HLA-A3 (A3) is a human leukocyte antigenserotype 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 B2Mlocus.[1] This group currently is dominated by A*03:01. 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.[2]
^Arce-Gomez B, Jones EA, Barnstable CJ, Solomon E, Bodmer WF (February 1978). "The genetic control of HLA-A and B antigens in somatic cell hybrids: requirement for beta2 microglobulin". Tissue Antigens. 11 (2): 96–112. doi:10.1111/j.1399-0039.1978.tb01233.x. PMID77067.