Proposition for the treatment of acute refractory TTP. *As defined by absence of platelet count doubling from baseline after 4 full days of standard treatment. A worsening of the disease was defined as the reappearance of organ dysfunction, thrombocytopenia, and hemolysis after an initial improvement. HUS indicates hemolytic uremic syndrome; Abs, anti-ADAMTS13 antibodies; HIV, human immunodeficiency virus; HELLP, hemolysis, elevated liver enzymes, low platelet count; MAHA, microangiopathic hemolytic anemia.