Bone marrow homing and engraftment by clinically transplanted hematopoietic stem and
progenitor cells is a complex process that is not fully understood. We report that the pan-
leukocyte CD45 phosphatase plays an essential role in trafficking and repopulation of the
bone marrow by immature human CD34+ cells and leukemic cells in transplanted nonobese
diabetic severe combined immunodeficient mice. Inhibiting CD45 function by blocking
antibodies or a CD45 inhibitor impaired the motility of both normal and leukemic human …