Understanding the Different Types of Apheresis & Their Applications
Apheresis is the process of removing whole blood from a donor, separating the blood into cellular and soluble components, removing a specified element and then returning the remainder of the blood to the donor. There are several kinds, all named after which element of the blood is removed (e.g., red blood cells, platelets or plasma).
Below, we explore the different types of apheresis, their broad applications and the techniques through which they’re completed.
What Is Apheresis Used For?
Apheresis has two main purposes: to treat various disorders or to collect cells for clinical trials or research purposes. The former is broadly known as therapeutic apheresis (TA). The latter is known as donor or cellular therapy apheresis.
The 2016 evidence-based guidelines for therapeutic apheresis issued by the American Society for Apheresis (ASFA) lists over 80 conditions for which TA can be used. The conditions range from multiple sclerosis to lung transplantation to acute liver failure.
In addition to research and clinical trials, cellular therapy apheresis can be used to collect cells from healthy donors for patients needing CAR-T cell therapy or bone marrow transplantation.
What Are the Different Types of Apheresis?
There are many different types of therapeutic and cellular therapy apheresis. Several common procedures are discussed below.
- Leukapheresis removes white blood cells (WBCs) from the whole blood. It is most commonly used for patients with acute or chronic leukemia in conjunction with chemotherapy. Leukapheresis reduces WBC counts by 30 to 60%, and can be conducted daily as needed to maintain WBC counts.
- LDL apheresis removes low-density lipoprotein (LDL) from the whole blood. When used therapeutically, this treatment is aimed at individuals with familial hypercholesterolemia and those with high levels of LDL who do not respond to, or have an adverse reaction to, medication. One treatment can lower LDL levels by approximately 70 to 83%. To maintain low LDL, patients typically require treatment every two weeks.
- Therapeutic plasma exchange (TPE), also known as plasmapheresis, is used for treatment of conditions caused by pathologic antibodies or harmful substances found within the plasma such as immune thrombotic thrombocytopenic purpura (TTP). It can also be used to remove drugs and low-density lipoproteins — though it is not as efficient as LDL apheresis for removing LDLs — and to correct plasma clotting deficiencies. The frequency and duration of treatment varies, however typically consists of every other day over the course of 14 days.
- Therapeutic erythrocytapheresis, known as red blood cell exchange, removes the donor’s red blood cells (RBCs) from the whole blood and replaces them with red blood cells from a blood bank, and/or saline/albumin. Erythrocytapheresis is most often used when there is a problem in a patient’s RBCs as in the cases of sickle cell disease or a malaria infection. This is an efficient therapy without significant side effects.
- Thrombocytapheresis is a process that safely and rapidly lowers a patient’s platelet count for the treatment of thrombocytosis, thrombosis and myeloproliferative disorders. It is also commonly used on donors undergoing organ transplantation. This therapy can be performed daily or as needed.
Other examples of apheresis include extracorporeal photopheresis, immunoadsorption and therapeutic phlebotomy.
How Is Apheresis Completed?
The two main ways to separate the whole blood components during apheresis are centrifugation and membrane filtration.
Centrifugal apheresis is a highly efficient process, achieving a plasma extraction rate of close to 80%. It can be done intermittently or as a continuous flow and requires lower blood flow rates, allowing it to be performed using either peripheral or central venous access.
Intermittent flow centrifugation involves repeated cycles of blood being drawn, processed, and re-infused. While it only uses a single site venous access, the procedure time is longer. Continuous flow centrifugation, on the other hand, removes, processes and re-infuses the blood components simultaneously. This is a faster process, but requires two sites of vascular access.
Membrane filtration filter the whole blood through membranes. Membrane filtration is less efficient with a much lower plasma extraction rate of approximately 30%.
Ongoing innovation in cellular therapies will allow many different types and parts of cells to be used to treat a variety of diseases and conditions. Venous access is crucial to the success of an apheresis procedure. Often this can be performed using peripheral IV lines, but sometimes central venous access may be required or more appropriate. Central venous access can be temporary or long term (eg. tunneled catheters, subcutaneous ports, fistulas).
Comprehensive Cell Solutions welcomes your inquiries concerning the outsourcing of leukapheresis. Your team can initiate a request by calling (866) 956-6922.