The HLA System

A man dies because his body has rejected a heart transplant; a woman is crippled by rheumatoid arthritis; a child goes into a coma that is brought on by cerebral malaria; another child dies of an infection because of an immunodeficiency; an elderly man has advanced hepatic cirrhosis caused by iron overload. These five clinical situations are as diverse as can be, yet all have one thing in common: the cause of all of them involves the human leukocyte antigen (HLA) system, the human version of the major histocompatibility complex (MHC). Malfunction of the HLA system, which is at the . . .