IL-8 and TNF-α, but not IL-6, stimulated the release of ULVWF multimers. HUVECs were stimulated with TNF-α (50 ng/mL), IL-6 (100 ng/mL), or IL-8 (100 ng/mL) for 30 minutes and then perfused with washed platelets suspended in Tyrode buffer at 2.5 dyne/cm². The formation of the platelet-decorated ULVWF strings was detected on endothelial cells stimulated with TNF-α (A) or IL-8 (B), but not on those stimulated with IL-6 (C). Histamine-stimulated endothelial cells (D) were used as positive control. No strings formed on untreated endothelial cells (E). The figure is a representative of 6 separate experiments (bar = 100 μm).