Affiliations: Department of Neurology, Mayo Clinic College of
Medicine, Rochester MN, USA | Laboratory Medicine and Pathology, Mayo Clinic College
of Medicine, Rochester MN, USA | Department of Immunology, Mayo Clinic College of
Medicine, Rochester MN, USA | Department of Neurology, Mayo Clinic Scottsdale, AZ,
USA
Note: [] Corresponding author: Dr. Brian Weinshenker, Mayo Clinic College
of Medicine, 200 First St. SW, Rochester MN 55905, USA. Tel.: +1 507 538 1039;
Fax: +1 507 266 4419; E-mail: weinb@mayo.edu
Abstract: Neuromyelitis optica (NMO) is an inflammatory demyelinating disease
that principally targets the optic nerves and spinal cord and often leads to
severe disability and occasionally life threatening respiratory failure.
Although its clinical manifestations overlap with those of multiple sclerosis
(MS), in established cases these two conditions can be distinguished on the
basis of clinical, radiological, and routine spinal fluid studies. The
diagnosis in early cases or limited forms of NMO is difficult. We recently
discovered a unique IgG autoantibody (NMO-IgG) that is highly specific to
patients with NMO and thus a valuable diagnostic aid. Its antigen, aquaporin-4
(AQP4), is the central nervous system's predominant water channel protein. This
antibody has not yet been proven to be pathogenic, but several facts suggest
that it might be, including the similarity of the immunohistochemical pattern
of NMO-(AQP4) IgG binding to mouse CNS tissues to the pattern of immune complex
deposition in autopsied patients' spinal cord tissue. The spectrum of diseases
identified by NMO-IgG is broader than has previously been recognized clinically
and includes incomplete forms of NMO, such as recurrent transverse myelitis
without optic neuritis and recurrent optic neuritis without myelitis.
