Neurological Autoimmunity Associated With Homer-3 Antibody: A Case Series From China.

Abstract

BACKGROUND AND OBJECTIVE:

To present 6 new cases with Homer-3 antibodies that expand their clinical spectra and to evaluate the effect of immunotherapy.

METHODS:

Patients with suspected autoimmune cerebellar disorder were tested for rare autoimmune cerebellar ataxia (ACA) antibodies (anti-Tr(DNER)/Zic4/ITPR1/Homer-3/NCDN/PKCγ/PCA-2/AP3B2/mGluR1/ATP1A3 antibodies) using both cell-based and tissue-based assays. Patients with positive serum or CSF results who were diagnosed with ACA were registered and followed up. This study reports and analyzes cases with Homer-3 antibodies.

RESULTS:

Of the serum and CSF samples of 750 patients tested, 6 were positive for Homer-3 antibodies. All manifested subacute or insidious-onset cerebellar ataxia. Furthermore, 2 patients each exhibited encephalopathy, myeloradiculopathy, REM sleep behavior disorder, and autonomic dysfunction. Brain magnetic resonance images were normal (n = 1) or revealed cerebellar atrophy (n = 1), cerebellum and pons atrophy with the hot cross bun sign (n = 2), and bilateral cerebral abnormalities (n = 2). Definite leukocytosis was identified in the CSF of 2 patients, protein concentration elevation was observed in the CSF of 1 patient, and oligoclonal bands were present in 2 patients. All patients received immunotherapy, including corticosteroid, IV immunoglobulin, plasma exchange, and mycophenolate mofetil, after which the residual disability was still severe (modified Rankin Scale score ≥3 at the last follow-up in 4 patients and final Scale for the Assessment and Rating of Ataxia scores of 12-29), although 4 patients partially improved and 1 patient stabilized. The remaining 1 patient continued to deteriorate after repeated immunotherapy. Two patients relapsed.

DISCUSSION:

Disorders associated with Homer-3 antibody can mimic multiple system atrophy with cerebellar features in both clinical and radiologic aspects. Accurate identification of autoimmune-mediated cases is critical. Timely, comprehensive immunotherapy is warranted, given the possibility of long-term clinical benefit.

• Authors: Mange Liu, Haitao Ren, Siyuan Fan, Weihe Zhang, Yao Xu, Weili Zhao, Hongzhi Guan, Encephalitis Collaborative Group
• Journal: Neurology(R) neuroimmunology & neuroinflammation (Neurol Neuroimmunol Neuroinflamm) Vol. 8 Issue 6 (11 2021) ISSN: 2332-7812 [Electronic] United States
• PMID: 34580182 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2021 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.

Chemical References

• Autoantibodies
• Homer Scaffolding Proteins
• Immunologic Factors

Topics

• Adolescent
• Adult
• Aged
• Aged, 80 and over
• Autoantibodies (blood, cerebrospinal fluid, immunology)
• Autoimmune Diseases of the Nervous System (drug therapy, immunology, pathology, physiopathology)
• Cerebellar Ataxia (drug therapy, immunology, pathology, physiopathology)
• China
• Disease Progression
• Female
• Homer Scaffolding Proteins (immunology)
• Humans
• Immunologic Factors (pharmacology)
• Magnetic Resonance Imaging
• Male
• Middle Aged
• Young Adult