Therapeutic Plasma Exchange

Therapeutic plasma exchange is a blood purification technique designed for the removal of large molecular weight toxins such as pathogenic antibodies and lipoproteins. ^[1] Plasma exchange can be performed either by membrane separation or by centrifugation, with centrifugal exchange more common in the United States and membrane separation more popular in Germany and Japan. ^[1]

In the membrane separation technique, the membrane's pores are large enough to allow removal of all circulating molecules while retaining the cellular components. ^[1] In antibody-mediated disease it is used to rapidly remove pathogenic autoantibody, typically alongside steroids and cytotoxic therapy to prevent ongoing autoantibody production and tissue inflammation. ^[2]

In immune thrombotic thrombocytopenic purpura, prompt initiation of therapy with therapeutic plasma exchange, corticosteroids, and rituximab improves survival from almost zero to approximately 93%. ^[3] For Guillain-Barre syndrome, a European guideline recommends a course of plasma exchange in patients within four weeks after onset of weakness who are unable to walk unaided. ^[4] For chronic inflammatory demyelinating polyradiculoneuropathy, plasma exchange is strongly recommended if intravenous immunoglobulin and corticosteroids are ineffective. ^[5] In catastrophic antiphospholipid syndrome, triple therapy with anticoagulation, glucocorticoids, and plasma exchange and/or intravenous immunoglobulins is associated with a better prognosis, and improved knowledge has reduced the reported mortality rate from 50% to 25-30%. ^[6] A systematic review and meta-analysis found that plasma exchange was significantly associated with higher 30-day and overall survival in acute liver failure and could improve survival in acute-on-chronic liver failure, though randomized-trial subgroups showed no difference in the latter. ^[7] The established indications documented in this evidence are specific disease states, and the retrieved sources do not establish an anti-aging or longevity benefit for therapeutic plasma exchange.

The current availability of plasma separation membranes compatible with continuous renal replacement therapy systems has dramatically increased the potential for almost all nephrologists to perform these treatments. ^[1] In immune thrombotic thrombocytopenic purpura, a life-threatening thrombotic microangiopathy, treatment with therapeutic plasma exchange, corticosteroids, and rituximab is associated with 30-day survival rates of more than 90%. ^[3]