Garnache-Ottou et al. proposed that the following co-expression combinations would mean a diagnosis of BPDCN could be made: CD4+, CD56+/−, CD123+ cells, and BDCA-2/4+, and the absence of CD3+, CD11c+, MPO+, and CD79a+ [21]. This evidence concerns the gene CD4 and CD4+/CD56+ hematodermic neoplasm.