title: HLA-E polymorphism and clinical outcome after allogeneic hematopoietic stem cell transplantation in Egyptian patients.
abstract: Human leukocyte antigen-E (HLA)-E in a non-classical major histocompatibility complex (MHC) class I (Ib) molecule. HLA-E-peptide complex acts as a ligand for natural killer (NK) cells and CD8+ T lymphocytes playing a dual role in natural and acquired immune responses. The difference in expression levels between HLA-E alleles was suggested to have impact on transplantation outcome. The aim of the study is to evaluate the clinical effect of HLA-E alleles on transplantation in a group of Egyptian patients. HLA-E genotyping was analyzed in eighty-eight recipients of stem cell transplantation using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). HLA-E*01:03 allele showed a trend towards lower cumulative incidence of relapse at 2 years compared to homozygous HLA-E*01:01 genotype (8% versus 21.5%, p=0.09, HR: 0.30, 95% CI: 0.91-1.69). HLA-E was the only factor showing near significant association with relapse incidence. HLA-E polymorphism did not affect the cumulative incidence of acute GVHD grades II-IV at 100 days, the 2-year cumulative incidence of extensive chronic GVHD, transplant related mortality (TRM) or overall survival (OS).
  
  
  CONCLUSIONS
  the suggested association of HLA-E polymorphism with reduced risk of relapse needs verification in a larger cohort. However, its proposed role in GVL helps better understanding of alloreactivity of T cells and NK cells and their implication in immunotherapy post allogeneic hematopoietic stem cell transplantation.
authors.affiliation: Bone Marrow Transplantation Laboratory Unit, National Cancer Institute, Cairo University, Cairo, Egypt. Electronic address: ghadamossallam@hotmail.com.
authors.forename: Ghada I
authors.initials: GI
authors.lastname: Mossallam
authors.affiliation: Department of Medical Oncology, National Cancer Institute, Cairo University, Cairo, Egypt.
authors.forename: Raafat Abdel
authors.initials: RA
authors.lastname: Fattah
authors.affiliation: Department of Pediatric Oncology, National Cancer Institute, Cairo University, Cairo, Egypt.
authors.forename: Alaa
authors.initials: A
authors.lastname: El-Haddad
authors.affiliation: Department of Medical Oncology, National Cancer Institute, Cairo University, Cairo, Egypt.
authors.forename: Hossam K
authors.initials: HK
authors.lastname: Mahmoud
mesh_terms: D000293:Adolescent; D000328:Adult; D000483:Alleles; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004534:Egypt; D005260:Female; D005500:Follow-Up Studies; D005838:Genotype; D006084:Graft Rejection / Q000209:etiology / Q000235:genetics / Q000276:immunology*; D006086:Graft vs Host Disease / Q000235:genetics / Q000276:immunology*; D018380:Hematopoietic Stem Cell Transplantation; D015395:Histocompatibility Antigens Class I / Q000235:genetics*; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology*; D007951:Leukemia, Myeloid / Q000276:immunology / Q000401:mortality / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011183:Postoperative Complications / Q000235:genetics / Q000276:immunology; D016019:Survival Analysis; D016896:Treatment Outcome; D055815:Young Adult; D000097625:HLA-E Antigens
chemical_list: D015395:Histocompatibility Antigens Class I; D000097625:HLA-E Antigens
keywords: Graft versus leukemia (GVL); HLA-E; Hematopoietic stem cell transplantation; Relapse