Plasmapheresis in acute disseminated encephalomyelitis.

Though the indication mentioned for resorting to plasmapheresis in the report is the unaffordability of intravenous immunoglobulin (IVIG) therapy, I wish to highlight other important reasons for preferring plasmapheresis over IVIG. Firstly, IVIG is known to exert its immunomodulatory effects for a prolonged period of time. The mean duration of action of IVIG is 53 days and the half life of immunoglobulin in the serum is 3-4 weeks(2). Therefore, employing plasmapheresis immediately after IVIG therapy would result in removal of circulating IVIG, thereby giving little time for IVIG to show its efficacy. This removal could be avoided by opting for IVIG therapy only after plasmapheresis has failed. Secondly, there are published reports of plasmapheresis succeeding even in IVIG-refractory cases of ADEM(3,4).