Mesenchymal Stem Cells Enhance The Impact Of Kir Receptor-Ligand Mismatching On Acute Graft-Versus-Host Disease Following Allogeneic Hematopoietic Stem Cell Transplantation In Patients With Acute Myeloid Leukemia But Not In Those With Acute Lymphocytic Leukemia

Killer cell immunoglobulin-like receptor (KIR) receptor-ligand mismatch has been shown to be protective for acute and chronic graft-versus-host disease (aGVHD, cGVHD) following allogeneic hematopoietic stem cell transplantation (allo-HSCT) for acute leukemia. Mesenchymal stem cells (MSC) have been considered as one of the most promising prophylaxis for severe GVHD. However, there are no prospective or retrospective studies determining whether they can work synergistically on GVHD. To investigate the potential influence of KIR matching and MSCs, and their synergism on aGVHD and cGVHD after allo-HSCT in acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) patients. Data from 104 patients with AML and 50 patients with ALL treated with allo-HSCT in the transplantation unit were retrospectively analyzed. KIR genotyping was performed by the PCR-SSO method. The amplicons were quantified on the Luminex 200 flow analyzer and analyzed using the Quick-Type for Lifecodes software to generate KIR data. Cox proportional hazards models were used in multivariate analyses. KIR receptor-ligand matching was associated with an increased risk of grade II-IV aGVHD compared to KIR receptor-ligand mismatching (p < 0.001) in AML patients, but KIR ligand-mismatching had no significant effect on aGVHD or cGVHD in ALL patients. In contrast, MSCs reduced the incidence of grade II-IV aGVHD in both AML and ALL patients (AML: p = 0.006; ALL: p = 0.008) regardless of KIR mismatching. The combination of KIR receptor-ligand mismatch and MSC transplantation significantly suppressed grade II-IV aGVHD occurrence in AML patients (p = 0.039). In the KIR mismatch group, the incidence of aGVHD was 2.8% in patients receiving MSC compared to 14.6% in those who did not (p = 0.047). KIR receptor-ligand mismatch, MSC transplantation and their combined use significantly reduced the risk of aGVHD after allo-HSCT. These data provide a clinically applicable strategy to reduce aGVHD, thus improving allo-HSCT outcome.