hematology and oncology
Therapeutic Apheresis
Cytapheresis
In cytapheresis, the cellular components of blood (eg, RBCs, white blood cells [WBCs], platelets) are separated. This is often done on donated blood so that each component may be given to a different recipient. Cytapheresis also may be done therapeutically to remove excess or defective cellular components. Therapeutic cytapheresis removes cellular components from blood, returning plasma. It is most often used to remove defective RBCs and substitute normal ones in patients with Sickle Cell Disease who have the following conditions: acute chest syndrome, stroke, pregnancy, or frequent, severe sickle cell crises. RBC exchange achieves hemoglobin S levels of Therapeutic cytapheresis may also be used to reduce severe thrombocytosis or leukocytosis (cytoreduction) in acute leukemia or in accelerated or blast crisis phase of Chronic Myeloid Leukemia (CML) when there is risk of hemorrhage, thrombosis, or pulmonary or cerebral complications of extreme leukocytosis (leukostasis). Therapeutic platelet removal (plateletpheresis) is effective in Essential Thrombocythemia because platelets are not replaced as rapidly as white blood cells. One or two procedures may reduce platelet counts to a lower level, but the effect is temporary and the platelet count is not restored to normal. Therapeutic WBC removal (leukapheresis) can remove kilograms of buffy coat in a few procedures, and it often relieves leukostasis. However, the reduction in WBC count itself may be mild and only temporary. Other uses of cytapheresis include collection of peripheral blood stem cells for autologous or allogeneic bone marrow reconstitution (an alternative to bone marrow transplantation) and collection of lymphocytes for use in immune modulation cancer therapy (adoptive immunotherapy). 