Glomerular transcriptomics predicts long term outcome and identifies therapeutic strategies for patients with assumed benign IgA nephropathy

Some patients diagnosed with benign IgA nephropathy (IgAN) develop a progressive clinical course, not predictable by known clinical or histopathological parameters. To assess if gene expression can differentiate between progressors and non-progressors with assumed benign IgAN, we tested microdissected glomeruli from archival kidney biopsy sections from adult patients with stable clinical remission (21 non-progressors) or from 15 patients that had undergone clinical progression within a 25-year time frame. Based on 1 240 differentially expressed genes from patients with suitable sequencing results, we identified eight IgAN progressor and nine non-progressor genes using a two-component classifier. These genes, including APOL5 and ZXDC, predicted disease progression with 88% accuracy, 75% sensitivity and 100% specificity on average 21.6 years before progressive disease was clinically documented. APOL lipoproteins are associated with inflammation, autophagy and kidney disease while ZXDC is a zinc-finger transcription factor modulating adaptive immunity. Ten genes from our transcriptomics data overlapped with an external genome wide association study dataset, although the gene set enrichment test was not statistically significant. We also identified 45 drug targets in the DrugBank database, including angiotensinogen, a target of sparsentan (dual antagonist of the endothelin type A receptor and the angiotensin II type 1 receptor) currently investigated for IgAN treatment. Two validation cohorts were used for substantiating key results, one by immunohistochemistry and the other by nCounter technology. Thus, glomerular mRNA sequencing from diagnostic kidney biopsies from patients with assumed benign IgAN can differentiate between future progressors and non-progressors at the time of diagnosis.

Use of corticosteroids in Norwegian patients with immunoglobulin a nephropathy progressing to end-stage kidney disease: a retrospective cohort study

BACKGROUND

Despite several clinical trials, the use of corticosteroid therapy for treating immunoglobulin A nephropathy (IgAN) remains controversial. We aimed to describe the use of corticosteroid therapy combined with supportive therapy in Norwegian patients with IgAN who had progressed to end-stage kidney disease.

METHODS

We conducted a retrospective cohort study using data from the Norwegian Renal Registry. Overall, 143 patients with primary IgAN who progressed to end-stage kidney disease were divided into two groups: the corticosteroid group, who had been treated with corticosteroids and supportive therapy, and the non-corticosteroid group, which had underwent only supportive therapy. The kidney function, time to end-stage kidney disease, and adverse effects were described. The observation period lasted from the diagnostic kidney biopsy until the initiation of kidney replacement therapy.

RESULTS

Of the 143 included patients, 103 underwent supportive therapy alone, and 40 were treated with corticosteroids. Most patients (94%) were treated with renin-angiotensin-system blockade, and all patients reached end-stage kidney disease after a median of 5 years (interquartile range; 2-9 years). Time from diagnosis until end-stage kidney disease was similar in the two study groups (p = 0.98). During 6 months of corticosteroid therapy, median eGFR declined from 21 (interquartile range; 13-46) mL/min/1.73 m2 to 20 (interquartile range; 12-40) mL/min/1.73 m2, and median proteinuria decreased from 5.5 g/24 h to 3.0 g/24 h. Most patients (87.5%) treated with corticosteroids reported adverse events. In our linear regression analysis investigating the time to ESKD, we found that age (β = -0.079, p = 0.008) and proteinuria at diagnosis (β = -0.50, p = 0.01) exhibited statistically significant associations with a delay in the progression to ESKD.

CONCLUSIONS

In this cohort of Norwegian patients with IgAN, corticosteroid therapy did not affect the time from diagnosis until end-stage kidney disease among a cohort of patients who all reached end-stage kidney disease. The treatment was also associated with adverse effects.

Long-term follow-up of IgA nephropathy: clinicopathological features and predictors of outcomes

Background

The establishment of the Oxford classification and newly developed prediction models have improved the prognostic information for immunoglobulin A nephropathy (IgAN). Considering new treatment options, optimizing prognostic information and improving existing prediction models are favorable.

Methods

We used random forest survival analysis to select possible predictors of end-stage kidney disease among 37 candidate variables in a cohort of 232 patients with biopsy-proven IgAN retrieved from the Norwegian Kidney Biopsy Registry. The predictive value of variables with relative importance >5% was assessed using concordance statistics and the Akaike information criterion. Pearson's correlation coefficient was used to identify correlations between the selected variables.

