Hultman K, Edsfeldt A, Björkbacka H, et al. - Since information is lacking about the role of COMP (cartilage oligomeric matrix protein) in human atherosclerotic disease despite the evidence of a role for COMP in murine atherosclerosis, researchers desired to know whether COMP was correlated with a stable or a vulnerable human atherosclerotic plaque phenotype by analyzing 211 carotid plaques for COMP expression using immunohistochemistry. Compared with asymptomatic plaques, plaque area that stained positive for COMP was significantly larger in atherosclerotic plaques related to symptoms. COMP has been positively associated with plaque lipids and CD68 cells but has been associated negatively with collagen, elastin, and smooth muscle cells. Findings suggested a positive association of COMP with CD163, a scavenger receptor for hemoglobin/haptoglobin and a marker of Mhem macrophages, and with intraplaque hemorrhage, measured as glycophorin A staining.