Neutrophil adhesion in the presence of (top) a PAF receptor antagonist (WEB 2086; 20 μg/mL) or after (bottom) platelet monolayer treatment either with PAF-acetylhydrolase or the solvent (placebo). The placebo and acetylhydrolase group were compared with an untreated monolayer, and the data are presented as a percentage of adhesion relative to the 10-minute value for untreated platelet monolayers. *P < .05 relative to placebo value. (A) (◍) WEB 2086-treated neutrophils; (▧) untreated neutrophils. (B) (•) Placebo-treated monolayers; (□) PAF-acetylhydrolase–treated monolayers.