HLA-DQ3

Within molecular and cell biology, HLA-DQ3 (DQ3) is a broad serotype category with split antigens HLA-DQ7, DQ8, and DQ9. Historically, originally recognized as MB3 a DC4 serotype, DQw3 was one of three early determined antigens recognized as HLA-DQ along with HLA-DQ1 and HLA-DQ2. While the DQ3 molecules are structurally similar in beta chain, the DQ molecules differ markedly in function, even when present with the same DQ alpha subunit. For this reason they are best treated independently. The serotyping efficiency of DQ3 recognition relative to DQ2, DQ7, DQ8, and DQ9 is shown to the left. Compared to DQ2 serotyping of DQB10201 positive individuals (98%), the efficiency of DQ3 recognition is relatively low and error prone. This compares to genotyping efficiency of 100%. The recognition of DQB10303 by DQ9 and or DQ3 is poorest, DQ2 which recognizes a different DBB1group recognizes DQB10303 as efficiently as DQ3. For this reason DQ3 serotyping is a poor method of typing for transplantation or disease association prediction or study. Nonetheless, it is still widely used and association purported in the literature.