Since an increasing body of evidence suggests a possible role of endothelium in pathophysiology of RRTs and GVHD, in this study, we evaluated cellular (CECs) and soluble plasma biomarkers (VCAM1, ICAM1) to assess the level of endothelial damage and to evaluate their potential diagnostic/prognostic value as biomarkers for GVHD and early transplant related complications in patients undergoing HSCT. This evidence concerns the gene ICAM1 and graft versus host disease.