MMP9 and coronary artery disorder: In an attempt to determine the source of circulating MMP-9 in a non-infectious, inflammatory state, Jonsson et al. [44] fractionated blood cells from patients with CAD and from healthy controls into peripheral blood mononuclear cells (PBMCs) and neutrophils, and found that the dominant source of MMP-9 is neutrophils and that neutrophils from CAD patients secreted more MMP-9 than those from the controls in vitro.