Natural killer (NK) cells are regulated by killer immunoglobulin-like receptor (KIR) interactions with HLA class I ligands. Various models of NK cell alloreactivity have been associated with outcomes after allogeneic hematopoietic cell transplant (alloHCT), but results have varied widely.
We hypothesized that somatic mutations in acute myeloid leukemia (AML) in the context of KIR profiles may further refine their association with transplant outcomes.
In this single-center retrospective observational study, eighty-one AML patients who underwent matched-related donor alloHCT were included. Post-HCT outcomes were assessed based on mutational status and KIR profiles with the Kaplan-Meier method and log-rank test.
On multivariable analysis those with any somatic mutations and C1/C2 heterozygosity had less acute graft-versus-host disease (GvHD) (Hazard ratio [HR] 0.32, 95% confidence interval [CI] 0.14-0.75; P = .009), more relapse (3.02, 1.30-7.01; P = .010), inferior relapse-free survival (RFS) (2.22, 1.17-4.20; P = .014) and overall survival (OS) (2.21, 1.17-4.20; P = .015) while those with a missing KIR ligand had superior RFS (0.53, 0.30-0.94; P = .031). The presence of a somatic mutation and donor haplotype A was also associated with less acute GvHD (HR 0.38, 95% CI 0.16-0.92; P = .032), more relapse (2.72, 1.13-6.52; P = .025), inferior RFS (2.11, 1.07-4.14; P = .030) and OS (2.20, 1.11-4.38; P = .024).
Enhanced NK cell alloreactivity from more KIR activating signals (donor B haplotype) and less inhibitory signals (recipient missing KIR ligand or C1 or C2 homozygosity) may help mitigate the adverse prognosis associated with some AML somatic mutations. These results may have implications for improving patient risk stratification prior to transplant and optimizing donor selection.

Copyright © 2021. Published by Elsevier Inc.