COMPOUNDS BIOLOGICALLY SIMILAR TO PLATELET-ACTIVATING-FACTOR ARE PRESENT IN STORED-BLOOD COMPONENTS

Agents which prime the neutrophil NADPH oxidase develop during routine storage of whole blood and packed red blood cells. This plasma primin g activity can be inhibited by bepafant (WEB 2170), a specific platele t activating factor (PAF) receptor antagonist. Quantitation of the pri ming agent(s), by a commercially available radioimmunoassay for PAF, r eproducibly demonstrated high levels of PAF activity. However, analysi s of these plasma samples from stored blood components by gas chromato graphy/mass spectroscopy did not reveal any 1-O-alkyl-2-acetyl-sn-glyc ero-3-phosphocholine. We conclude that the polyclonal antibody to PAF used in these studies may have recognized different epitopes of a fami ly of heterogeneous, biologically active lipids that manifest their ef fects through the PAF receptor.