there are four commonly encountered dqa1 alleles: dqa1*0101, *0102, *0103, *0104. these alleles are always found in haplotypes with hla-dqb1*05 (dq5) and hla-dqb1*06 (dq6). dq1 is a serotype, rare among serotypes for human class ii antigens, in that the antibodies to dq1 react to the alpha chain of hla dq, these dqa1 allele gene products.