Soluble CD163, a novel marker of activated macrophages, is elevated and associated with noncalcified coronary plaque in HIV-infected patients

Background. Pro-inflammatory monocytes/macrophages may contribute to increased atherosclerosis in human immunodeficiency virus (HIV) - infected patients. We investigate - to our knowledge, for the first time - sCD163 and other markers of monocyte activation in relationship to atherosclerotic plaque in HIV-infected patients. Methods. One hundred two HIV-infected and 41 HIV-seronegative men with equivalent cardiovascular risk factors and without history of coronary artery disease were prospectively recruited and underwent computed tomography coronary angiography. Results. sCD163 levels and presence of plaque were significantly higher among antiretroviral-treated subjects with undetectable HIV RNA levels, compared with seronegative controls (1172±646 vs. 883±561 ng/mL [P=.02] for sCD163 and 61% vs. 39% [P = .03] for presence of plaque). After adjusting for age, race, lipids, blood pressure, glucose, smoking, sCD14, and HIV infection, sCD163 remained independently associated with noncalcified plaque (P = .008). Among HIV-infected patients, sCD163 was associated with coronary segments with noncalcified plaque (r = 0.21; P = .04), but not with calcium score. In contrast, markers of generalized inflammation, including C-reactive protein level, and D-dimer were not associated with sCD163 or plaque among HIV-infected patients. Conclusions. sCD163, a monocyte/macrophage activation marker, is increased in association with noncalcified coronary plaque in men with chronic HIV infection and low or undetectable viremia. These data suggest a potentially important role of chronic monocyte/macrophage activation in the development of noncalcified vulnerable plaque. Clinical Trial Registration. NCT00455793