Genotype-Phenotype Correlations in Alport Syndrome-A Single-Center Experience

BACKGROUND

Alport syndrome (AS) is a common and heterogeneous genetic kidney disease, that often leads to end-stage kidney disease (ESKD).

METHODS

This is a single-center, retrospective study that included 36 adults with type IV collagen (COL4) mutations. Our main scope was to describe how genetic features influence renal survival.

RESULTS

A total of 24 different mutations were identified, of which eight had not been previously described. Mutations affecting each of the type IV collagen α chains were equally prevalent (33.3%). Most of the patients had pathogenic variants (61.1%). Most patients had a family history of kidney disease (71%). The most prevalent clinical picture was nephritic syndrome (64%). One-third of the subjects had extrarenal manifestations, 41.6% of patients had ESKD at referral, and another 8.3% developed ESKD during follow-up. The median renal survival was 42 years (95% CI, 29.98-54.01). The COL4A4 group displayed better renal survival than the COL4A3 group (p = 0.027). Patients with missense variants had higher renal survival (p = 0.023). Hearing loss was associated with lower renal survival (p < 0.001).

CONCLUSIONS

Patients with COL4A4 variants and those with missense mutations had significantly better renal survival, whereas those with COL4A3 variants and those with hearing loss had worse prognoses.

Characteristics and prognosis of acute renal failure on dialysis in ANCA vasculitis

Renal involvement in ANCA (Anti Neutrophil Cytoplasmic Antigen) vasculitis is common and is associated with increased mortality with a significant risk of progression to end-stage renal disease. The aim of this study is to investigate the epidemiological, clinicopathological, therapeutic and evolutionary characteristics of patients with ANCA vasculitis with acute renal injury, and to evaluate the impact of haemodialysis in the acute phase on mortality and renal recovery. Secondary objectives are to investigate other risk factors that impact on overall and renal survival. 31 patients were included ; the mean follow-up time was 30 months. The mean age was 68.52 years, and the sex ratio 0.72. All patients had acute renal failure, with histology revealing a mixed form in 45% of cases and a sclerotic form in 12.9% of cases. Pulmonary involvement was found in 58% of cases. 71% of patients had ANCA with anti-myeloperoxydase specificity, and 25.8% anti-proteinase 3 specificity. 32.2% of patients required haemodialysis, of which 60% were weaned. As initial treatment, 58.1% of patients received cyclophosphamide and 35.5% rituximab. The relapse rate was 6.5%. Infectious and cardiovascular complications affected more than half of the patients. The mortality rate was 19.35%. Comparing the two groups of patients dialysed in the acute phase and not dialysed, it appears that the overall and renal mortality was comparable. The progression to end-stage renal failure was higher in the dialysis patients. In a multivariate study, the presence of chronic kidney disease in the history and pulmonary involvement were associated with higher mortality.

Circulating alternative pathway complement cleavage factor Bb is associated with vascular lesions and outcomes in IgA nephropathy

BACKGROUND

Complement alternative pathway (AP) activation is linked to immunoglobulin A nephropathy (IgAN) prognosis severity, but Bb fragment's role is unclear. We examined the relationship between serum Bb fragment concentration at IgAN diagnosis and disease activity and outcomes.

METHODS

This retrospective study included 125 biopsy-proven IgAN patients [age 39.9 years, 75% male, estimated glomerular filtration rate (eGFR) 82 ml/min, proteinuria 0.5 g/day] enrolled from 1984 to 2010 and followed for a minimum of 18 months. Monitoring continued until the last follow-up, end-stage kidney disease (ESKD) or death. Serum Bb fragment was measured using an enzyme-linked immunosorbent assay at diagnosis. Oxford classification and global optical score (GOS) were utilized for pathology assessment.

RESULTS

Patients were followed for a median of 16 years; 42% developed chronic kidney disease stage ≥3, 19% reached ESKD and 9% died. Serum Bb fragment concentration negatively correlated with eGFR values at the last follow-up and positively with vascular and tubular histopathological indices. In univariate Cox regression analyses, higher Bb fragment concentration was associated with ESKD alongside older age, increased body mass index, arterial hypertension, lower eGFR, higher proteinuria, E1, S1, T1-2, GOS and corticotherapy. Patients with Bb levels ≥14.3 μg/ml had shorter mean kidney survival time (19.5 versus 22.7 years, P = .07); after adjusting for progression risk factors, the association persisted [hazard ratio 4.76 (95% confidence interval 1.56-14.43)].

