Urinary tissue factor in glomerulonephritis: a potential marker of glomerular injury?

AIM To investigate the significance of urinary tissue factor (uTF) concentrations in patients with glomerulonephritis. METHODS Urine samples were collected from normal subjects (n = 57), patients with uncomplicated renal stones (n = 30), and patients with glomerulonephritis (n = 150). Samples were then centrifuged and the pellets solubilised in n-octyl-beta-glucopyranoside. uTF concentrations were determined using a one stage kinetic chromogenic assay. RESULTS The uTF concentration was higher in patients with glomerulonephritis than in normal controls (p < 0.01) or in patients with renal stones (p < 0.05). uTF activity correlated with the protein creatinine index (PCI, r = 0.41, p < 0.001) and seven patients with glomerulonephritis and a PCI < or = 0.1 g/mmol had raised uTF. Glomerulonephritis patients were subdivided into two groups depending on the PCI: < 0.2 g/mmol creatinine (mild to moderate proteinuria, group I) and > or = 0.2 g/mmol creatinine (heavy proteinuria, group II). In group I, uTF concentrations were higher in patients with either immune complex (IC) glomerulonephritis (p < 0.01) or non-IC (p < 0.05) glomerulonephritis than in normal controls. In group II, the IC glomerulonephritis group had higher uTF concentrations than normal controls (p < 0.001) or patients with renal stones (p < 0.01); and non-IC glomerulonephritis patients had higher uTF than normal controls (p < 0.01). When the glomerulonephritis groups were divided into broad WHO subtypes, the significance level varied with the type of glomerulonephritis. CONCLUSIONS uTF is increased in patients with glomerulonephritis, and its concentration may reflect the aetiopathogenesis of glomerulonephritis.