Ultrastructural changes of glomerular basement membrane in IgA nephritis: relationship to hematuria.

Ultrastructural changes in the glomerular basement membrane (GBM) of 415 samples from 344 patients with IgA nephritis, were examined for potential relationship to hematuria. The GBM showed various alteration: splitting, thinning, membranolysis with swelling of the lamina rara externa and interna, forming of small projections, and rupture. These lesions were present in 48% of IgA nephritis and in 16% of the controls. In the IgA nephritis group, the patients with hemispherical mesangial dense deposits had the highest rate (60%) of capillary wall abnormalities. Such lesions were more frequent in patients biopsied during severe hematuria (80%) than in those biopsied without hematuria (33%), (p less than 0.01). It is assumed that the ultrastructural abnormalities of GBM may contribute to the clinical evidence of severe hematuria.