CONCLUSIONS

Serum Bb fragment concentration at diagnosis may predict long-term IgAN outcomes, potentially due to AP activation at the endothelial surface. Further research is needed to confirm these results and evaluate Bb fragment's role in IgAN management.

Prognostic value of complement serum C3 level and glomerular C3 deposits in anti-glomerular basement membrane disease

Background and objectives

Activation of the complement system is involved in the pathogenesis of anti-glomerular basement membrane (anti-GBM) disease. Glomerular deposits of complement 3 (C3) are often detected on kidney biopsies. The primary objective of this study was to analyze the prognostic value of the serum C3 level and the presence of C3 glomerular deposits in patients with anti-GBM disease.

Methods

We conducted a retrospective cohort study of 150 single-positive patients with anti-GBM disease diagnosed between 1997 and 2017. Patients were categorized according to the serum C3 level (forming a low C3 (C3<1.23 g/L) and a high C3 (C3≥1.23 g/L) groups) and positivity for C3 glomerular staining (forming the C3+ and C3- groups). The main outcomes were kidney survival and patient survival.

Results

Of the 150 patients included, 89 (65%) were men. The median [interquartile range (IQR)] age was 45 [26-64]. At diagnosis, kidney involvement was characterized by a median [IQR] peak serum creatinine (SCr) level of 578 [298-977] µmol/L, and 106 (71%) patients required dialysis. Patients in the low C3 group (72 patients) had more severe kidney disease at presentation, as characterized by higher prevalences of oligoanuria, peak SCr ≥500 µmol/L (69%, vs. 53% in the high C3 group; p=0.03), nephrotic syndrome (42%, vs. 24%, respectively; p=0.02) and fibrous forms on the kidney biopsy (21%, vs. 8%, respectively; p=0.04). Similarly, we observed a negative association between the presence of C3 glomerular deposits (in 52 (41%) patients) and the prevalence of cellular forms (83%, vs. 58% in the C3- group; p=0.003) and acute tubulo-interstitial lesions (60%, vs. 36% in the C3- group; p=0.007). When considering patients not on dialysis at diagnosis, the kidney survival rate at 12 months was poorer in the C3+ group (50% [25-76], vs. 91% [78-100] in the C3- group; p=0.01), with a hazard ratio [95% confidence interval] of 5.71 [1.13-28.85] (p=0.04, after adjusting for SCr).

Conclusion

In patients with anti-GBM disease, a low serum C3 level and the presence of C3 glomerular deposits were associated with more severe disease and histological kidney involvement at diagnosis. In patients not on dialysis at diagnosis, the presence of C3 deposits was associated with worse kidney survival.

Predicting kidney outcomes among Latin American patients with lupus nephritis: The prognostic value of interstitial fibrosis and tubular atrophy and tubulointerstitial inflammation

OBJECTIVE

To assess the effect of tubulointerstitial inflammation (TII) and interstitial fibrosis and tubular atrophy (IFTA) on kidney survival in lupus nephritis (LN).

METHODS

Two hundred eighty five patients with biopsy-proven LN were retrospectively studied. Kidney survival was defined as the time from initial biopsy to end-stage kidney disease (ESKD), dialysis, or transplant. Kidney survival analysis was performed by the Kaplan-Meier method and the statistical difference between survival curves compared by the log-rank test. Cumulative incidence functions with competing risk of death for kidney survival were also graphed. Multivariable Cox proportional hazards regression and competing-risk analyses were performed to identify independent predictors of ESKD.

