Autoimmune myelopathies

Abstract

Autoimmune myelopathies are a heterogeneous group of immune-mediated spinal cord disorders with a broad differential diagnosis. They encompass myelopathies with an immune attack on the spinal cord (e.g., aquaporin-4-IgG (AQP4-IgG) seropositive neuromyelitis optica (NMO) and its spectrum disorders (NMOSD)), myelopathies occurring with systemic autoimmune disorders (which may also be due to coexisting NMO/NMOSD), paraneoplastic autoimmune myelopathies, postinfectious autoimmune myelopathies (e.g., acute disseminated encephalomyelitis), and myelopathies thought to be immune-related (e.g., multiple sclerosis and spinal cord sarcoidosis). Spine magnetic resonance imaging is extremely useful in the evaluation of autoimmune myelopathies as the location of signal change, length of the lesion, gadolinium enhancement pattern, and evolution over time narrow the differential diagnosis considerably. The recent discovery of multiple novel neural-specific autoantibodies accompanying autoimmune myelopathies has improved their classification. These autoantibodies may be pathogenic (e.g., AQP4-IgG) or nonpathogenic and more reflective of a cytotoxic T-cell-mediated autoimmune response (collapsin response mediator protein-5(CRMP5)-IgG). The presence of an autoantibody may help guide cancer search, assist treatment decisions, and predict outcome/relapse. With paraneoplastic myelopathies the initial goal is detection and treatment of the underlying cancer. The aim of immunotherapy in all autoimmune myelopathies is to maximize reversibility, maintain benefits (while preventing relapse), and minimize side effects.

Keywords: aquaporin-4-IgG; autoimmune myelopathy; neuromyelitis optica; paraneoplastic myelopathy; spinal cord sarcoidosis; transverse myelitis.