Killer immunoglobulin-like receptors (KIR) play a role in regulation of NK-lymphocyte reactivity and affect immunological response in stem cell transplantation (SCT) recipients.
Patients were transplanted for malignant (89) or non-malignant diseases (113) from matched sibling donors (MSD, 35), matched donors (MD, 133) or partially matched donors (MMD/HAPLO, 33). The donor samples were tested for KIR genotype using KIR typing kit (Miltenyi, DE). The effects of diagnosis, degree of HLA-match, pre-transplant conditioning, and KIR-genotyping results on survival were analyzed.
Neither differences in single KIR loci, nor the KIR B-content score affected patients’ OS/EFS/TRM/DFS. The graft-versus-host (GVH) KIR-ligand mismatch was observed in 13 patients and host-versus-graft (HVG) in 9 cases. The probability of OS was superior in non-malignant entities 83.96 % vs 60.5% (p=0.0004). Better donor choice (MSD vs MUD vs MMD/HAPLO) was associated with higher probability of OS (94.3% vs 80% vs 31.2%, p=0.00001) and EFS (88.6% vs 77% vs 28.8%, p=0.00001). The probability of OS was decreased in the presence of any HLA mismatch (61.02% vs 88.99%, p=0.00008), and GVH KIR mismatch (41.6% vs 81.5%, p=0.002). The multivariate analysis using the Cox regression model revealed GVH KIR mismatch as the factor relevant for OS, EFS, HVG mismatch for TRM, and in non-malignant entities degree of donor’s HLA B match was significant for OS.
KIR associated mechanisms affect patients outcome after SCT. In case of partially matched donors, the optimal donor choice algorithm should eliminate the presence of KIR ligand GVH mismatch.