B-NDG hIL6 mice are well suited for human monocytes reconstitution. Human CD34+ HSCs (0.15 M) were intravenous implanted into homozygous B-NDG hIL6 and B-NDG mice (female, 6 week-old, n=15). All mice were treated with 1.6 Gy-irradiation. Flow cytometry analysis were performed with PBMCs from mice engrafted with human CD34+ HSCs. B-NDG hIL6 mice show higher percentages of human myeloid cells and monocytes compared with B-NDG mice.