PA-IGG ON PLATELET SUBPOPULATIONS OF DIFFERENT BUOYANT DENSITIES - HIGH-LEVELS ON THE LOW-DENSITY POPULATION IS AN ARTIFACT

We isolated subpopulations of normal blood platelets from platelet ric h plasma (PRP) and, in parallel, from platelet rich saline (PRS) on th e basis of their buoyant densities. The MPV, being smallest in the lig htest subpopulation, correlated significantly with platelet buoyant de nsity (P < 0.002). In agreement with previous reports, we showed that the least dense platelet subpopulation, separated from PRP, had a high level of PA-IgG (3,486 mol/plt). This value was significantly greater (P < 0.02) than PA-IgG in the lightest subpopulation separated from P RS (693 mol/plt). We believe that the procedure of separating platelet s from PRP artificially increased PA-IgG in the least dense subpopulat ion. Our data showed that when subpopulations were prepared from PRS, PA-IgG correlated with platelet buoyant density (P < 0.002), and that the subpopulation with the highest density had the highest level of PA -IgG. (C) 1994 Wiley-Liss, Inc.