HLA-DQ5

HLA-DQ5 (DQ5) is a HLA-DQ serotype that recognizes the beta chain varaints encoded by the HLA-DQB1*05 subgroup. DQ5 is synonymous with HLA-DQB1*05. The serotype recognizes with moderate efficiency the gene products of the DQB1*0501, *0502, *0503, *0504 alleles. DQ5 is a split antigen of the older HLA-DQ1 which recognized the alpha chain of DQ.

Serology
The efficiency of DQ1 recognition relative to DQ5 and DQ6 is listed above. Since DQ1 recognizes alpha, the DQ5 and DQ6 recognition are to beta chain. Meaning that DQ1 is corecognized with DQ5 and DQ6. Efficient recognition of a genotyped allele approaches 100%. Compared to DQ2 serotyping of DQB1*0201 positive individuals (98%), the efficiency of DQ5 recognition is relatively low and error prone.

While DQ5 recognizes DQB1*05 alleles more efficiently than DQ1, the serotyping is rather poor method of typing for transplantation or disease association prediction or study.

By serotype
DQ5 is negatively associated with DQ5 Idiopathic nephrotic syndrome in Polish children,, and adrenocortical failure (Addison's disease).

A study on the relationship between HLA-DR, DQ antigen, and intracranial aneurysm in the Han nationality show DQ5 more likely, AIDP type of Guillain Barré syndrome, and irritable bowel disease but not crohn's disease in the same (jewish) population. Other studies show DQ5 is associated with extrachromosomal manifestations of Crohn's.

DQ5 appears to be associated with Analgesic intolerance

By haplotype
MuSK antibody-positive myasthenia gravis HLA-DR14-DQ5, probably DRB1*1402:DQA1*0104:DQB1*0503. DR1-DQ5 is associated with acid anyhydride sensitivity

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