The only non-responder died of multi-organ failure after three weeks.179 ADAMTS13 antigen levels were marginal or low either post-HCT or at the onset of TMA and did not change significantly after rituximab-induced remission.179 It remains unclear whether these patients actually had TA-TMA (or TTP), thus making the use of rituximab in this setting uncertain. Here, ADAMTS13 is linked to thrombotic thrombocytopenic purpura.