The different paradigms of NK cell death in patients with severe trauma

Lymphocyte decline, particularly the depletion of NK cells, is a prominent feature of immunosuppression following severe tissue injury, heightening the susceptibility of severe trauma patients to life-threatening infections. Previous research indicates that the reduction in the number of NK cells is closely associated with the process of cell death. Nonetheless, the precise mechanism of NK cell death remains unknown. Here, we discovered that following severe traumatic injury, NK cells undergo several cell death pathways, dominated by apoptosis and pyroptosis with coexistence of necrotic cell death, immunogenic cell death, ferroptosis, and autophagy. These NK cells with different paradigms of death have diverse cytokine expression profiles and diverse interactions with other immune cells. Further exploration revealed that hypoxia was strongly associated with this diverse paradigm of NK cell death. Detailed investigation of paradigms of cell death may help to enhance comprehension of lymphopenia post-severe trauma, to develop new strategy in preventing immunosuppression, and then to improve outcome for severe trauma population.