Significance of donor-specific antibodies in acute rejection

Significant advances in recent years in the diagnosis of antibody-mediated graft rejection have led to the re-evaluation of humoral alloreactivity in organ transplantation. By introducing the "C4d-test" into the work-up of transplant biopsies, donor-specific antibodies were claimed to be directly involved in about 30% of acute rejection episodes. The diagnostic criteria for antibody-mediated rejections of renal grafts are now incorporated in the "Banff classification" as refined at a recent consensus conference. Capillary C4d is not always concordant with circulating anti-HLA-antibodies, even if these are assayed with improved techniques. Antibody absorption within the graft and antigens other than HLA, therefore, have to be considered. Effective therapy of humoral rejection is now available. Serial assessment of humoral alloreactivity also in the posttransplantation period is now mandatory to identify at-risk patients.