In contrast, this increase of apoptosis at early stage was significantly enhanced in the XIAP−/− mice as compared with wild-type mice, even that slightly increase of apoptosis-positive cells was detected at late stage in the XIAP−/− mice (Figure 4b).We also measured the effects of XIAP deletion on acinar cell necrosis during cerulein (with or without LPS)-induced pancreatitis. Here, XIAP is linked to pancreatitis.