The emigration of leukocytes from the peripheral circulaor shed-soluble ligand (Murphy et al., 2000; Rossi and tion into an allograft is an essential component of organ Zlotnik, 2000). transplant rejection. Ischemic damage and surgical Chemokines can be further classified according to trauma set the stage for early leukocyte infiltration and function and regulation of expression (Murphy et al., activation, leadinginturntotherecruitmentofadditional 2000; Zlotnik and Yoshie, 2000). Some chemokines are effector leukocytes and the propagation of damage to important in the control of inflammatory processes, the graft. Productive alloreactivity in vivo also requires while others are involved in normal trafficking of leukoprocesses controlled within secondary lymphoid organs cytes through primary and secondary lymphoid organs