ACCUMULATION OF T-LYMPHOCYTES AND EXPRESSION OF INTERLEUKIN-2 RECEPTORS IN NONRHEUMATIC STENOTIC AORTIC VALVES

Objectives. Cell specific antibodies were used to identify immunocompe tent cells in a comparison of valves from patients who had symptomatic tricuspid aortic stenosis with subjects who had no evidence of valvul ar heart disease. Background. Nonrheumatic valvular aortic stenosis is the most common valvular heart disease among adults. The biologic pro cesses involved in the development of this disease are poorly understo od. Methods. Tricuspid stenotic aortic valves were obtained from 19 pa tients undergoing surgery for nonrheumatic valvular aortic stenosis, a nd 10 control valves were collected at autopsy. The valves were fixed in formaldehyde, cryosectioned and stained with antibodies against fib roblasts, endothelial cells, macrophages, T lymphocytes and interleuki n-2 receptors. A subset of valves were also analyzed with antibodies a gainst T-helper cells and cytotoxic T cells. Results. Stenotic valves were characterized by a basal accumulation of calcium deposits and a c ell-rich subendothelial thickening. The immunohistologic analysis indi cated that the cells in the subendothelial connective tissue were fibr oblasts. T lymphocytes appeared to be the most common cell type in the vicinity of the calcium deposits and were also found close to the end othelial lining of the valves. T helper cells were more frequent than cytotoxic T cells. Expression of interleukin-2 receptors occurred at t he same location as T lymphocytes. Control valves lacked subendothelia l thickening and contained only few cells reacting with antibodies aga inst lymphocytes and macrophages. Conclusions. The presence of activat ed T lymphocytes in tricuspid stenotic valves suggests that immunologi c mechanisms may be involved in the etiology of nonrheumatic aortic st enosis.