(A) Quantification of each blood monocyte per DC subset. Percentage of monocytes and cDCs and plasmacytoid DCs (pDCs) was analyzed and calculated based on the number of total PBMCs. Each dot represents an individual, and the bar represents the mean ± SEM. Expression of HLA-DR on each cell type (B) and Mo-DCs (C) were measured from each population (R1 = Lin^–HLA⁺, R2 = CD14⁺CD11c⁺, R3 = CD16⁺CD11c⁺, R4 = CD14^–CD16^–CD11c^–CD123^hi, and R5 = CD14^–CD16^–CD11c⁺CD123^–, and flow cytometry images are described in Supplemental Figure 6A) and compared by MFI. Values are expressed as the mean ± SEM; n = 8 for control and n = 7 for carrier (open bar represents controls and closed bar represents Blimp1 SLE carriers). (D) Blimp1 and let-7c expression was measured from Mo-DCs by qPCR. Each dot represents an individual, and the bar represents the mean ± SEM. (E) Cytokine expression was measured from Mo-DCs with or without TLR agonists (poly [I:C], 5 μg/ml; LPS, 1 μg/ml; and Gardiquimod, 2 μg/ml) overnight. IL-6 in the supernatants was measured by MSD assay. Open circle denotes a control individual, and closed circle denotes a risk carrier individual. Each dot represents an individual, and the bar represents the mean ± SEM. (F) Blimp1 binding to let-7c was assessed by ChIP assay. Nuclear extracts were prepared from 10⁷ human Mo-DCs stimulated with LPS and incubated with control rabbit IgG, control goat IgG (not shown), Goat anti–Blimp1, or Rabbit anti–Blimp1 antibodies. PCR was performed with the primers described in Methods. Representative image is from 3 independent experiments.