Rare autosomal dominant tubulointerstitial kidney disease is caused by mutations in the genes encoding uromodulin (UMOD), hepatocyte nuclear factor-1β (HNF1B), renin (REN), and mucin-1 (MUC1). ...Multiple names have been proposed for these disorders, including ‘Medullary Cystic Kidney Disease (MCKD) type 2’, ‘Familial Juvenile Hyperuricemic Nephropathy (FJHN)’, or ‘Uromodulin-Associated Kidney Disease (UAKD)’ for UMOD-related diseases and ‘MCKD type 1’ for the disease caused by MUC1 mutations. The multiplicity of these terms, and the fact that cysts are not pathognomonic, creates confusion. Kidney Disease: Improving Global Outcomes (KDIGO) proposes adoption of a new terminology for this group of diseases using the term ‘Autosomal Dominant Tubulointerstitial Kidney Disease’ (ADTKD) appended by a gene-based subclassification, and suggests diagnostic criteria. Implementation of these recommendations is anticipated to facilitate recognition and characterization of these monogenic diseases. A better understanding of these rare disorders may be relevant for the tubulointerstitial fibrosis component in many forms of chronic kidney disease.
Preemptive rituximab infusions prevent relapses in immune thrombotic thrombocytopenic purpura (iTTP) by maintaining normal ADAMTS13 activity. However, the long-term outcome of these patients and the ...potential adverse events of this strategy need to be determined. We report the long-term outcome of 92 patients with iTTP in clinical remission who received preemptive rituximab after identification of severe ADAMTS13 deficiency (activity <10%) during the follow-up. Thirty-seven patients had >1 iTTP episode, and the median cumulative relapse incidence before preemptive rituximab was 0.33 episode per year (interquartile range IQR, 0.23-0.66). After preemptive rituximab, the median cumulative relapse incidence in the whole population decreased to 0 episodes per year (IQR, 0-1.32; P < .001). After preemptive rituximab, ADAMTS13 activity recovery was sustained in 34 patients (37%) during a follow-up of 31.5 months (IQR, 18-65), and severe ADAMTS13 deficiency recurred in 45 patients (49%) after the initial improvement. ADAMTS13 activity usually improved with additional courses of preemptive rituximab. In 13 patients (14%), ADAMTS13 activity remained undetectable after the first rituximab course, but retreatment was efficient in 6 of 10 cases. In total, 14 patients (15%) clinically relapsed, and 19 patients (20.7%) experienced benign adverse effects. Preemptive rituximab treatment was associated with a change in ADAMTS13 conformation in respondent patients. Finally, in the group of 23 historical patients with iTTP and persistently undetectable ADAMTS13 activity, 74% clinically relapsed after a 7-year follow-up (IQR, 5-11). In conclusion, persistently undetectable ADAMTS13 activity in iTTP during remission is associated with a higher relapse rate. Preemptive rituximab reduces clinical relapses by maintaining a detectable ADAMTS13 activity with an advantageous risk-benefit balance.
•TTP patients who display persistent and severe ADAMTS13 deficiency after remission have a relapse rate of 74% during long-term follow-up.•Preemptive rituximab can decrease TTP relapses in 85% of patients with a favorable benefit-risk balance.
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HNF1B-related disease is an emerging condition characterized by an autosomal-dominant inheritance, a 50% rate of de novo mutations, and a highly variable phenotype (renal involvement, maturity-onset ...diabetes of the young type 5, pancreatic hypoplasia, and urogenital tract and liver test abnormalities). Given the current lack of pathognomonic characteristics and the wide overlap with other conditions, a genetic test is the diagnostic gold standard. However, pre-genetic screening is mandatory because genetic testing has substantial costs. Our aim was to develop a HNF1B score, based on clinical, imaging, and biological variables, as a pivotal tool for rational genetic testing. A score was created using a weighted combination of the most discriminative characteristics based on the frequency and specificity in published series. The HNF1B score is calculated upon 17 items including antenatal discovery, family history, and organ involvement (kidney, pancreas, liver, and genital tract). The performance of the score was assessed by a ROC curve analysis in a 433-individual cohort containing 56 HNF1B cases. The HNF1B score efficiently and significantly discriminated between mutated and nonmutated cases (AUC 0.78). The optimal cutoff threshold for the negative predictive value to rule out HNF1B mutations in a suspected individual was 8 (sensitivity 98.2%, specificity 41.1%, and negative predictive value over 99%). Thus, the HNF1B score is a simple and accurate tool to provide a more rational approach to select patients for HNF1B screening.
