Immune Reconstitution Following Unmanipulated HLA-Mismatched/Haploidentical Transplantation Compared with HLA-Identical Sibling Transplantation

In this study, we prospectively investigated the immune reconstitution in patients with hematological malignancies after human leukocyte antigen (HLA)-mismatched/unmanipulated haploidentical transplantation (50 cases) and HLA-matched transplant (25 cases). Transplant-related mortality, relapse, leukemia-free survival, and overall survival were similar between the two transplant strategies, although the cumulative incidence of CMV antigenemia was significantly higher in haploidentical recipients than in HLA-matched recipients (49.9 ± 7.2% versus 13 ± 7%, P = 0.007). Compared with HLA-matched recipients, T-cell subset and dendritic cell subgroup cell counts in the first 90 days after grafting were lower in haploidentical recipients. The difference was most striking for CD4⁺ and CD4⁺ naïve T cells. Reconstitution of B cells and monocytes was comparable between groups. T cells appeared equally functional in both groups among patients without graft-versus-host disease. Our results suggest that the clinical outcomes were not compromised by the early delayed immune reconstitution following haploidentical transplantation.