major histocompatibility complex (human), class I, B7
|Alleles||B*0702, *0703, *0704, *0705
|Structure (See HLA-B)|
|Alleles (See Serotyping)|
HLA-B7 (B7) is an HLA-B serotype. The serotype identifies the more common HLA-B*07 gene products. (For terminology help see: HLA-serotype tutorial) B7, previously HL-A7, was one of the first 'HL-A' antigens recognized, largely because of the frequency of B*0702 in Northern and Western Europe and the United States. B7 is found in two major haplotypes in Europe, where it reaches peak frequency in Ireland. One haplotype A3-B7-DR15-DQ1 can be found over a vast region and is in apparent selective disequilibrium. B7 is a risk factor for cervical cancer, sarcoidosis, and early-onset spondylarthropathies.
|Alleles link-out to IMGT/HLA Databease at EBI|
|||Australia New South Wales||12.0|
|||Azores S. Maria & Miguel||9.0|
|||Saudi Arabia Guraiat and Hail||8.3|
|||Azores Central Islands||8.0|
|||France South East||7.2|
|||Italy North pop 1||6.7|
|||Senegal Niokholo Mandenka||5.8|
|||India Mumbai Marathas||4.9|
|||Zimbabwe Harare Shona||4.6|
|||South Africian Natal Zulu||4.5|
|||South Korea (3)||3.5|
|||Shijiazhuang Tianjian Han, China||3.4|
|||India North Delhi||3.3|
|||China Guangzhou Han||2.4|
|||Mexico Chihuahua Tarahumara||2.3|
|||Singapore Javanese Indonesians||2.0|
|||Spain Eastern Andalusia Gipsy||2.0|
|||USA Alaska Yupik Natives||1.6|
|||Argentina Toba Rosario||1.2|
|||Singapore Chinese Han||1.2|
|||USA Arizona Pima||1.1|
|||Japan Ainu Hokkaido||1.0|
|||Singapore Riau Malay||1.0|
A relationship between HLA-B7 and sarcoidosis has been known for 30+ years. However the association is weak and has not been reproducible in all studies. A common serologically defined haplotype in Europeans is HLA A3-Cw7-B7-DR15-DQ6.2 which is composed of alleles A*0301:Cw*0701:B*0702:DRB1*1501:DQA1*0102:DQB1*0602. In persistent sarcoidosis this haplotype was found to be increased in sarcoidosis, and further study eliminated risk contributed by A3-Cw7 and DQ6.2 indicating B7-DR15 haplotype contains risk of disease (OR = 2.5). The region of chromosome 6 contains nearly on million nucleotides so that these genes, or a closely linked gene could be involved in disease.
In Croatian children, two HLA-B27 alleles were found associated with disease, B*2702, B*2705. The study showed also B*0702 in cooperation with B*27, the HLA-B*07/B*27 combination with D6S273-134 genomic marker allele and was found not to be the result of linkage disequilibrium. B*2705 was found to be dominant allele associated.
The HFE gene responsible for haemochromatosis is distal on chromosome 6 from HLA-A and more so from HLA-B, the distance suffices (3 million nucleotides) to allow equilibration of the loci. Nonetheless, a linkage has been found between A3-B7 haplotype and haemochromatosis. The region is almost 1.4 million nucleotides in length and contains many other genes that could be involved. A more recent study looked at a number of linked gene-alleles and found I82-2:D6S265-1:HLA-A3:D6S128-2:HLA-F1:D6S105-8 was constantly associated while B7 appeared beyond the haplotype linked to disease.
- Marsh SG, Albert ED, Bodmer WF et al. (2005). "Nomenclature for factors of the HLA system, 2004". Tissue Antigens 65 (4): 301–69. doi:10.1111/j.1399-0039.2005.00379.x. PMID 15787720.
- derived from IMGT/HLA
- Middleton D, Menchaca L, Rood H, Komerofsky R (2003). "New allele frequency database: http://www.allelefrequencies.net". Tissue Antigens 61 (5): 403–7. doi:10.1034/j.1399-0039.2003.00062.x. PMID 12753660.
- Wang SS, Wheeler CM, Hildesheim A et al. (November 2001). "Human leukocyte antigen class I and II alleles and risk of cervical neoplasia: results from a population-based study in Costa Rica". J. Infect. Dis. 184 (10): 1310–4. doi:10.1086/324209. PMID 11679920.
- Bhattacharya P, Sengupta S (October 2007). "Predisposition to HPV16/18-related cervical cancer because of proline homozygosity at codon 72 of p53 among Indian women is influenced by HLA-B*07 and homozygosity of HLA-DQB1*03". Tissue Antigens 70 (4): 283–93. doi:10.1111/j.1399-0039.2007.00894.x. PMID 17767549.
- Rybicki BA, Iannuzzi MC (March 2004). "Sarcoidosis and human leukocyte antigen class I and II genes: it takes two to tango?". Am. J. Respir. Crit. Care Med. 169 (6): 665–6. doi:10.1164/rccm.2401005. PMID 15003948.
- Grunewald J, Eklund A, Olerup O (March 2004). "Human leukocyte antigen class I alleles and the disease course in sarcoidosis patients". Am. J. Respir. Crit. Care Med. 169 (6): 696–702. doi:10.1164/rccm.200303-459OC. PMID 14656748.
- Harjacek M, Margetić T, Kerhin-Brkljacić V, Martinez N, Grubić Z (2008). "HLA-B*27/HLA-B*07 in combination with D6S273-134 allele is associated with increased susceptibility to juvenile spondyloarthropathies". Clin. Exp. Rheumatol. 26 (3): 498–504. PMID 18578977.
- Raha-Chowdhury R, Bowen DJ, Burnett AK, Worwood M (June 1995). "Allelic associations and homozygosity at loci from HLA-B to D6S299 in genetic haemochromatosis". J. Med. Genet. 32 (6): 446–52. doi:10.1136/jmg.32.6.446. PMC 1050484. PMID 7666396.