A pathogenic and clonally expanded B cell transcriptome in active multiple sclerosis

Abstract

Central nervous system B cells have several potential roles in multiple sclerosis (MS): secretors of proinflammatory cytokines and chemokines, presenters of autoantigens to T cells, producers of pathogenic antibodies, and reservoirs for viruses that trigger demyelination. To interrogate these roles, single-cell RNA sequencing (scRNA-Seq) was performed on paired cerebrospinal fluid (CSF) and blood from subjects with relapsing-remitting MS (RRMS; n = 12), other neurologic diseases (ONDs; n = 1), and healthy controls (HCs; n = 3). Single-cell immunoglobulin sequencing (scIg-Seq) was performed on a subset of these subjects and additional RRMS (n = 4), clinically isolated syndrome (n = 2), and OND (n = 2) subjects. Further, paired CSF and blood B cell subsets (RRMS; n = 7) were isolated using fluorescence activated cell sorting for bulk RNA sequencing (RNA-Seq). Independent analyses across technologies demonstrated that nuclear factor kappa B (NF-κB) and cholesterol biosynthesis pathways were activated, and specific cytokine and chemokine receptors were up-regulated in CSF memory B cells. Further, SMAD/TGF-β1 signaling was down-regulated in CSF plasmablasts/plasma cells. Clonally expanded, somatically hypermutated IgM+ and IgG1+ CSF B cells were associated with inflammation, blood–brain barrier breakdown, and intrathecal Ig synthesis. While we identified memory B cells and plasmablast/plasma cells with highly similar Ig heavy-chain sequences across MS subjects, similarities were also identified with ONDs and HCs. No viral transcripts, including from Epstein–Barr virus, were detected. Our findings support the hypothesis that in MS, CSF B cells are driven to an inflammatory and clonally expanded memory and plasmablast/plasma cell phenotype.

Ectopic Lymphoid Follicles in Multiple Sclerosis: Centers for Disease Control?

“…Furthermore, in the absence of TLR signaling, these cells will preferentially differentiate into PBs upon stimulation with IFN-γ and IL-21, thus representing a source of OCBs that may be unrelated to CNS autoantigens ( 204 ). This would be in line with a recent study that suggested that novel OCBs in RRMS patients result from the clonal expansion of memory and PB/PC populations in the CSF ( 84 ).…”

“…OCBs are thought to be produced by ASCs derived from the local antigen-driven reactivation of memory B cells within the CNS, indicated by mutations highly concentrated within the CDR3 regions ( 82 ). This finding has been corroborated by other studies ( 83 , 84 ). This evidence of a CSF-restricted humoral response demonstrates that B cells participate in and potentially contribute to compartmentalized inflammation seen during later disease stages ( 85 ).…”

Neurological Manifestations of COVID-19 Feature T Cell Exhaustion and Dedifferentiated Monocytes in Cerebrospinal Fluid

“…Non-manual cluster annotation supported our cluster labeling ( Figure S1 B). We thus replicated the known composition and phenotype of hematopoietic lineages in the CSF ( Esaulova et al., 2020 ; Farhadian et al., 2018 ; Ramesh et al., 2020 ; Schafflick et al., 2020 ).…”

“…For example, while CD4 + T cells are the most abundant cell type in CSF, myeloid and B cells are reduced compared with blood ( Han et al., 2014 ; Kowarik et al., 2014 ). Applying modern technologies, such as single-cell transcriptomics to the CSF, multiplies the potential of the CSF to decipher the pathogenesis of neurological diseases ( Meyer Zu Hörste et al., 2020 ) as previously exemplified in multiple sclerosis and Alzheimer’s disease ( Gate et al., 2020 ; Ramesh et al., 2020 ; Schafflick et al., 2020 ).…”

Evaluating Infectious, Neoplastic, Immunological, and Degenerative Diseases of the Central Nervous System with Cerebrospinal Fluid-Based Next-Generation Sequencing

“…Interestingly, NGS of CD8+ and CD4+ T-cell receptor gene repertoires from CSF was used recently to support the diagnosis of MS [ 158 ] and to test the efficacy of treatment with autologous hematopoietic stem cell transplantation [ 159 ]. Furthermore, recently single-cell transcriptomics revealed increased transcriptional diversity in blood, and increased cell-type diversity in CSF including a higher abundance of cytotoxic phenotype T helper cells clonally expanded B cell in MS [ 160 , 161 ].…”