ITGAM encodes the alpha M subunit of the CD11b/CD18 integrin complex, which functions as a critical adhesion and phagocytic receptor on myeloid cells. The protein mediates complement-mediated phagocytosis by serving as the CR3 receptor for iC3b complement fragments and recognizes fibrinogen and ICAM1 ligands to facilitate leukocyte adhesion to endothelium 1. Recent mechanistic studies demonstrate that CD11b agonists can reprogram tumor-associated macrophages by simultaneously suppressing NF-κB signaling through p65 degradation while activating STING/STAT1-mediated interferon responses via FAK-dependent mitochondrial dysfunction 2. The protein also regulates dermal dendritic cell differentiation, with CD11b expression levels distinguishing DC2 subsets that respond differently to IL-13 signaling 3. Multiple meta-analyses consistently demonstrate strong associations between ITGAM polymorphisms, particularly rs1143679, and systemic lupus erythematosus susceptibility across diverse populations (OR 1.77-1.86) 456. The rs1143679 variant shows particularly strong association with lupus nephritis in Europeans (OR 2.13) 5. ITGAM variants are also associated with IgA nephropathy 7 and cardiac cachexia in heart failure patients 8, highlighting its broader role in inflammatory disease pathogenesis.