CD34 Full Donor Chimerism Linked to Improved Survival, Reduced Relapse in AML, MDS

CD34 full donor chimerism after donor lymphocyte infusion is associated with lower relapse and superior overall survival (OS) in patients with acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS) who received allogeneic hematopoietic stem cell transplant (HSCT), according to a recent study.

“Regular monitoring of CD34 donor chimerism is a highly sensitive method of predicting relapse in allogeneic HSCT recipients with AML or MDS,” wrote Joanne LC Tan, MBBS, of The Alfred Hospital in Australia, and colleagues. “There are limited studies assessing the efficacy of donor lymphocyte infusion triggered by mixed CD34 donor chimerism in addressing falling chimerism.”

The retrospective analysis evaluated patients who underwent consecutive allogeneic HSCT from 2012 to 2023 and received donor lymphocyte infusion for mixed CD34 donor chimerism. Of 21 evaluable patients, 14 (66.7%) achieved full donor chimerism after donor lymphocyte infusion.

The two-year cumulative incidence of relapse was lower in those who achieved full donor chimerism than in those who didn’t (21.4% vs 85.7%, respectively; P<0.001). Patients who achieved full donor chimerism also had superior OS than those who didn’t (median years not reached vs 0.67 years, respectively; P< .001).

After donor lymphocyte infusion, grade 2-4 graft-versus-host disease (GVHD) occurred in 14.9% of patients. Moderate-to-severe GVHD occurred in 42.8% of patients who achieved full donor chimerism. The five-year non-relapse mortality (NRM) was 7.1% in the full donor chimerism group.

“Our study shows the restoration of CD34 [full donor chimerism] post [donor lymphocyte infusion] is associated with reduced relapse and improved [OS], with low NRM,” the researchers concluded.

Reference

Tan JL, Curtis DJ, Muirhead J, et al. CD34 Chimerism Directed Donor Lymphocyte Infusion With or Without Azacitidine Results in Reduced Relapse and Superior Overall Survival When Full Donor Chimerism is Achieved in Allogeneic Stem Cell Transplant Recipients With Acute Myeloid Leukaemia/Myelodysplastic Syndrome. Clin Lymphoma Myeloma Leuk. 2024. doi:10.1016/j.clml.2024.07.006