Practical review of current approaches to diagnosis and treatment of transplant-associated thrombotic microangiopathy

Abstract

Transplant-associated thrombotic microangiopathy (TA-TMA) is a rare complication of hematopoietic stem cell transplantation with an endothelial damage being the major cause of clinical signs. Currently, four major set of diagnostic criteria exist which capture different populations of patients with variable severity of endothelial dysfunction and target organ involvement. Absence of widely excepted criteria for TA-TMA severity, outcome and response measures complicate the comparison of different treatment approaches. Withdrawal or tapering of calcineurin inhibitors is a widely excepted intervention; however, there are studies that indicate no benefit of this intervention in improving overall survival. Different strategies of substituting calcineurin inhibitors with other immunosuppressive may also have impact on survival in TA-TMA patients. Novel approaches in treatment include oligonucleotides and complement inhibitors. Indications for these treatments according to different diagnostic criteria are still to be defined. Currently published evidence highlight the need for cooperative effort to gather empirical data and harmonize definitions required for comparative clinical studies of novel agents.