Early Renal Recovery after the First Flare of Pauci-Immune Glomerulonephritis.

INTRODUCTION: Renal involvement is a severe manifestation of antineutrophil cytoplasmic antibody-associated vasculitis. Patients often progress to end-stage renal disease. The potential for renal recovery after the first flare has seldom been studied. Our objectives were to describe the evolution of the estimated glomerular filtration rate (eGFR) and identify factors associated with the change in the eGFR between diagnosis and the follow-up at 3 months (ΔeGFRM0-M3). METHODS: This was a retrospective study over the period 2003-2018 of incident patients in the Nord-Pas-de-Calais (France). The primary outcome was the ΔeGFRM0-M3. RESULTS: One hundred and seventy-seven patients were included. The eGFR at 3 months was significantly higher than at diagnosis (mean ± standard deviation, 40 ± 24 vs. 28 ± 26 mL/min/1.73 m2, p < 0.001), with a ΔeGFRM0-M3 of 12 ± 19 mL/min/1.73 m2. The eGFR at 12 months was higher than at 3 months (44 ± 13 vs. 40 ± 24 mL/min/1.73 m2, p = 0.003). The factors significantly associated with the ΔeGFRM0-M3 in multivariate analysis were the percentage of cellular crescents and neurological involvement. The mean increase in the eGFR was 2.90 ± 0.06 mL/min/1.73 m2 for every 10-point gain in the percentage of cellular crescents. CONCLUSIONS: Early renal recovery after the first flare of pauci-immune glomerulonephritis occurred mainly in the first 3 months of treatment. The percentage of cellular crescents was the main independent predictor of early renal recovery.

Prognostic Value of Microscopic Hematuria after Induction of Remission in Antineutrophil Cytoplasmic Antibodies-Associated Vasculitis.

BACKGROUND: Pauci-immune glomerulonephritis (PIGN) is a major prognostic factor in antineutrophil cytoplasmic antibodies-associated vasculitis (AAV). Renal remission is usually defined as improvement or stabilization of serum creatinine and proteinuria levels but the significance of hematuria is unclear. We evaluated the prognostic value of microscopic hematuria in patients in remission from a first flare of PIGN. METHODS: A multicenter retrospective study was conducted of all patients with histologically proven PIGN in northern France who presented a first renal flare of AAV between 2003 and 2013. All patients received conventional induction treatment and were considered in remission. Two groups were defined by the presence (H+) or absence (H-) of hematuria (dipstick 1+ and/or cytology ≥10,000 erythrocytes/mL). The primary outcome measure was the occurrence of renal relapse (RR) and/or end-stage renal disease (ESRD). RESULTS: Eighty-six patients were included: 41 (48%) had hematuria at remission. The median follow-up time was 44 ± 34 months. There was no significant difference between the groups in terms of the primary endpoint or the number of RR. However, the survival rate without RR was significantly lower in the H+ group (p = 0.002). In multivariate analysis, risk factors for RR were hematuria at remission for relapses within 44 months (hazard ratio [HR] 4.15; 95% CI 1.15-15.01; p = 0.03) and the duration of maintenance immunosuppressive therapy (HR 0.96 per additional month; 95% CI 0.94-0.99; p = 0.002). CONCLUSION: Hematuria at remission after a first PIGN flare was not associated with ESRD but with the occurrence of RR within 44 months of remission.

Mutation Update of the CLCN5 Gene Responsible for Dent Disease 1.

Dent disease is a rare X-linked tubulopathy characterized by low molecular weight proteinuria, hypercalciuria, nephrocalcinosis and/or nephrolithiasis, progressive renal failure, and variable manifestations of other proximal tubule dysfunctions. It often progresses over a few decades to chronic renal insufficiency, and therefore molecular characterization is important to allow appropriate genetic counseling. Two genetic subtypes have been described to date: Dent disease 1 is caused by mutations of the CLCN5 gene, coding for the chloride/proton exchanger ClC-5; and Dent disease 2 by mutations of the OCRL gene, coding for the inositol polyphosphate 5-phosphatase OCRL-1. Herein, we review previously reported mutations (n = 192) and their associated phenotype in 377 male patients with Dent disease 1 and describe phenotype and novel (n = 42) and recurrent mutations (n = 24) in a large cohort of 117 Dent disease 1 patients belonging to 90 families. The novel missense and in-frame mutations described were mapped onto a three-dimensional homology model of the ClC-5 protein. This analysis suggests that these mutations affect the dimerization process, helix stability, or transport. The phenotype of our cohort patients supports and extends the phenotype that has been reported in smaller studies.