Serum uromodulin concentrations correlate with glomerular filtration rate in patients with chronic kidney disease.

INTRODUCTION Urinary uromodulin excretion has been associated with kidney diseases. However, serum uromodulin concentrations have not been extensively studied in patients with chronic kidney disease (CKD), and the results of published studies are inconsistent. OBJECTIVES The aims of the study were to evaluate serum uromodulin concentrations in patients with CKD and to assess the utility of serum uromodulin measurements for diagnosing CKD stages. PATIENTS AND METHODS This observational study included 170 patients with CKD stages 1 to 5, not treated by renal replacement therapy, and 30 healthy individuals. The serum levels of creatinine, cystatin C, and uromodulin were measured, and estimated glomerular filtration rate (eGFR) was calculated according to the 2012 CKD Epidemiology Collaboration cystatin­creatinine equation. RESULTS Among patients with CKD, serum uromodulin concentrations were significantly lower than in controls, and were strongly negatively correlated with renal retention markers (ie, serum creatinine and cystatin C) and strongly positively correlated with eGFR. An inverse, hyperbolic relationship between serum creatinine and uromodulin levels was analogous to the well­known association between serum creatinine concentrations and eGFR. A receiver­operating characteristic curve analysis showed a high diagnostic accuracy of the measurement of serum uromodulin concentrations in the assessment of CKD stages. CONCLUSIONS Serum uromodulin concentrations are closely correlated with eGFR, which is the recommended measure of renal function. As uromodulin is produced exclusively by renal tubular cells, the assessment of uromodulin levels in patients with CKD may be an alternative method for evaluating the number of functioning nephrons.

[Rapidly progressive ANCA-negative glomerulonephritis in the course of pauci immune microscopic vasculitis with hemolytic anemia probable in the course of Wilson's disease]. / Gwaltownie postepujace klebuszkowe zapalenie nerek w przebiegu ANCA-negatywnego "niemego- immunologicznie" mikroskopowego zapalenia naczyn z towarzyszaca anemia hemolityczna prawdopodobnie w przebiegu choroby Wilsona.

Pauci-immune glomerulonephritis, i.e., with no evidence of immune deposits in the blood vessel, is the most prevalent form of rapidly progressive glomerulonephritis (RPGN). In the pathogenesis of pauci-immune renal disease inflammation of blood vessels in the presence of circulating anti-neutrophil cytoplasm antibodies (ANCA) takes place. However the lack of ANCA (about 5-30% of patients) does not exclude pauci-immune vasculitis. The patients without circulating ANCA might have fewer extrarenal symptoms than those who are ANCA-positive. We describe a case of a 40-year old women with ANCA-negative renal limited pauci-immune small-vessel vasculitis with rapidly decreasing kidney function. She was ineffectively treated with plasmapheresis combined with a puls of cyclophosphamide (i.v.) and 3 pulses of methyloprednisolone (i.v.). The patient progressed to end-stage renal disease and should be treated with renal replacement therapy. In differential diagnosis we excluded other causes of pauci-immune vasculitis (Churg-Strauss syndrome, Wegener's granulomatosis), vasculitis with immune complexes deposition (systemic lupus erythematosus, Schoenlein-Henoch purpura, post-infection RPGN), Goodpasture disease, haemolytic-uremic syndrome (HUS), disseminated intravascular coagulation (DIC) and Wilson's disease.