FAS and systemic sclerosis: Some studies have confirmed the loss of memory B cells in SSc, which reported the augmented spontaneous apoptosis of CD27 + memory B cells, upregulation of the apoptosis regulator CD95 (Fas) [22], and downregulation of the antiapoptotic regulator B-cell lymphoma 2 (Bcl-2) [23] in subsets of memory B cells.