SPIC (Spi-C transcription factor) is a DNA-binding transcription factor that controls the development of red pulp macrophages required for red blood cell recycling and iron homeostasis. SPIC binds to PU-box sequences (5'-GAGGA[AT]-3') and regulates transcription through RNA polymerase II, including regulation of VCAM1 gene expression. In the immune context, SPIC expression is downregulated when Kupffer cells transition from a resident macrophage phenotype toward a monocyte-like state 1. Mechanistically, SPIC nuclear translocation can be promoted via PKC-mediated phosphorylation at T191, which enhances NK cell adhesion and cytotoxicity toward hepatic stellate cells through modulation of Itga4-VCAM1 binding in liver fibrosis models 2. SPIC represents a key transcriptional regulator integrating innate immune cell identity and function with iron metabolism homeostasis. Its expression status serves as a marker of macrophage differentiation state, with implications for understanding immune cell plasticity in response to inflammatory signals. Further research is needed to clarify the full spectrum of SPIC target genes and its role in disease pathology beyond macrophage development.