Inferior Overall Survival After Haploidentical Donor Lymphocyte Infusions in Relapsed Myeloid Neoplasms.

Objectives: Allogeneic hematopoietic stem cell transplantation (HSCT) effectively treats high-risk myeloid neoplasms, but relapses post-HSCT, particularly in acute myeloid leukemia (AML) and myelodysplastic neoplasms (MDS), pose significant challenges. Donor lymphocyte infusion (DLI) has been utilized, but its effectiveness, especially in haploidentical settings, remains insufficiently clarified, and graft-versus-host disease (GvHD) poses a substantial risk.

Methods: In this retrospective cohort study, 57 patients with AML or MDS who received DLI after allogeneic HSCT at our center from 2002 to 2023 were analyzed. Herein, only preemptively or therapeutically applied DLI were included, and endpoints included overall survival (OS), progression-free survival (PFS), and GvHD incidence post-DLI.

Results: Median OS after DLI was 517 days, with a 1-year OS of 62.5%. Factors associated with longer OS included patient age, HLA-identical donor, post-HSCT treatment naivety, and preemptive DLI indication. Haploidentical DLI was associated with inferior OS compared to HLA-identical DLI; however, PFS and GvHD incidence post-DLI did not differ significantly.

Conclusions: Our study findings indicate that OS rate is inferior in patients with relapsed AML or MDS treated with haploidentical DLI in comparison to those who received HLA-identical DLI. Given the limitations of haploidentical DLI, alternative strategies, such as higher cell doses or combination treatment approaches, warrant further investigation.