Pro-inflammatory c-Met+ CD4 T cells in multiple sclerosis

Objective Hepatocyte growth factor (HGF) binds exclusively the c-Met surface receptor, and the HGF/c-Met axis regulates T-cell function in autoimmune diseases. We analyzed c-Met expression on human CD4 T cells in the blood and cerebrospinal fluid (CSF) from patients with multiple sclerosis (MS) versus non-inflammatory neurological disease (NIND), to better understand the role of CD4 T cells in MS. Methods We recruited 34 untreated MS patients (aged 28–43 years) and 10 NIND (aged 34–51 years) who underwent paired blood and CSF sampling at the time of diagnosis work-up. Phenotypic and functional CD4 T cells characterization was determined by flow cytometry and bulk RNA sequencing. Adhesion and transmigration capacities were studied to further characterize the function of c-Met+ CD4 T cells. Results c-Met+ memory CD4 T cells were detected at higher levels in both blood (median of 1.98%) and CSF (5.88%) in MS compared to NIND (0.37% and 0.68% respectively) (p<0.0001). Ex vivo c-Met+ CD4 T cells exhibited higher levels of GM-CSF, IL-17, IFN-γ and double positive IL-17+IFN-γ+ expression, compared with c-Met- CD4 T cells. c-Met+ CD4 T cells expressed increased levels of integrins – Itgα4β1 (VLA-4) and ItgαLβ2 (LFA-1) – compared with c-Met- CD4 T cells. Anti-Itgα4 (natalizumab) and anti-ItgαLβ2 (odulimomab) inhibited CD4 T cell transmigration with predominant inhibition of CD4 T cells expressing c-Met. Interpretation These results emphasize c-Met as an immune marker of highly pro-inflammatory and migratory CD4 T lymphocytes in both the periphery and central nervous system of MS patients.