Single-cell RNA and TCR sequencing of IgG4-related disease cerebrospinal fluid. Single-cell RNA and TCR sequencing of IgG4-related disease cerebrospinal fluid

Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) is a fibroinflammatory disorder signified by aberrant infiltration of IgG4-restricted plasma cells in a variety of organs. Clinical presentation is heterogeneous and pathophysiological mechanisms of IgG4-related autoimmunity remain elusive. Secondary parenchymal lesions of IgG4-RD in the central nervous system (CNS) are rare and there are very few cases of IgG4-RD with isolated CNS manifestation. Patients suffering from IgG4-RD frequently require prolonged treatment with glucocorticoids and are often unable to taper these medications. By leveraging single-cell sequencing of the cerebrospinal fluid (CSF) of a patient with an unusual inflammatory intracranial pseudotumor we provide novel insights into the immuno-pathophysiology of IgG4-RD by illustrating an IgG4-RD-associated polyclonal T cell response in the CSF and multifaceted cell-cell interaction between immune cell subsets and pathogenic B cells.