Two representative examples of BPDCN patients. Live cells are gated on a first forward scatter (FCS)/side scatter (SSC) to exclude debris and a FCS area (A)/FSC height (H) gate to select singlets (not shown). The CD45bright /SSClow cells are lymphocytes (blue), and CD45dim /CD123bright cells are a BPDCN blastic population (pink). (A) Patient P165. Blasts are CD4+ (lower than T lymphocytes in blue) and CD56+ with a bimodal expression, CD303+, CD304+ HLA-DR+, cTCL1+, ILT7low, CD36+, CD38+, and CD43+.There is no expression of classical dendritic cell markers (CD1c, CD141, and CD11c) or immature markers (CD34, CD133, and Tdt). (B) Patient P149. Blasts are CD4+ and CD56partial and low, CD303+, CD304+ HLA-DR+, cTCL1+, ILT7−, CD36−/partial, and CD38+. The blasts also expressed CD7 and CD33 without CD13. Classical dendritic cell markers (CD1c, CD141, and CD11c) and immature markers (CD34 and CD133) are negative. APC, allophycocyanin; FITC, fluorescein isothiocyanate; PE, phycoerythrin.