors related to inflammation, including platelet-activating factor
(PAF), apparently have a role in chronic otitis media with effusion. P
AF is metabolized to the biologically inactive lyso-PAF by the enzyme
PAF-acetylhydrolase (PAF-AH). We have obtained evidence that PAF-AH ac
tivity is present in human middle ear effusions in patients with chron
ic otitis media with effusion. The present study revealed the enzyme i
n human middle ear effusions to be the plasma type PAF-AH. We suggest
that PAF-AH may be involved in regulating inflammation in the middle e
ar by inactivating PAF, the potent proinflammatory autacoid.