CXCL12 and allergic disease: Indeed, normal and CML stem cells express CXCR4, the receptor for SDF‐1; and disruption of SDF‐1 activity is considered to lead to stem cell mobilization.71, 72, 76, 77, 78 In this regard, it is worth noting that in patients with severe allergies where basophils may also increase, the numbers of circulating colony‐forming progenitor cells also increase.79 There may be also other mechanisms through which basophils can modulate stem cell‐niche interaction.