Leukapheresis
Encyclopedia
Leukapheresis is a laboratory procedure in which white blood cell
s are separated from a sample of blood. It is a specific type of apheresis
, the more general term for separating out one particular constituent of blood and returning the remainder to the circulation.
Leukapheresis may be performed to decrease a very high white blood cell count, to obtain autologous (i.e., the patient's own) blood cells for later transplant back into the patient, or to obtain cells for research purposes. In the case of hematological malignancies such as acute leukemias, white blood cell counts may be high enough to cause hemostasis
and "sludging" in the capillaries. This can affect retinal vasculature leading to vision changes, pulmonary vasculature leading to shortness of breath from decreased efficiency in oxygen exchange, as well as other organ systems such as the brain which would become clinically apparent with neurological deterioration of a patient from cerebrovascular compromise.
Leukapheresis may also be performed to obtain the patient's own blood cells for later transplant. White blood cells may be removed to protect them from damage before high-dose chemotherapy, then transfused back into the patient, in the treatment of advanced breast cancer. Another novel use of cells obtained through leukapheresis is to stimulate a patient’s immune system to target prostate cancer cells.
Alternatively, only granulocyte
s, macrophage
s and monocyte
s can be removed, leaving the lymphocyte
count largely unchanged. This is used as a treatment for autoimmune diseases such as ulcerative colitis
and rheumatoid arthritis
, where these cells play an active part in the inflammation process.
Leukapheresis, typically for granulocytes, is a rarely performed blood donation
process. The product is collected by automated apheresis
and is used for systemic infections in patients with neutropenia
. The donor is typically a blood relative who has received stimulating medications (a directed donation), and the product is irradiated to prevent GVHD. The product generally has a 24 hour shelf life from collection and is often transfused before infectious disease
testing is completed. It is a therapy of last resort, and its use is controversial and rare.
White blood cell
White blood cells, or leukocytes , are cells of the immune system involved in defending the body against both infectious disease and foreign materials. Five different and diverse types of leukocytes exist, but they are all produced and derived from a multipotent cell in the bone marrow known as a...
s are separated from a sample of blood. It is a specific type of apheresis
Apheresis
Apheresis is a medical technology in which the blood of a donor or patient is passed through an apparatus that separates out one particular constituent and returns the remainder to the circulation...
, the more general term for separating out one particular constituent of blood and returning the remainder to the circulation.
Leukapheresis may be performed to decrease a very high white blood cell count, to obtain autologous (i.e., the patient's own) blood cells for later transplant back into the patient, or to obtain cells for research purposes. In the case of hematological malignancies such as acute leukemias, white blood cell counts may be high enough to cause hemostasis
Hemostasis
Hemostasis or haemostasis is a process which causes bleeding to stop, meaning to keep blood within a damaged blood vessel . Most of the time this includes blood changing from a liquid to a solid state. Intact blood vessels are central to moderating blood's tendency to clot...
and "sludging" in the capillaries. This can affect retinal vasculature leading to vision changes, pulmonary vasculature leading to shortness of breath from decreased efficiency in oxygen exchange, as well as other organ systems such as the brain which would become clinically apparent with neurological deterioration of a patient from cerebrovascular compromise.
Leukapheresis may also be performed to obtain the patient's own blood cells for later transplant. White blood cells may be removed to protect them from damage before high-dose chemotherapy, then transfused back into the patient, in the treatment of advanced breast cancer. Another novel use of cells obtained through leukapheresis is to stimulate a patient’s immune system to target prostate cancer cells.
Alternatively, only granulocyte
Granulocyte
Granulocytes are a category of white blood cells characterized by the presence of granules in their cytoplasm. They are also called polymorphonuclear leukocytes because of the varying shapes of the nucleus, which is usually lobed into three segments...
s, macrophage
Macrophage
Macrophages are cells produced by the differentiation of monocytes in tissues. Human macrophages are about in diameter. Monocytes and macrophages are phagocytes. Macrophages function in both non-specific defense as well as help initiate specific defense mechanisms of vertebrate animals...
s and monocyte
Monocyte
Monocytes are a type of white blood cell and are part of the innate immune system of vertebrates including all mammals , birds, reptiles, and fish. Monocytes play multiple roles in immune function...
s can be removed, leaving the lymphocyte
Lymphocyte
A lymphocyte is a type of white blood cell in the vertebrate immune system.Under the microscope, lymphocytes can be divided into large lymphocytes and small lymphocytes. Large granular lymphocytes include natural killer cells...
count largely unchanged. This is used as a treatment for autoimmune diseases such as ulcerative colitis
Ulcerative colitis
Ulcerative colitis is a form of inflammatory bowel disease . Ulcerative colitis is a form of colitis, a disease of the colon , that includes characteristic ulcers, or open sores. The main symptom of active disease is usually constant diarrhea mixed with blood, of gradual onset...
and rheumatoid arthritis
Rheumatoid arthritis
Rheumatoid arthritis is a chronic, systemic inflammatory disorder that may affect many tissues and organs, but principally attacks synovial joints. The process produces an inflammatory response of the synovium secondary to hyperplasia of synovial cells, excess synovial fluid, and the development...
, where these cells play an active part in the inflammation process.
Leukapheresis, typically for granulocytes, is a rarely performed blood donation
Blood donation
A blood donation occurs when a person voluntarily has blood drawn and used for transfusions or made into medications by a process called fractionation....
process. The product is collected by automated apheresis
Apheresis
Apheresis is a medical technology in which the blood of a donor or patient is passed through an apparatus that separates out one particular constituent and returns the remainder to the circulation...
and is used for systemic infections in patients with neutropenia
Neutropenia
Neutropenia, from Latin prefix neutro- and Greek suffix -πενία , is a granulocyte disorder characterized by an abnormally low number of neutrophils, the most important type of white blood cell...
. The donor is typically a blood relative who has received stimulating medications (a directed donation), and the product is irradiated to prevent GVHD. The product generally has a 24 hour shelf life from collection and is often transfused before infectious disease
Transfusion transmitted infection
A Transfusion transmitted infection is a virus, parasite, or other potential pathogen that can be transmitted in donated blood through a transfusion to a recipient...
testing is completed. It is a therapy of last resort, and its use is controversial and rare.