MMP19 and Buschke-Ollendorff syndrome: In addition, BOS significantly reduced the number of F4/80+ macrophages in MMP19WT-AAV-infected mice lung tissues (Fig. 5L), and alleviated MMP19-induced lung fibrosis, as evidenced by decreased hydroxyproline levels and collagen deposition in BLM challenged mouse lungs (Fig. 5K, M).