TGFB1 and Buschke-Ollendorff syndrome: In this regard, a recent study [63] analysed concentrations of VEGF produced by distal-derived lung fibroblasts, before and after stimulation with TGF-β, in LTx patients with BOS and in stable LTx recipients and healthy controls, at baseline and follow-up (3, 6 and 12 months).