{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,24]],"date-time":"2026-02-24T10:19:06Z","timestamp":1771928346321,"version":"3.50.1"},"reference-count":19,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,1,30]],"date-time":"2026-01-30T00:00:00Z","timestamp":1769731200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Immunol."],"abstract":"<jats:p>Autoimmune encephalitis (AE) has been linked to various autoantibodies, with anti-neural cell adhesion molecule 1 (NCAM1) antibodies recently identified in patients with schizophrenia. Their pathogenic potential has been demonstrated in passive transfer experiments in mice. We report the first case of AE associated with anti-NCAM1 antibodies in a 15-year-old female who presented with acute-onset psychiatric symptoms, including delusions, hallucinations, and catalepsy, along with fever and impaired consciousness. Cerebrospinal fluid analysis showed a high IgG index, and electroencephalography revealed generalized slow-wave activity. However, brain magnetic resonance imaging was unremarkable. A pelvic tumor was identified, and adnexectomy confirmed a right mature cystic teratoma. Given the clinical presentation, anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis was initially suspected, and the patient was treated with intravenous methylprednisolone and intravenous immunoglobulin, resulting in significant improvement. Despite a subsequent relapse of hallucinations, additional immunotherapy led to complete resolution of symptoms. Notably, anti-NMDAR and other well-known neuronal surface antibodies were negative in both serum and cerebrospinal fluid, whereas anti-NCAM1 antibodies were detected. Immunohistochemical analysis confirmed NCAM1 expression in the excised ovarian tissue, and post-treatment serum tests showed the disappearance of anti-NCAM1 antibodies. The concurrent resolution of clinical symptoms and the disappearance of these antibodies support their pathogenic role. The clinical presentation and paraneoplastic association with teratoma closely resemble anti-NMDAR encephalitis, suggesting that anti-NCAM1 antibodies may define a novel form of AE with psychotic manifestations. Further research is needed to clarify their role in neuroinflammatory disorders.<\/jats:p>","DOI":"10.3389\/fimmu.2026.1587199","type":"journal-article","created":{"date-parts":[[2026,1,30]],"date-time":"2026-01-30T06:43:34Z","timestamp":1769755414000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Case Report: Anti-neural cell adhesion molecule 1 antibody-positive encephalitis presenting with schizophrenia-like symptoms and an ovarian teratoma"],"prefix":"10.3389","volume":"17","author":[{"given":"Nanami","family":"Yamanaka","sequence":"first","affiliation":[{"name":"Department of Neurology and Clinical Neuroscience, Yamaguchi University Graduate School of Medicine","place":["Ube, Yamaguchi, Japan"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Masaya","family":"Honda","sequence":"additional","affiliation":[{"name":"Department of Neurology and Clinical Neuroscience, Yamaguchi University Graduate 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