HLA-DPA1 (Major Histocompatibility Complex, Class II, DP Alpha 1): The HLA-DPA1 gene is part of the human leukocyte antigen (HLA) system, which plays a crucial role in the immune system. Specifically, this gene is involved in presenting peptides derived from extracellular proteins to T cells. Its significance lies in regulating the immune response and its association with various autoimmune diseases. The diversity of alleles in the HLA-DPA1 gene is essential to the adaptive immune response, making it a key focus in transplant medicine, autoimmune disease research, and vaccine response studies.