Adventitial lymphocytic inflammation in human coronary arteries with intimal atherosclerosis

Abstract

The relationship between adventitial inflammation, plaque type, and culprit plaque morphology in the epicardial arterial circulation has not been studied in detail. We studied semiserial sections of coronary arteries at autopsy from patients dying with severe coronary disease, 81 men (age 50 + or - 12 years) and 13 women (age 52 + or - 13 years). Lesions were classified at 3- to 5-mm segments according to modified AHA criteria. Adventitial lymphocyte aggregates were assessed at every 5-mm interval and graded semiquantitatively. Macrophage density in the adventitial fat and intima was assessed with anti-CD68 staining. Adventitial lymphocytic inflammation increased with percent stenosis (P<.0001) and not calcification (P>.2). Hemorrhage into late core, rupture, erosion, and thin caps all had greater adventitial lymphocytic inflammation independent of percent stenosis (P<.0001). Peri-adventitial adipose macrophage density was increased in plaques with atheromas (206 + or - 22 mm(2) vs. 121 + or - 15 mm(2) in fibrous plaques; P=.02) and correlated positively with adventitial lymphocytes (P<.0001) and intimal macrophage content (P<.0001). Features associated with plaque instability are associated with significantly greater degrees of adventitial lymphocytic inflammation, both as lymphocyte aggregates and as adipocyte-derived macrophages. Further study is required to determine the nature of the association between intimal and adventitial lymphocytic inflammation.