RANTES chemokine expression in transplant-associated accelerated atherosclerosis.

The pathogenesis of transplantation-associated accelerated atherosclerosis is poorly understood, but it is likely to be an alloimmune response involving infiltration of the vessel wall by T lymphocytes and monocytes leading to smooth muscle cell proliferation and extracellular matrix deposition. RANTES is a chemokine that selectively chemoattracts T lymphocytes, NK cells, monocytes, and eosinophils. The expression of RANTES in accelerated atherosclerosis was investigated by in situ hybridization and immunohistochemistry. Coronary arteries from six patients undergoing accelerated atherosclerosis were obtained at the time of retransplantation. Normal coronary arteries from two patients with idiopathic dilated cardiomyopathy were used as controls. Messenger RNA for RANTES was localized with digoxigenin-labeled complementary DNA probes. RANTES protein was detected by use of a monoclonal antibody and a three-step horseradish peroxidase method. RANTES mRNA and protein were detected in the lymphocytes, macrophages, myofibroblasts, and endothelial cells of arteries undergoing accelerated atherosclerosis but not in normal coronary arteries. In view of its in vitro biologic activity and in vivo expression pattern, RANTES may be a pivotal mediator of the cellular infiltrate seen in graft atherosclerosis. This information may help in the design of novel diagnostic and therapeutic approaches to this increasingly important disease process.