Analysis of clinical and laboratory characteristics and pathology of lupus nephritis-based on 710 renal biopsies in China

Changes in retinal and choroidal thickness and vascular density in patients with systemic lupus erythematosus: Assessed by optical coherence tomography angiography

OBJECTIVE

The aim was to investigate the changes in retinal and choroidal thickness and vascular density in patients with systemic lupus erythematosus (SLE) using optical coherence tomography angiography (OCTA).

METHODS

Twenty-nine patients with SLE (29 eyes) and 25 control subjects (25 eyes) were enrolled. SLE activity was assessed using the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Retinal thickness (RT), inner retinal thickness (IRT), outer retinal thickness (ORT), choroidal thickness (ChT), retinal superficial vascular density (SVD), retinal deep vascular density (DVD), choriocapillary vascular density (CCVD), foveal avascular zone (FAZ), superficial FAZ (sFAZ), and deep FAZ (dFAZ) were measured using OCTA. The retinal and choroidal thickness and vascular density between the control group and SLE group were compared. The relationships between SLEDAI scores and the retinal and choroidal thickness and vascular density in SLE group were analyzed.

RESULTS

The SVD was significantly increased, and the DVD and CCVD were significantly decreased in the SLE group compared to the control group (p < .05). The results of receiver operating characteristic (ROC) showed that the area under the curve (AUC) values of SVD, DVD, and CCVD were 0.873, 0.729, and 0.727, indicating a high accuracy in discriminating patients with SLE from controls. Correlation analysis showed that the SLEDAI scores were positively correlated with dFAZ (r = 0.589, p = .001) and FAZ (r = 0.451, p = .018), and negatively correlated with DVD (r = -0.491, p = .009) and CCVD (r = -0.521, p = .005).

CONCLUSIONS

DVD and CCVD were decreased in the SLE and might be related to the disease activity. SVD, DVD, and CCVD may hold promise in the discovery of biomarkers for diagnosing SLE.

Anti-C1q antibodies in lupus nephritis children with glomerular microthrombosis

AIM

Glomerular microthrombosis (GMT) was a common vascular lesion in patients with lupus nephritis (LN). The objective of this study was to investigate the relationship between serum anti-beta2-glycoprotein I antibodies (a-β2GP1) and anti-complement 1q antibodies (a-C1q) antibodies and to investigate the possible mechanism of GMT in children with LN.

METHODS

The subjects were 191 children with LN diagnosed by renal biopsy in our hospital from January 2017 to January 2020. The patients were divided into GMT group and non-GMT group. The clinical manifestations, laboratory tests, renal pathology, prognosis of the two groups and the relationship between a-β2GP1 and a-C1q antibodies were observed.

RESULTS

In 191 children with LN, 52 cases (27.23%) presented with GMT. The value of C3, haemoglobin (Hb), estimate glomerular filtration rate (eGFR) and anticardiolipin antibody (ACA) in GMT group were lower than that of non-GMT group (p < .05, p < .01). The value of serum creatinine (Scr), 24 h proteinuria (PRO), urine red blood cells (RBC), N-acetyl-β-d-glucosidase (NAG) and retinol-binding protein (RBP), a-C1q, a-β2GP1, Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) and renal histopathological activity index (AI) score in GMT group were higher than that of non-GMT group (p < .05, p < .01). The positive proportions of serum a-C1q and a-β2GP1 in GMT group were higher than those in non-GMT group (p < .05). According to Spearman correlation analysis, a-C1q was positively correlated with AI score, SLEDAI, a-β2GP1, GMT, LN-III and LN-IV. Hb, eGFR and a-C1q Ab were associated with the formation of GMT in children with LN. The complete proteinuria remission and renal survival in GMT group were significantly lower than those in non-GMT group (p < .05, p < .01).

CONCLUSION

LN children with GMT had more severe clinical manifestations and renal pathologic damages, and poor outcome. Serum a-C1q level was positively correlated with a-β2GP1, and a-β2GP1 may be involved in the formation of GMT in children with LN, which might involve in the activation of complement classical pathway.

Lupus nephritis or not? A simple and clinically friendly machine learning pipeline to help diagnosis of lupus nephritis

OBJECTIVE

Diagnosis of lupus nephritis (LN) is a complex process, which usually requires renal biopsy. We aim to establish a machine learning pipeline to help diagnosis of LN.

