The HLA system: genetics, immunology, clinical testing, and clinical implications

Yonsei Med J. 2007 Feb 28;48(1):11-23. doi: 10.3349/ymj.2007.48.1.11.


The human major histocompatibility complex HLA is located on the short arm of chromosome 6. It is known to be the most polymorphic genetic system in humans. The biological role of the HLA class I and class II molecules is to present processed peptide antigens. The HLA system is clinically important as transplantation antigens. Molecular HLA allele typing is routinely performed to provide HLA class I and class II allele matching in unrelated donor hematopoietic stem cell transplantation. Prospective lymphocyte crossmatching is critical in solid organ transplantation to prevent allograft rejection. HLA alloimmunization causes various problems in transfusion therapy. The HLA system is associated with certain diseases, but its underlying mechanisms are not yet fully explained.

Publication types

  • Review

MeSH terms

  • Blood Transfusion
  • HLA Antigens / genetics*
  • HLA Antigens / immunology*
  • Haplotypes
  • Hematopoietic Stem Cell Transplantation
  • Histocompatibility Testing
  • Humans


  • HLA Antigens