Histocompatibility, or tissue compatibility, is the property of having the same, or sufficiently similar, alleles of a set of genes called human leukocyte antigens (HLA), or major histocompatibility complex (MHC). Each individual expresses many unique HLA proteins on the surface of their cells, which signal to the immune system whether a cell is part of the self or an invading organism. T cells recognize foreign HLA molecules and trigger an immune response to destroy the foreign cells. Histocompatibility testing is most relevant for topics related to whole organ, tissue, or stem cell transplants, where the similarity or difference between the donor's HLA alleles and the recipient's triggers the immune system to reject the transplant. The wide variety of potential HLA alleles lead to unique combinations in individuals and make matching difficult.
The major histocompatibility complex (MHC) is a large locus on vertebrate DNA containing a set of closely linked polymorphic genes that code for cell surface proteins essential for the adaptive immune system. These cell surface proteins are called MHC molecules.
The human leukocyte antigen (HLA) system or complex is a complex of genes on chromosome 6 in humans which encode cell-surface proteins responsible for regulation of the immune system. The HLA system is also known as the human version of the major histocompatibility complex (MHC) found in many animals.
HLA-A69 (A69) is a human leukocyte antigen serotype within HLA-A serotype group. The serotype is determined by the antibody recognition of α69 subset of HLA-A α-chains. For A69, the alpha "A" chain are encoded by the HLA-A*69 allele group and the β-chain are encoded by B2M locus. This group currently is dominated by A*6901. A69 and A*69 are almost synonymous in meaning. A69 is a split antigen of the broad antigen serotype A28. A69 is a sister serotype of A68.
HLA-A43 (A43) is a human leukocyte antigen serotype within HLA-A serotype group. The serotype is determined by the antibody recognition of α43 subset of HLA-A α-chains. For A43, the alpha "A" chain are encoded by the HLA-A*43 allele group and the β-chain are encoded by B2M locus. This group currently is dominated by A*4301. A43 and A*43 are almost synonymous in meaning. A43 is a split antigen of the broad antigen serotype A10. A43 is a sister serotype of A25, A26, A34, and A66.
HLA-A66 (A66) is a human leukocyte antigen serotype within HLA-A serotype group. The serotype is determined by the antibody recognition of α66 subset of HLA-A α-chains. For A66, the alpha "A" chain are encoded by the HLA-A*66 allele group and the β-chain are encoded by B2M locus. A66 and A*66 are almost synonymous in meaning. A66 is a split antigen of the broad antigen serotype A10. A66 is a sister serotype of A25, A26, A34, and A43.
HLA-A33 (A33) is a human leukocyte antigen serotype within HLA-A serotype group. The serotype is determined by the antibody recognition of α33 subset of HLA-A α-chains. For A33, the alpha "A" chain are encoded by the HLA-A*33 allele group and the β-chain are encoded by B2M locus. A33 and A*33 are almost synonymous in meaning. A33 is a split antigen of the broad antigen serotype A19. A33 is a sister serotype of A29, A30, A31, A32, and A74.
HLA-B*82 (B*82) is an HLA-B allele-group. There is no current useful serotyping for HLA-B*82 gene products. B*8201 was first identified by sequence analysis and appears to be derived by gene conversion between B*5602 and another HLA class I allele., later B*8202 was identified in a caucasian and was suggested to be ancestral to B*8201, as product between gene conversion of B*5602 allele and B*4501 allele. B*82 is more common in East Africa, Kenya and Sudan, the frequency of B*8201 is found in the peoples to the west, sporadically in Central and West Africa, B*8202 is found in Sudan and Saudi Arabia.
HLA-B73 (B73) is an HLA-B serotype. The serotype identifies the HLA-B*7301 gene product. Part of B*7301 is similar to the HLA-B22 family, however part resembles the domains seen in other apes. B73 is more common in Western Indian Ocean, Mediterranean and Africa.
HLA-B67 (B67) is an HLA-B serotype. The serotype identifies the more common HLA-B*67 gene products. B67 is region specific recombinant haplotype formed by the gene conversion of B*39, an allele common along the Northwest Pacific Rim, and B7, B22, or B27.
HLA-B59 (B59) is an HLA-B serotype. The serotype identifies the more common HLA-B*## gene products. B59 is a hybrid between B*55 and B*51. B59 is more common in Japan, Korea, N. China and Mongolia.
HLA-B18 (B18) is an HLA-B serotype. The serotype identifies the more common HLA-B*18 gene products. B*1801, the most common allele is at highest frequencies in Northern Italy and the Balkans, a peak frequency distribution it shares with B*3501.
HLA-B8 (B8) is an HLA-B serotype. The serotype identifies the HLA-B*08 gene products. HLA-B8, previously known as HL-A8 was one of the first identified of the HLA antigens. It coined the "Super B8" haplotype, also called the ancestral European haplotype because of its common occurrence in Europe, particular the isles and Scandinavia. B8 is a component gene-allele of the AH8.1 haplotype in Northern and Western Europeans. Genes between B8 and DR3 on this haplotype are frequently associated with autoimmune disease.
HLA-B55 (B55) is an HLA-B serotype. B55 is a split antigen from the B22 broad antigen, sister serotypes are B54 and B56. The serotype identifies the more common HLA-B*55 gene products.
HLA-B54 (B54) is an HLA-B serotype. B54 is a split antigen from the B22 broad antigen, sister serotypes are B55 and B56. The serotype identifies the more common HLA-B*55 gene products.
HLA-B50 (B50) is an HLA-B serotype. B50 is a split antigen from the B21 broad antigen, the sister serotype B49. The serotype identifies the more common HLA-B*50 gene products.
HLA-B57 (B57) is an HLA-B serotype. B57 is a split antigen from the B17 broad antigen, the sister serotype B58. The serotype identifies the more common HLA-B*58 gene products. Like B58, B57 is involved in drug-induced inflammatory skin disorders.
HLA-B38 (B38) is an HLA-B serotype. The serotype identifies the B*38 allele products of the HLA-B gene-locus.
HLA-B70 (B70) is an HLA-B serotype. The serotype identifies certain B*15 gene-allele protein products of HLA-B. B70 is one of many split antigens of the broad antigen, B15.
HLA-B62 (B62) is an HLA-B serotype. The serotype identifies certain B*15 gene-allele protein products of HLA-B.