METHODS

A cohort of 681 systemic lupus erythematosus (SLE) patients without LN and 786 SLE patients with LN was established, and a total of 95 clinical, laboratory data and 17 meteorological indicators were collected. After tenfold cross-validation, the patients were divided into training set and test set. The features selected by collective feature selection method of mutual information (MI) and multisurf were used to construct the models of logistic regression, decision tree, random forest, naive Bayes, support vector machine (SVM), light gradient boosting (LGB), extreme gradient boosting (XGB), and artificial neural network (ANN), the models were compared and verified in post-analysis.

RESULTS

Collective feature selection method screens out antistreptolysin (ASO), retinol binding protein (RBP), lupus anticoagulant 1 (LA1), LA2, proteinuria and other features, and the hyperparameter optimized XGB (ROC: AUC = 0.995; PRC: AUC = 1.000, APS = 1.000; balance accuracy: 0.990) has the best performance, followed by LGB (ROC: AUC = 0.992; PRC: AUC = 0.997, APS = 0.977; balance accuracy: 0.957). The worst performance is naive Bayes model (ROC: AUC = 0.799; PRC: AUC = 0.822, APS = 0.823; balance accuracy: 0.693). In the composite feature importance bar plots, ASO, RF, Up/Ucr, and other features play important roles in LN.

CONCLUSION

We developed and validated a new and simple machine learning pathway for diagnosis of LN, especially the XGB model based on ASO, LA1, LA2, proteinuria, and other features screened out by collective feature selection.

Prevalence and Patterns of Renal Involvement Among Patients With Systemic Lupus Erythematous at a Tertiary Center

BACKGROUND

Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder characterized by widespread inflammation and damage to multiple organ systems. One of the most common and severe manifestations of SLE is lupus nephritis (LN).

OBJECTIVES

To determine the prevalence of LN among subjects with SLE and to identify the demographic, clinical, and laboratory parameters of SLE in subjects diagnosed with LN.

METHODS

This is a descriptive study conducted at a tertiary hospital. Medical records were reviewed from outpatients who visited between January 2015 and October 2019 and who has fulfilled the classification criteria for diagnosis of SLE and had LN.

RESULTS

Among 365 patients with SLE, 36% had LN. The most prevalent World Health Organization class of LN was IV, which significantly correlated with both abnormal creatinine levels and nephrotic range proteinuria. Elevated serum creatinine correlated with the presence of hypertension and thrombocytopenia. Cutaneous manifestations were noted to be present in 100% of LN patients, followed by arthritis and/or arthralgia (82.9%), anemia (94.6%), and lymphopenia (87.6%).

CONCLUSION

This study aids in the recognition of the demographic, clinical, laboratory features, and the histological patterns of LN patients in Saudi Arabia, that probably has a role in the development and disease progression. A significant correlation was found between abnormal kidney function and hypertension, thrombocytopenia and nephrotic range proteinuria. The presence of World Health Organization class IV LN correlated with both impaired kidney function and nephrotic range proteinuria.

Sex differences in systemic lupus erythematosus (SLE): an inception cohort of the Chinese SLE Treatment and Research Group (CSTAR) registry XVII

BACKGROUND

The onset and clinical presentation of systemic lupus erythematosus (SLE) are sex-related. Few studies have investigated the distinctions in clinical characteristics and treatment preferences in male and female SLE patients in the initial cohort. This study aimed to improve the understanding of Chinese SLE patients by characterizing the different sexes of SLE patients in the inception cohort.

METHODS

Based on the initial patient cohort established by the Chinese SLE Treatment and Research Group, a total of 8713 patients (795 men and 7918 women) with newly diagnosed SLE were enrolled between April 2009 and March 2021. Of these, 2900 patients (347 men and 2553 women) were eligible for lupus nephritis (LN). A cross-sectional analysis of the baseline demographic characteristics, clinical manifestations, laboratory parameters, organ damage, initial treatment regimens, and renal pathology classification was performed according to sex.

