Case Report: Anti-ADAM23 antibody: an overlooked autoantibody against VGKC-complex in autoimmune encephalitis

ObjectivesAntibodies against voltage-gated potassium channel (VGKC) complexes include anti-LGI1 and anti-CASPR2. Anti-ADAM23 antibodies have not been previously reported in autoimmune encephalitis (AE).Case reportWe report a 71-year-old female patient who presented with rapidly progressive short-ter...

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Main Authors: Pinfei Ni, Lin Bai, Nan Jiang, Siyuan Fan, Ming Yao, Haitao Ren, Hongzhi Guan
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-05-01
Series:Frontiers in Immunology
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Online Access:https://www.frontiersin.org/articles/10.3389/fimmu.2025.1589360/full
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author Pinfei Ni
Lin Bai
Nan Jiang
Siyuan Fan
Ming Yao
Haitao Ren
Hongzhi Guan
author_facet Pinfei Ni
Lin Bai
Nan Jiang
Siyuan Fan
Ming Yao
Haitao Ren
Hongzhi Guan
author_sort Pinfei Ni
collection DOAJ
description ObjectivesAntibodies against voltage-gated potassium channel (VGKC) complexes include anti-LGI1 and anti-CASPR2. Anti-ADAM23 antibodies have not been previously reported in autoimmune encephalitis (AE).Case reportWe report a 71-year-old female patient who presented with rapidly progressive short-term memory loss, psychobehavioural abnormalities, and impaired consciousness. Six months earlier, she had recovered from herpes simplex encephalitis (HSE). Cerebrospinal fluid (CSF) analysis suggested lymphocytic inflammation. AE was considered after the exclusion of HSV reactivation and other infectious etiologies. A comprehensive screening for commercially available autoimmune and paraneoplastic antibodies yielded negative results. A tissue-based assay (TBA) of CSF revealed a pattern of neuropil reactivity (neuropil pattern, suggesting the presence of neuronal surface antibodies (NS-Ab). A laboratory-developed antibody panel screening using a cell-based assay (CBA) identified an anti-ADAM23 antibody. Immunofluorescence staining showed that ADAM23 colocalized with Tuj1, which is expressed on the surface of neurons. Subclass analysis revealed that the anti-ADAM23 antibody predominantly belonged to the IgG4 subclass. Finally, the patient was diagnosed with an anti-ADAM23 antibody-associated AE. During the early stages of the disease, the patient underwent several courses of intravenous immunoglobulin (IVIg) with limited efficacy. Following the addition of high-dose methylprednisolone pulse therapy, the patient's consciousness improved from coma to stupor and the seizures were relieved.ConclusionWe propose that anti-ADAM23 antibody, a previously overlooked autoantibody targeting the VGKC complex, may have diagnostic significance for autoimmune encephalitis.
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spelling doaj-art-ee946b26f0904ba9ba9de9da73b739292025-08-20T03:21:56ZengFrontiers Media S.A.Frontiers in Immunology1664-32242025-05-011610.3389/fimmu.2025.15893601589360Case Report: Anti-ADAM23 antibody: an overlooked autoantibody against VGKC-complex in autoimmune encephalitisPinfei NiLin BaiNan JiangSiyuan FanMing YaoHaitao RenHongzhi GuanObjectivesAntibodies against voltage-gated potassium channel (VGKC) complexes include anti-LGI1 and anti-CASPR2. Anti-ADAM23 antibodies have not been previously reported in autoimmune encephalitis (AE).Case reportWe report a 71-year-old female patient who presented with rapidly progressive short-term memory loss, psychobehavioural abnormalities, and impaired consciousness. Six months earlier, she had recovered from herpes simplex encephalitis (HSE). Cerebrospinal fluid (CSF) analysis suggested lymphocytic inflammation. AE was considered after the exclusion of HSV reactivation and other infectious etiologies. A comprehensive screening for commercially available autoimmune and paraneoplastic antibodies yielded negative results. A tissue-based assay (TBA) of CSF revealed a pattern of neuropil reactivity (neuropil pattern, suggesting the presence of neuronal surface antibodies (NS-Ab). A laboratory-developed antibody panel screening using a cell-based assay (CBA) identified an anti-ADAM23 antibody. Immunofluorescence staining showed that ADAM23 colocalized with Tuj1, which is expressed on the surface of neurons. Subclass analysis revealed that the anti-ADAM23 antibody predominantly belonged to the IgG4 subclass. Finally, the patient was diagnosed with an anti-ADAM23 antibody-associated AE. During the early stages of the disease, the patient underwent several courses of intravenous immunoglobulin (IVIg) with limited efficacy. Following the addition of high-dose methylprednisolone pulse therapy, the patient's consciousness improved from coma to stupor and the seizures were relieved.ConclusionWe propose that anti-ADAM23 antibody, a previously overlooked autoantibody targeting the VGKC complex, may have diagnostic significance for autoimmune encephalitis.https://www.frontiersin.org/articles/10.3389/fimmu.2025.1589360/fullautoimmune encephalitisvoltage-gated potassium channel complexanti-ADAM23 antibodytissue-based assaycell-based assay
spellingShingle Pinfei Ni
Lin Bai
Nan Jiang
Siyuan Fan
Ming Yao
Haitao Ren
Hongzhi Guan
Case Report: Anti-ADAM23 antibody: an overlooked autoantibody against VGKC-complex in autoimmune encephalitis
Frontiers in Immunology
autoimmune encephalitis
voltage-gated potassium channel complex
anti-ADAM23 antibody
tissue-based assay
cell-based assay
title Case Report: Anti-ADAM23 antibody: an overlooked autoantibody against VGKC-complex in autoimmune encephalitis
title_full Case Report: Anti-ADAM23 antibody: an overlooked autoantibody against VGKC-complex in autoimmune encephalitis
title_fullStr Case Report: Anti-ADAM23 antibody: an overlooked autoantibody against VGKC-complex in autoimmune encephalitis
title_full_unstemmed Case Report: Anti-ADAM23 antibody: an overlooked autoantibody against VGKC-complex in autoimmune encephalitis
title_short Case Report: Anti-ADAM23 antibody: an overlooked autoantibody against VGKC-complex in autoimmune encephalitis
title_sort case report anti adam23 antibody an overlooked autoantibody against vgkc complex in autoimmune encephalitis
topic autoimmune encephalitis
voltage-gated potassium channel complex
anti-ADAM23 antibody
tissue-based assay
cell-based assay
url https://www.frontiersin.org/articles/10.3389/fimmu.2025.1589360/full
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