Transplantation of CD34⁺ FLCs improves the production of human immunoglobulin in NOD/SCID mice that received a graft of human fetal Thy/Liv. At the indicated time points after human tissue/cell transplantation, serum was collected and human IgM (left) and IgG (right) were detected by ELISA. Open bars represent NOD/SCID mice that received human fetal Thy/Liv only (n = 4), and closed bars represent mice that received Thy/Liv and CD34⁺ FLCs (n = 6). Data are mean ± SEMs. *P < .05.