[Immunological implications in the pathogenesis of Horton arteritis].

Fragments of temporal artery obtained by surgical biopsy from 3 patients suffering from Horton arteritis were employed for immunopathologic studies by direct immunofluorescence. In 2 of the cases, granular deposition of IgM, C1q and C3 but not of albumin were observed in the wall of vasa vasorum of the temporal artery. Elution techniques determined the disappearance of the immunoreactants. In one case in which biopsy fragments of temporal artery were obtained prior to and after steroid treatment it was observed that IgM and complement, previously present, disappeared after such treatment. The data reported indicate that indeed immunologic factors play a role in the pathogenesis of the disease and that the immunoreagents present on the wall of vasa vasorum are not evidence of increased vascular permeability but indicate an active immunologic process which takes place in them.