Safety and Efficacy of BAFF-R CART for Refractory Neuroimmune Diseases

"Biological: BAFF-R CART cells Subjects will undergo leukapheresis to isolate peripheral blood mononuclear cells (PBMCs) to manufacture BAFF-R CART cells, during which cyclophosphamide will be administered for the purpose of lymphocytes depletion. After lymphodepletion, subjects will receive one dose treatment with BAFF-R CART cells by intravenous (IV) infusion. The initial dose of 0.5×10\^6 CART cells/kg will be infused on day 0.~Drug: Cyclophosphamide and fludarabine Subjects will receive one 3-day cycle of lymphodepletion starting 4 days prior to BAFF-R CART cells infusion on Day 0.~Subjects will be given IV infusion of cyclophosphamide 250 mg/m2/day on day -5, -4 and -3, and fludarabine 30 mg/m2 over 30 minutes administered immediately after cyclophosphamide."