Figure 5: Development of CD14+ cells from lymphoid precursors is promoted by TLR ligation in acute lymphoblastic leukemias. BM CD34+ cells were purified from all investigated acute leukemia subtypes and stimulated with Pam3CSK4 (TLR2 ligand), LPS (TLR4 ligand), Flagellin (TLR5 ligand), MALP2 (TLR2/6 ligand), Poly(I:C) (TLR3 ligand), PolyU (TLR8 ligand), and CpG-ODN (TLR9 ligand) agonists for 48 h, followed by a 30 day-stromal cell coculture. Newly produced CD14+ cells were further identified and enumerated by multiparametric flow cytometry (a). The indicated gates were used to determine cell frequencies within the culture (b). Under these culture conditions, acute myeloid leukemia showed poor differentiation potentials and no apparent influence by TLR exposure. ProB-ALL: B-cell precursor ALL with prevalence of CD34+CD10+CD19+ cells; PreB-ALL: B-cell precursor ALL with prevalence of CD3CD10+/−CD19+ cells; C-ALL: congenital ALL; M-ALL: mixed ALL; AML: acute myeloid leukemia.