Accumulation of lymphocytes, dendritic cells, and granulocytes in the aortic wall affected by Takayasu's disease.

The aim of this study was to analyze the cellular composition of the arterial wall in Takayasu's disease and to investigate the contribution of the various cell types to the immunoinflammatory processes and degenerative alterations of the vessel wall in this disease. Specimens of aorta were obtained at operation from 10 patients with Takayasu's arteritis. The duration of disease ranged from 2 months to 13 years. Immunohistochemical investigation was carried out using the antibodies CD3 (to identify T-cells), CD20 (B-cells), S-100 (dendritic cells), CD68 (macrophages), CD15 (granulocytes), von Willebrand factor (endothelial cells), and alpha-smooth muscle actin (smooth muscle cells). All specimens showed distinctive histologic features of Takayasu's arteritis and contained inflammatory infiltrates, but the degree of their accumulation within the aortic wall varied. Inflammatory infiltrates within the deep part of the intima, around areas of neovascularization and within the adventitia contained T-cells colocalizing with dendritic cells. Nodules formed by large numbers of intermingling T-cells and B-cells enriched with dendritic cells were observed in the adventitia. Massive accumulation of granulocytes and their destruction within the adventitia were prominent in all cases. This is the first study that establishes the presence of dendritic cells and granulocytes in Takayasu's disease. Dendritic cells are probably involved in the immunoinflammatory processes through their interaction with T-cells and B-cells. The present observations may help understanding of the pathogenesis of Takayasu's disease.