plasmapéresis

Plasmaphérèse, or plasma exchange, is a medical procedure that removes plasma from the blood and replaces it with a substitute fluid. By removing plasma, it reduces circulating autoantibodies, immune complexes, cryoglobulins, and inflammatory mediators that contribute to autoimmune and inflammatory diseases.

Two main methods are used: centrifugation-based plasmapheresis and membrane filtration (plasma exchange). A typical session exchanges about 1 to 1.5 times the patient’s plasma volume and lasts 1.5 to 3 hours. Replacement fluids are usually 5% albumin; fresh frozen plasma is used when coagulation factors are needed. Anticoagulation during the procedure is commonly achieved with regional citrate or heparin. Vascular access is via a central venous catheter or, less commonly, a peripheral line.

Indications include autoimmune conditions such as Guillain-Barré syndrome, myasthenia gravis crisis, autoimmune encephalitis, ANCA-associated vasculitis, and Goodpasture syndrome; thrombotic microangiopathy; hyperviscosity from monoclonal gammopathy; cryoglobulinemia. It may be used in other selected settings such as antibody-mediated transplant rejection or certain severe toxic or infectious processes, depending on clinical judgment and available evidence.

Clinical benefit varies by condition and timing; in Guillain-Barré syndrome and myasthenia gravis crises, rapid improvement has been reported in some patients. Safety considerations include hypotension, citrate toxicity with hypocalcemia, allergic reactions to plasma, infections related to vascular access, and electrolyte disturbances. The procedure requires monitoring by trained staff and appropriate replacement therapy.