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CASE REPORT article

Front. Immunol.
Sec. Autoimmune and Autoinflammatory Disorders : Autoimmune Disorders
Volume 15 - 2024 | doi: 10.3389/fimmu.2024.1436733

Paraneoplastic progressive encephalomyelitis with rigidity and myoclonus associated with monoclonal B-cell lymphocytosis in the setting of longstanding methotrexate use: case report

Provisionally accepted
Fangzhi (Frank) Jia Fangzhi (Frank) Jia 1,2,3*Mohammad R. Amin Mohammad R. Amin 1Gi Tae Kwon Gi Tae Kwon 1Amir Mousapasandi Amir Mousapasandi 1Pei Dai Pei Dai 1Jed Kitson Jed Kitson 1Adrian Selim Adrian Selim 1Jerome Ip Jerome Ip 1,4,5
  • 1 Neurology, Nepean Hospital, Penrith, Australia
  • 2 Neurology, St Vincent’s Hospital Sydney, Darlinghurst, New South Wales, Australia
  • 3 St Vincent's Healthcare Clinical Campus, Discipline of Medicine, School of Clinical Medicine, UNSW, Sydney, Australia
  • 4 Neurology, Sydney Adventist Hospital, Sydney, New South Wales, Australia
  • 5 Neurology, Hornsby Ku-ring-gai Hospital, Hornsby, New South Wales, Australia

The final, formatted version of the article will be published soon.

    Progressive encephalomyelitis with rigidity and myoclonus (PERM) is a rare but debilitating disease within the stiff-person syndrome (SPS) spectrum and is characterised by muscle rigidity, spasms, myoclonus, dysautonomia and brainstem dysfunction. The exact pathogenetic mechanism is unclear, although there is an association with the presence of glycine receptor antibodies in serum and cerebrospinal fluid, and some cases are paraneoplastic. Here we report a case of paraneoplastic, glycine receptor antibody-positive PERM associated with an otherwise subclinical monoclonal B-cell lymphocytosis (MBL) of the non-CLL phenotype, which may be in turn likely secondary to longterm methotrexate use (i.e. methotrexate-associated lymphoproliferative disorder, MTX-LPD) or underlying autoimmune disease. Treatment with multiple lines of initial induction immunomodulatory therapies, followed by maintenance rituximab achieved long-term remission of the neurologic, haematological and rheumatologic disease. This is, to our knowledge, the first reported association between PERM and MBL, or between PERM and MTX-LPD.

    Keywords: progressive encephalomyelitis with rigidity and myoclonus, Glycine receptor antibody, Monoclonal B-cell lymphocytosis, paraneoplastic neurological disorder, Methotrexate-associated lymphoproliferative disorder

    Received: 23 May 2024; Accepted: 25 Sep 2024.

    Copyright: © 2024 Jia, Amin, Kwon, Mousapasandi, Dai, Kitson, Selim and Ip. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Fangzhi (Frank) Jia, Neurology, Nepean Hospital, Penrith, Australia

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