HLA-A3
Human leukocyte antigen serotype
title: "HLA-A3" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["hla-a-alleles"] description: "Human leukocyte antigen serotype" topic_path: "general/hla-a-alleles" source: "https://en.wikipedia.org/wiki/HLA-A3" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Human leukocyte antigen serotype ::
::data[format=table title="Infobox monoisoform"]
| Field | Value |
|---|---|
| isoformgroup | HLA-A3 |
| polymer_type | MHC Class I, A cell surface antigen |
| image | Illustration_HLA-A.png |
| protein_type | transmembrane receptor/ligand |
| structure | αβ heterodimer |
| subunit_genes | HLA-A*03--, β2-microglobulin |
| linkout | HAwA |
| alias | HL-A3 |
| isoformCount | 2 |
| subunit1 | allele |
| nick1 | A3.1 |
| allele1a | 03:01 |
| nick2 | A3.2 |
| allele2a | 03:02 |
| rareIsoforms | 1 |
| rnick1 | A3.5 |
| rallele1a | 03:05 |
| :: |
| isoformgroup = HLA-A3 | polymer_type = MHC Class I, A cell surface antigen | image = Illustration_HLA-A.png | protein_type = transmembrane receptor/ligand | structure = αβ heterodimer | subunit_genes = HLA-A*03--, β2-microglobulin | linkout = HAwA | alias = HL-A3 | isoformCount = 2 | subunit1 = allele | nick1 = A3.1 | allele1a = 03:01 | nick2 = A3.2 | allele2a = 03:02 | rareIsoforms = 1 | rnick1 = A3.5 | rallele1a = 03:05
HLA-A3 (A3) is a human leukocyte antigen serotype within HLA-A serotype group. The serotype is determined by the antibody recognition of α3 subset of HLA-A α-chains. For A3, the alpha, "A", chain are encoded by the HLA-A allele group and the β-chain are encoded by B2M locus. This group currently is dominated by A*03:01. A3 and A are almost synonymous in meaning. A3 is more common in Europe, it is part of the longest known multigene haplotype, A3~B7~DR15~DQ6.
Serotype
| color1 = #B0E0FF |color2=#E0F0FF | color3 = #F0F8FF | gene = A | type = 3 | types = 1 | allelegroup = 03 | alleles = 3 | allele1 = :01 |type1alle1freq = 99 |N1 = 3504 | allele2 = :02 |type1alle2freq = 78 |N2 = 342 | allele3 = :05 |type1alle3freq = |N3 = 5 A3 is primarily composed of A*03:01 and 03:02 which serotype well with anti-A3 antibodies. There are 26 non-synonymous variants of A03, 4 nulls, and 22 protein variants.
Associated diseases
A3 serotype is a secondary risk factor for myasthenia gravis and lower CD8+ levels in hemochromatosis patients. The HFE (Hemochromatosis) locus lies between A3 and B7 within the A3~DQ6 superhaplotype.
In HIV
HLA-A3 selects HIV evolution for a mutation Gag KK9 epitope and results in a rapid decline in the CD8 T-cell response. CD8 T-cells are responsible for quickly killing HIV infected CD4+ cells. This type of evolved response may not be specific for HLA-A3 and since HIV is capable of adapting quickly in situ to selective factors.
Alleles
| Placement = right | Allele = A03:01 | Freq1 = 25.0 | People1 = Finland | Freq2 = 20.5 | People2 = India Tamil Nadu Nadar | Freq3 = 18.9 | People3 = Czech Republic | Freq4 = 17.1 | People4 = Belgium | Freq5 = 14.3 | People5 = Ireland Northern | Freq6 = 13.8 | People6 = Australia New South Wales | Freq7 = 13.8 | People7 = Georgia Svaneti Svans | Freq8 = 13.8 | People8 = Georgia Tbilisi Georgian… | Freq9 = 13.0 | People9 = Pakistan Burusho | Freq10 = 12.0 | People10 = Cape Verde Northwestern I… | Freq11 = 11.6 | People11 = Ireland South | Freq12 = 11.6 | People12 = Romanian | Freq13 = 11.0 | People13 = Croatia | Freq14 = 10.8 | People14 = USA Caucasians (3) | Freq15 = 9.7 | People15 = Italy North (1) | Freq16 = 9.4 | People16 = USA African Americans (2) | Freq17 = 9.3 | People17 = India Mumbai Marathas | Freq18 = 9.0 | People18 = India West Bhils | Freq19 = 9.0 | People19 = Portugal Centre | Freq20 = 8.7 | People20 = Pakistan Pathan | Freq21 = 8.6 | People21 = Cameroon Beti | Freq22 = 7.8 | People22 = Cameroon Bamileke | Freq23 = 7.5 | People23 = Pakistan Kalash | Freq24 = 7.5 | People24 = Saudi Arabia Guraiat and … | Freq25 = 7.3 | People25 = USA Hispanic | Freq26 = 7.2 | People26 = India North Delhi | Freq27 = 7.0 | People27 = Madeira | Freq28 = 6.9 | People28 = Russia Tuva (2) | Freq29 = 6.7 | People29 = Tunisia | Freq30 = 6.7 | People30 = USA North American Native… | Freq31 = 6.5 | People31 = Cape Verde Southeastern I… | Freq32 = 6.4 | People32 = Azores Santa Maria and Sa… | Freq33 = 6.3 | People33 = Pakistan Baloch | Freq34 = 6.2 | People34 = Guinea Bissau | Freq35 = 6.0 | People35 = Israel Arab Druse | Freq36 = 6.0 | People36 = South African Natal Zulu | Freq37 = 6.0 | People37 = USA South Texas Hispanics | Freq38 = 5.8 | People38 = India North Hindus | Freq39 = 5.8 | People39 = Zambia Lusaka | Freq40 = 5.6 | People40 = Iran Baloch | Freq41 = 5.5 | People41 = Uganda Kampala | Freq42 = 5.2 | People42 = Jordan Amman | Freq43 = 5.2 | People43 = Kenya | Freq44 = 5.1 | People44 = Brazil | Freq45 = 5.1 | People45 = Oman | Freq46 = 5.0 | People46 = Cameroon Pygmy Baka | Freq47 = 5.0 | People47 = Georgia Tbilisi Kurds | Freq48 = 4.8 | People48 = Sudanese | Freq49 = 4.6 | People49 = Bulgaria | Freq50 = 4.6 | People50 = Pakistan Brahui | Freq51 = 4.5 | People51 = China Beijing | Freq52 = 4.4 | People52 = Australia Indig. Cape Yor… | Freq53 = 4.4 | People53 = China Inner Mongolia | Freq54 = 4.4 | People54 = Mali Bandiagara | Freq55 = 4.4 | People55 = Pakistan Sindhi | Freq56 = 4.1 | People56 = China Qinghai Hui | Freq57 = 4.0 | People57 = Zimbabwe Harare Shona | Freq58 = 3.8 | People58 = Cameroon Sawa | Freq59 = 3.8 | People59 = Senegal Niokholo Mandenka | Freq60 = 3.6 | People60 = Kenya Luo | Freq61 = 3.4 | People61 = Morocco Nador Metalsa Cla… | Freq62 = 3.1 | People62 = Kenya Nandi | Freq63 = 3.1 | People63 = Mex. Guadalajara Mestizos… | Freq64 = 2.9 | People64 = China Guangzhou | Freq65 = 2.9 | People65 = China North Han | Freq66 = 2.9 | People66 = Mongolia Buriat | Freq67 = 2.5 | People67 = China Tibetans | Freq68 = 2.5 | People68 = China Yunnan Nu | Freq69 = 2.4 | People69 = Mexico Mestizos | Freq70 = 2.0 | People70 = American Samoa | Freq71 = 2.0 | People71 = Singapore Javanese Indone… | Placement = left | Allele = A03:02 | Freq1 = 8.3 | People1 = Georgia Tbilisi Kurds | Freq2 = 4.1 | People2 = Morocco Nador Metalsa Cla… | Freq3 = 2.8 | People3 = Pakistan Karachi Parsi | Freq4 = 2.5 | People4 = Israel Arab Druse | Freq5 = 2.3 | People5 = India New Delhi | Freq6 = 2.3 | People6 = Sudanese | Freq7 = 2.2 | People7 = India North Delhi | Freq8 = 2.0 | People8 = India West Coast Parsis | Freq9 = 2.0 | People9 = Portugal Centre | Freq10 = 1.7 | People10 = India Andhra Pradesh Goll… | Freq11 = 1.7 | People11 = Pakistan Kalash | Freq12 = 1.6 | People12 = Pakistan Baloch | Freq13 = 1.4 | People13 = Georgia Tbilisi Georgian… | Freq14 = 1.4 | People14 = Saudi Arabia Guraiat and … | Freq15 = 1.3 | People15 = Oman | Freq16 = 1.3 | People16 = Pakistan Sindhi | Freq17 = 1.0 | People17 = India North Hindus | Freq18 = 1.0 | People18 = Pakistan Pathan | Freq19 = 1.0 | People19 = South Africa Natal Tamil | Freq20 = 0.8 | People20 = USA South Texas Hispanics
Associated diseases
A*03:01 modulates increased risk for multiple sclerosis
A3~B haplotypes
A3-B7 is part of the A3~DQ2 superhaplotype A3-B8 (Romania, svanS)
A3~B35 (Bulgaria, Croatia, E. Black Sea)
A3~B55 (E. Black Sea)
A3~Cw7~B7
A3~B7 is bimodal in frequency in Europe with one node in Ireland and the other in Switzerland, relatively speaking Switzerland appears to be higher. A3~Cw7~B7 is one of the most common multigene haplotypes in the western world, particularly in Central and Eastern Europe.
A ~ C ~ B ~ DRB1 ~ DQA1 ~ DQB1
References
References
- (February 1978). "The genetic control of HLA-A and B antigens in somatic cell hybrids: requirement for beta2 microglobulin". Tissue Antigens.
- (January 2008). "Variation analysis and gene annotation of eight MHC haplotypes: the MHC Haplotype Project". Immunogenetics.
- (1999). "Correlation of thymic pathology with HLA in myasthenia gravis.". Clinical Immunology.
- (2005). "HLA haplotype A03-B07 in hemochromatosis probands with HFE C282Y homozygosity: frequency disparity in men and women and lack of association with severity of iron overload.". Blood Cells Mol Dis.
- (2006). "A study of 82 extended HLA haplotypes in HFE-C282Y homozygous hemochromatosis subjects: relationship to the genetic control of CD8+ T-lymphocyte numbers and severity of iron overload.". BMC Med Genet.
- (July 2008). "HLA haplotype map of river valley populations with hemochromatosis traced through five centuries in Central Sweden". Eur. J. Haematol..
- (July 2004). "Selection, transmission, and reversion of an antigen-processing cytotoxic T-lymphocyte escape mutation in human immunodeficiency virus type 1 infection". J. Virol..
- (2000). "Multiple sclerosis: a modifying influence of HLA class I genes in an HLA class II associated autoimmune disease.". Tissue Antigens.
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