Progressive appearance of distinct plasmacytoid and myeloid DC precursors in whole peripheral blood after Allo-HSCT. Dot plots were obtained as reported in “Patients, materials, and methods” at the indicated time points from a patient treated with Allo-HSCT for severe aplastic anemia. Before Allo-HSCT, this patient had a significant number of lymphocytes but was totally deficient in myeloid and plasmacytoid DC precursors. After Allo-HSCT, there was a gradual and progressive appearance of myeloid and plasmacytoid mononuclear cells. The percentages of DC subtypes are referred to WBC.