HLAs help determine self vs non-self and indicate a person’s tissue type. Which option correctly reflects this function?

HLAs help determine self vs non-self and indicate a person’s tissue type. Which option correctly reflects this function?

• A. They help determine a person's blood type.
• B. They help determine self vs non-self and indicate a person's tissue type.
• C. They control liver enzymes.
• D. They are only relevant to skin grafts.

Answer: (B)

HLAs are the human leukocyte antigens that encode surface MHC molecules, which present peptide fragments to T cells and mark cells as self. This self/non-self recognition is the cornerstone of how the immune system distinguishes belonging from foreign, and it directly informs tissue compatibility for transplantation. By comparing HLA types between donor and recipient, clinicians predict how likely a graft is to be accepted and how to minimize rejection, which is exactly what is described when saying they determine self vs non-self and indicate a person’s tissue type. The other options don’t fit because blood type is defined by ABO antigens on red blood cells, liver enzyme control is a metabolic/genetic regulation separate from HLA function, and HLAs matter for all transplants, not only skin grafts.

HLAs are the human leukocyte antigens that encode surface MHC molecules, which present peptide fragments to T cells and mark cells as self. This self/non-self recognition is the cornerstone of how the immune system distinguishes belonging from foreign, and it directly informs tissue compatibility for transplantation. By comparing HLA types between donor and recipient, clinicians predict how likely a graft is to be accepted and how to minimize rejection, which is exactly what is described when saying they determine self vs non-self and indicate a person’s tissue type. The other options don’t fit because blood type is defined by ABO antigens on red blood cells, liver enzyme control is a metabolic/genetic regulation separate from HLA function, and HLAs matter for all transplants, not only skin grafts.