Temporal arteritis in polymyalgia rheumatica: immune complex deposits and the role of the leukocyte elastase in the pathogenesis.

Immunohistochemical studies were performed on the temporal artery of 34 patients with clinically established polymyalgia rheumatica (PR) or temporal arteritis, 6 patients with vasculitis, and 25 patients with various diseases. The combined immunofluorescence and peroxidase-anti-Peroxidase Methode zeigte Immunoglobulin- und C3-Ablagerunin histologically affected and to some degree also in unaffected arteries of patients with PR and in all patients with temporal arteritis. The deposits were found both inter- and intracellularly, and contained IgA and to a lesser extend IgG, IgM, and C3. Linear deposits of leukocyte elastase were found along the fragmented internal lamina, and decaying polymorphonuclear (PMN) leukocytes surrounded by elastase-containing inclusions were found in the neighborhood of zones rich in elastic material. These findings suggest that immune complex deposition is a prominent feature of temporal arteritis and that the PMN elastase is probably involved in the destruction of elastic fibers. The combined immunohistochemical investigation appears to increase the diagnostic value of temporal artery biopsy.