Platelet activating factor (Paf-acether, AGEPC) is a family of ether-linked phospholipids known to be released from a range of inflammatory cell types. In vitro and in experimental animals, it seems to be a mediator of inflammation, and intradermal injection of Paf-acether in man elicits a biphasic inflammatory response, reminiscent of the dual response to allergen in sensitized individuals. In
... [Show full abstract] the present study, cutaneous histology was assessed in sequential skin biopsies from six normal volunteers after intradermal injection of 200 or 800 pmol Paf-acether. Paf-acether (200 pmol) induced intravascular accumulation of neutrophils, accompanied by a p erivascular mixed cellular infiltrate which was composed predominantly of neutrophils at 4 and 12 hours, and lymphocytes and histiocytes at 24 hours. Control injections of lyso-Paf and normal saline induced no noteworthy histological changes. Paf-acether (800 pmol) resulted in vessel destruction, gross endothelial swelling and a perivascular infiltrate of mononuclear cells and neutrophils, accompanied by occasional evidence of leucocytoclasis. By virtue of its ability to induce inflammatory cell accumulation in human skin, Paf-acether should be considered as a potential mediator of inflammatory disorders such as psoriasis.