FVIIIRAg immunostaining of sinusoidal endothelial cells from a cirrhotic liver. (a) The sinusoid, S, is seen in transverse section. The black arrow labels anendothelial cell displaying granular immune deposits of FVIIIRAg (brown color) in the cytoplasm. FVIIIRAg-negative endothelial cell (blue arrow) is also present in the same sinusoidal lining. The wall of this sinusoid is only slightly thickened with fibrous tissue. (b) The wall of this sinusoid, S, sectioned longitudinally, is prominently thickened with fibrous tissue—slightly gray in the hematoxylin counterstained section. The endothelial cells reveal granular FVIIIRAg immunostaining (brown color) in the cytoplasm.