<p>Graft-versus-leukemia (GvL) reactions are responsible for the effectiveness of allogeneic hematopoietic cell transplantation as a treatment modality for myeloid neoplasia, whereby donor T- effector cells recognize leukemia neoantigens. However, a substantial fraction of patients experience relapses because of the failure of the immunological responses to control leukemic outgrowth. Here we demonstrate, through a broad immunogenetic study, that germline and somatic reduction of human leucocyte antigen (HLA) heterogeneity enhances the risk of leukemic recurrence. We show that preexistent germline-encoded low evolutionary divergence of class II HLA genotypes constitutes an independent factor associated with disease relapse and that acquisition of clonal somatic defects in HLA alleles may lead to escape from GvL control. Both class I and II HLA genes are targeted by somatic mutations as clonal selection factors potentially impairing cellular immune responses and responses to immunomodulatory strategies. These findings define new molecular modes of post-transplant leukemia escape contributing to relapse.</p><p>The present dataset provides HLA peripheral blood and bone marrow samples supporting the genotyping studies performed for this research. This sample set originates from patients with acute myeloid leukemia or myelodysplastic syndromes receiving allogeneic hematopoietic cell transplantation and relapsing after transplant.</p>

Leukemia Relapse via Genetic Immune Escape after Allogeneic Hematopoietic Cell Transplantation