BTLA and systemic lupus erythematosus: These lupus effector T cells express higher levels of BTLA than activated effector T cells from HC (MFI 3762 ± 387 in HC vs 5199 ± 461, p<0.05, Figure 6F) and more interestingly, the enhanced expression of BTLA by effector T cells is only observed in lupus patients displaying high BTLA expression levels by aTregs (MFI 3310 ± 268 in lupus patients with low BTLA expression by aTregs vs 6678 ± 646 in lupus patients with high BTLA expression by aTregs, p<0.001, Figure 6F).