Integrated single-cell transcriptomics of cerebrospinal fluid cells in treatment-naive multiple sclerosis

Multiple sclerosis (MS) is a chronic and often disabling autoimmune disease of the central nervous system (CNS). Cerebrospinal fluid (CSF) surrounds and protects the CNS. Analysis of CSF can aid the diagnosis of CNS diseases, help to identify the prognosis, and underlying mechanisms of diseases. Several recent studies have leveraged single-cell RNA-sequencing (scRNA-seq) to identify MS-associated changes in CSF cells that are considerably more altered than blood cells in MS. However, not all alterations were replicated across all studies. We therefore integrated multiple available scRNA-seq datasets of CSF cells from MS patients with early relapsing-remitting (RRMS) disease. We provide a searchable and interactive resource of this integrated analysis (https://CSFinMS.bxgenomics.com) facilitating diverse visualization and analysis methods without requiring computational skills. In the present joint analysis, we replicated the known expansion of B lineage and the recently described expansion of natural killer (NK) cells and some cyto-toxic T cells and decrease of monocytes in the CSF in MS. The previous observation of the abundance of Th1-like Th17 effector memory cells in the CSF was not replicated. Expanded CSF B lineage cells resembled class-switched plasmablasts/-cells (e.g., SDC1/CD138, MZB1) as expected. Our integrative analysis thus validates increased cell type diversity and B cell maturation in the CSF in MS and improves accessibility of available data.

Automated summary

Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system. Analysis of cerebrospinal fluid (CSF) can help diagnose and understand MS. Recent studies using single-cell RNA sequencing have identified changes in CSF cells associated with MS. However, not all changes were consistent across studies. This study integrated multiple datasets to validate the expansion of B cells and other cell alterations in the CSF of MS patients.