Results

The median follow-up period was 13.7 years. An isolated analysis of histological variables identified six variables with relative importance >5%: T %, segmental glomerular sclerosis without characteristics associated with other subtypes (not otherwise specified, NOS), normal glomeruli, global sclerotic glomeruli, segmental adherence and perihilar glomerular sclerosis. When histopathological and clinical variables were combined, estimated glomerular filtration rate (eGFR), proteinuria and serum albumin were added to the list. T % showed a better prognostic value than tubular atrophy/interstitial fibrosis (T) lesions with C-indices at 0.74 and 0.67 and was highly correlated with eGFR. Analysis of the subtypes of segmental glomerulosclerosis (S) lesions revealed that NOS and perihilar glomerular sclerosis were associated with adverse outcomes.

Conclusions

Reporting T lesions as a continuous variable, normal glomeruli and subtypes of S lesions could provide clinicians with additional prognostic information and contribute to the improved performance of the Oxford classification and prognostic tools.

Antiglomerular Basement Membrane Disease Possibly Triggered by Undiagnosed Renal Cell Carcinoma: A Case Report

Antiglomerular basement membrane (anti-GBM) disease is a rare, small-vessel vasculitis that affects the capillary beds of the kidneys and lungs. Although exceedingly rare, several case reports have described anti-GBM disease with a concurrent cancer diagnosis, suggesting a possible correlation between these 2 conditions. Herein, we describe the first known case to our knowledge of a woman in her early 60s with simultaneous anti-GBM disease and clear cell renal cell carcinoma, in which the tumor was thought to have been the substrate for anti-GBM disease. We believe that renal cell carcinoma may have contributed to the production of anti-GBM autoantibodies and, thus, anti-GBM disease. The concurrence of these 2 conditions complicated the treatment of the patient, who was hemodialysis-dependent at the time of hospital discharge. This report highlights the importance of considering anti-GBM disease as a potential diagnosis in patients with acute kidney failure, and how important it is to identify both clear cell renal cell carcinoma and anti-GBM disease at an early stage to improve outcomes.

Validation of two IgA nephropathy risk-prediction tools using a cohort with a long follow-up

BACKGROUND

Recently, two immunoglobulin A nephropathy prediction tools were developed that combine clinical and histopathological parameters. The International IgAN Prediction Tool predicts the risk for 50% declines in the estimated glomerular filtration rate or end-stage renal disease up to 80 months after diagnosis. The IgA Nephropathy Clinical Decision Support System uses artificial neural networks to estimate the risk for end-stage renal disease. We aimed to externally validate both prediction tools using a Norwegian cohort with a long-term follow-up.

METHODS

We included 306 patients with biopsy-proven primary immunoglobulin A nephropathy in this study. Histopathologic samples were retrieved from the Norwegian Kidney Biopsy Registry and reclassified according to the Oxford classification. We used discrimination and calibration as principles for externally validating the prognostic models.

RESULTS

The median patient follow-up was 17.1 years. A cumulative dynamic time-dependent receiver operating characteristic analysis showed area under the curve values of ranging from 0.90 at 5 years to 0.83 at 20 years for the International IgAN Prediction Tool, while time-naive analysis showed an area under the curve value at 0.83 for the IgA Nephropathy Clinical Decision Support System. The International IgAN Prediction Tool was well calibrated, while the IgA Nephropathy Clinical Decision Support System tends to underestimate risk for patients with higher risk, and overestimates risk in the lower risk categories.

CONCLUSIONS

We have externally validated two prediction tools for IgA nephropathy. The International IgAN Prediction Tool performed well, while the IgA Nephropathy Clinical Decision Support System has some limitations.

