Studies of peritoneal neutrophils from aged rats [13] have shown reduced levels of cholesterol and increased membrane fluidity, associated with reduced superoxide generating ability. Other studies have shown dysregulation of receptor recruitment to lipid rafts, which will have very broad effects in compromising receptor signaling functions and downstream biological effects. Abbreviations: PKB, protein kinase B; PI3K, phosphoinositide-3-kinase; JAK, JAK, JAK-STAT signaling (JAK, Janus kinase; STAT Signal Transducers and Activators of Transcription).