PED/PEA-15 protein was measured in white-blood cells (WBC) lysates obtained from 10 to 12 ml of freshly collected uncoagulated whole blood, after separation with dextran 6%, using Western blot analysis. For Western blot analysis WBC were solubilized at 4°C in TAT buffer, centrifuged at 500g for 20 min, and supernatant fractions were stored at -20°C until used. The amount of 50 μg of lysate proteins were heated at 100°C in Laemmli buffer. Proteins were separated by 15% SDS-PAGE and then transferred to 0•45-mm Immobilon-P membranes (Millipore, Bedfort, MA). Filters were probed with PED/PEA-15 antiserum at 1:2000 dilution, revealed by enhanced chemiluminescence and autoradiography. The protein bands were quantified by laser densitometry and expressed as percentage of pixels (arbitrary units).