An update on opsoclonus.
OBJECTIVE
The aim of this article is to review opsoclonus, with particular emphasis on its immunopathogenesis and pathophysiology.


RESULTS
Infections (West Nile virus, Lyme disease), neoplasms (non-Hodgkin's lymphoma, renal adenocarcinoma), celiac disease, and allogeneic hematopoietic stem cell transplantation can cause opsoclonus. Newly identified autoantibodies include antineuroleukin, antigliadin, antiendomysial, and anti-CV2. Evidence suggests that the autoantigens of opsoclonus reside in postsynaptic density, or on the cell surface of neurons or neuroblastoma cells (where they exert antiproliferative and proapoptotic effects). Most patients, however, are seronegative for autoantibodies. Cell-mediated immunity may also play a role, with B and T-cell recruitment in the cerebrospinal fluid linked to neurological signs. Rituximab, an anti-CD20 monoclonal antibody, seems efficacious as an adjunctive therapy. Although changes in synaptic weighting of saccadic burst neuron circuits in the brainstem have been implicated, disinhibition of the fastigial nucleus in the cerebellum, or damage to afferent projections to the fastigial nucleus, is a more plausible pathophysiologic mechanism which is supported by functional magnetic resonance imaging findings in patients.


CONCLUSIONS
There is increasing recognition that both humoral and cell mediated immune mechanisms are involved in the pathogenesis of opsoclonus. Further studies are needed to further elucidate its immunopathogenesis and pathophysiology in order to develop novel and efficacious therapy.
Wong
Agnes
A
Department of Ophthalmology and Vision Sciences, University of Toronto, Hospital For Sick Children, Toronto, Ontario, Canada. agnes.wong@utoronto.ca
D001323:Autoantibodies / Q000276:immunology; D001324:Autoantigens / Q000276:immunology; D020274:Autoimmune Diseases of the Nervous System / Q000276:immunology / Q000473:pathology / Q000503:physiopathology*; D001933:Brain Stem / Q000276:immunology / Q000503:physiopathology*; D002529:Cerebellar Nuclei / Q000276:immunology / Q000503:physiopathology*; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D009415:Nerve Net / Q000276:immunology / Q000503:physiopathology*; D015835:Ocular Motility Disorders / Q000276:immunology / Q000473:pathology / Q000503:physiopathology*; D053578:Opsoclonus-Myoclonus Syndrome / Q000276:immunology / Q000473:pathology / Q000503:physiopathology
D001323:Autoantibodies; D001324:Autoantigens; D007166:Immunosuppressive Agents