Increasing relevance of donor-specific antibodies in antibody-mediated rejection.

One of the major concerns in organ transplantation is the early detection of humoral rejection, through improved diagnostic and prognostic biomarkers. Long-term survival of renal allografts is significantly lower in recipients developing donor-specific anti-HLA antibodies (DSAs) either pretransplant or posttransplant. Patients can form antibodies following blood transfusions, pregnancies or previous transplants. DSAs can lead to endothelial damage through complement-dependent or independent pathways. Universal testing of kidney transplant patients and careful monitoring of graft function if DSAs are detected are recommended. Since there are different techniques to detect DSAs presence and serum levels, nephrologists have to face challenges in their interpretation due to variable sensitivity and specificity. Moreover, other biomarkers of rejection (T-cell reactivity, gene expression pattern modulation, early features of immunological damage in protocol renal biopsies) may be adopted together with DSAs detection tools, thus providing a global approach to the issue. To date, however, there are no well-defined strategies of intervention in cases of humoral graft damage. Future resolution of both interpretative and therapeutic concerns will make DSAs monitoring a very effective way to predict incoming immunological events. Therefore, an operative protocol for DSAs detection in renal recipients has been illustrated.