[Immunohistochemical study of lesions in Horton's temporal arteritis before and during corticotherapy]

The immunohistochemical study was performed on temporal artery biopsies from eight patients with giant cell (temporal) arteritis: three before treatment, four after a short period of corticosteroid therapy (from 1 day to 7 days) and one during relapse occurring after a treatment of 9 years; from four subjects with clinical symptoms but without histological features of giant cell arteritis and from five negative controls. Before treatment, biopsies of patients with temporal arteritis showed an inflammatory infiltrate with macrophages and T cells, essentially CD4+ and memory T cells (CD45 RO+), expressing the markers of activation IL2 receptor and HLA DR. Few B and NK cells were also detected. Adhesion molecules, LFA1 and I-CAM1, were strongly expressed by T cells and macrophages. In contrast, the ligand to the CD2, the CD58 marker, was rarely detected. These immunohistochemical features were also observed after a short corticosteroid treatment (by intravenous methylprednisolone or oral prednisone), with presence of activated T cells, memory T cells, macrophages and I-CAM1 and LFA1 expressing cells in the infiltrate. A temporal biopsy, performed after a long time of corticosteroid therapy, showed activated T cells, macrophages and memory cells in o,ne arteriole. In controls, this study showed some mononuclear cells dispersed in intima and adventia, but without activated or memory T cells. Our results support the presence of immune local response in temporal arteritis, incompletely improved by a short corticosteroid treatment.