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

Figure 4.

Figure 4.

Immunoglobulin G contained in immune-mediated thrombotic thrombocytopenic purpura plasma are mainly involved in permeabilized human microvascular endothelial cells from derm activation. (A) Von Willebrand Factor (VWF) secretion detected by fluorescence microscopy after permeabilized human microvascular endothelial cells from derm (HMVEC-d) incubation with complete immune-mediated thrombotic thrombocytopenic purpura (iTTP) (A) or immunoglobulin (IgG)-depleted (B) plasma samples (original magnification X20, scale bar=30 mm). (B) Fluorescence intensity (AU) of the Ca2+ flux induction in HMVEC-d after a 20-second incubation with complete iTTP or IgG-depleted plasma samples (n=15, ***P<0.001). (C) VWF secretion detected by fluorescence microscopy after HMVEC-d incubation with IgG purified from control (A) or iTTP plasma samples (b) (original magnification X40, scale bar=30 mm). (D) VWF quantification by enzyme-linked immunosorbant assay in the supernatants of cells treated with IgG purified from control (n=7) or iTTP plasma samples (n=16, *P<0.05). (E) Fluorescence intensity (AU) of Ca2+ flux induction in HMVEC-d after 20 seconds incubation with IgG from control (n=6) or iTTP plasma samples (n=16, **P<0.01). (F) VWF secretion detected by fluorescence microscopy after HMVEC-d incubation with IgG (a) from iTTP plasma samples or F(ab)’2 fragments (b) purified from these IgG (original magnification X63, scale bar=20 mm). (G) Fluorescence intensity (AU) of Ca2+ flux induction in HMVEC-d after a 20-second of incubation with medium alone (EBM2), A23187 calcium (Ca2+) ionophore, IgG (IgG) from iTTP plasma samples, or F(ab)’2 fragments purified from these IgG (n=10, **P<0.01).