ADAMTS13 and thrombotic thrombocytopenic purpura: The mortality rate of HLH among patients in the intensive care unit is high, and its overall mortality reaches up to 57.8%.[1] On the other hand, thrombotic thrombocytopenic purpura (TTP) is a fatal clinical syndrome, primarily caused by autoantibodies against von Willebrand factor (VWF)-cleaving metalloprotease a disintegrin and metalloprotease with thrombospondin type 1 repeats, member 13 (ADAMTS13).