Definition

A type of molecule found on the surface of most cells in the body. HLAs play an important part in the body’s immune response to foreign substances. They make up a person’s tissue type, which varies from person to person. HLA tests are done before a donor stem cell or organ transplant, to find out if tissues match between the donor and the person receiving the transplant. Also called human leukocyte antigen and human lymphocyte antigen.