MMP9 and autoimmune disease: The indirect effects of MMPs, leading to the understanding of the autoimmune processes took longer to be accepted and went from the identification of neutrophil MMP-9/gelatinase B (10, 11), via the discovery of glycosylated remnant epitopes of type II collagen (12) to studies evaluating the therapeutic effects of MMP inhibitors (13, 14) in autoimmune diseases (15).