Decreased number of circulating plasmacytoid dendritic cells in patients with atherosclerotic coronary artery disease

In Brief Background Dendritic cells are potent antigen-presenting and immune modulating cells that have been implicated in the development of atherosclerosis. In human blood, two distinct lineages are distinguished: plasmacytoid dendritic cells and myeloid dendritic cells. Although dendritic cells have been described in atherosclerotic plaques, no information exists concerning circulating blood dendritic cells in atherosclerosis. This study aims to evaluate the number of circulating dendritic cells in patients with coronary artery disease. The relation with the extent of coronary artery disease, the clinical syndrome and with a marker of inflammation will be documented. Methods Patients with angiographically proven coronary artery disease (n=18) and age and sex-matched controls (n=18) were included. Myeloid dendritic cells and plasmacytoid dendritic cells were detected with the specific blood dendritic cell antigens, blood dendritic cell antigen-1 and blood dendritic cell antigen-2, respectively. Results Absolute and relative numbers of circulating plasmacytoid dendritic cells were significantly lower in patients with coronary artery disease (5722±601/ml and 0.08±0.01%) than in controls (12640±1289/ml and 0.21±0.02%). Plasmacytoid dendritic cells were more decreased in patients with troponin-positive unstable coronary syndromes than in patients with low troponin values, and tended to be lower in more extensive coronary artery disease. Absolute myeloid dendritic cells numbers tended to be reduced in patients, whereas relative numbers were significantly decreased: 11 857±1895/ml versus 15 226±928/ml and 0.17±0.03% versus 0.26±0.01% in controls. Conclusions The present study shows a significant decrease of circulating blood dendritic cell antigen-2 positive plasmacytoid dendritic cells in patients with coronary artery disease. The decrease tended to be more pronounced in unstable coronary syndromes and extensive coronary artery disease, suggesting a possible role of dendritic cells in plaque progression and rupture. Dendritic cells are potent antigen-presenting cells and immune modulating cells that have been implicated in atherogenesis. In human blood, two distinct lineages of dendritic cells are distinguished: plasmacytoid dendritic cells andmyeloid dendritic cells. Although it is known that the number of vascular dendritic cells is increased in atherosclerotic arteries, no information exists concerning blood dendritic cells and atherosclerosis. This study evaluates the number of circulating dendritic cells in patients with severe coronary artery disease). Myeloid dendritic cells and plasmacytoid dendritic cells were detected with the specific blood dendritic cells antigens, blood dendritic cells antigen-1and blood dendritic cells antigen-2, respectively. The absolute numbers ofmyeloid dendritic cells tended to be reduced in patients, while relative numbers were significantly decreased.The absolute and relative numbers of circulating plasmacytoid dendritic cells were significantly lower in patients with coronary artery disease. This decrease tended to be more pronounced in unstable coronary syndromes and extensive coronary artery disease, suggesting a possible role of dendritic cells in plaque progression and rupture.