Transplantation of CD34⁺ FLCs improves multilineage human hematopoiesis in NOD/SCID mice that received a graft of human fetal Thy/Liv. NOD/SCID mice that received Thy/Liv only (□,n = 8) or Thy/Liv/CD34⁺ FLCs (▴,n = 13) were bled to measure human chimerism in the peripheral blood mononuclear cells (PBMCs) at the indicated time points; all mice were killed between 18 to 25 weeks after human tissue/cell transplantation for analysis of human-cell repopulation in bone marrow (BM), spleen (SPL), liver, and lymph nodes (LNs). (A-C) Data are mean ± SEMs, and the differences in mean values at the time points later than 6 weeks are statistically significant. (A) Kinetics of human CD45⁺, CD3⁺, and CD19⁺ cell levels in the PBMCs. (B) Levels of human CD14⁺ monocytes/macrophages in the PBMCs at death between 18 and 25 weeks after human tissue/cells transplantation. (C) Levels of various lineages of human hematopoietic cells in BM, SPL, liver, and LNs at death between 18 and 25 weeks after human tissue/cell transplantation. nd indicates not detected. (D) Macroscopic and FCM analyses of representative mesenteric lymph nodes taken from NOD/SCID mice that received Thy/Liv (top panel) or Thy/Liv/CD34⁺ FLCs (bottom panel) at week 20. For FCM analysis, single-cell suspensions were stained for the markers of human hematopoietic cells (CD45), T cells (CD3, CD4, and CD8), and B cells (CD19).