MO268: Use of Corticosteroids in a Norwegian Cohort of Patients with IGA Nephropathy and Rapid Progression to End-Stage Renal Disease

BACKGROUND AND AIMS

Despite several clinical trials, treatment with corticosteroids in patients with Immunoglobulin A nephropathy (IgAN) remains controversial [1, 2]. The recently updated KDIGO guidelines suggests that treatment with corticosteroids could be considered in patients with persistent proteinuria above 0.75 to 1.0 g per day in patients with estimated glomerular filtration rate (eGFR) above 30 mL/min/1.73 m2 despite intensive supportive care [3]. This is a more liberal approach compared with the 2012 guidelines, which suggested that patients selected for treatment with steroids should have eGFR above 50 mL/min/1.73 m2 [4]. It could be valuable to identify clinicians decision on when to initiate immunosuppressive treatment, since this could have implication on how future therapeutics might be used in patients with IgAN [5]. Our aim is to describe the use of corticosteroids and evaluate the effect of this treatment using a Norwegian cohort of patients with IgAN.

METHOD

We identified patients with biopsy-proven IgAN from the Norwegian Kidney Biopsy Registry and the Norwegian Renal Registry, who all had progressed to end-stage renal disease (ESRD) and collected clinical, treatment and biochemical data from patient records.

RESULTS

A total of 151 patients with a diagnostic kidney biopsy performed between 1988 and 2010 were included. The median time from biopsy to ESRD was 5 years. A majority of 94% of the patients received supportive treatment with Renin–Angiotensin–Aldosterone System blockade. A total of 40 patients (27%) received treatment with corticosteroids, with a median eGFR and proteinuria at time of biopsy at 49.5 mL/min/1.73 m2 and 5.1 g per day, respectively. Median time from biopsy to steroid treatment was 12 months. Patients treated with corticosteroids had a significant decrease in proteinuria from 5.6 to 3 g per day (P = .02), but there was no difference in time to progression to ESRD between the two groups (P = .58). The vast majority (87.5%) of the patients treated with corticosteroids reported on adverse events.

CONCLUSION

We found that the use of corticosteroids had significant impact on proteinuria but did not delay progression to ESRD. Adverse events were common in patients treated with corticosteroids. The patients were treated according to the current guidelines

MO447: Glomerular Transcriptomics in IGA Nephropathy Differentiates Between Disease Progression and Stability in Low-Risk Patients After Prolonged Follow-Up

BACKGROUND AND AIMS

IgA nephropathy (IgAN) is the most common primary glomerulonephritis worldwide. We have previously shown that patients with assumed benign IgAN can develop progressive kidney failure, including end-stage kidney disease, after a sufficiently long follow-up period [1]. In the reported patient cohort [1], histological, clinical and laboratory findings at the time of diagnosis were unable to predict a subsequent stable or progressive disease course. Thus, we hypothesized that glomerular transcriptomics from the diagnostic kidney biopsy could help make this distinction.

METHOD

We included all progressive patients (n = 27) and patients with the stable or remitting disease (non-progressors, n = 42) from our previously reported cohort of adult patients with biopsy-proven and assumed benign IgAN (n = 192). Progression was defined as a ≥ 50% decline in eGFR from the diagnostic kidney biopsy, performed between 1988 and 1999 until follow-up examination [1]. The median follow-up time was 22 years. Glomerular cross-sections were obtained through laser-capture microdissection from archival kidney biopsy sections for RNA extraction and sequencing, using NovaSeq 6000 (Illumina, USA) at Functional Genomics Centre Zurich, Switzerland. Samples yielding insufficient sequencing quality were excluded, leaving n = 8 progressors and n = 9 non-progressors for analysis, using limma [2] and edgeR [3] in R Bioconductor.

RESULTS

In the first round of analysis, we identified 1818 differentially expressed genes (P ≤ 0.05, absolute fold change ≥ 2), of which 1562 genes were overrepresented in progressors and 256 genes were overrepresented in non-progressors. Principal component analysis and hierarchical cluster analysis revealed a separation between the two study groups, indicating that underlying transcriptomic differences are present many years prior to the overt manifestation of disease progression. Interestingly, in progressors, the nuclear factor-kappa B complex, linked to IgAN pathogenesis [4], was the most overabundant transcription factor and Fc Fragment of IgA Receptor (FCAR) was the most overrepresented differentially abundant mRNA. Ingenuity Pathway Analysis (Qiagen, USA) suggested an overrepresentation of the phagosome formation pathway (P = 3.09E-08, Z-score = 8.43), indicating phagosome activation in progressors, possibly a response to the observed FCAR overexpression. To identify potential markers for disease progression, we used an unsupervised K Nearest Neighbour analysis of 1818 differentially expressed genes, allowing combinations of ≤ 10 genes. A two-component classifier (APOL5 and ZXDC) performed best, classifying 15/17 samples correctly (sensitivity 75%, specificity 100%, accuracy 88.24%) on average 21 years prior to a manifested decrease in eGFR. Further refinements of the statistical analyses and confirmation studies are planned to substantiate our initial findings.

