Abstract Details

Title Clinical and Imaging Characteristics of Non-paraneoplastic Cerebellar Ataxia Associated with Anti-metabotropic Glutamate Receptor Type 1 Autoantibodies

Topic Autoimmune Neurology

Presentation(s) Autoimmune Neurology Posters (7:00 AM-5:00 PM)

Poster/Presentation
Number 028

Objective To determine the clinical and imaging characteristics of patients with cerebellar ataxia associated with anti-metabotropic glutamate receptor type 1 (mGluR1) autoantibodies (anti-mGluR1 Abs).

Background Autoimmune-mediated cerebellar ataxia associated with anti-mGluR1 Abs is known to be a rare cause of paraneoplastic cerebellar ataxia, but the clinical and imaging characteristics of non-paraneoplastic cases remain unknown.

Design/Methods Case series. We measured anti-mGluR1 Abs in serum and cerebrospinal fluid (CSF) with a cell-based assay using COS-7 cells transfected with mGluR1.

Results Using the cell-based assay, we identified three Japanese patients (a 51-year-old woman, a 51-year-old man, and a 71-year-old man) among 59 patients with subacute cerebellar ataxia of unknown etiology. Their serum and CSF showed characteristic immunostaining of hippocampus and cerebellum in rat brain sections. All their main initial symptoms indicated subacute progressive ataxia of the trunk and of unilateral upper and lower extremities. Extra-cerebellar symptoms were dysgeusia in two patients and myokymia in another. Scale for the Assessment and Rating of Ataxia (SARA) scores peaked at 15, 8, and 16.5 points at first admission. CSF analysis revealed mild pleocytosis in two patients and elevation of protein levels in one. None of the three patients exhibited cerebellar atrophy on brain MRI at diagnosis, and none showed evidence of malignancy during follow-up. All three patients received immunotherapy at first admission: steroid-pulse therapy for three; plasma exchange for three; high-dose immunoglobulin (IVIg) for one; and rituximab (RTX) for one. Maintenance treatments were also provided: oral prednisolone for two; tacrolimus for two; and azathioprine for one. Responses to immunotherapy were favorable in all three patients. Recurrences in one patient were improved by IVIg and RTX; however, follow-up brain MRI revealed cerebellar atrophy.

Conclusions Our results suggest that autoimmune cerebellar ataxia with anti-mGluR1 Abs occurs without malignancy and that immunotherapy is highly effective.

Authors/Disclosures
Nobuaki Yoshikura, MD, PhD (Gifu univesity graduate school of medicine department of neurology) PRESENTER	Dr. Yoshikura has nothing to disclose.
Akio Kimura, MD (Gifu University Graduate School of Medicine)	Dr. Kimura has nothing to disclose.
Takayoshi Shimohata, MD, FAAN (Department of Neurology, Gifu University)	Dr. Shimohata has nothing to disclose.

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