Although our results in mice are complemented by RNA-Seq analysis supporting TGF-β1 as a key regulator of human AM gene expression in early life, it remains to be determined whether TGF-β1 signaling promotes maturation and restricts chemokine expression in these AMs to limit inflammatory responses to environmental stimuli and whether this is disrupted in childhood asthma. The gene discussed is TGFB1; the disease is childhood onset asthma.