Intravenous immunoglobulin (IVIG)
Intravenous immunoglobulin (IVIG) is a form of treatment that delivers concentrated antibodies from healthy blood donors directly into the bloodstream through an IV line. An IV line (also known as a catheter or drip) is a soft, flexible tube inserted into a vein, usually in the hand or arm.
The antibodies that are delivered help modulate the immune system and, in the case of AE, can reduce brain inflammation. There are many mechanisms by which inflammation is reduced, including by physically blocking harmful antibodies from targeting brain cells or interfering with inflammatory pathways to decrease the production of pro-inflammatory molecules.
An IVIG infusion can take a few hours, but a full dose may be divided over the course of two to five days. The treatment may be repeated and, in some cases, can last for months.
Plasma exchange
Plasma is the liquid component of blood. Plasma exchange (also called plasmapheresis or PLEX) is a procedure that removes harmful antibodies and inflammatory substances from the blood by filtering the plasma and replacing it with an albumin protein solution. Sometimes donor plasma is used.
The procedure involves using a machine to separate the plasma from the blood cells, which are then returned to the body. Only a small amount of blood is out of the body at any one time.
Plasma exchange is always carried out in a hospital setting by a nurse or technician trained in the procedure. The procedure normally takes a couple of hours and the full treatment course often involves several sessions over a week or two.
Outcomes
Most people, including children and pregnant mothers, do not have adverse reactions to IVIG or plasma exchange. Indeed, both treatment options are considered safe and effective for autoimmune neurological diseases including AE.
However, possible mild side effects may include fever, shivering, muscle aches, sickness and headaches, particularly if you are receiving the treatment for the first time or after 8 weeks. With plasma exchange, it is possible to experience changes in blood pressure though this is usually harmless. There is also a small risk of children developing an allergic reaction to replacement plasma.
Other information
More recently, subcutaneous immunoglobulin replacement therapy (SCIG) has been emerging as a possible immunotherapy option for encephalitis.
It requires smaller doses compared to IVIG, which leads to shorter infusion times. It is also possible to self-administer SCIG at home rather than going to the clinic. Furthermore, SCIG offers a cheaper treatment alternative, with a 2017 study in Iran, for example, reporting that the total cost of IVIG and SCIG per year is $1370 and $121, respectively.
By Prav Prathapan, Encephalitis International and reviewed by Dr Matteo Gastaldi, Neuroimmunology Laboratory, IRCCS Mondino Foundation, Pavia, Italy
FS084V1 Intravenous immunoglobulin (IVIG) and plasma exchange for autoimmune encephalitis (AE)
Date created: August 2025 / Last updated: September 2025 / Review date: August 2028
Disclaimer: We try to ensure that the information is easy to understand, accurate and up-to-date as possible. If you would like more information on the source material and references the author used to write this document please contact Encephalitis International. None of the authors of the above document has declared any conflict of interest, which may arise from being named as an author of this document.
