Plasma exchange linked to improved recovery in rare inflammatory disease

A systematic review and meta-analysis have found that plasma exchange was associated with high rates of recovery in people with myelin oligodendrocyte glycoprotein antibody-associated disease, particularly those with inflammation of the optic nerve

Plasma exchange has been associated with substantial recovery in people with myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), according to a recent systematic review and meta-analysis. The findings suggest that the treatment could offer an important option for people who fail to respond adequately to corticosteroid therapy or who present at clinic with severe neurological attacks.

The review found that most people treated with plasma exchange experienced either excellent or good recovery following a period of MOGAD while treatment-related adverse effects were uncommon. However, the researchers stressed that the available evidence demonstrated an association rather than proof that plasma exchange directly caused the observed improvements.

MOGAD is a rare autoimmune inflammatory disorder of the central nervous system. In affected individuals, the immune system produces antibodies that attack myelin oligodendrocyte glycoprotein, a protein found on the protective myelin sheath that surrounds nerve fibres. 

Damage to this insulating layer disrupts nerve signalling and can lead to symptoms including vision loss, muscle weakness, paralysis, seizures, headache and confusion. Some attacks can result in permanent neurological disability if treatment fails to halt the inflammatory process rapidly.

Plasma exchange – also known as therapeutic plasma exchange or plasmapheresis – removes circulating antibodies and other inflammatory substances from the bloodstream. During the procedure, blood is withdrawn from the patient and separated into plasma and blood cells. 

The plasma, which contains disease-associated antibodies, is discarded and replaced with a substitute fluid before the blood cells are returned to the circulation. The treatment aims to reduce the immune attack responsible for neurological damage.

The review analysed all available published evidence on plasma exchange in MOGAD. Researchers examined 10 studies involving 1,045 people who experienced a total of 1,368 disease attacks during the study period.

Among these attacks, 41 per cent involved optic neuritis, an inflammation of the optic nerve. A further 29 per cent involved a combination of optic neuritis, spinal cord inflammation that caused symptoms such as muscle weakness, and brain inflammation that produced neurological symptoms including confusion and headache. Spinal cord symptoms were present in only 12 per cent of patients.

Participants were followed on average for 11 months. Researchers assessed recovery using clinical measures including visual acuity, which evaluates the ability to distinguish fine detail at a standard distance. Recovery was classified as excellent when symptoms resolved completely or almost completely and visual acuity returned to 20/25 or better, or neurological symptoms disappeared. Recovery was considered good when participants regained meaningful function but did not return fully to their pre-attack condition.

The analysis found particularly favourable outcomes among people with optic neuritis. Eighty-one per cent achieved excellent recovery following plasma exchange. Among people who experienced combined optic nerve, spinal cord or brain involvement, 94 per cent achieved good recovery. Treatment-related complications were uncommon, with only 3 per cent of participants experiencing side effects attributed to plasma exchange.

The findings are particularly relevant because corticosteroids remain the standard first-line treatment for acute MOGAD attacks, yet not every patient responds well. Delays in effective treatment may increase the risk of permanent neurological injury, especially when vision or spinal cord function is affected.

“This evidence was exciting, as many people do not respond well to the main steroid treatment for MOGAD and [so] without quick, effective treatment some of the damage can be irreversible,” said Dr. Marina Vilardo of Harvard University, Cambridge, Massachusetts, USA, and a member of the American Academy of Neurology.

The researchers suggested that plasma exchange should receive consideration when corticosteroids fail to produce sufficient improvement or when patients present with severe neurological deficits.

“This analysis suggested that plasma exchange should be considered for people who do not respond completely to steroid treatment for MOGAD and for people who have severe attacks with symptoms such as complete loss of vision or paralysis,” Vilardo said.

The authors also highlighted important limitations of the evidence. The review combined studies that differed in design, treatment protocols and definitions of recovery, making direct comparisons inevitably difficult and limiting the certainty of the conclusions. 

As all included studies were observational, the analysis could identify associations but could not establish that plasma exchange alone was responsible for the improved outcomes.

Nevertheless, the consistency of favourable results across multiple studies has strengthened support for further prospective clinical research to determine the optimal timing, patient selection and treatment protocols for plasma exchange in people with MOGAD.

For further reading please visit: https://www.neurology.org/journal/wnl