Donor lymphocyte infusions to displace residual host hematopoietic cells after allogeneic bone marrow transplantation for β-thalassemia major

Purpose: Donor lymphocyte infusion (DLI) was used to reverse relapse after allogeneic bone marrow transplantation (BMT) in a patient with β- thalassemia major. Patients and Methods: The patient with unstable mixed chimerism after BMT was treated with graded increments of donor lymphocytes (10⁵ T cells/kg to 5x10⁷ T cells/kg) to displace residual hematopoietic host cells. Results: DLI resulted in complete donor-derived reconstitution of the hematopoietic compartment. The patient developed mild graft-versus-host disease (GVHD) that could be controlled by steroid treatment. Conclusions: This case report shows that DLI can effectively eradicate host stem cells in mixed chimeras after BMT in nonmalignant hematopoietic diseases.