There is evidence that B cells in the CSF of MS patients have a greater degree of CD80, a co-stimulatory molecule;[29] also, B cell activating factor (BAFF), a cytokine essentially for B cell survival, is upregulated in the CSF of MS patients as compared to CSF of controls.[30] Other B cell chemokines, such as CXCL12, CXCL13, and α-lymphotoxin, have been found in MS lesions.[31]. This evidence concerns the gene CXCL12 and myeloid sarcoma.