CONCLUSION

Glomerular mRNA sequencing performed at the time of diagnosis of assumed benign IgAN can differentiate between subsequent stable and progressive disease courses in the distant future. In our cohort, combining APOL5 and ZXDC can predict subsequent disease course with 88.24% accuracy already 21 years prior to the discovery of progression with conventional means.

Utilizing the MEST score for prognostic staging in IgA nephropathy

Background

The Oxford classification/MEST score is an established histopathologic scoring system for patients with IgA nephropathy (IgAN). The objective of this study was to derive a prognostic model for IgAN based on the MEST score and histopathologic features.

Methods

A total of 306 patients with biopsy-proven primary IgAN were included. Histopathologic samples were retrieved from the Norwegian Kidney Biopsy Registry and reclassified according to the Oxford classification. The study endpoint was end-stage renal disease (ESRD). Patients were subclassified into three risk models based on histologic features (Model A), a composite score calculated from the adjusted hazard ratio values (Model B), and on quartiles (Model C).

Results

The mean follow-up time was 16.5 years (range 0.2–28.1). In total, 61 (20%) patients reached ESRD during the study period. Univariate analysis of M, E, S, T and C lesions demonstrated that all types were associated with an increased risk of ESRD; however, a multivariate analysis revealed that only S, T and C lesions were associated with poor outcomes. Statistical analysis of 15-year data demonstrated that Models A and B were as predictive as the MEST score, with an area-under-the-curve at 0.85. The Harrel c index values were 0.81 and 0.80 for the MEST score and Models A and B, respectively. In the present cohort, adding C lesions to the MEST score did not improve the models prognostic value.

Conclusions

Patients can be divided into risk classes based on their MEST scores. Histopathologic data provide valuable prognostic information at the time of diagnosis. Model B was the most suitable for clinical practice because it was the most user-friendly.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02653-y.

A young woman with dyspnoea and proteinuria

BACKGROUND

Systemic lupus erythematosus and anti-phospholipid syndrome may cause severe haematological complications despite few other symptoms of disease.

CASE PRESENTATION

A previously healthy woman in her late twenties was admitted to hospital with chest pain and dyspnoea. CT of the thorax revealed bilateral pulmonary embolism and urine sampling showed haematuria and proteinuria. A few days after hospital admission, she developed transfusion-requiring anaemia. The investigation revealed a positive direct antiglobulin test, presence of anti-nuclear antibodies, lupus anticoagulant, anti-cardiolipin and anti-glycoprotein antibodies.

INTERPRETATION

Pulmonary embolism in a young, previously healthy woman may be caused by different predisposing conditions. Systemic lupus erythematosus with accompanying anti-phospholipid syndrome was the diagnosis in this case. Severe autoimmune haemolytic disease may occur as a secondary phenomenon to systemic lupus erythematosus, and the condition must not be overlooked.

Severe nephritis as initial sign of Waldenström's macroglobulinemia

Waldenström's macroglobulinemia (WM), characterized with monoclonal immunoglobulins of type M and lymphoplasmacytic lymphoma, is a rare clonal Bcell disorder. WM usually present as an indolent lymphoma, and renal involvement is, in contrast to multiple myeloma, very rarely seen. We present a patient presenting with severe nephritis and nephrotic range proteinuria of more than 9 g/day as initial manifestations of WM. Furthermore, we discuss diagnostic and therapeutic approaches for this rare manifestation of the disease, in the light of recent research and treatment recommendations.

