PD-1 genotype of the donor is associated with acute graft-versus-host disease after HLA-identical sibling donor stem cell transplantation

Programmed death 1 (PD-1) activation triggers an immune checkpoint resulting in inhibition of T cells that leads to peripheral tolerance. Some PD-1 polymorphisms have been described and associated with the development of autoimmune diseases or cancer predisposition, but there are few data concerning the relevance of such polymorphisms on the clinical outcome after allogeneic hematopoietic stem cell transplant (alloHSCT). We analyzed the distribution of the SNPs PD-1.1G/A (rs36084323) and PD-1.3G/A (rs11568821) genotypes of the donor in a cohort of 1485 alloHSCT from HLA-identical sibling donors. We found an increased risk of grades II to IV graft-versus-host disease (GvHD) in patients receiving grafts from donors homozygous for the G allele at the rs36084323 SNP (P = 0.033; hazard ratio [HR] 2.2; 95% confidence interval [CI] 1.1 to 4.8) and also from donors homozygous for the A allele at the rs11568821 position (P < 0.001; HR 4.5, 95%CI 2.0 to 10.1). In contrast, the PD-1 genotype of the donor did not show association with overall survival or relapse incidence. These results suggest that the PD-1 genotype of the donor plays an important role for the development of acute GvHD after alloHSCT from HLA-identical sibling donors.