B Cell Differentiation in MS

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the Central Nervous System (CNS) affecting primarily young adults. This disease is the leading cause of non-traumatic disability in this population. MS has long been considered as a T-cell mediated disease. However, the remarkable efficacy of anti-CD20 monoclonal antibodies in this disease has highlighted the major role of B-lymphocytes in the pathophysiology of this disease. Despite many advances made recently in understanding the role of B-lymphocytes in the pathophysiology of MS, the precise involvement of plasma cells and their function at different stages of the disease remains unclear. In this project, the investigators plan to analyze the differentiation abilities of circulating B-lymphocytes in patients with MS. Follicular helper T cells (TFH) play a crucial role in B lymphocyte differentiation. These cells are located within germinal centers in secondary lymphoid organs, and their memory compartment also circulates in the blood. Several circulating TFH subpopulations have recently been defined, with different helping capacities. There is currently very little data on these cells in MS patients. The investigators therefore plan, in a second step, to characterize the phenotype of the different subpopulations of TFH at the periphery, but also in the CSF of MS patients.