Addition of eGFR and Age Improves the Prognostic Absolute Renal Risk-Model in 1,134 Norwegian Patients with IgA Nephropathy

BACKGROUND

Predicting outcome in individual patients with IgA nephropathy (IgAN) is difficult but important. For this purpose, the absolute renal risk (ARR) model has been developed in a French cohort to calculate the risk of end-stage renal disease (ESRD) and death. ARR (0-3) is scored in individual IgAN patients based on the presence of proteinuria ≥1 g/24 h, hypertension, and severe histopathological lesions (1 point per risk factor). We have validated the ARR model in a Norwegian cohort of IgAN patients and tested whether adding data on initial estimated glomerular filtration rate (eGFR) and age improved prediction.

METHODS

IgAN patients diagnosed between 1988 and 2012 were identified in the Norwegian Kidney Biopsy Registry, and endpoints were identified by record linkage with the Norwegian Renal Registry (ESRD) and the Population Registry (deaths).

RESULTS

We identified 1,134 IgAN patients. The mean duration of follow-up was 10.2 years (range 0.0 to 25.7 years). Two hundred and fifty one patients developed ESRD and there were 69 pre-ESRD deaths. The ARR model significantly stratified the IgAN cohort according to risk of ESRD/death. The inclusion of eGFR and age significantly improved the ARR prognostic model; in the receiver operator characteristics (ROC) analysis, area under the curve (AUC) at 10-years of follow-up increased from 0.79 to 0.89, p < 0.001.

CONCLUSIONS

ARR is a suitable prognostic model for stratifying IgAN patients according to the risk of ESRD or death. Including initial eGFR and age in the model substantially improved its accuracy in our nationwide cohort.

Improved prognosis in Norwegian patients with glomerulonephritis associated with anti-neutrophil cytoplasmic antibodies

Background

Glomerulonephritis associated with anti-neutrophil cytoplasmic antibodies (ANCA) is associated with increased mortality and a high risk of end-stage renal disease (ESRD). Here, we investigated whether the prognosis has improved over the last 25 years.

Methods

Patients were identified in the Norwegian Kidney Biopsy Registry. We included all patients with pauci-immune crescentic glomerulonephritis and a positive ANCA test from 1988 to 2012. Deaths and ESRD in the cohort were identified through record linkage with the Norwegian Population Registry (deaths) and the Norwegian Renal Registry (ESRD). Outcomes of patients diagnosed in 1988–2002 were compared with outcomes of patients diagnosed in 2003–12.

Results

A cohort of 455 patients with ANCA-associated glomerulonephritis was identified. The mean follow-up was 6.0 years (range, 0.0–23.4). During the study period, 165 (36%) patients died and 124 (27%) progressed to ESRD. Compared with patients diagnosed in 1988–2002, those diagnosed in 2003–12 had higher mean initial estimated glomerular filtration rates (37 versus 27 mL/min/1.73 m²) and lower risk of ESRD (1-year risk: 13 versus 19%; 10-year risk: 26 versus 37%). The composite endpoint, ESRD or death within 0–1 year after diagnosis, was reduced from 34 to 25%. In patients over 60 years old, 1-year mortality fell from 33 to 20%.

Conclusions

In Norwegian patients with ANCA-associated glomerulonephritis, prognosis was significantly better in 2003–12 compared with 1988–2002. This improvement was probably partly due to a shorter diagnostic delay, and better therapeutic management in older patients.

Mortality in patients with IgA nephropathy

BACKGROUND

Immunoglobulin A nephropathy (IgAN) is the most common glomerulonephritis globally. Few studies have investigated mortality in patients with IgAN compared with the age- and sex-adjusted general population.

STUDY DESIGN

Cohort study with record linkage between the Norwegian Kidney Biopsy Registry, Norwegian Cause of Death Registry, and Norwegian Renal Registry.

SETTING & PARTICIPANTS

633 patients diagnosed with IgAN in 1988-2004.

PREDICTOR

Estimated glomerular filtration rate (eGFR), age, and sex.

OUTCOMES

Deaths and causes of death before and after the onset of end-stage renal disease through 2008.

