As a multifunctional cytokine, IL-6 is secreted by a variety of cells such as macrophages and T cells (Tanaka et al., 2014), and promotes the progression of severe pneumonia complicated with sepsis through three mechanisms: first, inducing the release of inflammatory mediators such as tumor necrosis factor-α and interleukin-1β to amplify the inflammatory cascade; second, promoting the differentiation of T cells into Th17 cells to regulate the balance of immune response; third, promoting the production of coagulation factors to cause coagulation dysfunction (McElvaney et al., 2021). Here, IL6 is linked to pneumonia.