Mechanisms of stem-/progenitor-cell mobilization: the anti-VLA-4 paradigm.

Since the introduction of mobilized peripheral blood stem cells for transplantation purposes, many studies have been performed using mobilized cells with different mobilization schemes, primarily to optimize mobilization protocols. Studies aiming at mechanisms of mobilization have been few, but have provided useful insights. However, conclusions about mobilization mechanisms were largely inferential. We have attempted to analyze the mobilization process Involving the VLA-4/VCAM-1 pathway. Our findings are summarized and an attempt is made to put our experience into a general model of mobilization.