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Updated: Dec 29, 2025

Flow Cytometric Analysis of Lymphocyte Infiltration in Central Nervous System during Experimental Autoimmune Encephalomyelitis
Published on: November 17, 2020
Intrathecal B-cell activation in LGI1 antibody encephalitis
Klaus Lehmann-Horn1, Sarosh R Irani2, Shengzhi Wang2
1From the Department of Neurology (K.L.-H., S.W., A.P., S.J., A.L.G., R.D., J.M.G., M.D.G., M.R.W., S.S.Z., H.-C.v.B.), UCSF Weill Institute for Neurosciences; Program in Immunology (K.L.-H., S.S.Z.), UCSF, San Francisco, CA; Department of Neurology (K.L.-H., G.L.), Klinikum rechts der Isar, Technische Universität München, Germany; and Oxford Autoimmune Neurology Group (S.R.I., S.M.), John Radcliffe Hospital, University of Oxford, UK. klaus.lehmann-horn@tum.de.
Objective:
To study intrathecal B-cell activity in leucine-rich, glioma-inactivated 1 (LGI1) antibody encephalitis. In patients with LGI1 antibodies, the lack of CSF lymphocytosis or oligoclonal bands and serum-predominant LGI1 antibodies suggests a peripherally initiated immune response. However, it is unknown whether B cells within the CNS contribute to the ongoing pathogenesis of LGI1 antibody encephalitis.
Methods:
Paired CSF and peripheral blood (PB) mononuclear cells were collected from 6 patients with LGI1 antibody encephalitis and 2 patients with other neurologic diseases. Deep B-cell immune repertoire sequencing was performed on immunoglobulin heavy chain transcripts from CSF B cells and sorted PB B-cell subsets. In addition, LGI1 antibody levels were determined in CSF and PB.
Results:
Serum LGI1 antibody titers were on average 127-fold higher than CSF LGI1 antibody titers. Yet, deep B-cell repertoire analysis demonstrated a restricted CSF repertoire with frequent extensive clusters of clonally related B cells connected to mature PB B cells. These clusters showed intensive mutational activity of CSF B cells, providing strong evidence for an independent CNS-based antigen-driven response in patients with LGI1 antibody encephalitis but not in controls.
Conclusions:
Our results demonstrate that intrathecal immunoglobulin repertoire expansion is a feature of LGI1 antibody encephalitis and suggests a need for CNS-penetrant therapies.
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