Two cytokines involved in survival and attraction of B cells into the CNS in neuroinflammation are B cell-activating factor (BAFF) and chemokine CXC ligand 13 (CXCL-13), which have been studied in the CSF of MS patients [31,35,36,37,38,39]. The gene discussed is TNFSF13B; the disease is myeloid sarcoma.