If the discarded donor lung tissue was obtained from donors having lung inflammation or injury due to mechanical ventilation, infection, or other inflammatory responses in the study of Nkyimbeng et al. [19], this could have elevated MMP-8 protein levels in the donor lung and contributed to the lack of a difference in MMP-8 levels between IPF and donor lungs in this study. Here, MMP8 is linked to idiopathic pulmonary fibrosis.