Prolonged cultures of unstimulated human neutrophils lead to the apparition and persistence of rest-in-plate structures (RIPs) recognized by professional phagocytes in vitro and in vivo.

Polymorphonuclear neutrophil cells (PMNs) are known to spontaneously undergo apoptosis and then eliminated by professional phagocytes to prevent inflammation, a process called efferocytosis. However, when efferocytosis is impaired, PMNs will fall into secondary necrosis. Whether this state can persist for a certain period of time is unclear, since most of the studies investigating secondary necrosis are performed within 24h following induction by a proapoptotic agent.