CASE REPORT article

Front. Immunol.

Sec. Autoimmune and Autoinflammatory Disorders : Autoimmune Disorders

Dual response to efgartigimod in myasthenia gravis and comorbid autoimmune disorders: a case series

  • 1. Department of Neurology, The First Affiliated Hospital of China Medical University, Shenyang, China

  • 2. Key Laboratory of Neurological Disease Big Data of Liaoning Province, Shenyang, China

  • 3. Clinical Medical Research Center for Difficult and Serious Diseases of the Nervous Systems, Shenyang, China

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Abstract

The coexistence of myasthenia gravis (MG) with other IgG-mediated autoimmune diseases represents a clinically heterogeneous condition, driven by pathogenic autoantibodies. Efgartigimod, a neonatal Fc receptor antagonist, has the ability to clear all IgG subclasses. Here, we report four cases of MG concomitant with IgG-mediated autoimmune diseases, specifically idiopathic inflammatory myopathies (IIM), Isaacs syndrome, autoimmune encephalitis (AE), and IgG4-related disease (IgG4-RD). All of them demonstrated a favorable therapeutic response to efgartigimod, with marked improvement in QMG and MG-ADL scores, along with disease-specific clinical or laboratory manifestations of the overlapping autoimmune conditions. These cases provide preliminary evidence supporting efgartigimod as a promising treatment option for patients with MG complicated by IgG-mediated autoimmune diseases.

Summary

Keywords

autoimmune encephalitis, efgartigimod, Idiopathic inflammatory myopathies, IgG4-related disease, Isaacs Syndrome, Myasthenia Gravis

Received

15 January 2026

Accepted

18 February 2026

Copyright

© 2026 Li, Yang, Zhu and Zhu. 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: Ruixia Zhu

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All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

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