RESULTS

Mean follow-up was 11.8 (range, 0-20.8) years. During the observation period, the observed number of deaths was 80 and the expected number was 42.1, resulting in a standardized mortality ratio (SMR) of 1.9 (95% CI, 1.5-2.4). Risk stratification based on initial eGFR showed that SMR was 1.0 (95% CI, 0.6-1.6) if eGFR was ≥60 mL/min/1.73 m(2), 1.9 (95% CI, 1.3-2.8) if eGFR was 30-60 mL/min/1.73 m(2), and 3.6 (95% CI, 2.6-5.0) in patients with eGFR <30 mL/min/1.73 m(2). Renal replacement therapy (RRT) was initiated in 146 patients and 35 of the 80 deaths occurred after the start of RRT. The age- and sex-adjusted SMR was not increased significantly in the pre-RRT period (1.3; 95% CI, 1.0-1.7), but was increased after initiation of RRT (4.9; 95% CI, 3.5-7.0). The most common cause of death was cardiovascular disease, accounting for 45% of all deaths.

LIMITATIONS

Treatment during follow-up is not known.

CONCLUSIONS

Mortality in patients with IgAN was twice the expected rate, but not significantly increased before RRT. The risk of end-stage renal disease was substantially higher than risk of death.

Educational and psychosocial issues related to new treatment advances for metastatic breast cancer

OBJECTIVES

To explore educational issues as well as psychosocial issues relating to finances, family, and hope that may arise with the introduction of new treatment strategies for metastatic breast cancer.

DATA SOURCES

Review articles, textbooks, and personal communications.

CONCLUSIONS

New treatment advances in metastatic breast cancer are multifaceted and complex. Nurses must provide a holistic approach to patients and are in an excellent position to guide patients towards treatment advances.

IMPLICATIONS FOR NURSING PRACTICE

Patients look to nurses to provide answers and to serve as resources as new treatment advances develop.

Cardiac tamponade

OBJECTIVES

To review the oncologic emergency of cardiac tamponade through a case study presentation/analysis and a discussion of the pathophysiology, diagnosis, treatment, and nursing management.

DATA SOURCES

Research studies, review articles, book chapters, abstracts, and clinical practice.

CONCLUSIONS

Cardiac tamponade is a potentially life-threatening condition that is not uncommon in the oncology setting. It can result directly from the malignant or metastatic process or from the treatment of the malignancy. Observation and prompt intervention are mandatory to deal effectively with cardiac tamponade.

IMPLICATIONS FOR NURSING PRACTICE

Oncology nurses play important roles in identifying patients at risk for cardiac tamponade and in recognizing signs and symptoms of cardiac tamponade early so this life-threatening emergency can be treated promptly.

The macrophage-induced gene mig as a marker for clinical pathogenicity and in vitro virulence of Mycobacterium avium complex strains

The capacity of 20 Mycobacterium avium complex isolates to multiply intracellularly in human monocyte-derived macrophages was assessed and correlated to the clinical relevance of each isolate and its reactivity with several candidate genetic virulence markers. The strongest correlation with a virulence phenotype was found for a conserved coding sequence of the macrophage-induced gene mig identified by a specific mig restriction fragment length polymorphism type.

Polycythemia vera

OBJECTIVES

To review the proliferative nature of polycythemia vera (PV), clinical features, laboratory findings, treatment options and controversies, and nursing management.

DATA SOURCES

Textbook chapters and review articles that pertain to polycythemia vera.

CONCLUSIONS

Polycythemia vera is a chronic myeloproliferative disorder that can evolve into acute leukemia. Treatment options include phlebotomy, myelosuppressive agents, interferon, and platelet inhibitors.

IMPLICATIONS FOR NURSING PRACTICE

Nursing management of the patient with PV is challenging because of the evolving nature of the disease and treatment-related complications. Close monitoring and compliance with the treatment plan is necessary.

Sudden idiopathic hearing loss: psychopathology and antecedent stressful life-events

Otologists repeatedly state that patients suffering from Sudden Idiopathic Hearing Loss (SIHL) often have significant emotional problems or stressful living conditions. The study described here compared males and females suffering from SIHL with controls without any impairment of the inner ear. Personality data were gathered by means of Faschingbauer's Abbreviated MMPI (FAM). Stress factors were assessed by an Inventory of Stressful Life-Events (ILE). SIHL patients reported more stressful life-events, whose distressing effects lasted until onset of symptoms, than controls. There was no significant influence of personality upon report of stress. Stress factors and inability to cope with these seem to be important psychological factors in SIHL patients, while psychopathological disturbances may be important for some but not for the majority of cases.