Anti-Neuronal IgG4 Autoimmune Diseases and IgG4-Related Diseases May Not Be Part of the Same Spectrum: A Comparative Study

Verena Endmayr, Cansu Tunc, Lara Ergin, Anna De Rosa, Rosa Weng, Lukas Wagner, Thin-Yau Yu, Andreas Fichtenbaum, Thomas Perkmann, Helmuth Haslacher, Nicolas Kozakowski, Carmen Schwaiger, Gerda Ricken, Simon Hametner, Sigrid Klotz, Lívia Almeida Dutra, Christian Lechner, Désirée de Simoni, Kai-Nicolas Poppert, Georg Johannes MüllerSusanne Pirker, Walter Pirker, Aleksandra Angelovski, Matus Valach, Michelangelo Maestri, Melania Guida, Roberta Ricciardi, Florian Frommlet, Daniela Sieghart, Miklos Pinter, Karl Kircher, Gottfried Artacker, Romana Höftberger, Inga Koneczny

Research output: Journal article (peer-reviewed)Journal article

12 Citations (Scopus)


Background: IgG4 is associated with two emerging groups of rare diseases: 1) IgG4 autoimmune diseases (IgG4-AID) and 2) IgG4-related diseases (IgG4-RLD). Anti-neuronal IgG4-AID include MuSK myasthenia gravis, LGI1- and Caspr2-encephalitis and autoimmune nodo-/paranodopathies (CNTN1/Caspr1 or NF155 antibodies). IgG4-RLD is a multiorgan disease hallmarked by tissue-destructive fibrotic lesions with lymphocyte and IgG4 plasma cell infiltrates and increased serum IgG4 concentrations. It is unclear whether IgG4-AID and IgG4-RLD share relevant clinical and immunopathological features.

Methods: We collected and analyzed clinical, serological, and histopathological data in 50 patients with anti-neuronal IgG4-AID and 19 patients with IgG4-RLD.

Results: A significantly higher proportion of IgG4-RLD patients had serum IgG4 elevation when compared to IgG4-AID patients (52.63% vs. 16%, p = .004). Moreover, those IgG4-AID patients with elevated IgG4 did not meet the diagnostic criteria of IgG4-RLD, and their autoantibody titers did not correlate with their serum IgG4 concentrations. In addition, patients with IgG4-RLD were negative for anti-neuronal/neuromuscular autoantibodies and among these patients, men showed a significantly higher propensity for IgG4 elevation, when compared to women (p = .005). Last, a kidney biopsy from a patient with autoimmune paranodopathy due to CNTN1/Caspr1-complex IgG4 autoantibodies and concomitant nephrotic syndrome did not show fibrosis or IgG4+ plasma cells, which are diagnostic hallmarks of IgG4-RLD.

Conclusion: Our observations suggest that anti-neuronal IgG4-AID and IgG4-RLD are most likely distinct disease entities.

Original languageEnglish
Article number785247
Pages (from-to)785247
JournalFrontiers in Immunology
Publication statusPublished - 14 Jan 2022


  • Autoantibodies/immunology
  • Autoantigens/immunology
  • Female
  • Humans
  • Immunoglobulin G4-Related Disease/immunology
  • Male
  • Neurons/immunology


Dive into the research topics of 'Anti-Neuronal IgG4 Autoimmune Diseases and IgG4-Related Diseases May Not Be Part of the Same Spectrum: A Comparative Study'. Together they form a unique fingerprint.

Cite this