This type of MΦ polarization has previously been found in other, more common inflammatory skin diseases including atopic dermatitis and psoriasis, which both share some clinical and molecular features with aGvHD.9 Although skin-resident MΦs may produce high levels of IL-10 and TGF-β, providing anti-inflammatory functions in tissue repair, they are highly plastic, and promote tissue inflammation in Th-2-mediated conditions including contact dermatitis and asthma,45,46 rather than dampening the inflammatory response. This evidence concerns the gene IL10 and atopic eczema.