Human leukocyte antigens (HLAs)

Definition

Human leukocyte antigens (HLAs) are proteins found on the surface of most cells in the body that help the immune system distinguish between self and non-self. They play a crucial role in organ transplantation by influencing graft acceptance or rejection.

5 Must Know Facts For Your Next Test

1. HLAs are encoded by genes located on chromosome 6 within the major histocompatibility complex (MHC).
2. There are three main classes of HLA genes: Class I, Class II, and Class III, with Class I and II being most relevant for organ transplantation.
3. HLA matching between donor and recipient reduces the risk of transplant rejection.
4. The presence of pre-existing anti-HLA antibodies in a recipient can lead to hyperacute rejection of the transplanted organ.
5. HLA typing is a critical step in the pre-transplant evaluation process to ensure compatibility.

Review Questions

• What role do HLAs play in organ transplantation?
• Why is it important to match HLAs between donor and recipient?
• Which chromosome contains the genes encoding HLAs?

Related terms

Major Histocompatibility Complex (MHC):

A set of genes that encode cell surface proteins essential for immune recognition.

Hyperacute Rejection: A rapid transplant rejection occurring within minutes to hours due to pre-existing antibodies against donor antigens.

HLA Typing: The process of determining HLA alleles present in an individual for compatibility assessment.