Autoimmune neurologic diseases
Clonally expanded memory CD8+T cells are involved in multiple sclerosis (MS). We have shown that up to 87% of expanded CD8+T cells in brain-lesions of MS patients can be found in the cerebrospinal fluid (CSF) and 37% in the blood of the patients. We now aim to study CD8+T cells in the blood of MS patients at single-cell level to identify a molecular signature of pathogenic CD8+T cells and more precisely of the clonally expanded CD8+T cells.
To analyze single-cells from MS patients and controls, we used the C1 Single-Cell Auto-Prep System (Fluidigm) with subsequent microfluidic qPCR of 96 well-chosen genes and TCR Vβ-chain genes followed by sequencing. In parallel, we performed β-chainTCR immunosequencing on pooled memory CD8+T cells to analyze the repertoire and identify expanded clones.
We detected clear clustering and increased expression of more than 20 genes in MS patients compared to healthy volunteers (HV). Most of those genes are associated with CD8+T cell activation or MS. We also identified clonally expanded CD8+T for which we can compare the phenotype to the non-expanded CD8+T cells.
Our data are the first to describe a phenotypic analysis of CD8+T cells from MS patients at single-cell level and to link this phenotype to the TCR clonality. We detected in MS a gene expression profile which is clearly different to that of HVs. The gene expression differences and the clustering can serve as the basis to develop a biomarker to detect MS specific pathogenic cells in the peripheral compartments.