title: HLA-A74
text: # HLA-A74
  
  HLA-A74 (A74) is a human leukocyte antigen serotype within HLA-A serotype group. The serotype is determined by the antibody recognition of $α^{74}$ subset of HLA-A α-chains. For A74, the alpha "A" chain are encoded by the HLA-A*74 allele group and the β-chain are encoded by B2M locus. A74 and A*74 are almost synonymous in meaning. A74 is a split antigen of the broad antigen serotype A19. A74 is a sister serotype of A29, A30, A31, A32, and A33.
  
  A74 is more common in Subsaharan Africa. A74 is a rare HLA-A allele group.
  
  ## Serotype
  
  A74 recognition of some HLA A*74 gene products :
  
  | A*74 | A74 | A19 | Sample |
  | - | - | - | - |
  | allele | % | % | size (N) |
  | *7401 | 40 | 11 | 119 |
  | *7403 | 17 | 0 | 29 |
  
  A74 has a poor serotyping rate.
  
  ## Disease associations
  
  A significant association has been found between A74 and nasal polyposis.
  
  ## Sources
  
  * Madrigal JA, Belich MP, Hildebrand WH, et al. (November 1992). "Distinctive HLA-A,B antigens of black populations formed by interallelic conversion" (PDF). J. Immunol. 149 (10): 3411–5. PMID 1431115.
  