The detection and treatment of allograft rejection has historically focused upon T-cell-mediated processes. The existence of vascular or humoral rejection was suspected, as antibodies reactive to donor HLA antigens were regularly found in the sera of recipients undergoing rejection (1). However, until recently, diagnosis of antibody-mediated rejection (AMR) was hampered by lack of a reliable histologic marker providing evidence of antibody deposition in biopsy specimens of rejecting grafts (2,3). Antibody-mediated rejection is typically unresponsive to conventional antirejection therapy (3), and therefore has recently been recognized as a major cause of allograft loss.
On April 23–24, 2003, a national conference was held at the National Institutes of Health to assess current knowledge regarding humoral rejection in solid organ transplantation. The objectives were to: develop a risk profile for recipient susceptibility to AMR; examine new criteria to diagnose AMR; assess the effectiveness of innovative treatment protocols; and develop immunologic strategies of basic science research. Workgroups addressed each of these topics, with participants selected for their expertise in these areas. Background papers and questions to focus interaction were distributed before the conference. The organizers summarized the findings of the various workgroups in this compendium and distributed them to participants who provided recommendations for the final report.