Contents lists available at ScienceDirect Transfusion and Apheresis Science journal homepage: www.elsevier.com/locate/transci Current state of apheresis technology and its applications Robert W. Maitta Department of Pathology, University Hospitals Cleveland Medical Center, Case Western Reserve University School of Medicine, Andrews 647A PTH 5077, 11100 Euclid Avenue, Cleveland, OH 44106, United States ARTICLE INFO Keywords: Apheresis Therapeutic plasma exchange Automated red cell exchange Equipment Leukocytapheresis Stem cell collections Instrumentation ABSTRACT Apheresis is at the forefront of therapeutic approaches for an increasing number of indications caused by for- mation of pathologic antibodies treated by therapeutic plasma exchange, or through the use of red cell ex- changes to overcome complications secondary to sickle cell crises. Likewise, the number of hematopoietic stem cell transplants has continued to grow annually and this is the direct result of the expansion of apheresis col- lections. Over the years a number of apheresis platforms have been utilized, but as one of the oldest and most widely used systems, the COBE Spectra, has ceased to be used therapeutically and at blood centers for donations there is an active search to find suitable systems that will replace it and have the versatility to perform as many procedures as possible. Computer innovations have made it possible with current apheresis technology to obtain more real-time information of the procedure which permits the operator to adjust parameters not only to op- timize the specific procedure but also to safeguard against potential adverse events. The focus of this review is to go over available clinical data describing the operation, outcomes and applications of apheresis platforms, and discuss those systems that are likely to meet clinical demands and those of blood donation centers. 1. Background Apheresis technology has been in use since the 1960s when the first automated cell separator was developed by engineer George T. Judson in close collaboration with Emil Freireich at the National Cancer Institute which permitted for the first time separation of leukocytes in a centrifuge from venous blood while simultaneously returning all other cellular components and plasma to the donating subject [1]. This technological breakthrough would prove to be the foundation for the next fifty years of apheresis technology that has become either primary or adjuvant therapy for an increasing number of disease presentations [2]. Procedures can either remove a specific blood component: leuko- cytapheresis (leukocyte depletion/ collection), thrombocytapheresis (platelet depletion/ collection), erythrocytapheresis (red blood cell collections), plasmapheresis (plasma collection), and hematopoietic stem cell (HSC) collection; or exchange a blood component: ery- throcytes (red cell exchanges [RCE]) and plasma (therapeutic plasma exchanges [TPE]). Since the vast majority of literature on apheresis describes cen- trifugal systems and not those dependent on membrane filtration, the focus of this review will be to present available data on centrifugal systems. The technology relies on centrifugal forces that depending upon density differences of each blood element is able to separate blood into its components. As the apheresis systems have become more sophisticated, their use has expanded to blood collection centers such that in countries like the United States (US) apheresis donations are a growing proportion of donations; such is the case with single donor platelets (SDP) collected by apheresis which represent the largest pro- portion of platelet units currently collected in the US. To understand the changes that new apheresis technology has led to, each procedure in this review will be discussed independently to present the relevant data available for a given instrument in the context of the procedure it performs. 2. Therapeutic plasma exchange (TPE) Of all apheresis procedures currently performed, TPE has become the most commonly used in order to treat an expanding number of clinical indications [3]. TPE utilization has changed the way that many diseases are treated, and for diseases with previously high mortality such as thrombotic thrombocytopenic purpura it has been instrumental in significantly reducing morbidity and mortality associated with this diagnosis [4,5]. Every couple of years the American Society for Apheresis (ASFA) publishes detailed guidelines based on the latest clinical and scientific evidence for the appropriate use of TPE [2]. Diseases are classified according to these guidelines from Category I in which apheresis is first-line therapy to Category IV in which apheresis has proven of no benefit in the disease process. Furthermore, https://doi.org/10.1016/j.transci.2018.09.009 E-mail address: robert.maitta@case.edu. Transfusion and Apheresis Science xxx (xxxx) xxx–xxx 1473-0502/ © 2018 Published by Elsevier Ltd. Please cite this article as: Maitta, R.W., Transfusion and Apheresis Science, https://doi.org/10.1016/j.transci.2018.09.009