No active MMPs in BOS patients, only MMP‐7 activity was detected in stable LTR. However, TIMP‐1‐bound MMP‐7, ‐8, and ‐9 and TIMP‐2‐bound MMP‐8 and ‐9 were increased in BOS, suggesting earlier activity of these MMPs. This evidence concerns the gene TIMP1 and Buschke-Ollendorff syndrome.