What's new--what's hot in basic science: American Transplant Congress 2004

The field of transplantation biology has, in the past year, given rise to several improved models explaining the in vivo phenomena of allograft rejection and acceptance. Although T-cells remain central participants in allorecognition, innate immune cells are increasingly recognized as critical. There is also growing acceptance that T-cell responses can vary widely not only based on their repertoire, but also on their immune experience in general, and their participation in homeostatic proliferation. Additional signaling pathways and molecules, such as the Janus kinase pathway and vascular endothelial growth factor have been added to those recognized as important in pharmacologic immunosuppression, and the concepts of regulation, once polarized between CD8+ and CD4+ camps, have begun to converge upon a recognition that there are many phenotypes of regulatory cells. In addition to improved basic science, several translational fields have accelerated in the past 12 months. Promising and clinically applicable islet transplant regimens have been developed and look appropriate for near-term clinical trials. Significant progress in discordant xenotransplantation is also apparent. This manuscript will review the past year in transplantation science as reported at the 2004 American Transplant Congress.