B*2705-β2MG with bound peptide 2bst
major histocompatibility complex (human), class I, B27
Alleles	B*2701, 2702, 2703, . . .
Structure (See HLA-B)		Available 3D structures
EBI-HLA	B*2701
	B*2702
	B*2703
	B*2704
	B*2705	2bsr, 2bss, 2bst, 2a83, 1w0v, 1uxs, 1ogt, 1hsa, 1jgd, 1jge
	B*2706
	B*2709	1w0w, 1uxw, 1of2, 1k5n

Human Leukocyte Antigen B*27 (subtypes B*2701-2724) is a class I surface antigen encoded by the B locus in the major histocompatibility complex (MHC) on chromosome 6 and presents microbial antigens to T-cells. HLA-B27 is strongly associated with a certain set of autoimmune diseases referred to as the "seronegative spondyloarthropathies". In the general population, about 8% Caucasian, 4% African, 2-9% Chinese, and 0.1-0.5% Japanese have the HLA-B27 antigen. In Northern Scandinavia (Lapland), 24% of people are HLA-B27 positive while 1.8% have associated ankylosing spondylitis (AS).

[edit] Serotype

[edit] Disease associations

[edit] Spondylarthropathies

The relationship between HLA-B27 and many diseases has not yet been fully elucidated. Though it is associated with a wide range of pathology, it does not appear to be the sole mediator in development of disease.^{[citation needed]} For example, while 90% of people with ankylosing spondylitis (AS) are HLA-B27 positive, only a fraction of people with HLA-B27 ever develop AS. This raises two important questions: why don't all HLA-B27 positive people develop AS, and why do some people who are HLA-B27 negative develop it?^{[citation needed]} The literature is inconclusive, though several theories have been suggested. Research however has been discontinued in many countries due to lack of funding.^{[citation needed]}

[edit] Juvenile Spondylarthropathies

In Croatian children, two B27 alleles were found associated with disease, B*2702, B*2705.^[3] The study showed also B*0702 in coorperation 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*2795 was found to be dominant allele associated.

[edit] Associated pathology

In addition to its connection with ankylosing spondylitis, HLA-B27 is implicated in reactive arthritis, certain eye disorders such as acute anterior uveitis and iritis, psoriatic arthritis and ulcerative colitis. The common association with HLA-B27 leads to increased association of these disorders with each other.^[4]

[edit] See also

• ABDUL MANNAN Human leukocyte antigen

[edit] External links

• HLA-B27 Syndromes at eMedicine by A. Luisa Di Lorenzo, MBBCh
• Bowness P (2002). "HLA B27 in health and disease: a double-edged sword?". Rheumatology (Oxford) 41 (8): 857–68. doi:10.1093/rheumatology/41.8.857. PMID 12154202. 
• Online 'Mendelian Inheritance in Man' (OMIM) 142830
• MeSH HLA-B27

[edit] References

This article includes a list of references or external links, but its sources remain unclear because it has insufficient inline citations. Please help to improve this article by introducing more precise citations where appropriate. (April 2009)