Donorreactive

Donorreactive refers to immune responses directed against donor-derived antigens in the context of transplantation. The term encompasses both donor-reactive T cells and donor-reactive antibodies (often called donor-specific antibodies or DSA) that recognize and respond to antigens from a donor.

Donorreactive T cells are sensitized lymphocytes that recognize donor major histocompatibility complex or human leukocyte antigen (HLA) peptides presented by donor or host antigen-presenting cells. In solid organ transplantation, donorreactive T cells can mediate cellular rejection, while in hematopoietic stem cell transplantation they can contribute to graft-versus-host disease and, in some settings, can participate in graft-versus-leukemia effects.

Donorreactive antibodies bind to donor HLA antigens on transplanted tissue, leading to antibody-mediated rejection and systemic or organ-specific dysfunction. These antibodies are detected through pretransplant screening and post-transplant monitoring, with the goal of assessing risk and guiding management.

Detection and assessment methods include crossmatching (physical or virtual) to identify donorreactive antibodies and flow cytometry-based and complement-dependent cytotoxic assays. Solid-phase platforms, such as Luminex single-antigen bead assays, help identify specific DSA and estimate their strength.

Clinical relevance centers on risk stratification and donor selection. Pretransplant identification of donorreactive antibodies informs desensitization strategies (for example, plasmapheresis, intravenous immunoglobulin, and targeted therapies) and decisions about organ allocation. In addition, understanding donorreactive T-cell responses influences immunosuppression regimens and monitoring for rejection or GVHD.

Overall, donorreactive immune responses are a fundamental consideration in transplantation immunology, shaping approaches to improve graft survival and reduce immunologic complications.