Role of Apoptosis in Pseudomonas aeruginosa Pneumonia

Apoptosis plays a central role in the complex balance between invading pathogen and host defense. Depending on the pathogen, apoptosis of host cells may be beneficial or detrimental to survival. Studies using a clinically relevant intra-abdominal model of sepsis (peritonitis) have indicated that two types of cells, lymphocytes and gastrointestinal epithelial cells, undergo accelerated apoptosis (1, 2). Apoptosis appears to be confined predominantly to these two cell types, possibly because these cells normally die by apoptotic mechanisms. Furthermore, blocking lymphocyte apoptosis in peritonitis has been shown to improve survival (3–5). Consequently, some investigators have speculated that prevention of apoptosis may be efficacious in sepsis by preventing immune suppression (6, 7).