Levels of expression of Fcγ receptor IIA (CD32) are decreased on peripheral blood monocytes in patients with severe atherosclerosis

To obtain information in vivo concerning the role of Fcγ receptors (FcγR) in atherosclerosis, we used quantitative flow cytometry to measure the levels of expression of FcγRI and FcγRIIA on peripheral monocytes in patients with severe atherosclerosis. Expression of several other markers was also measured. We found that differences in the levels of expression of FcγRI were not statistically significant when compared between patients and control subjects. For FcγRIIA, levels of expression were decreased in the patient group, a difference that was statistically significant. Levels of expression of CD14 and CD36 were also significantly decreased in the patient group. The decrease in expression of FcγRIIA was statistically significant when the effects of current cigarette smoking status or medication use, including statins, were taken into account. There was also a positive and statistically significant correlation between high-density lipoprotein-cholesterol and levels of expression of FcγRIIA for all subjects. In contrast, decreased levels of expression of CD14 and CD36 were strongly associated with current smoking status or statin use. In summary, levels of expression of FcγRIIA on peripheral blood monocytes were significantly decreased in patients with clinical atherosclerosis. Additional studies are warranted to determine if levels of expression of FcγRIIA have utility as a phenotypic marker for assessing relative risk of atherosclerotic disease.