Plasmapheresis in immune hematology: review of clinical outcome data with respect to evidence-based medicine and clinical experience.

The objective of this paper is to assess the role of plasmapheresis in immune hematology by reviewing published clinical outcome data and narrative review articles. This information will be used to define evidence levels for appraisal of the efficacy and rank of plasmapheresis among other management options. This evidence-based strategy conforms to the concepts of the American Society of Hematology (ASH). as put forward in 1996 in the context of immune thrombocytopenia (ITP) treatment. The term 'experimental' is used to describe indications where the only scientific evidence of the efficacy of plasmapheresis consists of pathophysiological reasoning and empiric clinical findings. We reviewed the available literature on the use of plasmapheresis in autoimmune hemolytic anemia (AIHA), hemolytic disease of the newborn (HDN), autoimmune thrombocytopenic purpura (AITP), heparin-induced thrombocytopenia type II (HIT II), post-transfusion purpura (PTP), refractoriness to platelet transfusion (RPT), coagulation factor inhibitor (CFI) and catastrophic antiphospholipid syndrome (CAS). Plasmapheresis completes the spectrum of management options as it eliminates physically circulating free antibodies involved in the pathogenesis of these immune hematological syndromes. Because of the paucity of data, evidence levels had to be defined based on the findings of uncontrolled case series and the opinions of independent experts. In many cases, randomized clinical trials were not feasible because the syndromes are so rare. When defined as an 'experimental indication', plasmapheresis has a firm scientific basis, but larger scale clinical experience with the method is still lacking. In these cases, the detection and monitoring of symptomatic disease-related circulating free antibodies or immune complexes is a mandatory prerequisite for the use of plasmapheresis. The therapeutic benefit of plasmapheresis is substantiated by the level V of evidence of its efficacy in treatment of HDN, HIV-associated AITP, induction of tolerance in CFI and in CAS. The goal of future studies should be to establish a firmer base of scientific evidence for indications classified as experimental by setting up case series large enough for proper assessment of plasmapheresis alone or combination with other treatment measures. This goal can only be achieved through multiinstitutional cooperation.