RESULTS

Fifty-seven patients (20%) progressed to ESKD during a median time of 4.2 (2.0-55.2) months after biopsy. TII was present in 206 (72.3%) biopsies, while IFTA in 99 (34.7%) biopsies. Patients with moderate-to-severe IFTA had worse kidney survival than those with none or mild IFTA in both the Kaplan-Meier (p = 0.018) and the competing-risk analyses (p = 0.017). Patients with class IV ± V LN had worse kidney survival than those with non-class IV LN by the Kaplan-Meier method (p = 0.050), but not in the competing-risk analysis (p = 0.154). Worse kidney survival was also found among those with fibrous crescents than those without, in both the Kaplan-Meier (p = 0.010) and the competing-risk (p = 0.011) analyses. By multivariable Cox regression analysis, older age (HR 1.04, 95% CI 1.01-1.07) and class IV ± V LN (HR 5.06, 95% CI 1.82-14.09) were associated with higher risk of ESKD after adjusting for sex, ethnicity, TII, and IFTA. By competing-risk analyses, class IV ± V LN (SHR 3.32, 95% CI 1.25-8.83) and no response to immunosuppressive therapy (SHR 4.55, 95% CI 1.54-13.41) were associated with a higher risk of ESKD, while eGFR >90 mL/min/1.73 m² (SHR 0.98 for each ml/min/1.73 m², 95% 0.97-0.99) with a lower risk.

CONCLUSIONS

Patients with moderate-to-severe IFTA had worse kidney survival than those with none or mild IFTA. Worse kidney survival was also found among those with class IV LN and fibrous crescents versus those without IV LN and fibrous crescents, respectively.

Negative anti-phospholipase A2 receptor antibody status at three months predicts remission in primary membranous nephropathy

Background

The value of anti-phospholipase A2 receptor antibody (anti-PLA2R ab) monitoring at 3 months after diagnosis in membranous nephropathy (MN) remains uncertain.

Methods

We retrospectively examined the outcome on 1 August 2020 of 59 adult patients (age 54 (44, 68) years, 69% male, SCr 1.0 (0.9, 1.3) mg/dL) diagnosed with MN (kidney biopsy, positive serum anti-PLA2R ab). The outcomes were: kidney survival; partial and/or complete remission.

Results

Most of the studied patients (97%) received immunosuppression, cyclophosphamide regimens were the most frequent (87%), followed by cyclosporine (10%). The median time to remission was 12.0 months and the cumulative remission rates were 34% at 6, 54% at 12, and 73% at 24 months. Forty (69%) patients had negative anti-PLA2R ab at 3 months, they had similar age, serum creatinine, albumin, proteinuria, and treatment with the group with positive ab at 3 months. In the Cox proportional hazard model, three months anti-PLA2R ab negativization (HR 0.4 (95%CI 0.1, 0.9)) was an independent predictor for remission, while baseline hypoalbuminemia (HR 3.0 (95%CI 1.5, 5.7)) was associated with absence of remission. Six (10%) patients died, mostly due to cardiovascular disease and infections. A total of five (9%) patients started dialysis. Mean kidney survival time was 50.3 months and there was no survival difference in relation to baseline anti-PLA2R ab titer (p .09) or 3 months negativization (p .8).

Conclusions

Three months anti-PLA2R ab negativization seems to be a late predictor of remission, and lower serum albumin at diagnosis is an early marker for remission absence. Abbreviations: anti-P LA2R ab, anti-phospholipase A2 receptor antibody; eGFR, estimated glomerular filtration rate; ESKD, end stage kidney disease; MN, membranous nephropathy; NELL-1, neural epidermal growth factor-like 1 protein; RAAS: renin–angiotensin–aldosterone system; RBC: red blood cells; RRT, renal replacement therapy; T HSD7A, thrombospondin type-1 domain containing 7A

Hypovitaminosis D Is Prevalent in Patients With Renal AL Amyloidosis and Associated With Renal Outcome

INTRODUCTION

Vitamin D deficiency is common, but no data have been reported on vitamin D levels in light chain (AL) amyloidosis.

PATIENTS AND METHODS

In this exploratory study, stored serum samples from 173 patients with newly diagnosed AL amyloidosis were analyzed for vitamin studies which included 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)₂D] and vitamin D binding protein (DBP). Measurements were made by liquid chromatography-tandem mass spectrometry. Kidney survival and overall survival (OS) were assessed in association to vitamin D status.

