An ultrastructural study of glomerular basement membrane in rheumatoid arthritis patients with urinary abnormalities.

We measured the thickness of the glomerular basement membrane (GBM) in 48 rheumatoid arthritis (RA) patients with proteinuria and/or hematuria and studied its relationship to clinical features of RA. Ten cases with minor glomerular abnormalities, renal cancer, donor of renal transplantation, were studied as controls. Secondary glomerular diseases and hereditary thin basement membrane disease (TBMD) were excluded. Mean GBM thickness was 289 +/- 74 nm (mean +/- SD) in RA patients, which was significantly thinner than that of control group (342 +/- 38 nm) (p < 0.01). Mean GBM thickness were 276 +/- 72 nm and 336 +/- 68 nm in RA patients with and without gold sodium thiomalate (GST) treatment, respectively (p < 0.05). Mean GBM thickness of RA patients without GST and controls were not different statistically, but RA patients with GST had significantly thinner GBM, compared with controls (p < 0.01). The mean thickness of GBM were also 274 +/- 69 nm and 344 +/- 72 nm in RA patients with and without hematuria, respectively (p < 0.01). According to these results, we suspect that the thinning of GBM in RA patients may be related to GST treatment.