Increased levels of circulating endothelial cells in chronic periaortitis as a marker of active disease

Background. The pathogenesis of chronic periaortitis (CP) has not been clarified. The histologic features and the association with autoimmune diseases suggest an immune-mediated disorder with marked inflammatory vascular and perivascular lesions. To clarify the role of vascular damage we looked for the presence and the surface phenotype of circulating endothelial cells (CECs) in the peripheral blood of patients with chronic periaortitis. Methods. Eleven patients with CP were evaluated for the presence of CECs; 9 patients had active and 2 inactive disease. Three patients with active disease were also evaluated 3 months after therapy. Ten atherosclerotic patients, 10 patients with renal insufficiency of variable degree and etiology, and 40 healthy subjects were evaluated as controls. Five-parameter, 3-color flow cytometry was performed with a FACScan. CECs were defined as CD45 negative, CD31, P1H12, and CD36 positive, and activated CECs as CD45 negative and P1H12, CD62 positive. Results. The median number of CECs in patients with CP (10(6) cells/ mL) was significantly higher than in healthy controls ( 16 cells/ mL, P = 0.0004) and atherosclerotic patients (25 cells/ mL, P = 0.0005) Two patients with inactive disease had a CEC count comparable to that of normal subjects. In 2 of the 3 patients reevaluated, 3 months after therapy CEC numbers normalized. Almost all CECs were microvascular in origin and showed an activated phenotype. Conclusion. The presence of a high number of CECs in the active phase of chronic periaortitis and their normalization during inactive disease suggest that endothelial damage may play a role in the pathogenesis of the disease.