In this article, the author discusses some of the most notable aspects
of the work of Mehdi Tavassoli and others on the homing of intravenou
sly transplanted hematopoietic stem cells to the marrow. It is well-re
cognized that homing of stem cells is a highly selective process, perh
aps similar to the homing of lymphocytes to lympoid tissues, The natur
e of the selectivity of stem cell homing is unclear, however, and may
be mediated through a specific homing receptor or through a method of
selective capture, retainment, or survival advantage afforded by the m
arrow. In this article, the focus is on current research in the identi
fication of a specific homing receptor, the potential regulation of su
ch a receptor by cytokines, the homing phenomenon as a multi-step proc
ess, and secondary adhesive interactions mediated by known adhesive mo
lecules, These interactions may serve to strengthen the initial recogn
ition and engraftment of stem cells within the hematopoietic compartme
nt of the marrow.