Unlike the double-negative and switched memory populations, IgD+CD27+ non-switched memory B cells are proportionally reduced in active SLE (Wehr et al., 2004; Korganow et al., 2010; Rodriguez-Bayona et al., 2010), inversely correlating with autoantibody titers (Rodriguez-Bayona et al., 2010). This evidence concerns the gene CD27 and systemic lupus erythematosus.