HLA-E and chronic graft versus host disease: Altogether six single nucleotide substitutions (NKG2A rs7301582; NKG2D rs1049174, rs1154831; HLA-E rs1264457; MICA rs1051792, rs1063635) were genotyped, and the influence of polymorphisms was analysed on acute and chronic graft-versus-host disease (GvHD), cytomegalovirus (CMV) infection incidence, disease relapse and survival.