[Thrombotic complications after hematopoietic stem cell transplantation].

Hematopoietic stem cell transplantation (HSCT) involves some serious transplant-associated complications (TACs) or vascular disorders, such as veno-occlusive disease (VOD), thrombotic microangiopathy (TMA), and graft-versus-host disease (GVHD). VOD is related to a clinical syndrome characterized by tender hepatomegaly, jaundice, fluid retention, and unexplained weight gain. When TMA is described in patients who have undergone HSCT, it is often implied that the clinical diagnosis of TMA is similar to that of thrombotic thrombocytopenic purpura. Therefore, levels of cytokines, chemokines, and soluble molecules are useful biomarkers for VOD and TMA after HSCT. Acute GVHD (aGVHD) occurs in the early period after transplantation and is initiated by alloreactive donor T cells. The mechanisms whereby immune responses trigger this post-transplantation condition remain unclear, but endothelial cell function might play a role in this. The authors investigated the expression of endothelial cell activation markers such as sE-selectin, sVCAM-1, PAI-1, and microparticle in patients undergoing allogeneic HSCT. Levels of endothelial cell activation markers were significantly higher in 143 patients who developed aGVHD than in those who did not develop aGVHD. Moreover, patients who received rTM exhibited a significantly lower frequency of aGVHD and reduced levels of endothelial cell activation markers. These findings suggest that endothelial cell activation might be linked to TAC and that rTM may, at least in part, act to prevent TAC through its effect on endothelial cells.