Insufficient immune reconstitution (IR) is a major determinant of morbidity and mortality after allogeneic hematopoietic cell transplantation (allo-HCT). Strategies for graft-versus-host disease (GVHD)-prophylaxis, such as anti-thymocyte globulin (ATG) and post-transplant cyclophosphamide (PTCy), modulate immune recovery, but their effects on IR in matched unrelated donor (MUD) allo-HCT remain incompletely defined.
In this retrospective bi-centric study, we analyzed patients with myeloid malignancies undergoing MUD allo-HCT who received ATG or PTCy per center policy. Longitudinal IR and clinical outcomes were assessed.
IR was defined as sustained recovery of CD3+CD4+ cells >200/μl and CD19+ cells >50/μl. The impact of GVHD-prophylaxis (ATG vs PTCy) on IR dynamics was explored.
A total of 252 patients were included. By day +365, 16.7% achieved IR, which was independently associated with superior OS (HR 0.39, 95% CI 0.17–0.90; p=0.026) and lower TRM (HR 0.08, 95% CI 0.01–0.63; p=0.017).
In multivariable competing-risk analyses, younger donor age (sHR 0.97, 95% CI 0.94–1.00; p=0.037) and PTCy (sHR 0.49, 95% CI 0.27–0.84; p=0.01) were associated with higher probability of IR by month +18.
Frontiers in Immunology published a clinical update in Infectious Disease on 28 Apr 2026.
The item focuses on Impact of post-transplant cyclophosphamide and anti-thymocyte globulin on immune reconstitution in MUD allo-HCT.
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