Leukapheresis

Leukapheresis is a medical procedure in which whole blood is drawn from a patient or donor, separated by an apheresis device to remove leukocytes (white blood cells), and the remaining components are returned to circulation. The process concentrates or reduces white cells while preserving red cells and plasma. It is used both therapeutically to reduce very high white cell counts and prevent leukostasis, and preparatively to collect cellular material for transplantation or certain immunotherapies.

Indications include hyperleukocytosis or leukostasis in acute leukemia, myeloproliferative neoplasms with high white blood cell counts, and the collection of peripheral blood stem cells for autologous or allogeneic transplantation. Leukapheresis may also be used to obtain cells for immunotherapy programs that rely on patient or donor leukocytes.

Technique and goals: Apheresis machines separate blood components by centrifugation. In leukapheresis, leukocytes are removed and the remainder is returned. Anticoagulation, commonly acid citrate dextrose or heparin, is used to prevent clotting; citrate can cause transient hypocalcemia, requiring monitoring and calcium supplementation if needed. Vascular access is usually via peripheral veins for shorter sessions or a central venous catheter for serial procedures. In stem cell collection, mobilizing agents such as G-CSF are often given to increase circulating CD34+ stem cells prior to leukapheresis.

Safety and limitations: Potential complications include citrate toxicity and hypocalcemia, hypotension, line infections or thrombosis, and anemia if red cells are removed; most events are mild and reversible with appropriate monitoring and treatment. The procedure is generally well tolerated but requires careful scheduling and postoperative care.