Widespread distribution of HLA-DR-expressing cells in macroscopically undiseased intima of the human aorta: a possible role in surveillance and maintenance of vascular homeostasis.

The architectonics and cell composition of the human large arteries are not sufficiently understood. The present study is the first to undertake an analysis of the distribution and quantities of HLA-DR-expressing cells in grossly undiseased human intima using immunohistochemical and immunofluorescent analysis, complemented by the advantages of confocal microscopy. The study revealed a widespread distribution of HLA-DR-expressing cells throughout the intimal space where the cells were integrated into continuous networks via long cell processes.