Summary
Background
Cardiac involvement is a major cause of mortality in patients with thrombotic thrombocytopenic purpura (TTP). However, diagnosis remains underestimated and delayed, owing to ...subclinical injuries. Cardiac troponin‐I measurement (cTnI) on admission could improve the early diagnosis of cardiac involvement and have prognostic value.
Objectives
To assess the predictive value of cTnI in patients with TTP for death or refractoriness.
Patients/Methods
The study involved a prospective cohort of adult TTP patients with acquired severe ADAMTS‐13 deficiency (< 10%) and included in the registry of the French Reference Center for Thrombotic Microangiopathies. Centralized cTnI measurements were performed on frozen serum on admission.
Results
Between January 2003 and December 2011, 133 patients with TTP (mean age, 48 ± 17 years) had available cTnI measurements on admission. Thirty‐two patients (24%) had clinical and/or electrocardiogram features. Nineteen (14.3%) had cardiac symptoms, mainly congestive heart failure and myocardial infarction. Electrocardiogram changes, mainly repolarization disorders, were present in 13 cases. An increased cTnI level (> 0.1 μg L−1) was present in 78 patients (59%), of whom 46 (59%) had no clinical cardiac involvement. The main outcomes were death (25%) and refractoriness (17%). Age (P = 0.02) and cTnI level (P = 0.002) showed the greatest impact on survival. A cTnI level of > 0.25 μg L−1 was the only independent factor in predicting death (odds ratio OR 2.87; 95% confidence interval CI 1.13–7.22; P = 0.024) and/or refractoriness (OR 3.03; 95% CI 1.27–7.3; P = 0.01).
Conclusions
A CTnI level of > 0.25 μg L−1 at presentation in patients with TTP appears to be an independent factor associated with a three‐fold increase in the risk of death or refractoriness. Therefore, cTnI level should be considered as a prognostic indicator in patients diagnosed with TTP.
Monoclonal gammopathy of renal significance (MGRS) regroups renal disorders caused by a monoclonal immunoglobulin without overt hematological malignancy. MGRS includes tubular disorders, glomerular ...disorders with organized deposits, and glomerular disorders with non-organized deposits, such as proliferative glomerulonephritis with monoclonal IgG deposits. Since glomerular involvement related to monotypic IgA deposits is poorly described we performed retrospective analysis and defined clinico-biological characteristics, renal pathology, and outcome in 19 referred patients. This analysis allowed distinction between 2 types of glomerulopathies, α-heavy chain deposition disease (5 patients) and glomerulonephritis with monotypic IgA deposits (14 patients) suggestive of IgA-proliferative glomerulonephritis with monoclonal immunoglobulin deposits in 12 cases. Clinicopathologic characteristics of α-heavy chain deposition disease resemble those of the γ-heavy chain disease, except for a higher frequency of extra-capillary proliferation and extra-renal involvement. IgA-proliferative glomerulonephritis with monoclonal immunoglobulin deposits should be differentiated from diseases with polytypic IgA deposits, given distinct clinical, histological, and pathophysiological features. Similarly to IgG-proliferative glomerulonephritis with monoclonal immunoglobulin deposits, overt hematological malignancy was infrequent, but sensitive serum and bone marrow studies revealed a subtle plasma cell proliferation in most patients with IgA-proliferative glomerulonephritis with monoclonal immunoglobulin deposits. Anti-myeloma agents appeared to favorably influence renal prognosis. Thus, potential progression towards symptomatic IgA multiple myeloma suggests that careful hematological follow-up is mandatory. This series expands the spectrum of renal disease in MGRS.
