Background：

HLA-DQB2 belongs to the family of HLA class II beta chain paralogs. Class II molecules are heterodimers consisting of an alpha (DQA) and a beta chain (DQB)， both anchored in the membrane. They play a central role in the immune system by presenting peptides derived from extracellular proteins. Class II molecules are expressed in antigen presenting cells (APC: B lymphocytes， dendritic cells， macrophages). Polymorphisms in the alpha and beta chains specify the peptide binding specificity， and typing for these polymorphisms is routinely done for bone marrow transplantation. However this gene， HLA-DQB2， is not routinely typed， as it is not thought to have an effect on transplantation. There is conflicting evidence in the literature and public sequence databases for the protein-coding capacity of HLA-DQB2. Because there is evidence of transcription and an intact ORF， HLA-DQB2 is represented in Entrez Gene and in RefSeq as a protein-coding locus.