Donor-specific antibody

Donor-specific antibodies (DSA) are a concept in transplantation medicine and describe the presence of antibodies specific to the Donor's HLA-Molecules. These antibodies can cause antibody-mediated rejection and are therefore considered a contraindication against transplantation in most cases. DSA are a result of B cell and plasma cell activation and bind to HLA and/or non-HLA molecules on the endothelium of the graft. They were first described in 1969 by Patel et al., who found that Transplant recipients who were positively tested for DSA using a complement-dependent cytotoxicity crossmatch assay had a higher risk of transplant rejection. DSA can either be pre-formed (e.g. by pregnancy, prior transplantation or blood transfusion) or can be formed as a response to the transplantion. (De novo DSA)

Almost a third of patients who are waitlisted for transplantation may have a degree of pre-formed DSA. Pre-formed antibodies increase the chances of immunological failure of the allograft by causing positive crossmatches and, thereby, result in the exclusion of donors. For patients with pre-formed DSA, successful transplantation can still be possible by employing strategies such as desensitisation, paired exchange and acceptable mismatching.