apheresis

Apheresis is a family of medical procedures that remove whole blood from a patient or donor, separate it into components, and return one or more components back to the circulation. The technique is used to collect specific blood components or to remove substances such as antibodies, toxins, or immune complexes.

Most apheresis methods are either centrifugation-based or membrane-filtration-based. In plasma exchange (plasma apheresis), plasma is separated and discarded while a replacement solution such as donor plasma or albumin is infused. Plateletpheresis removes platelets and returns RBCs, plasma, and other components. Leukapheresis removes white blood cells, usually to treat very high counts or for cellular therapies. Erythroapheresis or red blood cell exchange replaces a patient’s RBCs, useful in conditions with abnormal or dangerous circulating RBCs or antibodies. Double filtration or other specialized apheresis techniques may be used to remove specific immune complexes or lipids.

Indications vary and include autoimmune and inflammatory disorders (for example, certain neuropathies, myasthenia gravis, and thrombotic microangiopathies), hyperviscosity syndromes (such as those caused by certain monoclonal gammopathies), antibody-mediated rejection in organ transplantation, and toxin removal in select poisonings. Apheresis can be a standalone therapy or used in conjunction with medications.

Procedures are typically performed in a hospital or specialized clinic. Blood is removed through a vascular access site, anticoagulated to prevent clotting, processed by the apheresis device, and then returned to the patient. Potential risks include citrate-related hypocalcemia, hypotension, infection from access sites, bleeding, and rare reactions to plasma products.

Overall, apheresis is a versatile, generally well-tolerated approach for selectively removing or replacing blood components to treat specific medical conditions.