MMP2 and COVID-19: To better define the role of MMPs in severe COVID-19 lungs, we investigate the expression of MMPs in the lung parenchyma and the association between the bronchoalveolar-tracheal levels and activity of MMP-2 and MMP-8 to the immune response associated with sHLA-G and sTREM-1 release, in addition to tissue damage by oxidative stress in COVID-19 outcomes.