CD4 and acute myeloid leukemia: All mice transplanted with adult NH9+ LSKs developed AML (Fig. 3a, b) characterised by intermediate CD11b and Gr-1 expression levels (i.e. overt AML distinct to myeloproliferative phenotype which was observed prior to clinical signs of AML and characterized by CD11bhiGr-1hi expression), with low or no expression of lymphoid markers CD19, B220, CD4 and CD8 (Fig. 3a, c) and positive staining for MPO by IHC (Fig. 3d).