CXCR4 and allergic asthma: For allergic asthma, scRNA‐seq of lung neutrophils in mice exposed to a proallergic dose of lipopolysaccharides (LPSlo) or a protective dose of LPS (LPShi) before exposure to house dust mites (HDM) found that exposure to LPSlo instructed recruited neutrophils to upregulate the expression of the chemokine receptor CXCR4 and to release neutrophil extracellular traps (NETs), which indicates that unrelated environmental risk factors can shape recruited lung neutrophils to promote the initiation of allergic asthma.76