Finally, another recent finding (overexpression of the B cell-promoting cytokine BAFF due to an MS-associated genetic variant; [23]) seems to be in line with the substantial impact of B cell-depleting therapies on MS course [24], but is yet to be reconciled with the worsening effects resulting from an anti-BAFF trial on disease activity [24,25]. This evidence concerns the gene TNFSF13B and myeloid sarcoma.