Systemic lupus erythematosus (SLE) is a highly prevalent human autoimmune diseases that causes progressive glomerulonephritis, arthritis and an erythematoid rash. Mice deficient in deoxyribonuclease I (Dnase1) develop an SLE-like syndrome. Here we describe two patients with a heterozygous nonsense mutation in exon 2 of DNASE1, decreased DNASE1 activity and an extremely high immunoglobulin G titer against nucleosomal antigens. These data are consistent with the hypothesis that a direct connection exists between low activity of DNASE1 and progression of human SLE.

Abstract-We reported previously that urinary angiotensinogen (UAGT) levels provide a specific index of the intrarenal renin-angiotensin system (RAS) status in angiotensin II-dependent hypertensive rats. To study this system in humans, we recently developed a human angiotensinogen ELISA. To test the hypothesis that UAGT is increased in hypertensive patients, we recruited 110 adults. Four subjects with estimated glomerular filtration levels Ͻ30 mL/min per 1.73 m 2 were excluded because previous studies have already shown that UAGT is highly correlated with estimated glomerular filtration in this stage of chronic kidney disease. Consequently, 106 paired samples of urine and plasma were analyzed from 70 hypertensive patients (39 treated with RAS blockers [angiotensin-converting enzyme inhibitors or angiotensin II type 1 receptor blockers; systolic blood pressure: 139Ϯ3 mm Hg] and 31 not treated with RAS blockers [systolic blood pressure: 151Ϯ4 mm Hg]) and 36 normotensive subjects (systolic blood pressure: 122Ϯ2 mm Hg). UAGT, normalized by urinary concentrations of creatinine, were not correlated with race, gender, age, height, body weight, body mass index, fractional excretion of sodium, plasma angiotensinogen levels, or estimated glomerular filtration. However, UAGT/urinary concentration of creatinine was significantly positively correlated with systolic blood pressure, diastolic blood pressure, urinary albumin:creatinine ratio (rϭ0.5994), and urinary protein:creatinine ratio (rϭ0.4597). UAGT/urinary concentration of creatinine was significantly greater in hypertensive patients not treated with RAS blockers (25.00Ϯ4.96 g/g) compared with normotensive subjects (13.70Ϯ2.33 g/g). Importantly, patients treated with RAS blockers exhibited a marked attenuation of this augmentation (13.26Ϯ2.60 g/g). These data indicate that UAGT is increased in hypertensive patients, and treatment with RAS blockers suppresses UAGT, suggesting that the efficacy of RAS blockade to reduce the intrarenal RAS activity can be assessed by measurements of UAGT.

These data indicate that urinary angiotensinogen is a powerful tool for determining intrarenal RAS status and associated renal derangement in patients with IgA nephropathy.

Background We previously reported that kidney and urinary angiotensinogen levels were significantly increased before the development of diabetic nephropathy in diabetic rats. To address this system in humans, we have developed an enzyme-linked immunosorbent assay for human angiotensinogen and reported that urinary excretion of angiotensinogen levels is enhanced in patients with chronic kidney disease, including patients with type 2 diabetes. On the basis of these findings, this study was performed to demonstrate that urinary angiotensinogen levels increased before the onset of microalbuminuria and that urinary angiotensinogen can be an early biomarker of intra-renal renin-angiotensin system status in normoalbuminuric patients with type 1 diabetes compared with age- and sex-matched control subjects. Methods The study included 28 patients with type 1 diabetes and 21 control subjects. No subject received renin-angiotensin system blockades. Random spot urine samples as well as blood samples were obtained and analyzed. Results Urinary albumin:creatinine ratio or urinary protein:creatinine ratio did not increase in patients compared with control subjects, suggesting that these patients were in their premicroalbuminuric phase of diabetic nephropathy. However, the urinary angiotensinogen:creatinine ratio was significantly higher in patients than in control subjects (12.1 ± 3.2 µg/g versus 4.2 ± 0.7 µg/g). Importantly, an increase in plasma angiotensinogen levels was not observed (26.3 ± 1.3 µg/mL versus 29.5 ± 3.3 µg/mL). Conclusions Thus, in patients, an increase in urinary angiotensinogen levels is observed, and this increase is precedent to an increase in urinary albumin levels, suggesting that urinary angiotensinogen may function as an early marker of diabetic nephropathy.