In general, plasma exchange is more effective than plasma infusion in treating thrombotic thrombocytopenic purpura (TTP) because its pathogenesis is mediated by ultra-large Von Willebrand Factor (VWF) multimers and autoantibodies to a disintegrin and metalloproteinase with thrombospondin type-1 motif, member 13 (ADAMTS-13). This evidence concerns the gene VWF and thrombotic thrombocytopenic purpura.