Autoimmune thrombotic thrombocytopenic purpura (TTP) can be associated with other autoimmune disorders, but their prevalence following autoimmune TTP remains unknown. To assess the prevalence of ...autoimmune disorders associated with TTP and to determine risk factors for and the time course of the development of an autoimmune disorder after a TTP episode, we performed a cross sectional study. Two-hundred sixty-one cases of autoimmune TTP were included in the French Reference Center registry between October, 2000 and May, 2009. Clinical and laboratory data available at time of TTP diagnosis were recovered. Each center was contacted to collect the more recent data and diagnosis criteria for autoimmunity. Fifty-six patients presented an autoimmune disorder in association with TTP, 9 years before TTP (median; min: 2 yr, max: 32 yr) (26 cases), at the time of TTP diagnosis (17 cases) or during follow-up (17 cases), up to 12 years after TTP diagnosis (mean, 22 mo). The most frequent autoimmune disorder reported was systemic lupus erythematosus (SLE) (26 cases) and Sjögren syndrome (8 cases). The presence of additional autoimmune disorders had no impact on outcomes of an acute TTP or the occurrence of relapse. Two factors evaluated at TTP diagnosis were significantly associated with the development of an autoimmune disorder during follow-up: the presence of antidouble stranded (ds)DNA antibodies (hazard ratio (HR): 4.98; 95% confidence interval (CI) 1.64-15.14) and anti-SSA antibodies (HR: 9.98; 95% CI 3.59-27.76). A follow-up across many years is necessary after an acute TTP, especially when anti-SSA or anti-dsDNA antibodies are present on TTP diagnosis, to detect autoimmune disorders early before immunologic events spread to prevent disabling complications.
Minimal-change nephrotic syndrome (MCNS) is a common cause of steroid sensitive nephrotic syndrome (NS) with frequent relapse. Although steroids and calcineurin inhibitors (CNIs) are the cornerstone ...treatments, the use of rituximab (RTX), a monoclonal antibody targeting B cells, is an efficient and safe alternative in childhood.
Because data from adults remain sparse, we conducted a large retrospective and multicentric study that included 41 adults with MCNS and receiving RTX.
Complete (NS remission and withdrawal of all immunosuppressants) and partial (NS remission and withdrawal of at least one immunosuppressants) clinical responses were obtained for 25 and 7 patients, respectively (overall response 78%), including 3 patients that only received RTX and had a complete clinical response. After a follow-up time of 39 months (6-71), relapses occurred in 18 responder patients 56%, median time 18 months (3-36). Seventeen of these received a second course of RTX and then had a complete (n = 13) or partial (n = 4) clinical response. From multivariate analysis, on-going mycophenolate mofetil (MMF) therapy at the time of RTX was the only predictive factor for RTX failure HR = 0.07 95% CI (0.01-0.04), P = 0.003. Interestingly, nine patients were still in remission at 14 months (3-36) after B-cell recovery. No significant early or late adverse event occurred after RTX therapy.
RTX is safe and effective in adult patients with MCNS and could be an alternative to steroids or CNIs in patients with a long history of relapsing MCNS.
