ADAMTS4 and juvenile idiopathic arthritis: The thesis of the intensified enzymatic degradation of PGs/GAGs is confirmed by significantly higher concentrations of MMP-3 (metalloproteinase-3) or ADAMTS-4 (a disintegrin and metalloproteinase with thrombospondin motifs 4), found in blood of JIA patients, which was reported in our earlier research [7, 9].