Neuromyelitis optica (NMO) antibody positivity in patients with transverse myelitis and no visual manifestations.

BACKGROUND AND PURPOSE: To describe a subgroup of patients with IgG antibody to Aquaporin 4 Protein (AQP4) specific to neuromyelitis optica (NMO), who did not have clinical manifestations of optic nerve involvement at the time of diagnosis.

METHODS

Assessment of five patients (four African Americans and one Latino) with myelitis, who were NMO IgG antibody positive, who had no detected optic nerve involvement, over a span of one to eighteen years.

RESULTS

Cerebrospinal fluid (CSF) studies showed lymphocytic pleocytosis, elevated interleukin (IL6), oligoclonal bands (OCB), myelin basic protein (MBP), and elevated albumin and IgG index. Serology showed an association with antinuclear antibody (ANA) positivity and antithyroid peroxidase (TPO) antibody. Our patients responded well to acute treatment with intravenous corticosteroids and long-term treatment with oral prednisone and azathioprine.

CONCLUSIONS

The aquaporin protein autoimmune disease previously identified as neuromyelitis optica (NMO) may more correctly be identified as neuromyelitis (NM), and future diagnostic criteria should take into account the population of patients with antibody to aquaporin 4 protein, without clinically evident optic nerve pathology. Future research may indicate that the entity of NMO is a subcategory of the NM population.