FACS analysis on microparticles derived from adherent PMNs. Flow cytometric analysis of adherent PMN (to HUVEC monolayers)–derived microparticles, with acquisition of 5 to 10 000 events per sample. (A) Dot plot showing the heterogeneity in microparticle sizes; circled dots refer to 1-μm beads run in parallel as internal control. (B-F) Histograms demonstrating detection of AnxA1, L-selectin (CD62L), and phosphatidylserine (using FITC-labeled annexin V) in PMN-derived microparticles, with no signal observed for CD62P and CD14. Isotype control staining (gray histograms) is also shown. Data are representative from 3 or more independent microparticle preparations.