donorspecific

Donor-specific (often written donor-specific) is an adjective used in transplantation and immunology to describe characteristics, responses, or markers that are unique to a donor and can influence recipient biology. The most commonly encountered usage is donor-specific antibodies (DSA), which are antibodies in a transplant recipient that recognize and bind to donor human leukocyte antigen (HLA) antigens. DSAs can be preformed or develop after transplantation (de novo) and are associated with increased risk of acute and chronic rejection and, in some cases, graft loss, especially in solid organ transplantation such as kidney, heart, and lung.

Detection and interpretation: DSAs are typically identified with solid-phase assays that use Luminex technology and single-antigen beads. The strength of a DSA is often expressed as mean fluorescence intensity (MFI), though thresholds vary among laboratories and clinical contexts. The specific HLA targets, their class (I or II), and their ability to fix complement influence the clinical significance. Crossmatching and sensitization history also inform risk assessment.

Clinical implications and management: The presence of DSAs guides donor selection, risk stratification, and post-transplant monitoring. In sensitized recipients, desensitization strategies may be employed to reduce DSA levels before transplantation, or post-transplant therapies (such as plasmapheresis, intravenous immunoglobulin, and immunomodulatory drugs) may be used to mitigate their impact and improve graft outcomes. DSAs also play a role in research and clinical practice beyond solid organs, including hematopoietic stem cell transplantation, where donor-specific markers help assess engraftment and chimerism. Limitations include variability in assay methods and the fact that not all DSAs cause rejection; their significance depends on specificity, titer, and functional properties.