TGFB1 and Buschke-Ollendorff syndrome: Immunohistochemistry has revealed TGF-β expression in epithelial cells, interstitial cells, and macrophages in transplanted lungs, suggesting that TGF-β may serve as a critical mediator linking PGD and BOS, and could potentially function as a biomarker for both conditions (DerHovanessian et al., 2016).