auto PAF-AH.... Platelet-activating factor (PAF) is a biologically active phospholipid synthesized by a variety of mammalian celltypes. It is a mediator for allergic and inflammatory reactions. PAF is converted to the biologically inactive lyso-PAF by PAF acetylhydrolase (PAF-AH), which catalyzes the hydrolysis of the esterified acetate at the sn-2 position. + Learn More