Alloreactive donor T lymphocyte

Alloreactive donor T lymphocytes are a specific subset of immune cells from a transplant donor that recognize the recipient's tissues as foreign, primarily through the recognition of mismatched human leukocyte antigens (HLA) (Justiz Vaillant et al., StatPearls, 2023). Upon activation, these cells undergo clonal expansion and express specific surface markers such as CD25 (the IL-2 receptor alpha chain), CD69, and HLA-DR, which serve as indicators of their pathogenic potential (UniProt P01589; Amrolia et al., Blood, 2006). These activated cells are the primary mediators of Graft-versus-Host Disease (GvHD), a serious complication of hematopoietic stem cell transplantation where the donor immune system attacks the host's organs (Justiz Vaillant et al., StatPearls, 2023). Therapeutic interventions often target these cells to prevent or treat GvHD by either broadly suppressing T-cell activity or selectively depleting the activated alloreactive subsets (Amrolia et al., Blood, 2006). For example, monoclonal antibodies like basiliximab specifically bind to CD25 on activated T cells to inhibit their proliferation (StatPearls, 2023). The primary challenge in targeting these cells lies in maintaining a balance between preventing GvHD and preserving the beneficial graft-versus-leukemia (GvL) effect and general anti-pathogen immunity provided by non-alloreactive T cells (Amrolia et al., Blood, 2006).

Other names

Activated alloreactive T cellsHost-reactive T lymphocytesGvHD-mediating T cellsAlloreactive T-cell subsets

Selective depletion of activated T-cell subsets via antibody-dependent cellular cytotoxicity (ADCC) or immunotoxin-induced apoptosis; competitive inhibition of the IL-2 receptor to prevent alloreactive T-cell proliferation.