RESULTS

Cardiac and kidney involvement occurred in 69% and 63% of patients, respectively. 25(OH)D deficiency (<20 ng/mL) was seen in 56.6% of the patients and was notably found among patients with heavy proteinuria (96%), hypoalbuminemia (84.3%) and morbidly obese patients (68.3%). Heavy proteinuria (>5 gr/24-h) and vitamin D supplementation were independent predictors of 25(OH)D level on nominal multivariate regression analysis. 1,25(0H)₂D deficiency was noted in 37.6% of patients and was independently associated with low eGFR and hypoalbuminemia. Progression to ESRD occurred in 23.7% of evaluable patients. Patients who progressed to ESRD had lower serum 25(OH)D and 1,25(OH)₂D levels compared to those who did not progress to ESRD. On a multivariate analysis, severe 25(OH)D deficiency was an independent predictor of progression to ESRD as was renal stage, while 1,25(OH)₂D deficiency was not.

CONCLUSIONS

Hypovitaminosis D is common in AL amyloidosis, particularly among patients with heavy proteinuria. Severe 25(OH)D deficiency at time of diagnosis predicts progression to ESRD.

Inflammation-based modified Glasgow prognostic score and renal outcome in chronic kidney disease patients: is there a relationship?

BACKGROUND

Chronic kidney disease (CKD) progression is presumably related to inflammatory response. The modified Glasgow prognostic score (mGPS), based on combination between albumin and C-reactive protein, has been derived from oncology and validated in multiple diseases.

AIMS

We aimed to evaluate the relationship between the mGPS and CKD progression.

METHODS

The present retrospective unicentric cohort study included 547 CKD patients (age 60.2 years, 53% male, eGFR 42.0 mL/min, mean change -2 mL/min/year) admitted between January 1, 2007 and December 31, 2012. Patients records were reviewed from the CKD diagnosis to one of the four outcomes: end-stage kidney disease (ESKD), death, loss to follow-up, or until July 31, 2017.

RESULTS

The mGPS score was 0 for 420 (78%), 1 for 110 (19%), and 2 for 17 (3%) patients. More patients with rapid CKD progression were found in the group with the highest mGPS (p=0.05). mGPS was negatively correlated with baseline eGFR and positively with albuminuria. In the multivariate analysis, mGPS was associated with the eGFR slope. During the study period, 130 patients (24%) died and 109 (20%) reached ESKD. The mean kidney survival time was 8.1 (95%CI 7.9 to 8.4) years. Patients with zero mGPS had better kidney survival than those with the score of one and two (Kaplan-Meier, p=0.02). However, the kidney survival differences were not present after adjusting for CKD progression risk factors.

CONCLUSION

The inflammation-based mGPS score was associated with eGFR decline in CKD patients. Therefore, could prove useful in improving risk stratification of CKD patients. This article is protected by copyright. All rights reserved.

Validation of a Histologic Scoring Index for C3 Glomerulopathy

RATIONALE & OBJECTIVE

A previous study that evaluated associations of kidney biopsy findings with disease progression in patients with C3 glomerulopathy (C3G) proposed a prognostic histologic index (C3G-HI) that has not yet been validated. Our objective was to validate the performance of the C3G-HI in a new patient population.

STUDY DESIGN

Multicenter, retrospective cohort study.

SETTING & PARTICIPANTS

111 patients fulfilling diagnostic criteria of C3G between January 1995 and December 2019, from 33 nephrology departments belonging to the Spanish Group for the Study of Glomerular Diseases (GLOSEN).

PREDICTORS

Demographic, clinical parameters, C3G-HI total activity score, and the C3G-HI total chronicity score.

OUTCOME

Time to kidney failure.

ANALYTICAL APPROACH

Intraclass correlation coefficients and κ statistic were used to summarize inter-rater reproducibility for assessment of histopathology in kidney biopsies. The nonlinear relationships of risk of kidney failure with the total activity score and total chronicity score were modeled using Cox proportional hazards analysis that incorporated cubic splines.