Erdheim-Chester disease (ECD) is a rare histiocytic disorder, recently recognized to be neoplastic. The clinical phenotype of the disease is extremely heterogeneous, and depends on the affected ...organs, with the most frequently reported manifestations being bone pain, diabetes insipidus and neurological disorders including ataxia. In this article, we report on a case of a 48-year-old woman, whose initial symptom of gait instability was isolated. This was associated with positional nystagmus with central features: nystagmus occurring without latency, clinically present with only mild symptoms, and resistant to repositioning maneuvers. The cerebral MRI showed bilateral intra-orbital retro-ocular mass lesions surrounding the optic nerves and T2 hyperintensities in the pons and middle cerebellar peduncles. A subsequent CT scan of the chest abdomen and pelvis found a left "hairy kidney", while
F-FDG PET-CT imaging disclosed symmetric 18F-FDG avidity predominant at the diametaphyseal half of both femurs. Percutaneous US-guided biopsy of perinephric infiltrates and the kidney showed infiltration by CD68(+), CD1a(-), Langerin(-), PS100(-) foamy histiocytes with
mutation. The combination of the different radiological abnormalities and the result of the biopsy confirmed the diagnosis of ECD. Many clinical and radiological descriptions are available in the literature, but few authors describe vestibulo-ocular abnormalities in patients with ECD. Here, we report on a case of ECD and provide a precise description of the instability related to central positional nystagmus, which led to the diagnosis of ECD.
Enteric overabsorption of oxalate may lead to hyperoxaluria and subsequent acute oxalate nephritis (AON). AON related to chronic pancreatitis is a rare and poorly described condition precluding early ...recognition and treatment.
We collected the clinical characteristics, treatment, and renal outcome of 12 patients with chronic pancreatitis-associated AON followed in four French renal units.
Before AON, mild to moderate chronic kidney disease was present in all patients, diabetes mellitus in eight (insulin n = 6; oral antidiabetic drugs n = 2), and known chronic pancreatitis in only eight. At presentation, pancreas imaging showed gland atrophy/heterogeneity, Wirsung duct dilation, calcification, or pseudocyst. Renal findings consisted of rapidly progressive renal failure with tubulointerstitial profile. Acute modification of glomerular filtration preceded the AON (i.e., diarrhea and diuretics). Increase in urinary oxalate excretion was found in all tested patients and hypocalcemia in nine (<1.5 mmol/L in four patients). Renal biopsy showed diffuse crystal deposits, highly suggestive of oxalate crystals, with tubular necrosis and interstitial inflammatory cell infiltrates. Treatment consisted of pancreatic enzyme supplementation, oral calcium intake, and an oxalate-free diet in all patients and renal replacement therapy in five patients. After a median follow-up of 7 months, three of 12 patients reached end-stage renal disease.
AON is an under-recognized severe crystal-induced renal disease with features of tubulointerstitial nephritis that may occur in patients with a long history of chronic pancreatitis or reveal the pancreatic disease. Extrinsic triggering factors should be prevented.
In 2013, rituximab was approved in France for the treatment of ANCA-associated vasculitis (AAV). The aim of the study was to compare the treatment and health events of adult incident patients with ...granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA), included before rituximab approval (over 2010-2012, Group 1) and those included after rituximab approval (over 2014-2017, Group 2).
Data were extracted from the French National Health Insurance database (SNDS) including outpatient health care consumption and hospital discharge forms. Comparisons between inclusion periods were performed using Wilcoxon and χ² tests. Kaplan-Meier method was used to model the duration of treatment induction, maintenance, and off-drug periods. Fine and Gray tests were used to compare treatment phase durations.
A total of 694 GPA and 283 MPA patients were included in Group 1, while 668 GPA and 463 MPA patients were included in Group 2. Between the two inclusion periods, the proportions of patients treated with rituximab increased in the induction and maintenance phases whereas treatment with azathioprine declined. These proportions remained stable in the case of methotrexate, cyclophosphamide, and glucocorticoid-treated patients. Frequency of first-time hospitalized infections, diabetes and renal failure during the first year after inclusion increased for both groups.
This is a retrospective study based on claims data including only 76% of people covered by health insurance in France. The period studied includes the learning phase of using rituximab. This study lacks biological data and precise quantitative analysis for the use of steroids, therefore the criteria for establishing diagnosis and therapeutic choice were unknown.
Introduction of rituximab reduced the use of azathioprine without affecting the use of glucocorticoids or cyclophosphamide.
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