关键词: 重症肺炎, 免疫损伤, 巨噬细胞, 中性粒细胞, 细胞因子风暴

Abstract: The nature of severe pneumonia primarily involve an uncontrolled immune response and damage triggered by pulmonary infection. The recognition of pathogens leads to the excessive activation of the immune system，characterized by an imbalance in macrophage polarization and dysregulated formation of neutrophil extracellular traps（NETs），which are critical factors in this process. Excessive inflammatory responses are closely related to tissue cell damage and are the core mechanism of intrapulmonary and extrapulmonary immune pathological damage. Disorders of neuroimmune regulation may also play an important role. In the late stages of severe pneumonia，T cell depletion and immune paralysis occur，increasing the risk of secondary infections. Shifting the treatment strategy from simple anti-infection to immune regulation can help break the vicious cycle of immune imbalance and improve prognosis.

Key words: severe pneumonia, immune injury, macrophages, neutrophils, cytokine storm