CR1L (complement C3b/C4b receptor 1 like) is a complement receptor that plays important roles in immune regulation and cellular interactions. As a complement control protein, CR1L contains short consensus repeats characteristic of the complement receptor family and is structurally related to CR1 1. CR1L functions as a signaling receptor involved in regulating complement activation and complement-dependent cytotoxicity [GO annotations]. The receptor mediates cellular uptake through recognition of complement-tagged particles; dietary plant-derived mitochondria interact with lung macrophage CR1L via phosphatidic acid, enabling uptake and fusion with mitochondrial genomes to modulate immune responses in acute lung injury models 2. CR1L also restricts hepatitis C virus infection in mouse hepatocytes, serving as an intrinsic antiviral factor that limits HCV propagation and cooperatively regulates host defense gene expression 34. In cancer contexts, CR1L has emerged as both a therapeutic target and prognostic marker. Genome-wide CRISPR screening identified Cr1l as specifically essential for acute myeloid leukemia growth in vivo 5, while elevated plasma CR1L levels correlate with worse therapeutic responses and higher international prognostic index scores in diffuse large B-cell lymphoma patients treated with R-CHOP 6. Additionally, CR1L has been identified as a secreted protein with potential immunotherapeutic roles in cancer 7.