Up to today, several compounds targeting non-immune effectors have been explored in lung SR-cGVHD; among them, Alvelestat could be effective in blocking the damage induced by PMN in BOS; this neutrophil elastase inhibitor showed anti-inflammatory properties in human alveolar and bronchial epithelial cells by targeting neutrophil extracellular traps and can improve survival rates in mice models [187]. Here, ELANE is linked to Buschke-Ollendorff syndrome.