Fig. 5

Triple-label immunofluorescence showing the location of the plasma protein (pp) IgG in relation to the endothelial cell glycocalyx (EcG) labeled with UEA-l, and COLL4-positive basement membrane (bm) and wall of vascular bag (vb). a-f Transverse or oblique section through small vessel with a smooth endothelial cell layer (continuous open arrow) and vascular bag (closed arrow), which is attached to the basement membrane (broken open arrow) and contains IgG (star). g-i Longitudinal section through a capillary-size small vessel shows the UEA-l-labeled EcG (open arrows) and erythrocytes (ery). The tubular vascular bag (closed arrow) around the vessel, which is filled with IgG (star), is formed by a COLL4-positive external membrane and the basement membrane (broken open arrow). An endothelial indentation with detachment from the basement membrane (arrow head) is also seen, but there is no IgG deposition between the endothelial layer and basement membrane. Case 12 (pontine bleeding, SVD + VBI)