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Leukapheresis is a laboratory procedure in which white blood cells 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.〔Transfusion. 2003 Feb;43(2):259-64. Leukapheresis after high-dose chemotherapy and autologous peripheral blood progenitor cell transplantation: a novel approach to harvest a second autograft. Schwella N, Braun A, Ahrens N, Rick O, Salama A.〕 Another novel use of cells obtained through leukapheresis is to stimulate a patient’s immune system to target prostate cancer cells.〔Sipuleucel-T Immunotherapy for Castration-Resistant Prostate Cancer July 29, 2010Kantoff P.W., Higano C.S., Shore N.D., et al.N Engl J Med 2010; 363:411 - 422〕 Alternatively, only granulocytes, macrophages and monocytes can be removed, leaving the lymphocyte count largely unchanged. This is used as a treatment for autoimmune diseases such as ulcerative colitis 〔 * National Institute for Health and Clinical Excellence, (Leukapheresis for inflammatory bowel disease ) (guidance). Retrieved Oct. 06 2005〕 and rheumatoid arthritis,〔| author = G Hahn, B Stuhlmüller, N Hain, J R Kalden, K Pfizenmaier, and G R Burmester | year = 1993 | pmc=288038 | title = Modulation of monocyte activation in patients with rheumatoid arthritis by leukapheresis therapy | journal = The Journal of Clinical Investigation | volume = 91 | pages = 862–70 | doi = 10.1172/JCI116307 | pmid = 8450066 | issue = 3〕 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. ==References== 〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Leukapheresis」の詳細全文を読む スポンサード リンク
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