Significance of serum glycoprotein profiles in spontaneous tolerance after liver allograft transplantation

Liver allograft rejection usually occurs unless the donor's and the recipient's major histocompatibility complex is matched [1-3]. In contrast, it has been shown in rat models that tolerance could be induced spontaneously in orthotopic liver transplantation (OLT) between different strains [4, 5]. In addition, the recipient lost the ability to reject other allografts from the original liver donor by 60-day post-OLT serum (POD 60), and established rejection was rapidly reversed in animal models. Several possible mechanisms have been reported to explain this phenomenon; however, the underlying mechanisms and response elements involved are not yet fully understood. Previous studies have shown that several factors identified in OLT animals could maintain lifelong administration of immunosuppression, which is more potent than that achieved with immunosuppressive drugs [6-9].