What is Plasmapheresis?

Plasmapheresis is a method of filtering the blood in order to remove products that are known to cause disease in hopes of helping improve symptoms. First, a brief primer on how plasmapheresis works: components of blood include 1) the red blood cells themselves 2) buffy coat, which contains smaller cells including platelets which help with blood clotting and white blood cells which help to prevent infections and 3) plasma, the left over fluid left once the other components of blood are separated. Plasmapheresis, the plasma component of the blood, which also contains potentially harmful antibodies, are filtered, while the important white and red blood cells are given back to the patients.

The effectiveness of plasmapheresis in GBS was first demonstrated in the 1980’s, and up until 2001, a total of 6 clinical trials evaluating over 600 patients have confirmed the benefit of plasmapheresis. The benefits include speeding up improvement from GBS as well as increasing the chance of complete recovery from GBS. Two studies in the mid 1980’s and mid 1990’s, which were of high quality, tested plasmaphersis in a blinded and randomized fashion evaluating a small group of patients with CIDP (around 20-30). These studies showed an improvement in neurological disability scores and a review of these studies performed by the Cochrane group, which critically analyzes clinical trials, also confirmed that these two small studies did show that plasmapheresis improve neurological symptoms. More studies were recommended to confirm these results. Although it can be considered, plasmapheresis is not usually a commonly used treatment for MMN, both because of the lack of good studies proving that it works in this condition and because plasmapheresis is a difficult long-term solution in patients with MMN who often need prolonged, ongoing treatment. Other neurological diseases that are treated with plasmapheresis include inflammatory muscle diseases including myositis, various types of multiple sclerosis, inflammations of blood vessels affecting the brain, spine or nerves including vasculitis and encephalitis, and diseases of the connection between nerves and muscles (neuromuscular junction) such as myasthenia gravis and Lambert Eaton Myasthenic Syndrome.

Plasmapheresis must be performed in hospital and requires supervision by a transfusion medicine specialist, specialized equipment and specialized nurses who are present monitoring the transfusion to ensure safety. The number of exchanges varies from patient to patient and from treatment to treatment, however for most neuromuscular conditions, usually five exchanges are required to help with symptoms. These are often spaced out every other day to allow the patient to tolerate the procedure. The timing of each plasmapheresis treatment itself varies from patient to patient, but on average each treatment takes about 2 hours. There are multiple ways to perform plasmapheresis, including spinning the blood down, filtering blood across a membrane, absorbing the immune properties of the blood and a combination of these methods. When plasmapheresis is done in a certain way known as “centrifugal filtration”, it can be done through a peripheral intravenous line in the arms, however on occasion in order to give the full exchange, a larger catheter has to be placed in one of the veins in the arms, chest or neck. This also limits on going and frequent treatments.

During the plasmapheresis process, certain important chemicals in the body including calcium may be removed, but complications from this can be prevented by giving calcium supplements during the infusions. Other side effects to plasmapheresis include shifting of some of the fluid components in the body, blood clotting events, infections from the catheter infusion lines but these are all rare. In fact, when done with an expert group with a peripheral or intravenous line in the arms, few patients (less than 10%) have any side effects. Because of the specialized nature of the treatment and the need for hospital resources to perform the transfusions, plasmapheresis is not frequently as a first- line treatment in the treatment of neuropathies. Usually plasmapheresis will be used in patients who have not responded well to other treatments or are in a setting with severe symptoms such as the hospital. On occasion patients are treated over a period of time to help them bridge onto other therapies or get over a particularly severe attack of neurological dysfunction. Most patients start to feel improvements towards the end of the treatment cycle up to a few weeks after and patients may feel prolonged benefits from the treatment. Plasmapheresis can be used in combination with other medications given by mouth, but it is not usually given after infusion treatments such as IVIG, as the exchange will wash out the infusion given prior.