Additionally, we examined the levels of inflammatory cytokines in sputum and found that IL‐5, IL‐6, IL‐8, TNF‐α, IFN‐γ, CCL17, CCL22, CXCL10, CCL4, CCL2, IL‐4, IL‐13, and CCL26 were significantly lower in stable asthma than in acute asthma (Table 3). Here, TNF is linked to asthma.