Human lymphocyte antigen

Human Lymphocyte Antigens (HLA) are proteins found on the surface of white blood cells. These antigens play a crucial role in the immune system's recognition of self and non-self cells. They are involved in the body's defense against pathogens and are also important in organ transplantation.

Overview

HLA are part of the Major Histocompatibility Complex (MHC), a gene family found in many species. In humans, these genes are located on chromosome 6. The HLA system is highly polymorphic, meaning there are many different versions of the HLA genes in the human population. This diversity is beneficial for the immune system, as it allows for the recognition of a wide range of pathogens.

Function

HLA proteins present peptides (small pieces of proteins) to T cells, a type of white blood cell. This presentation is a crucial step in the immune response. If the T cell recognizes the peptide as foreign (non-self), it will initiate an immune response against the cells presenting that peptide.

Role in Disease

Certain HLA types are associated with an increased risk of certain diseases. For example, HLA-B27 is associated with an increased risk of ankylosing spondylitis, a type of arthritis. HLA-DQ2 and HLA-DQ8 are associated with celiac disease, an autoimmune disorder triggered by gluten.

Role in Transplantation

In organ transplantation, the HLA types of the donor and recipient are compared. A close match can reduce the risk of graft-versus-host disease (GVHD), a serious complication where the donor's immune cells attack the recipient's body.

See Also

• Major Histocompatibility Complex
• Immune System
• Organ Transplantation

References

Human lymphocyte antigen Resources
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