Increased frequency of CD14⁺HLA-DR^lo cells in the peripheral blood of untreated CLL patients. (A) Representative dot plots from flow cytometric (FACS) analyses showing the HLA-DR^lo cell frequency among peripheral blood CD14⁺ monocytes obtained from 37 healthy controls (HD) and 41 untreated CLL patients. (B) Frequency of HLA-DR^lo cells and CD14⁺ cells among monocytes and (non-CLL) PBMCs, respectively, were compared between HD (n = 40) and CLL patients (n = 44). (C) Representative histograms of the phenotypic FACS analyses of CD14⁺HLA-DR^lo cells from CLL patient samples (fine black line = isotype control and solid gray line = specific antibody). (D) Representative light microscopy image of cytospin preparations of FACS-sorted CD14⁺HLA-DR^lo cells from CLL patients stained according to Pappenheim. (E) A representative dot plot of the FACS-based DC subset analysis. The lin^negHLA-DR⁺ DCs were further subdivided into CD11c⁺ myeloid (m)DCs and CD123⁺ plasmacytoid (p)DCs. (F) Correlation analyses of the peripheral mDC and pDC counts with the proportion of HLA-DR^lo cells among CD14⁺ cells in CLL patients. The bars represent the standard error of the mean. ***P < .001.