Collection of stem cells in (autologous) donors by apheresis
Cut Adeya Adella in Stem Cell Oncology, 2018
White blood cells (WBCs) can be collected with apheresis techniques. This is named leuka- pheresis or leukocytapheresis. Apheresis is a method of obtaining one or more blood components by machine processing of whole blood in which the residual components are returned to the donor or patient during or at the end of the process. The majority of the leukapheresis procedures are performed to collect cells for cellular therapies, of which the collections of autologous or allogeneic hematopoietic stem/progenitor cells (HPCs) are most frequent performed. HPCs are found in the bone marrow and are identified by the presence of the CD34 antigen on their surface, and therefore these cells are often named CD34 positive cells. HPCs are multipotent stem cells that can develop into all the blood cell types constituting from the myeloid (monocytes and macrophages, neutrophils, basophils, eosinophils, erythrocytes, megakaryocytes/platelets, dendritic cells), and lymphoid lineages (T-cells, B-cells, NK-cells).
Therapeutic apheresis
Jennifer Duguid, Lawrence Tim Goodnough, Michael J. Desmond in Transfusion Medicine in Practice, 2020
In 1914, Abel, Rowntree and Turner1 coined the term plasmaphaeresis (from the Greek word aphairesis – a withdrawal). Their early experiments were for the relief of symptoms following bilateral nephrectomy in dogs. Although these experiments were associated with deaths (due to apparent overbleeding and hemorrhage), the improvement in the clinical condition of the animals successfully treated was ‘marked’. The term apheresis has since been generalized to refer to the separation of blood into its components, removing one component, and returning the remainder. Thus, leukapheresis means the removal of leukocytes and erythrocytapheresis means the removal of erythrocytes. Alternative terminologies such as plasma exchange and red cell exchange are frequently used interchangeably for plasmapheresis and erythrocytapheresis, respectively. Some authors have suggested that the term ‘plasma exchange’ or therapeutic plasma exchange be reserved for low-volume procedures involving no more then 500–600 ml of plasma and plasmapheresis for large-volume procedures; however, these terms are frequently used interchangeably. Hemapheresis is also used as a broad term encompassing all apheresis procedures.
Concepts of Replacement Therapy: Blood Components, Blood Derivatives, and Medications
Harold R. Schumacher, William A. Rock, Sanford A. Stass in Handbook of Hematologic Pathology, 2019
Platelets are minute fragments of megakaryocyte cytoplasm that are responsible for primary hemostasis. Platelets are usually prepared from whole blood by centrifugation, removing the platelet-rich plasma, followed by an additional centrifugation step to concentrate the platelet product. Platelet concentrates, which have a volume of 50–70 mL, are stored at room temperature (20–24°C), with a shelf life of 5 days. An average platelet concentrate contains approximately 5.5 × 1011 platelets. Typically, these individual units are pooled prior to use to provide an appropriate dose. An increasingly popular method for obtaining platelets utilizes apheresis technology. Here, whole blood is removed from a donor and separated into its components by the apheresis equipment. The platelets are then directed into a collection bag, and the remaining components are returned to the donor. This technique provides a product equivalent to 6–10 units of pooled platelets in a plasma volume of 200–300 mL. The storage requirements and shelf life are identical to platelet concentrates. The advantages of this product include the reduced number of donor exposures to decrease the risk of transfusion-transmitted diseases and alloimmunization. The disadvantages include the need for specialized equipment and personnel, the requirement of two venipunctures, and the time commitment made by the donor.
The use of platelet-rich plasma to treat chronic tendinopathies: A technical analysis
Published in Platelets, 2018
Jean-François Kaux, Thibault Emonds-Alt
The large variety of platelet concentrations encountered in many studies is explained by the use of commercial kits to prepare PRP. The results of these kits vary significantly from one patient to another but also from one sample to another for the same patient [13,14]. Only use of an apheresis machine can obtain a constant concentration and reproducibility for each patient [80]. The donation of blood components through apheresis has become commonplace in modern blood transfusion practices. Technological progress in automated cell separators has improved the productivity and quality of platelet collection through apheresis [81]. There are a wide variety of instruments to extract platelets through apheresis, and many studies have compared different cell separators. Of those, Keklik et al. [82] compared three apheresis systems (Fenwal Amicus, Fresenius COM.TEC and Trima Accel) in terms of processing time, platelet output, efficiency, and speed of collection. The results showed that the volume of blood treated, the volume of ACD-A, and the average separation time were significantly higher with the COM.TEC system.
Risk of cytomegalovirus transmission by blood products after solid organ transplantation
Published in Baylor University Medical Center Proceedings, 2019
Deborah Jebakumar, Patti Bryant, Walter Linz
A common alternative approach to create a CMV safe blood product is leukocyte reduction. By definition, leukocyte reduction means that a blood product should have fewer than 5 × 106 leukocytes per unit. Several methodologies can achieve leukocyte reduction. First, leukocytes can be removed via filtration. Today, third and fourth-generation filters (either nonwoven depth or woven screen filters) are used. These filters, which are made from polyesters and take advantage of the negative electrostatic charge of leukocytes, achieve at least a 99.9% or 3-log reduction of leukocytes.11 Before the current era, leukocyte filtration was often performed at the patient’s bedside. After a non–leukocyte reduced unit of blood was issued, transfusion staff would use a blood administration kit that included a leukocyte reduction filter between the unit of blood and the recipient. Considered to yield inconsistent leukocyte reduction results,12 today that practice has been superseded. Most whole blood collected today is leukocyte reduced via an in-line filter—a procedure performed in blood component laboratories shortly after collection. Apheresis achieves similar results by separating cell fractions (i.e., plasma, buffy coat, red blood cells) via centrifugation, which takes advantage of the differential specific gravity of each fraction. As the fractions separate, the buffy coat is selectively removed, eliminating most of the leukocyte fraction from the blood component.
Treatment of inflammatory bowel disease from the immunological perspective
Published in Immunological Medicine, 2020
Treatment that prevents T cells from migrating locally to the intestinal tract can also control the adaptive immune system. One such treatment is an apheresis therapy. Apheresis therapy is a treatment for IBD patients that was developed in Japan. The mechanism of apheresis therapy is based on local immunomodulation achieved by removing leukocyte (granulocytes, monocytes and activated lymphocytes) from the peripheral blood with special columns. With no additional drugs, apheresis therapy appears to be a natural biologic therapy and a groundbreaking treatment method [43]. In addition, drug treatments with a mechanism of action similar to that of blood cell apheresis have emerged. Vedolizumab, a mAb that targets α4β7 integrins, exerting in a gut-selective mechanism of action, has emerged for the induction of remission in active IBD patients [44]. Based on clinical trials and actual clinical data, vedolizumab is expected to be effective in treating patients who are resistant to anti-TNF-α antibody treatment [45]. Since vedolizumab does not directly control inflammation occurring in mucous membranes, its effect is different from that of anti-TNFα antibodies. Therefore, for patients with high levels of disease activity, the concomitant use of a calcineurin inhibitor or TNF inhibitor should be considered at the time of remission induction [46]. Newer therapies targeting the endothelial cell adhesion molecule MAdCAM-1 and agents that inhibit the outflow of memory T cells from lymph nodes are now being tested in clinical trials [47–49].
Related Knowledge Centers
- Anticoagulant
- Coagulation
- Density
- Extracorporeal
- Blood
- Stem Cell
- Hematocrit
- Health Technology
- Venipuncture
- Bolus