PHENOTYPIC ANALYSIS OF MIGRANT, EFFERENT LYMPHOCYTES AFTER IMPLANTATION OF COLD-PRESERVED, PERIPHERAL-NERVE ALLOGRAFTS

Cold-preservation of peripheral nerve allografts in vitro (3 weeks, 5 degrees C) was performed to determine its effect on local lymphocyte m igration patterns in vivo, Lymphocyte migration was assessed by contin uously monitoring the cell output in the regional lymph for nearly 1 m onth. Cold-preservation delayed or prevented the typical biphasic incr ease in efferent lymphocyte output observed after fresh allograft impl antation. It also decreased the output of activated lymphocytes (CD 5 and MHC class II positive) compared with that seen in the fresh allogr aft response. These changes suggest that the host immune response to p reserved nerve allografts is altered over a prolonged period in vivo ( 3 weeks). Cold-preservation may be a useful method of reducing allogra ft immunogenicity, thereby limiting systemic immunosuppression require ments for the successful clinical utilization of peripheral nerve allo grafts.