Factors associated with the effectiveness of plasma exchange for the treatment of NMO-IgG-positive neuromyelitis optica spectrum disorders

Lim et al. published a study in 2013 on the effectiveness of plasma exchange (PE) in treating neuromyelitis optica spectrum disorders (NMOSDs). During plasma exchange, blood is removed from the body and the blood cells are separated from the plasma. The person receiving plasma exchange then gets their blood cells back, but the cells are mixed with donor plasma. The study included 31 women who were positive for NMO-IgG who received PE for a steroid-resistant attack of NMO. The NMO-IgG test indicates whether or not someone has antibodies for aquaporin 4 antigen, and being NMO-IgG positive is a characteristic of NMO.

In this study, 25 of the patients had an NMO diagnosis, and 6 had a diagnosis of longitudinally extensive transverse myelitis. All of the patients were characterized as moderately to severely disabled, and were given a disability score. The patients’ responses to plasma exchange were measured at 1-month and 6-month intervals after treatment with plasma exchange. Functional improvement was seen in 18 patients (58%) at 1 month and 20 patients (65%) at 6 months. Short-term improvement was associated with attacks that did not involve the optic nerve and attacks in which the patients’ reflexes were preserved. Similarly, long-term improvement was associated with non-optic nerve related attacks, but was also associated with a lower disability score at the onset of the NMOSD attack, and fewer prior attacks of NMOSD. Furthermore, improvement was seen more often in patients who did not have spinal cord atrophy than those that did. NMO-IgG levels at the beginning of plasma exchange and during the follow-up intervals were not different between those who responded favorably to the treatment and those who did not. Also, some patients received plasma exchange sooner after their onset of symptoms than other patients, but this was not associated with functional outcome. Lim et al. concluded that even though rapid onset of plasma exchange is recommended, it should be given to patients who have not recovered even after the acute phase of an attack of NMOSD.

This summary was written by Gabrielle (GG) deFiebre, Research Associate at a Public Health non-profit in New York city who was diagnosed with Transverse Myelitis in 2009. GG volunteers with the Transverse Myelitis Association.

Original research: Lim Y, Pyun SY, Kang B, Kim J, Kim K. Factors associated with the effectiveness of plasma exchange for the treatment of NMO-IgG-positive neuromyelitis optica spectrum disorders. Mult Scler. 2013; 19(9): 1216-1218.