Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 11 1 2012 03 15 15 21 EN Ehteramolsadat Hosseini Malignant Hematology and Stem Cell Transplantation Service, Alfred Hospital, Monash University, Melbourne, Australia Anthony P. Schwarer Malignant Hematology and Stem Cell Transplantation Service, Alfred Hospital, Monash University, Melbourne, Australia Mehran Ghasemzadeh Australian Centre for Blood Diseases, Monash University, Melbourne, Australia 2015 10 01 The  non-classical MHC  class-I mainly involves in the  regulation of  innate  immune responses where HLA-E  plays a significant role in the cell identification by natural killer cells. HLA-E is a main regulatory ligand for natural killer cells and given the importance of these effector cells in hematopoietic stem cell transplantation, we investigated the effect of HLA-E polymorphisms on post-hematopoietic stem cell transplantation outcomes. The study group included 56 donor-patient pairs with underlying malignant hematological disorders undergoing HLA-E  matched allogeneic hematopoietic stem cell transplantation. They were genotyped for HLA-E locus using a sequence specific primer-polymerase chain reaction. The  median follow-up was 20.6 months  (range 0.2-114.8) and  the  parameters assessed were acute and chronic graft-versus-host disease and overall survival. We showed a lower frequency of acute graft-versus-host disease (grade II or more; p=0.02)and chronic graft-versus-host disease (extensive; p=0.04) in the patients with HLA- E*0103/0103 genotype compared to other genotypes of HLA-E. There was also an association between HLA-E*0103/0103 and improved overall survival (p=0.001). Conclusively, our  results  suggest a  protective  role  for  HLA-E*0103/0103  genotypeagainst acute graft-versus-host disease (grade II or more) and chronic graft-versus-host disease (extensive) as well as an association between this genotype and a better overall survival after HLA-E matched allogeneic hematopoietic stem cell transplantation. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/326 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/326/326