 | ||
| HLA-B (alpha)-β2MG with bound peptide | ||
major histocompatibility complex (human), class I, B44 | ||
| Alleles | B*4401, 4402, 4403 . . | |
| Structure (See HLA-B) | ||
| Shared data | ||
| Locus | chr.6 6p21.31 | |
HLA-B44 (B44) is an HLA-B serotype. The serotype identifies the B*44 gene-allele protein products of HLA-B. [1]
B44 is a split antigen of the broad antigen B12, and is a sister type of B45.
| B*44 | B44 | B12 | B45 | Sample |
| allele | % | % | % | size (N) |
| *4402 | 98 | 6959 | ||
| *4403 | 94 | 2854 | ||
| *4404 | 65 | 42 | ||
| *4405 | 92 | 130 | ||
| *4406 | 44 | 9 | ||
| B*4401 was shown to be B*4402 after errors corrected. | ||||
| Alleles link-out to IMGT/HLA Database at EBI | ||||
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HLA-B44 increases recurrent sinopulmonary infections. [3] Protective effects: HLA-B44 appears to be protective against autoimmune lymphoproliferative syndrome in patients with C95 defect (ALPS type Ia). [4] B44 may be a cofactor in ankylosing spondylitis [5]
The human leukocyte antigen (HLA) system or complex is a group of related proteins that are encoded by the major histocompatibility complex (MHC) gene complex in humans. These cell-surface proteins are responsible for the regulation of the immune system. 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:
Autoimmune lymphoproliferative syndrome (ALPS), is a form of lymphoproliferative disorder (LPDs). It affects lymphocyte apoptosis.
HLA-DQ5 (DQ5) is a human leukocyte antigen serotype subgroup within HLA-DQ(DQ) serotypes. The serotype is determined by the antibody recognition of β5.x subset of DQ β-chains. The β-chain of DQ is encoded by HLA-DQB1 locus and DQ5 are encoded by the HLA-DQB1*05 allele group. This group currently contains 4 common alleles, DQB1*0501, *0502, *0503, and *0504. HLA-DQ5 and HLA-DQB1*05 are almost synonymous in meaning. DQ5 β-chains combine with α-chains, encoded by genetically linked HLA-DQA1 alleles, to form the cis-haplotype isoforms. These isoforms, are all HLA-DQ1 encoded by the DQA1*01 allele group.
HLA-DQ6 (DQ6) is a human leukocyte antigen serotype within HLA-DQ (DQ) serotype group. The serotype is determined by the antibody recognition of β6 subset of DQ β-chains. The β-chain of DQ isoforms are encoded by HLA-DQB1 locus and DQ6 are encoded by the HLA-DQB1*06 allele group. This group currently contains many common alleles, DQB1*0602 is the most common. HLA-DQ6 and DQB1*06 are almost synonymous in meaning. DQ6 β-chains combine with α-chains, encoded by genetically linked HLA-DQA1 alleles, to form the cis-haplotype isoforms. For DQ6, however, cis-isoform pairing only occurs with DQ1 α-chains. There are many haplotypes of DQ6.
HLA-DQ7 (DQ7) is an HLA-DQ serotype that recognizes the common HLA DQB1*0301 and the less common HLA DQB1*0304 gene products. DQ7 is a form of 'split antigen' of the broad antigen group DQ3 which also contains DQ8 and DQ9.
HLA-DQ1 is a serotype that covers a broad range of HLA-DQ haplotypes. Historically it was identified as a DR-like alpha chain called DC1; later, it was among 3 types DQw1, DQw2 and DQw3. Of these three serotyping specificities only DQw1 recognized DQ alpha chain. The serotype is positive in individuals who bear the DQA1*01 alleles. The most frequently found within this group are: DQA1*0101, *0102, *0103, and *0104. In the illustration on the right, DQ1 serotyping antibodies recognizes the DQ α (magenta), where antibodies to DQA1* gene products bind variable regions close to the peptide binding pocket.
HLA-DR52 is an HLA-DR serotype that recognizes gene products of HLA-DRB3 locus. Three allele groups can produce 35 isoforms.
HLA-DR17 (DR17) is an HLA-DR serotype that recognizes the DRB1*0301 and *0304 gene products. DR17 is found at high frequency in Western Europe. DR17 is part of the broader antigen group HLA-DR3 and is very similar to the group HLA-DR18.
