Other Isoforms
DQ2 beta chains can pair with trans to other alpha chain. However there is no precedance in cis isoforms for DQ2,4,7,8, or 9 binding DQ1 (DQA1*01) alpha chains. DQA1*03, *05 chains process to near identical alpha chains. The *04 chain can potentially complex with DQ2 forming DQ2.4. In East Asia there is the possibility of DQ2.6 resulting from pairing with DQA1*0601.
Read more about this topic: HLA-DQ2, DQ2 Isoforms and DQ2 Haplotypes