Donor leukocytes (DLI)

Donor leukocytes are a population of white blood cells, primarily T-lymphocytes, harvested from a healthy donor and infused into a recipient to provide an immune-mediated therapeutic effect [1][2]. This procedure, known as Donor Lymphocyte Infusion (DLI), is most frequently employed following allogeneic hematopoietic stem cell transplantation to treat or prevent disease relapse [1][4]. The biological basis for this therapy is the graft-versus-leukemia (GvL) effect, where donor T-cells recognize and destroy residual malignant cells in the recipient's body [1]. Beyond leukemia, donor leukocytes are also used to treat certain viral infections and to establish full donor chimerism in transplant recipients [4]. However, the administration of these cells carries a significant risk of graft-versus-host disease (GvHD), a condition where the donor cells attack the recipient's healthy organs [3]. To manage this risk, clinicians often use immunosuppressive drugs like cyclosporine or tacrolimus to modulate the activity of the donor leukocytes [3]. The success of the therapy depends on the balance between achieving a potent anti-tumor response and minimizing life-threatening systemic inflammation [1][4]. Monitoring involves assessing donor chimerism and CD3+ cell counts to evaluate the engraftment and activity of the infused cells [2]. Note: Donor leukocytes represent a cellular therapy rather than a single molecular target.

Other names

Donor lymphocytesAllogeneic leukocytesDonor white blood cellsDonor lymphocyte infusion (DLI)

Donor T-lymphocytes recognize minor histocompatibility antigens or tumor-associated antigens on recipient malignant cells via the T-cell receptor (TCR), leading to targeted cell lysis and cytokine-mediated antitumor activity (Graft-versus-leukemia effect) [1][4]. Immunosuppressive drugs like calcineurin inhibitors (e.g., cyclosporine) or mTOR inhibitors (e.g., sirolimus) are used to inhibit the activation and proliferation of these donor leukocytes to prevent or treat graft-versus-host disease [3].