BPIFB4 (BPI fold containing family B member 4) is a circulating protein with emerging roles in immunoregulation and vascular homeostasis beyond its putative olfactory functions. The longevity-associated variant (LAV) of BPIFB4 is enriched in long-living individuals and demonstrates potent anti-inflammatory and cardioprotective properties 12. Mechanistically, LAV-BPIFB4 operates through multiple pathways. It modulates macrophage polarization by activating the PI3K/AKT signaling pathway, shifting M1 pro-inflammatory macrophages toward protective M2 phenotypes 3. Platelets serve as a critical reservoir and delivery mechanism for BPIFB4, releasing the protein to mediate vascular protection and immune modulation 4. The protein also directly improves cardiac function by enhancing contractility and microvascular density while reducing fibrosis and senescence 56. Clinical relevance is substantial. Lower circulating BPIFB4 levels correlate with severe coronary artery disease and COVID-19 severity 67. LAV-BPIFB4 demonstrates therapeutic promise in cardiac ischemia, diabetic cardiomyopathy, COPD, and inflammatory bowel disease 638. Gene transfer reduces epigenetic aging and frailty in aged mice 1, supporting potential human therapeutic applications for age-related cardiovascular and inflammatory diseases.