Electron-dense deposits in extraglomerular vascular structures in IgA nephropathy. A retrospective study.

24 renal biopsies from 23 patients with IgA nephropathy (Berger's disease) were examined. This retrospective ultrastructural study focused on extraglomerular vascular structures since information about these structures in IgA nephropathy is lacking. Electron-dense deposits were observed in arterioles in 8 out of 18 biopsies (44%), in which arterioles were available for electron microscopic examination. Deposits were absent in peritubular capillaries and in all arteries. The presence of deposits had no correlation with the patient's blood pressure. The electron-dense deposits represent additional evidence that IgA nephropathy is a monosymptomatic form of a systemic disease that is mediated by circulating immune complexes of heterogeneous origin.