| αβ heterodimer|
| transmembrane receptor/ligand|
HLA-A74 (A74) is a human leukocyte antigen serotype within HLA-A serotype group. The serotype is determined by the antibody recognition of α74 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.
A74 has a poor serotyping rate.
A significant association has been found between A74 and nasal polyposis.