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

摘要： 重症肺炎的本质是感染引发的免疫反应失控及损伤。病原体识别驱动免疫系统过度激活、巨噬细胞极化失衡和中性粒细胞胞外诱捕网（NETs）的形成失调是关键环节。过度炎症反应与组织细胞损伤密切相关，是肺内和肺外免疫病理损伤的核心机制，神经免疫调节紊乱可能也发挥重要作用。重症肺炎后期会出现T细胞耗竭和免疫麻痹，导致继发感染风险增高。将救治策略从单纯抗感染转向免疫调节，有助于打破免疫失衡的恶性循环，改善预后。

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