Renal Complications after Hematopoietic Stem Cell Transplantation: Role of Graft-Versus-Host Disease in Renal Thrombotic Microangiopathy

Hematopoietic stem cell transplantation (HSCT) is a widely accepted treatment for mainly hematopoietic disorders. Recent advances in transplantation techniques have increased the number of long-time survivors with chronic kidney disease (CKD). The presence of CKD affects outcomes and is associated with high mortality rates. Therefore, physicians treating transplant survivors should consider renal complications and optimize management of patients with CKD after HSCT. The pathology of CKD after HSCT is affected by many factors, and the causes of renal thrombotic microangiopathy (TMA) are diverse and complicated. We have treated patients who underwent allogeneic HSCT and developed late-stage renal TMA possibly associated with graft-versus-host disease (GVHD). Administration of immunosuppressive drugs, such as calcineurin inhibitors, is typically reduced in patients with TMA. However, if renal TMA is caused by renal GVHD, the use of immunosuppressive drugs should be increased, contradicting conventional thinking. On the basis of previous findings and our own observations, we review the pathology of renal complications after HSCT and focus on the role of GVHD in the development of renal TMA.