ROLE OF ENDOTHELIAL-CELLS IN IGA NEPHROPATHY

Various polyspecific autoantibodies have been described in the sera of patients with IgA nephropathy, including anti-IgG, anti-IgA, antigala ctosyl, antifibronectin and antimesangial antibodies. We and other aut hors have demonstrated the presence of antivascular endothelial cell ( VEC) antibodies, in up to 32% of patients with IgA nephropathy. These antibodies were directed against molecules on the endothelial cell sur face. Some of these antibodies were directed against HLA class I antig ens; the majority, however, were reactive against antigens present on unstimulated endothelial cells, as prior stimulation of the cells with interferon-gamma or interleukin 1 did not result in an increase in an ti-VEC activity of the sera. The clinical significance of these anti-V EC antibodies in IgA nephropathy is unknown. A significant correlation was demonstrated between these antibodies and the presence of heavy p roteinuria, A significant association was also shown between the prese nce of these antibodies and the histopathologic markers of activity su ch as crescents and focal and segmental necrotizing lesions, as well a s immunoglobulin and C3 deposition in the vessel walls.