Histocompatibility

[4] The wide variety of potential HLA alleles lead to unique combinations in individuals and make matching difficult.

[7] In the 1930s and 1940s, George Snell and Peter Gorer individually isolated the genetic factors that when similar allowed transplantation between mouse strains, naming them H and antigen II respectively.

[8] The human version of the histocompatibility complex was found by Jean Dausset in the 1950s, when he noticed that recipients of blood transfusions were producing antibodies directed against only the donor cells.

[11] Individuals inherit two different HLA haplotypes, one from each parent, each containing more than 200 genes relevant to helping the immune system recognize foreign invaders.

[15] The wide variety of potential alleles and multiple loci in the HLA allow for many unique combinations in individuals.

[16] The number and selection of MHC molecules to be considered when determining whether two individuals are histocompatible fluctuates based on application, however matching HLA-A, HLA-B, and HLA-DR has been shown to improve patient outcomes.

[18] The degree of histocompatibility required is dependent on individual factors, including the type of tissue or organ and the medical condition of the recipient.

[24] Because of the clinical significance of histocompatibility in tissue transplants, several methods of typing are used to check for HLA allele expression.

Serological typing involves incubating lymphocytes from the recipient with serum containing known antibodies against the varying HLA alleles.

Molecular methods can more accurately identify rare and unique alleles, but do not provide information about expression levels.