RESULTS

The study group included 93 patients with C3 glomerulonephritis and 18 with dense-deposit disease. Participants had an overall meanage of 35±22 (SD) years. Forty-eight patients (43%) developed kidney failure after a mean follow-up of 65±27 months. The overall inter-rater reproducibility was very good for the total activity score (intraclass correlation coefficient [ICC]=0.63) and excellent for total chronicity score (ICC=0.89). Baseline estimated glomerular filtration rate (eGFR), 24-hour proteinuria, and treatment with immunosuppression were the main determinants of kidney failure in a model with only clinical variables. Only tubular atrophy and interstitial fibrosis were identified as predictors in a model with histological variables. When the total activity score and total chronicity score were added to the model, only the latter was identified as an independent predictor of kidney failure.

LIMITATIONS

Only a subset of the kidney biopsies was centrally reviewed. Residual confounding.

CONCLUSIONS

We validated the performance of C3G-HI as a predictor of kidney failure in patients with C3G. The total chronicity score was the principal histologic correlate of kidney failure.

Tubular vesicopyelostomy for the management of types 2 and 3 (long-segment) ureteric stenosis after kidney transplantation

Late ureteral stenosis following kidney transplantation needs immediate correction in order to protect allograft function and requires a complicated surgical procedure. In this study, we present the long-term results of tubular bladder reconfiguration and cystopyelostomy (tubular vesicopyelostomy), an innovative and practical procedure for the management of long-segment ureteric stenosis (types 2 and 3) after transplantation. Between 2002 and 2017, 722 kidney transplant patients were monitored at the University of Medical Sciences, Bozyaka Organ Transplantation and Research Center. Twenty-eight of these patients underwent tubular vesicopyelostomy operation; 17 male and 11 female patients with a mean age of 45.6 ± 10.5 years. Time to surgical intervention for urinary tract obstruction was 122.5 ± 114.7 months. The mean serum creatinine values previous to and 3 days following the tubular vesicopyelostomy operation were 3.46 ± 1.5 mg/dL and 1.75 ± 0.7 mg/dL, respectively (p < 0.0001). Within a mean follow-up period of 55.1 ± 40.9 months, functional grafts were recorded in 22 patients with a mean serum creatinine value of 1.92 ± 0.8 mg/dL. Only one patient developed anastomotic stenosis after the tubular vesicopyelostomy procedure, giving an overall success rate for tubular vesicopyelostomy of 96.4%. Six patients returned to hemodialysis. In five, the underlying etiology was not related to recurrent obstruction or surgical complications. Sixteen patients underwent allograft biopsy after the operation, but features of tubulointerstitial nephritis were seen in only one. Tubular vesicopyelostomy operation is a safe and successful method for the surgical treatment of late and complicated ureteral obstructions with excellent long-term results. It may be a good, practical alternative to other more sophisticated surgical options.

Validation study of Oxford Classification of IgA Nephropathy: the significance of extracapillary hypercellularity and mesangial IgG immunostaining

The Oxford classification (OC) of IgA Nephropathy (IgAN) identified mesangial hypercellularity (M), endocapillary hypercellularity (E), segmental glomerulosclerosis (S), and tubular atrophy/interstitial fibrosis (T) as predictors of outcome. We aimed to validate the OC and to investigate the clinical significance of extracapillary hypercellularity and IgG immunostaining. We examined the renal outcome at December 31, 2014, of 121 adult patients with biopsy proven primary IgAN between 2003 and 2013. The primary endpoint was doubling of serum creatinine or renal replacement therapy initiation. The mean observation period was 59.7 months. Thirty-one percent of the patients presented with a grade of extracapillary hypercellularity. In comparison with the group with no crescents, they had higher grade of inflammation, lower eGFR and increased proteinuria. There were no differences between the IgA and IgA&IgG immunostaining groups regarding the disease progression risk factors. Mean kidney survival time for the entire cohort was 10.6 (9.1, 12.0) years. In the Cox regression model, the independent predictors of decreased renal survival were eGFR at time of biopsy, S1 and the presence of crescents. Our study showed that extracapillary proliferation and S1 had the greatest importance in establishing the renal prognosis of patients with IgAN.