LILRB1 also known as CD85j, MIR7, ILT-2 is a member of the leukocyte immunoglobulin-like receptor (LIR) family, which is found in a gene cluster at chromosomal region 19q13.4. LILRB1 plays a crucial role in immune regulation by binding to major histocompatibility complex (MHC) class I molecules, which inhibits the activation of natural killer (NK) and T cells, thereby preventing excessive immune responses. The presence of LILRB1 on immune cells, such as monocytes, B cells, and dendritic cells, is vital for maintaining immune homeostasis and tolerance, particularly in preventing autoimmunity and modulating responses to pathogens. Additionally, LILRB1′s interaction with B cell antigen receptor and histocompatibility leukocyte antigens (HLA)-DR can inhibit calcium mobilization in myeloid cells, further underscoring LILRB1′s importance in immune signaling pathways.