HLA-DQB2 is a major histocompatibility complex class II beta-chain gene that encodes a component of MHC class II molecules involved in antigen presentation. HLA-DQB2 is specifically expressed in Langerhans cells, where it forms heterodimers with HLA-DQα2 to create a distinct MHC class II molecule capable of presenting exogenous peptide antigens to CD4+ T cells 1. The HLA-DQα2/β2 complex localizes to early endosomes and cell surface, mediating T cell stimulation including staphylococcal superantigen responses 1. Unlike classical HLA-DQ molecules, HLA-DQB2 exhibits minimal polymorphism and can form mixed heterodimers with HLA-DQβ1 chains 1. Clinically, HLA-DQB2 has emerging significance in kidney transplantation and infectious disease. Heightened HLA-DQB2 expression in pre-implantation kidney biopsies from young donors (18-49 years) predicts poor 1-year graft function (OR=22.5) 2, and elevated post-transplant soluble HLA-DQB2 serum levels associate with graft dysfunction 3. Additionally, the HLA-DQB2 rs7453920 G>A polymorphism correlates with increased tuberculosis susceptibility in the Chinese Uygur population 4. Genome-wide association studies identify HLA-DQB2 overexpression in immune-related pathways associated with primary antiphospholipid syndrome 5. HLA-DQB2 expression is downregulated by inhaled corticosteroids in healthy airways, reflecting its role in adaptive immunity 6.