[Isolation and partial characterization of (PAF) platelet-activating-factor].

Platelet-activating-factor is a new mediator of anaphylaxis released in numerous mammalian species from basophils and mastocytes by antigens, anti-IgE antiserum, ionophore A 23187, C3a, C5a and neutrophil cationic protein. It is probably a lyso-1-phosphatidylcholine, as evidenced by structural studies isomg phospholipases. It may explain the involvement of platelets in immunopathology.