Metabotropic glutamate receptor type 1 autoantibody-associated cerebellitis: a primary autoimmune disease?
OBJECTIVE
To report the third case of subacute cerebellar ataxia associated with metabotropic glutamate receptor type 1 autoantibodies (mGluR1-Abs), an uncommon syndrome known to be part of the group of paraneoplastic cerebellar degeneration syndromes linked to antineuronal antibodies and previously reported in only 2 other patients with long-term remission of Hodgkin lymphoma, and to discuss the underlying immunopathogenesis.


METHODS
Case report.


METHODS
University hospital.


METHODS
A 50-year-old woman admitted for acute severe isolated static and kinetic cerebellar syndrome. Magnetic resonance imaging of the brain showed diffuse abnormal hyperintensity in the whole cerebellum on fluid-attenuated inversion recovery and diffusion sequences.


RESULTS
Results of the biological workup were negative for general inflammation, vitamin deficiency, and bacterial and viral infections. Immunohistochemical analysis of the serum and cerebrospinal fluid of the patient demonstrated staining for Purkinje cell bodies and the molecular layer of the cerebellum. Finally, mGluR1-Abs were detected in serum and cerebrospinal fluid by a cell-based assay. Complete clinical examination, thoracoabdominal-pelvic computed tomography, and whole-body fludeoxyglucose F 18-positron emission tomography failed to show any underlying tumor, including Hodgkin lymphoma. The disease was stabilized after a course of intravenous immunoglobulins and continuous mycophenolate mofetil treatment during a follow-up of 40 months.


CONCLUSIONS
Cerebellitis associated with mGluR1-Abs should be considered in the differential diagnosis of patients with subacute cerebellar ataxia. This first case without any tumor found suggests a possible idiopathic autoimmune rather than a paraneoplastic mechanism. In consideration of this possible primitive autoimmune ataxia involving the directly pathogenic mGluR1-Abs, immunoactive therapy should be initiated as early as possible.
Marignier
Romain
R
Service de Neurologie A and European Database for Multiple Sclerosis Coordinating Center, Hôpital Neurologique Pierre Wertheimer, Hospices Civils de Lyon, 69677 Lyon-Bron CEDEX, France.
Chenevier
Florian
F
Rogemond
Veronique
V
Sillevis Smitt
Peter
P
Renoux
Christel
C
Cavillon
Gaëlle
G
Androdias
Geraldine
G
Vukusic
Sandra
S
Graus
Francesc
F
Honnorat
Jérôme
J
Confavreux
Christian
C
D001323:Autoantibodies / Q000032:analysis / Q000097:blood* / Q000134:cerebrospinal fluid; D002526:Cerebellar Diseases / Q000276:immunology* / Q000473:pathology / Q000503:physiopathology; D002531:Cerebellum / Q000276:immunology* / Q000473:pathology / Q000503:physiopathology; D020278:Demyelinating Autoimmune Diseases, CNS / Q000276:immunology* / Q000473:pathology / Q000503:physiopathology; D003937:Diagnosis, Differential; D004660:Encephalitis / Q000276:immunology* / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D020362:Paraneoplastic Cerebellar Degeneration / Q000175:diagnosis; D018094:Receptors, Metabotropic Glutamate / Q000276:immunology*
D001323:Autoantibodies; D018094:Receptors, Metabotropic Glutamate; C104077:metabotropic glutamate receptor type 1