HLA-B21

Last updated July 22, 2019

HLA-B21 (B21) is an HLA - B serotype. B21 is a broad antigen serotype that recognizes the B49 and B50 split antigen serotypes.^[1]

The human leukocyte antigen (HLA) system or complex is a gene complex encoding the major histocompatibility complex (MHC) proteins in humans. These cell-surface proteins are responsible for the regulation of the immune system in humans. The HLA gene complex resides on a 3 Mbp stretch within chromosome 6p21. HLA genes are highly polymorphic, which means that they have many different alleles, allowing them to fine-tune the adaptive immune system. The proteins encoded by certain genes are also known as antigens, as a result of their historic discovery as factors in organ transplants. Different classes have different functions:

HLA-B protein-coding gene in the species Homo sapiens

HLA-B is a human gene that provides instructions for making a protein that plays a critical role in the immune system. HLA-B is part of a family of genes called the human leukocyte antigen (HLA) complex. The HLA complex helps the immune system distinguish the body's own proteins from proteins made by foreign invaders such as viruses and bacteria.

A serotype or serovar is a distinct variation within a species of bacteria or virus or among immune cells of different individuals. These microorganisms, viruses, or cells are classified together based on their cell surface antigens, allowing the epidemiologic classification of organisms to the sub-species level. A group of serovars with common antigens is called a serogroup or sometimes serocomplex.

Related Research Articles

HLA-B5 (B5) is an HLA-B serotype. B5 is a broad antigen serotype that recognizes the B51 and B52 split antigen serotypes.

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-B47 (B47) is an HLA–B serotype. The serotype identifies the HLA-B*47 gene products. Comparison of B47 nucleotide sequence with other HLA-B sequences shows a segment of 228 bp identical with B44 in the alpha 1 domain and a segment of 218 bp identical with B27 in the alpha 2 domain, but only a 91 bp segment of identity with B13 in the alpha 1 domain. The complex pattern of substitutions and their degree of divergence indicate that HLA-B13 and HLA-Bw47 alleles are not related by a simple mutational event. B47 is linked to a gene that causes adrenal deficiency. B47 is generally low in frequency and with highest known frequencies in Central and Western Africa.

HLA-B41 (B41) is an HLA-B serotype. The serotype identifies HLA-B*4101, *4102, *4103 gene products.

HLA-B60 (B60) is an HLA - B serotype. B60 is a split antigen serotype that recognizes certain B40 serotypes.

HLA-B61 (B61) is an HLA - B serotype. B61 is a split antigen serotype that recognizes certain B40 serotypes.

HLA-B13 (B13) is an HLA-B serotype. The serotype identifies the more common HLA-B*13 gene products.

HLA-B12 (B12) is an HLA - B serotype. B12 is a broad antigen serotype that recognizes the B44 and B45 split antigen serotypes.

HLA-B16 (B16) is an HLA - B serotype. B16 is a broad antigen serotype that recognizes the B38 and B39 split antigen serotypes.

HLA-B17 (B17) is an HLA - B serotype. B17 is a broad antigen serotype that recognizes the B57 and B58 split antigen serotypes. B17 is still encountered in the current literature, although most studies now use B57/B58 or gene typing designators. Both serotypes are involved in slightly different drug-sensitive diseases.

HLA-B22 (B22) is an HLA - B serotype. B22 is a broad antigen serotype that recognizes the B54, B55, and B56 split antigen serotypes.

HLA-B14 (B14) is a HLA-B serotype. The serotype identifies the B*45 gene-allele protein products of HLA-B.

HLA-B56 (B56) is an HLA-B serotype. B56 is a split antigen from the B22 broad antigen, sister serotypes are B54 and B55. The serotype identifies the more common HLA-B*56 gene products.

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-B49 (B49) is an HLA-B serotype. B49 is a split antigen from the B21 broad antigen, the sister serotype B50. 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-B77 (B77) is an HLA-B serotype. The serotype identifies certain B*15 gene-allele protein products of HLA-B.

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.

References

↑ Marsh, S. G.; Albert, E. D.; Bodmer, W. F.; Bontrop, R. E.; Dupont, B.; Erlich, H. A.; Fernández-Viña, M.; Geraghty, D. E.; Holdsworth, R.; Hurley, C. K.; Lau, M.; Lee, K. W.; Mach, B.; Maiers, M.; Mayr, W. R.; Müller, C. R.; Parham, P.; Petersdorf, E. W.; Sasazuki, T.; Strominger, J. L.; Svejgaard, A.; Terasaki, P. I.; Tiercy, J. M.; Trowsdale, J. (2010). "Nomenclature for factors of the HLA system, 2010". Tissue Antigens. 75 (4): 291–455. doi:10.1111/j.1399-0039.2010.01466.x. PMC 2848993 . PMID 20356336.

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[pmid15787720-1] Marsh, S. G.; Albert, E. D.; Bodmer, W. F.; Bontrop, R. E.; Dupont, B.; Erlich, H. A.; Fernández-Viña, M.; Geraghty, D. E.; Holdsworth, R.; Hurley, C. K.; Lau, M.; Lee, K. W.; Mach, B.; Maiers, M.; Mayr, W. R.; Müller, C. R.; Parham, P.; Petersdorf, E. W.; Sasazuki, T.; Strominger, J. L.; Svejgaard, A.; Terasaki, P. I.; Tiercy, J. M.; Trowsdale, J. (2010). "Nomenclature for factors of the HLA system, 2010". Tissue Antigens. 75 (4): 291–455. doi:10.1111/j.1399-0039.2010.01466.x. PMC 2848993 . PMID 20356336.