SLAMF1 (signaling lymphocytic activation molecule family member 1) is a self-ligand immune receptor with multifaceted roles in pathogen defense and disease pathogenesis. Functionally, SLAMF1 acts as a principal cellular receptor for measles virus, mediating viral tropism toward immune cells 1. Beyond viral recognition, SLAMF1 regulates inflammatory responses through p38 MAPK signaling; it is highly induced on macrophages during CD4+ T cell interactions and enhances reactive oxygen species generation to restrict Mycobacterium tuberculosis replication 2. SLAMF1 similarly modulates tumor necrosis factor and interferon-β responses in human metapneumovirus infection 3. Clinically, SLAMF1 expression associates with protective immunity and disease outcomes across multiple conditions. In colorectal cancer, elevated SLAMF1+ innate lymphoid cells in patient blood correlates with improved survival 4. Conversely, SLAMF1 mediates hepatocyte death in nonalcoholic fatty liver disease, where elevated plasma and hepatic SLAMF1 levels correlate with disease severity and may serve as a noninvasive biomarker 5. SLAMF1 is also upregulated in rheumatoid arthritis, expressed on multiple immune cell subsets in diseased joints 6. Additionally, SLAMF1 is elevated in preclinical ulcerative colitis, supporting its role as an inflammatory biomarker 7.