Immune cell profiling reveals expanded stem cell–like memory T cells in anti-GAD65-associated neurological syndromes
- Sumanta Barman
- Saskia Räuber
- Katharina Eisenhut
- Daniela Esser
- Martijn van Duijn
- Madeleine Scharf
- Marisol Herrera-Rivero
- Paul Disse
- Lara-Maria Preuth
- Valeria Gulyaeva
- Ilja Schwan
- Eliza vom Stein
- Marius Jonas
- Duygu Pul
- Michael Heming
- Louisa Müller-Miny
- Manuela Paunovic
- Christine Strippel
- Ebru Haholu
- Jan Bartosch
- Elisabeth Kaufmann
- Justina Dargvainiene
- Sabine Kahl
- Marius Ringelstein
- Eric Bindels
- Heinz Wiendl
- Nikolas H. Stoecklein
- Johannes Fischer
- Norbert Goebels
- Lars Komorowski
- Michael Roden
- Andrea Rossi
- Monika Stoll
- Albert J. Becker
- Motaz Hamed
- Christian G. Bien
- Romana Höftberger
- Jan Bauer
- Sven G. Meuth
- Maarten J. Titulaer
- Frank Leypoldt
- Gerd Meyer zu Hörste
- Franziska Thaler
- Nico Melzer
- Juna M. de Vries
- Mariska M. P. Nagtzaam
- Suzanne C. Franken
- Yvette S. Crijnen
- Juliette Brenner
- Robin W. van Steenhoven
2026-03-25
The immunopathogenesis of autoimmune neurological syndromes (AINS) with antibodies against the 65 kDa isoform of glutamic acid decarboxylase (anti-GAD65 AINS) remains poorly understood. To elucidate underlying disease mechanisms and identify relevant cell populations, we performed single-cell RNA and immune repertoire sequencing of cerebrospinal fluid (CSF) and peripheral blood mononuclear cells (PBMCs) of eight anti-GAD65 AINS individuals compared to eight noninflammatory controls. In addition, PBMCs from 19 anti-GAD65 AINS individuals and 20 healthy controls were analyzed by multidimensional flow cytometry, and brain tissue specimens from four anti-GAD65 AINS individuals were examined histologically. We detected higher frequencies of stem cell–like memory T cells (TSCM) within the PBMCs and a marked enrichment and clonal expansion of activated CD4 + TSCM in the CSF of anti-GAD65 AINS individuals. Expanded T cells exhibited increased expression of proinflammatory genes. Histological analyses confirmed intraparenchymal CD8 + TSCM in three of four anti-GAD65 AINS individuals and rare meningeal/intraparenchymal CD4 + TSCM in one person. Although CSF B cell receptors (BCRs) displayed little to no clonal expansion, recombinant expression of 40 CSF BCRs revealed that 25% were GAD65-reactive with increased somatic hypermutations compared to non-GAD65-reactive BCRs. These findings further support the concept of an antigen-specific intrathecal immune response. In summary, we characterize the immune landscape of anti-GAD65 AINS at single-cell resolution and identify clonally expanded TSCM with cytotoxic properties as a hallmark of this disease.