RESULTS

In the SLE group, as compared to female patients, male patients had a later age of onset (male vs. female: 37.0 ± 15.8 years vs. 35.1 ± 13.7 years, P  = 0.006) and a higher SLE International Collaborative Clinic/American College of Rheumatology damage index score (male vs. female: 0.47 ± 1.13 vs. 0.34 ± 0.81, P  = 0.015), LN (male vs. female: 43.6% vs. 32.2%, P < 0.001), fever (male vs. female: 18.0% vs. 14.6%, P  = 0.010), thrombocytopenia (male vs. female: 21.4% vs. 18.5%, P  = 0.050), serositis (male vs. female: 14.7% vs. 11.7%, P  = 0.013), renal damage (male vs. female: 11.1% vs. 7.4%, P < 0.001), and treatment with cyclophosphamide (CYC) (P < 0.001). The frequency of leukopenia (male vs. female: 20.5% vs. 25.4%, P  = 0.002) and arthritis (male vs. female: 22.0% vs. 29.9%, P < 0.001) was less in male patients with SLE. In LN, no differences were observed in disease duration, SLE Disease Activity Index score, renal biopsy pathological typing, or 24-h urine protein quantification among the sexes. In comparisons with female patients with LN, male patients had later onset ages (P  = 0.026), high serum creatinine (P < 0.001), higher end-stage renal failure rates (P  = 0.002), musculoskeletal damage (P  = 0.023), cardiovascular impairment (P  = 0.009), and CYC use (P  = 0.001); while leukopenia (P  = 0.017), arthritis (P  = 0.014), and mycophenolate usage (P  = 0.013) rates were lower.

CONCLUSIONS

Male SLE patients had more severe organ damage and a higher LN incidence compared with female SLE patients; therefore, they may require more aggressive initial treatment compared to female patients.

Lupus nephritis diagnosis using enhanced moth flame algorithm with support vector machines

Systemic lupus erythematosus is a chronic autoimmune disease that affects the kidney in most patients. Lupus nephritis (LN) is divided into six categories by the International Society of Nephrology/Renal Pathology Society (ISN/RPS). The purpose of this research is to build a framework for discriminating between ISN/RPS pure class V(MLN) and classes III ± V or IV ± V (PLN) using real clinical data. The framework is developed by merging a hybrid stochastic optimizer, moth-flame algorithm (HMFO), with a support vector machine (SVM), dubbed HMFO-SVM. The HMFO is constructed by enhancing the original moth-flame algorithm (MFO) with a bee-foraging learning operator, which guarantees that the algorithm speeds convergence and departs from the local optimum. The HMFO is used to optimize parameters and select features simultaneously for SVM on clinical SLE data. On 23 benchmark tests, the suggested HMFO method is validated. Finally, clinical data from LN patients are analyzed to determine the efficacy of HMFO-SVM over other SVM rivals. The statistical findings indicate that all measures have predictive capabilities and that the suggested HMFO-SVM is more stable for analyzing systemic LN. HMFO-SVM may be used to analyze LN as a feasible computer-assisted technique.

Exploring the Differences in Molecular Mechanisms and Key Biomarkers Between Membranous Nephropathy and Lupus Nephritis Using Integrated Bioinformatics Analysis

Background: Both membranous nephropathy (MN) and lupus nephritis (LN) are autoimmune kidney disease. In recent years, with the deepening of research, some similarities have been found in the pathogenesis of these two diseases. However, the mechanism of their interrelationship is not clear. The purpose of this study was to investigate the differences in molecular mechanisms and key biomarkers between MN and LN. Method: The expression profiles of GSE99325, GSE99339, GSE104948 and GSE104954 were downloaded from GEO database, and the differentially expressed genes (DEGs) of MN and LN samples were obtained. We used Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) for enrichment analysis of DEGs. A protein-protein interaction (PPI) network of DEGs was constructed using Metascape. We filtered DEGs with NetworkAnalyst. Finally, we used receiver operating characteristic (ROC) analysis to identify the most significant DEGs for MN and LN. Result: Compared with LN in the glomerulus, 14 DEGs were up-regulated and 77 DEGs were down-regulated in MN. Compared with LN in renal tubules, 21 DEGs were down-regulated, but no up-regulated genes were found in MN. According to the result of GO and KEGG enrichment, PPI network and Networkanalyst, we screened out six genes (IFI6, MX1, XAF1, HERC6, IFI44L, IFI44). Interestingly, among PLA2R, THSD7A and NELL1, which are the target antigens of podocyte in MN, the expression level of NELL1 in MN glomerulus is significantly higher than that of LN, while there is no significant difference in the expression level of PLA2R and THSD7A. Conclusion: Our study provides new insights into the pathogenesis of MN and LN by analyzing the differences in gene expression levels between MN and LN kidney samples, and is expected to be used to prepare an animal model of MN that is more similar to human.

