2025 American Academy of Neurology Abstract Website

Claudia Papi¹, Chiara Milano², Takahiro Iizuka³, Mateus Simabukuro⁴, Laura Marmolejo Alcaide⁵, Esther Aguilar⁵, Mar Guasp⁵, Raffaele Iorio⁶, Yuki Fukami⁷, Mara Lúcia Schmitz Ferreira Santos⁸, Takashi Miwa⁹, TAKASHI ARAGA¹⁰, Yuto Uchida¹¹, Masanori Kurihara¹², Satoshi Okada¹³, Luz Victoria García Ruiz¹⁴, Kenichi Kaida¹⁵, Natália Spinola Costa Cunha¹⁶, Alberto Vogrig¹⁷, Florian LAMBLIN¹⁸, Livia Dutra¹⁹, Romana Höftberger²⁰, Juna De Vries²¹, Maarten Titulaer²¹, Lidia Sabater⁵, Eugenia Martinez-Hernandez⁵, Thais Armangue²², Francesc Graus²³, Josep Dalmau⁵, Marianna Spatola⁵
¹Neuroimmunology Program, Fundació de Recerca Clínic Barcelona-Institut d'Investigacions Biomédiques August Pi i Sunyer (FRCB-IDIBAPS), University of Barcelona, Spain; Caixa Research Institute (CRI), Barcelona, Spain; Department of Neuroscience, Catholic University of the Sacred Heart, Rome, Italy, ²Neuroimmunology Program, Fundació de Recerca Clínic Barcelona-Institut d'Investigacions Biomédiques August Pi i Sunyer (FRCB-IDIBAPS), University of Barcelona, Spain; Caixa Research Institute (CRI), Barcelona, Spain; Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy, ³Department of Neurology, Kitasato University School of Medicine, Japan, ⁴Division of Neurology, Hospital das Clinicas (HCFMUSP), Faculdade de Medicina, Universidade de Sao Paulo, São Paulo, Brazil; Instituto do Cancer do Estado de Sao Paulo (ICESP), Faculdade de Medicina da Universidade de Sao Paulo, Sao Paulo, Brazil., ⁵Neuroimmunology Program, Fundació de Recerca Clínic Barcelona-Institut d'Investigacions Biomédiques August Pi i Sunyer (FRCB-IDIBAPS), University of Barcelona, Spain; Caixa Research Institute (CRI), Barcelona, Spain, ⁶Department of Neuroscience, Catholic University of the Sacred Heart, ⁷Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan, ⁸Neurology Department, Hospital Pequeno Principe, Curitiba, Brazil, ⁹Department of Neurology, National Hospital Organization Osaka Minami Medical Center, Kawachinagano, Osaka, Japan, ¹⁰Division of Neurology, Department of Internal Medicine, St. Marianna University School of Medicine, Kawasaki, Japan, ¹¹Department of Neurology, Nagoya City University Graduate School of Medical Sciences, Japan, ¹²Department of Neurology, University of Tokyo, Tokyo, Japan, ¹³Department of Neurology, Ichikawa General Hospital Tokyo Dental College, Japan, ¹⁴Instituto Nacional de Salud del Niño, Breña, Lima, Perú, ¹⁵Department of Neurology, Saitama Medical Center, Saitama Medical University, Japan, ¹⁶Hospital da Criança de Brasília, Brasília, Brazil, ¹⁷Clinical Neurology Unit, Department of Medicine (DMED), University of Udine, Azienda Sanitaria Universitaria Friuli Centrale (ASUFC), Udine, Italy, ¹⁸Department of Neurology, University Hospital of La Réunion, Saint-Pierre (La Réunion), France, ¹⁹Faculdade Israelita de Ciências da Saúde Albert Einstein, Instituto do Cérebro do Hospital Israelita Albert Einstein, São Paulo SP, Brazil, ²⁰Division of Neuropathology and Neurochemistry, Department of Neurology, Medical University of Vienna, Vienna, Austria, ²¹Department of Neurology, Erasmus University Medical Center, Rotterdam, the Netherlands, ²²Neuroimmunology Program, Fundació de Recerca Clínic Barcelona-Institut d'Investigacions Biomédiques August Pi i Sunyer (FRCB-IDIBAPS), University of Barcelona, Spain; Caixa Research Institute (CRI), Barcelona, Spain; Pediatric Neuroimmunology Unit, Neurology Service, Sant Joan de Déu (SJD) Children's Hospital, University of Barcelona, Barcelona, Spain, ²³Neuroimmunology Program, Fundació de Recerca Clínic Barcelona-Institut d'Investigacions Biomédiques August Pi i Sunyer (FRCB-IDIBAPS), University of Barcelona, Spain

Objective:

This study aims to report the clinical course and outcome of patients with autoimmune encephalitis with antibodies against γ-aminobutyric acid type A receptor (GABA_AR).

Background:

GABA_AR encephalitis is associated with prominent seizures and multifocal brain lesions. The risk of clinical relapse and long-term outcome are unknown.

Design/Methods:

We retrospectively assessed clinical information of patients with GABA_AR antibodies (identified by rat brain immunohistochemistry and cell-based assay) referred to our center from worldwide between January 2016 and April 2024. Relapses were defined as onset/worsening of neurological symptoms (isolated seizures only if accompanied by new MRI changes) after ≥ 2 months of improvement/stabilization. Long-term outcome was determined in patients with a follow-up ≥ 18 months from onset, and ≥ 12 months from last clinical episode.

Results:

Twenty-nine patients were identified, 4 (14%) children and 25 (86%) adults. At first clinical episode, 28/29 (97%) patients developed seizures, evolving into status epilepticus in 16/28 (57%). In addition to seizures, 24/28 (86%) patients had other neurological symptoms, predominantly cognitive impairment (18/28, 64%). Tumors occurred in 17/29 (59%) patients (thymoma in 13/17, 76%). Brain MRI showed multifocal cortico-subcortical T2/FLAIR abnormalities in 22/27 (81%) patients; isolated cerebellar lesions were found in 3/27 (11%). Immunotherapy was administered in 25/29 (86%) patients. Sixteen of 29 (55%) patients had one or more clinical relapses (median 1, range 1-3) manifesting with seizures in 14/20 episodes (70%). Older age at onset (p=0.02) and no treatment with second-line immunotherapy (p=0.026) were associated with relapses. Four of 29 (14%) patients died. Long-term follow-up was assessable in 15 alive patients: 7 (47%) completely recovered and 8 (53%) showed partial recovery. Cognitive disturbances were the most frequent persistent neurological deficits (6/15, 40%).

Conclusions:

In GABA_AR encephalitis, relapses are not rare, often manifesting with seizure recurrence. Half of the patients with long-term follow-up were left with residual neurological deficits, mainly cognitive disturbances.