Spectrum and pathophysiology of post-HSCT endothelial complications. The Venn diagram highlights the overlap of endothelial syndromes, both diagnostically and pathophysiologically, with GVHD. Many clinical and pathophysiological features of GVHD parallel those of other EC activation syndromes in which a single organ is targeted. Here, atherosclerosis and several delayed forms of IPS have been proposed as late endothelial dysfunction syndromes overlapping with chronic GVHD. DAH, diffuse alveolar hemorrhage; PERDS, peri-engraftment respiratory distress syndrome.