HLA-DR15 (DR15) is a HLA-DR serotype that recognizes the DRB1*1501 to *1505 and *1507 gene products. DR15 is found at high levels from Ireland to Central Asia. DR15 is part of the older HLA-DR2 serotype group which also contains the similar HLA-DR16 antigens.
HLA-DR13(DR13) is a HLA-DR serotype that recognizes the DRB1*1301 to *13082, *1310 and some other *13 gene products. DR13 serotype is a split antigen of the older HLA-DR6 serotype group which also contains the similar HLA-DR14 antigens.
HLA-DR2 (DR2) of the HLA-DR serotype system, is a broad antigen serotype that is now preferentially covered by HLA-DR15 and HLA-DR16 serotype group. This serotype primarily recognizes gene products of the HLA-DRB1*15 and HLA-DRB1*16 allele groups.
HLA-DR4 (DR4) is an HLA-DR serotype that recognizes the DRB1*04 gene products. The DR4 serogroup is large and has a number of moderate frequency alleles spread over large regions of the world.
HLA-A1 (A1) is a human leukocyte antigen serotype within HLA-A "A" serotype group. The serotype is determined by the antibody recognition of α1 subset of HLA-A α-chains. For A1, the alpha "A" chain are encoded by the HLA-A*01 allele group and the β-chain are encoded by B2M locus. This group currently is dominated by A*0101. A1 and A*01 are almost synonymous in meaning. A1 is more common in Europe than elsewhere, it is part of a long haplotype that appears to have been frequent in the ancient peoples of Northwestern Europe. A1 is a frequent component of the AH8.1 haplotype. A1 serotype positivity is roughly linked to a large number of inflammatory diseases and conditions believed to have immune system involvement. Because of its linkage within the AH8.1 haplotype many studies showed association with A1 or A1,B8 only later to show the association drift toward the class II region gene alleles, DR3 and DQ2.5. While it is not clear what role A1 has in infectious disease, some linkage with infection rates in HIV remain associated within the A1 region of the haplotype.
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*03 allele group and the β-chain are encoded by B2M locus. This group currently is dominated by A*0301. A3 and A*03 are almost synonymous in meaning. A3 is more common in Europe, it is part of the longest known multigene haplotype, A3-B7-DR15-DQ6.
HLA-A11 (A11) is a human leukocyte antigen serotype within HLA-A "A" serotype group. The serotype is determined by the antibody recognition of α11 subset of HLA-A α-chains. For A11, the alpha "A" chain are encoded by the HLA-A*11 allele group and the β-chain are encoded by B2M locus. This group currently is dominated by A*1101. A11 and A*11 are almost synonymous in meaning. A11 is more common in East Asia than elsewhere, it is part of several long haplotypes that appear to have been frequent in the ancient peoples of Asia.
An immune disorder is a dysfunction of the immune system. These disorders can be characterized in several different ways:
HLA-B58 (B58) is an HLA-B serotype. B58 is a split antigen from the B17 broad antigen, the sister serotype B57. The serotype identifies the more common HLA-B*58 gene products. B*5801 is associated with allopurinol induced inflammatory necrotic skin disease.
HLA-B51 (B51) is an HLA-B serotype. The serotype identifies the more common HLA-B*51 gene products.
HLA A1-B8 is a multigene haplotype that covers the MHC Class I region of the human major histocompatibility complex on chromosome 6. A multigene haplotype is set of inherited alleles covering several genes, or gene-alleles; common multigene haplotypes are generally the result of identity by descent from a common ancestor. Chromosomal recombination fragments multigene haplotypes as the distance to that ancestor increases in number of generations.
Caspase-8 deficiency (CEDS) is a very rare genetic disorder of the immune system. It is caused by mutations in the CASP8 gene that encodes the protein caspase-8. The disorder is characterized by splenomegaly and lymphadenopathy, in addition to recurrent sinopulmonary infections, recurrent mucocutaneous herpesvirus or other viral infections, and hypogammaglobulinemia. Investigators in the laboratory of Dr. Michael Lenardo at the National Institutes of Health described this condition in two siblings from a consanguineous family in 2002, and several more affected family members have since been identified.