Regarding the interaction of IL-31 and TGF-β1 in the context of BLM-induced fibrosis, in vitro experiments showed that anti-TGF-β1 mAb decreased Il31 expression and increased Il31ra expression in fibroblasts from the lungs of BLM-SSc mice (Supplementary Fig. 10). Here, IL31 is linked to systemic sclerosis.