{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,27]],"date-time":"2026-10-27T12:37:07Z","timestamp":1793104627116,"version":"4.5.0"},"reference-count":7,"publisher":"Springer Science and Business Media LLC","issue":"11","license":[{"start":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T00:00:00Z","timestamp":1792713600000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T00:00:00Z","timestamp":1792713600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Neurol Sci"],"published-print":{"date-parts":[[2026,11]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Neuronal intermediate filament (NIF) autoimmunity is an uncommon paraneoplastic neurologic syndrome that has increasingly been recognized in association with immune checkpoint inhibitor (ICI) therapy. Merkel cell carcinoma is among the malignancies most frequently associated with NIF antibodies, although reported cases remain limited.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Case Presentation<\/jats:title>\n                    <jats:p>A 55-year-old female with stage IIIA Merkel cell carcinoma developed vertigo, gait instability, dysarthria, and persistent right hemifacial and cervical spasms after receiving second dose of pembrolizumab for recurrent disease. Brain MRI was unremarkable, while continuous electroencephalography demonstrated encephalopathy without a definitive electrocerebral correlate, raising suspicion for subcortical myoclonus. Cerebrospinal fluid (CSF) analysis revealed lymphocytic pleocytosis, elevated protein. CSF and positive NIF antibodies using cell-based assay. Pembrolizumab was discontinued, and the patient was treated with high-dose corticosteroids followed by monthly intravenous immunoglobulin, resulting in near complete resolution of her neurologic symptoms after 6 months.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>This case expands the growing spectrum of ICI-associated NIF paraneoplastic neurologic autoimmunity complicating Merkel cell carcinoma. To our knowledge, persistent hemifacial and cervical spasm has rarely been reported in this clinical setting. Early recognition of this syndrome, prompt antibody testing, discontinuation of ICI therapy, and initiation of therapy may improve neurological outcomes while informing further oncologic management.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1007\/s10072-026-09500-8","type":"journal-article","created":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T03:11:53Z","timestamp":1792725113000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Neuronal intermediate filament neurologic autoimmunity in a patient with Merkel cell carcinoma receiving pembrolizumab"],"prefix":"10.1007","volume":"47","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0847-6081","authenticated-orcid":false,"given":"Ali","family":"Hijazi","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Saffet","family":"Guleryuz","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mark A","family":"Walshauser","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ghazala","family":"Hayat","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maithreyi","family":"Chappidi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2026,10,23]]},"reference":[{"issue":"9","key":"9500_CR1","doi-asserted-by":"publisher","first-page":"1865","DOI":"10.1016\/j.mayocp.2019.02.003","volume":"94","author":"A Zekeridou","year":"2019","unstructured":"Zekeridou A, Lennon VA (2019) Neurologic Autoimmunity in the Era of Checkpoint Inhibitor Cancer Immunotherapy. Mayo Clin Proc 94(9):1865\u20131878. https:\/\/doi.org\/10.1016\/j.mayocp.2019.02.003. Epub 2019 Jul 26. PMID: 31358366","journal-title":"Mayo Clin Proc"},{"key":"9500_CR2","doi-asserted-by":"publisher","first-page":"578778","DOI":"10.1016\/j.jneuroim.2025.578778","volume":"409","author":"J Benoit","year":"2025","unstructured":"Benoit J, Joubert B, Vogrig A (2025) Role of antibodies in immune checkpoint inhibitor-related CNS toxicities: insights from challenging clinical cases. J Neuroimmunol 409:578778. https:\/\/doi.org\/10.1016\/j.jneuroim.2025.578778. Epub 2025 Oct 8. PMID: 41076750","journal-title":"J Neuroimmunol"},{"key":"9500_CR3","doi-asserted-by":"publisher","unstructured":"Farina A, Villagr\u00e1n-Garc\u00eda M, Vogrig A, Zekeridou A, Mu\u00f1iz-Castrillo S, Velasco R, Guidon AC, Joubert B, Honnorat J (2024) Neurological adverse events of immune checkpoint inhibitors and the development of paraneoplastic neurological syndromes. Lancet Neurol. ;23(1):81\u201394. https:\/\/doi.org\/10.1016\/S1474-4422(23)00369-1. PMID:38101905","DOI":"10.1016\/S1474-4422(23)00369-1"},{"issue":"18","key":"9500_CR4","doi-asserted-by":"publisher","first-page":"e1677","DOI":"10.1212\/WNL.0000000000006435","volume":"91","author":"E Basal","year":"2018","unstructured":"Basal E, Zalewski N, Kryzer TJ, Hinson SR, Guo Y, Dubey D, Benarroch EE, Lucchinetti CF, Pittock SJ, Lennon VA, McKeon A (2018) Paraneoplastic neuronal intermediate filament autoimmunity. Neurology 91(18):e1677\u2013e1689. https:\/\/doi.org\/10.1212\/WNL.0000000000006435. Epub 2018 Oct 3. PMID: 30282771; PMCID: PMC6207411","journal-title":"Neurology"},{"issue":"2","key":"9500_CR5","doi-asserted-by":"publisher","first-page":"425","DOI":"10.1002\/acn3.51284","volume":"8","author":"A McKeon","year":"2021","unstructured":"McKeon A, Shelly S, Zivelonghi C, Basal E, Dubey D, Flanagan E, Madhavan AA, Mariotto S, Toledano M, Tracy JA, Zekeridou A, Pittock SJ (2021) Neuronal intermediate filament IgGs in CSF: Autoimmune Axonopathy Biomarkers. Ann Clin Transl Neurol 8(2):425\u2013439 Epub 2020 Dec 28. PMID: 33369283; PMCID: PMC7886032","journal-title":"Ann Clin Transl Neurol"},{"key":"9500_CR6","doi-asserted-by":"publisher","first-page":"577882","DOI":"10.1016\/j.jneuroim.2022.577882","volume":"368","author":"A Dinoto","year":"2022","unstructured":"Dinoto A, McKeon A, Vattemi G, Carta S, Ferrari S, Mariotto S (2022) Neuronal intermediate filament paraneoplastic autoimmunity complicating avelumab therapy of Merkel cell carcinoma. J Neuroimmunol 368:577882. https:\/\/doi.org\/10.1016\/j.jneuroim.2022.577882. Epub 2022 May 5. PMID: 35580403; PMCID: PMC9637407","journal-title":"J Neuroimmunol"},{"issue":"11","key":"9500_CR7","doi-asserted-by":"publisher","first-page":"6145","DOI":"10.1007\/s00415-022-11191-y","volume":"269","author":"L Rettenmaier","year":"2022","unstructured":"Rettenmaier L, Abdel-Wahed L, McKeon A, Groth CL (2022) Paraneoplastic neuronal intermediate filament presenting as encephalopathy and myoclonus: a case report and literature review. J Neurol 269(11):6145\u20136147. https:\/\/doi.org\/10.1007\/s00415-022-11191-y. Epub 2022 May 23. 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In such cases, SLU investigators are not required to obtain IRB approval prior to beginning the activity.","order":1,"name":"Ethics","label":"Ethical approval","group":{"name":"EthicsHeading","label":"Declarations"}},{"value":"Written informed consent was obtained from the patient for this case report.","order":2,"name":"Ethics","label":"Consent","group":{"name":"EthicsHeading","label":"Declarations"}},{"value":"The authors have no relevant financial or non-financial interests to disclose.","order":3,"name":"Ethics","label":"Competing interests","group":{"name":"EthicsHeading","label":"Declarations"}}],"article-number":"882"}}