The PPBP ligand, one of the specific signatures of the C4 subtype in this study, is involved in various conditions; PPBP was detected in activated platelets that are involved in chronic inflammation during the development of atherogenesis and coronary heart disease (CHD), and thus could be used as a biomarker for CHD risk in postmenopausal Thai women [58]. Here, C4A is linked to coronary artery disorder.