HLA-DRB1 encodes the beta chain of HLA-DR molecules, which are MHC class II proteins that present peptide antigens to CD4+ T cells for immune recognition. The protein forms complexes that bind and present exogenous peptide antigens on the cell surface, playing a crucial role in adaptive immune responses 12. HLA-DRB1 contains a peptide binding groove with specific pockets (such as P4) that accommodate antigenic peptides, and alterations to this groove can modify peptide binding and T-cell recognition 12. Certain HLA-DRB1 alleles show strong disease associations, particularly HLA-DRB1*1501 with multiple sclerosis risk, especially when combined with Epstein-Barr virus infection 3. The HLA-DRB1*03 allele is strongly associated with Löfgren's syndrome, a distinct sarcoidosis subtype with favorable prognosis 4. Drug interactions with HLA-DRB1 can lead to adverse reactions, as demonstrated by ximelagatran and nevirapine, which bind to the peptide groove and alter immune responses, potentially causing hepatotoxicity 21. The high allelic diversity of HLA-DRB1, with numerous variants being continuously identified, reflects its critical role in immune system diversity and population-specific disease susceptibilities 567.