Engraftment potential into NOD/SCID mice of CD34(+) cells derived from human fetal liver as compared to fetal bone marrow

Background and Objectives. We hypothesized that qualitative or quantitative differences in hematopoietic stem cells from fetal liver (FL) and fetal bo ne marrow (FBM) may be the cause of their organ specificity. Design and Methods. To analyze possible differences in vivo, we compared th e engraftment potential of equal numbers of CD34(+) cells isolated from hum an FL or FBM into immunodeficient NOD/SCID mice. Results. Mice showing engraftment following transplantation of CD34+ cells from FL demonstrated 14% (range 2-76%) CD45(+) cells of human origin in the bone marrow compared to significantly lower levels of engraftment (4%, ran ge 2-20%, p < 0.04) of FBM CD34+ cells. Likewise, the percentage of CD34+ C D38(-) cells in FBM was 4 times lower than the percentage in FL (1.4 +/-0.9 % and 5.6 +/-0.7%, respectively). Similar organ distribution of engrafted h uman cells was found. Subset analysis of human cells in bone marrow of engr afted mice revealed identical distribution of the lymphoid, myeloid and ery throid lineages after transplantation of CD34+ cells from FIL or FBM. Interpretation and Conclusions. The FIL CD34+ cells showed a four-fold high er content of the CD34+ CD38- subset coinciding with a four-fold higher eng raftment of CD34+ cells into NOD/SCID mice. Since the organ distribution an d differentiation potential of the cells engrafted were similar, we conclud ed that CD34+ hematopoietic cells derived from FL and FBM have quantitative ly different, but qualitatively the same potential for engraftment into NOD /SCID mice. (C) 2001, Ferrata Storti Foundation.