BTLA and systemic lupus erythematosus: Moreover, the enhancement of BTLA expression on aTregs is significantly associated to the presence of circulating anti-dsDNA autoAbs, which are characteristic for lupus (MFI 3499 ± 620 in the group of patients with anti-dsDNA autoAbs vs MFI 2064 ± 228 in HC, p<0.05; Figure 3B).