Ofatumumab presents a potentially promising alternative to current second-line immunotherapy for refractory anti-N-methyl-D-aspartate receptor autoimmune encephalitis (NMDAR-AE). We aimed to evaluate the efficacy and safety of ofatumumab as a novel second-line immunotherapy for NMDAR-AE. This prospective, multicenter, nested cohort study compared patients with NMDAR-AE from the CHina Autoimmune encephalitiS outcomE study registry (CHASE) recruited between October 2011 and February 2024, treated with and without ofatumumab. The primary outcome was the proportion reaching a favorable functional outcome (modified Rankin Scale [mRS] score ≤2) at the last follow-up. Secondary outcomes included mRS scores and Clinical Assessment Scale in Autoimmune Encephalitis (CASE) scores over the first 24-month follow-up and the proportion with further mRS score improvement after ofatumumab initiation. A propensity score matching was performed to balance major confounders. A total of 715 patients with AE were screened. Fifty-eight propensity score-matched patients with NMDAR-AE each in the ofatumumab group and non-ofatumumab group were analyzed. Fifty-four patients (93.1%) in the ofatumumab group achieved further mRS score improvement with a median time of 14 days from ofatumumab initiation, and 53 (91.4%) reached a favorable functional outcome at the last follow-up. For those who failed first-line immunotherapy, the ofatumumab group demonstrated a faster mRS score and CASE score improvement and more frequently reached a favorable functional outcome at the last follow-up compared with the non-ofatumumab group (87.9% vs. 64.7%, odds ratio [OR] 3.95; 95% confidence interval [CI] 1.12-13.94; p = 0.026). No serious adverse events associated with ofatumumab treatment were reported. Ofatumumab showed substantial efficacy and safety, particularly in patients who failed first-line immunotherapy, warranting its consideration in NMDAR-AE management. ANN NEUROL 2025;98:80-92.

A vast range of neurological conditions impacting the central and peripheral nervous system are caused by ion channel dysfunctions, which are collectively referred to as channelopathies. These disorders, which are frequently autoimmune or genetic in nature, present as a variety of clinical syndromes, such as migraine, epilepsy, ataxia, neuropathic pain, and intermittent paralysis. The pathogenic mechanisms underlying these illnesses have been uncovered by recent developments in molecular genetics and electrophysiological research, opening up new avenues for accurate diagnosis and specialized treatment approaches. With an emphasis on important genetic variations and clinical manifestations, this study offers a targeted synthesis of channelopathies of the central and peripheral nervous system. By providing the most recent information on these complex disorders, this review aims to help physicians identify and treat channelopathies.

We report a case of a 22-year-old woman who presented with recurrent episodes of quadriparesis, often accompanied by jaundice. Neurologic examination showed symmetrical proximal predominant quadriparesis with generalized hyporeflexia. The differential diagnoses included were of metabolic, inflammatory, genetic (including channelopathies), and autoimmune causes. Serum creatine phosphokinase levels and electrophysiologic studies helped narrow the differential. The final diagnosis was one that was responsive to vitamin supplementation. This report provides a systematic clinical approach to a case of episodic weakness with jaundice and respiratory failure.

The objective of this study is to investigate the presence of astrocyte antibodies in patients, excluding aquaporin-4 or glial fibrillary acidic protein (GFAP) antibodies, while evaluating associated biomarkers and pathologies. Patient serum and cerebrospinal fluid (CSF) were tested for antibodies using tissue- and cell-based assays. Neurofilament light chain (NFL) and GFAP in the CSF were detected using single-molecule array (SIMOA). 116 patients accepted SIMOA. Fifteen functional neurological disorders patients without antibodies were designated as controls. Thirty-five patients were positive for astrocyte antibodies (Anti-GFAP: 7; Anti-AQP4: 7; unknown antibodies: 21, designed as the double-negative group, DNAP). The most frequent phenotype of DNAP was encephalitis (42.9%), followed by myelitis (23.8%), movement disorders (19.0%), and amyotrophic lateral sclerosis-like (ALS-like) disease (14.2%). The levels of CSF GFAP and NFL in DNAP were higher than in the control (GFAP: 1967.29 [776.60-13214.47] vs 475.38 [16.80-943.60] pg/mL, p < 0.001; NFL: 549.11 [162.08-2462.61] vs 214.18 [81.60-349.60] pg/mL, p = 0.002). GFAP levels decreased in DNAP (n = 5) after immunotherapy (2446.75 [1583.45-6277.33] vs 1380.46 [272.16-2005.80] pg/mL, p = 0.043), while there was no difference in NFL levels (2273.78 [162.08-2462.61] vs 890.42 [645.06-3168.06] pg/mL, p = 0.893). Two brain biopsy patterns were observed: one exhibited prominent tissue proliferation and hypertrophic astrocytes, with local loss of astrocytes, while the other showed severe astrocyte depletion with loss of neurofilaments around the vessels. Eighteen patients received immunotherapy, and improved except one with ALS-like symptoms. We identified anti-vimentin in this patient. There are unidentified astrocyte antibodies. The manifestations of double-negativity are heterogeneous; nevertheless, the pathology and biomarkers remain consistent with astrocytopathy. Immunotherapy is effective.

The autoimmune channelopathies represent a rapidly evolving scientific and clinical domain. The description of channels, expressed on neurons and glia, as targets of autoantibodies in neuromyelitis optica, autoimmune encephalitis, and related syndromes have revolutionized many areas of neurologic practice. To date, tens of surface antibody specificities have been described, a number that is likely to continue to increase. A central paradigm for all these disorders is that of pathogenic autoantibodies which target extracellular epitopes accessible for binding in vivo. Hence, in these disorders, the autoantibodies are causative diagnostic tools, and provide valuable reagents to model the diseases. Their production by B-lineage cells provides opportunities to study and modulate their production. Across these syndromes, early recognition and treatment are critical since most respond to immunotherapies. Yet, several unmet medical needs persist within treated patient populations, and widespread clinical under-recognition remains a challenge. In this review, we summarize the neuroscience and immunologic basis of autoantibody-mediated central nervous system channelopathies, the molecular effects of the autoantibodies, clinical phenotypes, and treatment approaches. We describe progress since the inauguration of the field through to open questions and potential future directions.