Apheresis can be used to
Obtain healthy blood components from a donor to transfuse Overview of Blood Transfusion A blood transfusion is the transfer of blood or a blood component from one healthy person (a donor) to a sick person (a recipient). Transfusions are given to increase the blood's ability... read more to a person with a disorder
Remove harmful substances or excessive numbers of blood cells from the blood of a person with a disorder (termed therapeutic apheresis)
The different components of blood that can be separated include
Plasma contains antibodies Antibodies One of the body's lines of defense (immune system) involves white blood cells (leukocytes) that travel through the bloodstream and into tissues, searching for and attacking microorganisms and... read more (immunoglobulins) and clotting factors Blood clotting factors Hemostasis is the body's way of stopping injured blood vessels from bleeding. Hemostasis includes clotting of the blood. Too little clotting can cause excessive bleeding from minor injury Too... read more , which are sometimes separated from plasma.
The two most common types of apheresis that are used to remove harmful substances from blood are
Cytapheresis may have different names, depending on the type of cell that is removed from the blood.
Plateletpheresis: Platelet removal
Leukapheresis: White blood cell removal
When plasma is separated from the blood, the procedure is called plasmapheresis. Plasmapheresis is often done on blood from healthy donors to obtain plasma for donation or to obtain specific substances such as clotting factors.
Red blood cell exchange also involves apheresis.
In plasma exchange, the person's blood is removed, and the plasma is separated from the blood cells and platelets. The plasma is discarded and the blood cells and platelets are returned to the person along with a plasma-replacing fluid, such as albumin.
Plasma exchange is used to treat disorders in which the person's plasma contains harmful substances (often antibodies). Such disorders include multiple sclerosis Multiple Sclerosis (MS) In multiple sclerosis, patches of myelin (the substance that covers most nerve fibers) and underlying nerve fibers in the brain, optic nerves, and spinal cord are damaged or destroyed. The cause... read more , myasthenia gravis Myasthenia Gravis Myasthenia gravis is an autoimmune disorder that impairs communication between nerves and muscles, resulting in episodes of muscle weakness. Myasthenia gravis results from malfunction of the... read more and Guillain-Barré syndrome Guillain-Barré Syndrome (GBS) Guillain-Barré syndrome is a form of polyneuropathy causing muscle weakness, which usually worsens over a few days to weeks, then slowly improves or returns to normal on its own. With treatment... read more (neurologic disorders that cause muscle weakness), Goodpasture syndrome Goodpasture Syndrome Goodpasture syndrome is an uncommon autoimmune disorder in which bleeding into the lungs and progressive kidney failure occur. People usually have difficulty breathing and may cough up blood... read more (an autoimmune disorder involving bleeding in the lungs and kidney failure), cryoglobulinemia Cryoglobulinemia Conditions that cause an abnormal protein or an abnormal amount of certain normal proteins in the blood can cause blood vessels to become fragile. When these fragile blood vessels break, people... read more (a disorder involving formation of abnormal antibodies), and thrombotic thrombocytopenic purpura Thrombotic Thrombocytopenic Purpura (TTP) Thrombotic thrombocytopenic purpura (TTP) is a serious disorder that involves the formation of small blood clots throughout the body that block the flow of blood to vital organs such as the... read more (a rare clotting disorder). Apheresis can help control some chronic diseases but generally does not cure them. However, thrombotic thrombocytopenic purpura Thrombotic Thrombocytopenic Purpura (TTP) Thrombotic thrombocytopenic purpura (TTP) is a serious disorder that involves the formation of small blood clots throughout the body that block the flow of blood to vital organs such as the... read more can be reversed with apheresis.
To be helpful, plasma exchange must be done often enough to remove the undesirable substance faster than the body produces it. However, apheresis is repeated only as often as necessary because the large fluid shifts between blood vessels and tissues that occur as blood is removed and returned may cause complications in people who are already ill.
In cytapheresis, excess numbers of certain blood cells are removed. Cytapheresis can be used to treat polycythemia Polycythemia Vera Polycythemia vera is a myeloproliferative neoplasm of the blood-producing cells of the bone marrow that results in overproduction of all types of blood cells. Polycythemia vera is due to mutations... read more (an excess of red blood cells), certain types of leukemia Overview of Leukemia Leukemias are cancers of white blood cells or of cells that develop into white blood cells. White blood cells develop from stem cells in the bone marrow. Sometimes the development goes awry... read more (a type of cancer in which there are excess white blood cells), and thrombocythemia Essential Thrombocythemia Essential thrombocythemia is a myeloproliferative neoplasm in which excess platelets are produced, leading to abnormal blood clotting or bleeding. The hands and feet may burn, turn red, and... read more (an excess of platelets).
Red blood cell exchange
In red blood cell exchange, diseased or abnormal red blood cells are removed by apheresis and then replaced by donor red blood cells. Red blood cell exchange is used to treat or sometimes prevent serious complications of sickle cell disease Sickle Cell Disease Sickle cell disease is an inherited genetic abnormality of hemoglobin (the oxygen-carrying protein found in red blood cells) characterized by sickle (crescent)-shaped red blood cells and chronic... read more , such as stroke and acute chest syndrome.