Transplant immunology I: mechanisms of rejection in solid organ transplants

Non-identical transplants (allogeneic) have been a modern medicine milestone; however, the major pitfall for completed succeed is the recognition of foreign organ by the immune system. The myriad variations in sequence of the molecules of the major histocompatibility complex (MHC) or human leukocyte antigen (HLA) between individuals are the major cause of allograft rejection. Thus, the recognition by the B or T lymphocytes of the receptor occurs in the hypervariable regions of the HLA molecules that triggers to the graft 3 types of rejection: hyperacute, acute, and chronic. In addition, the rejection could be cause antibody-mediated (ABMR), T-cell-mediated (TCMR), or both, which depends on the main branch is cause of rejection. This review will explore the mechanisms mentioned above and give an introductory insight into transplant immunology; thus, preparer the reader to delve into further reviews in a Histocompatibility or Immunogenetics laboratory purpose.