Human Leukocyte Antigen

Human leukocyte antigen (HLA) system is the name of the major histocompatibility complex (MHC) in humans. The super locus contains a large number of genes related to immune system function in humans. This group of genes resides on chromosome 6, and encodes cell-surface antigen-presenting proteins and many other genes.

The HLA genes are the human versions of the MHC genes that are found in most vertebrates. The proteins encoded by certain genes are also known as antigens, as a result of their historic discovery as factors in organ transplants. The major HLA antigens are essential elements for immune function.


Aside from the genes encoding the 6 major antigens, there are a large number of other genes, many involved in immune function, located on the HLA complex. Diversity of HLAs in the human population is one aspect of disease defense, and, as a result, the chance of two unrelated individuals with identical HLA molecules on all loci is very low. HLA genes have historically been identified as a result of the ability to successfully transplant organs between Human leukocyte antigen -similar individuals.

Any cell displaying some other HLA type is "non-self" and is an invader, resulting in the rejection of the tissue bearing those cells. Because of the importance of HLA in transplantation, the Human leukocyte antigen loci are among of the most frequently typed by serology or PCR relative to any other autosomal alleles.

article source: wikipedia