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. 2022 Dec 1;108(4):1127–1140. doi: 10.3324/haematol.2022.280651

Figure 1.

Figure 1.

Induction of Weibel-Palade bodies exocytosis on endothelial cells afer stimulation with immune-mediated thrombotic thrombocytopenic purpura plasma. (A) Confocal microscopy analysis of permeabilized human microvascular endothelial cells from derm (HMVEC-d) incubated with either control plasma (A) or immune-mediated thrombotic thrombocytopenic purpura (iTTP) plasma samples (B) using rabbit anti-von Willebrand Factor (VWF) antibodies and Alexa Fluor 594-conjugated donkey anti-rabbit immunoglobulin G (IgG) (original magnification X63, scale bar=10 mm). (B) Quantification of VWF fluorescence intensity (FI) after HMVEC-d stimulation with either control plasma (Control: n=9) or iTTP plasma samples during the acute phase (iTTP: n=14, ***P<0.001). (C) Kinetics of VWF HMVEC-d exocytosis visualized by fluorescence microscopy after incubation with iTTP plasma samples (original magnification X40, scale bar=10 mm). (D) Quantification of VWF FI over time on HMVEC-d stimulated with iTTP plasma samples (iTTP: n=5, *P<0.05, **P<0.01). (E) Endothelin-1 and (F) angiopoietin-2 concentrations in HMVEC-d supernatants stimulated with either control plasma (n=6) or iTTP plasma samples for 1h (n=25, *P<0.05). (G) P-selectin expression detected by confocal microscopy analysis using anti-rabbit P-selectin antibodies and Alexa Fluor 488-conjugated donkey anti-rabbit IgG (green) in HMVEC-d incubated with control (A) or iTTP plasma samples (B) (original magnification X63, scale bar=10 mm). (H) Percentage of P-selectin FI per cell on HMVEC-d stimulated with control plasma (n=10) (representing 100%) or iTTP plasma samples (n=23, ***P<0.001).