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Case Report: Low-dose donor lymphocyte infusion for secondary poor graft function after haploidentical HSCT in a child with β-thalassemia

Year: 2026

Type: article

Abstract: Poor graft function (PGF) is a serious complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT), particularly when persistent cytopenia occurs despite complete donor chimerism. We report a 5-year-old girl with transfusion-dependent β-thalassemia major who developed refractory secondary PGF after haploidentical allo-HSCT following cytomegalovirus reactivation. Bone marrow was markedly hypocellular, and and multilineage cytopenias progressively worsened after plasma CMV DNA became undetectable and antiviral therapy was completed. Contributions from infection-related injury, antiviral-associated myelotoxicity, or endothelial injury could not be fully excluded. Multiple supportive and immunomodulatory interventions failed. Because a CD34 + selected stem cell boost was not feasible, the patient received intentionally low-dose donor lymphocyte infusion (DLI) on days +270 and +284. Multilineage hematopoietic recovery occurred 27 days after the first infusion, and transfusion independence was maintained for more than 14 months. Post-DLI events included manageable grade I cutaneous graft-versus-host disease and transient tachypnea of uncertain etiology. Longitudinal immune profiling showed recovery of naive T-cell compartments, contraction of effector-memory subsets, and expansion of CD8 + CD28 - T cells without overt T-cell activation. This observation provides a hypothesis-generating rationale for prospective studies evaluating the efficacy and safety of low-dose DLI in pediatric secondary PGF.

Source: Frontiers in Immunology

DOI: 10.3389/fimmu.2026.1972748