Retinal Microvasculature and Conjunctival Vessel Alterations in Patients With Systemic Lupus Erythematosus-An Optical Coherence Tomography Angiography Study

Purpose: To evaluate the conjunctival and fundus retinal vessel density in patients with systemic lupus erythematosus (SLE) with optical coherence tomography angiography (OCTA), and to investigate the relationship between vessel density and clinical indicators.

Methods: Twelve patients with SLE (24 eyes) and 12 healthy controls (24 eyes) were recruited. OCTA was used to examine the superficial retina layer (SRL) and deep retina layer (DRL) in the macular retina and conjunctival capillary plexus of each eye. We calculated the density of the temporal conjunctival vessels, fundus microvascular (MIR), macrovascular (MAR) and total MIR(TMI) and compared the results in both groups. We used annular partitioning (C1–C6), hemispheric quadrants, and Early Treatment Diabetic Retinopathy Study partitioning (ETDRS) to analyze changes in the retinal vascular density. Correlation analysis was used to investigate the association between blood capillary density and clinical indicators.

Results: OCTA results showed significant differences in the conjunctival microvascular density (p < 0.001). There was no significant difference in MIR, TMI, and MAR in the superficial layers between the SLE and healthy group (p > 0.05). The DRL and DTMI (Deeper TMI) densities were decreased in the macular regions of SLE patients (p < 0.05). In the hemispheric segmentation analysis, the superficial MIR was significantly decreased in the IL (inferior left) region of the SLE patients (p < 0.05), and the deep MIR in the IR (inferior right) region was significantly reduced (p < 0.05). In the ETDRS partitioning analysis, the superficial MIR in the inferior, right, and left subdivisions was significantly decreased in the SLE patients (p < 0.05). In the circular segmentation analysis, the deep MIR in the C1 and C3 regions was significantly reduced in SLE patients (p < 0.05), while the superficial MIR density was decreased only in the C3 region (p < 0.05). The conjunctival vascular density was negatively correlated with the STMI (Superficial TMI) (r = −0.5107; p = 0.0108) and DTMI (r = −0.9418, p < 0.0001). There was no significant correlation between vascular density and SLEDAI-2k (Systemic Lupus Erythematosus Disease Activity Index−2000) (P > 0.05).

Conclusion: Clinically, patients with SLE and patients suspected of SLE should receive OCTA examination in a comprehensive eye examination to detect changes in ocular microcirculation at an early stage.

Changing trends in presentation and indications of biopsy in lupus nephritis: data from the Spanish Registry of Glomerulonephritis

Background

With the ageing population and changes in the indications of diagnostic and protocol biopsies in systemic lupus erythematosus in recent years, an impact on the incidence and presentation of lupus nephritis (LN) is expected. The aim of this study was to analyse the epidemiological changes regarding clinical and histological presentation of LN in kidney biopsies performed from 1994 to 2019 included in the Spanish Registry of Glomerulonephritis.

Methods

We analysed data from 28 791 kidney biopsies from 130 Spanish hospitals comparing demographic, clinical and histological data. We divided the cohort according to the age of onset of LN into pediatric onset (<18 years), adult onset (18–50 years) and late onset (>50 years).

Results

The incidence of LN has decreased from 9.6% of all kidney biopsies in the period 1994–2013 to 7% in the last quarter of the observation period (2014–2019) (P < 0.001), despite an increase in the proportion of patients with LN that underwent repeat biopsies (16.6–24%; P < 0.001). The age of onset of LN has increased from 32 ± 14 to 38 ± 14 years (P < 0.001), with an increase in the proportion of late-onset LN (from 13% to 22% of incident LN; P < 0.001). There were no differences in the distribution of histological features at presentation over the study period. Patients with late-onset LN showed fewer gender differences, had lower GFR and presented with less-proliferative forms of LN compared with early-onset LN.

Conclusions

The frequency of biopsy-proven LN has been decreasing in recent years, despite an increasing number of repeat biopsies. Late-onset LN is increasing, presenting with worse kidney function but fewer proliferative lesions compared with younger-onset LN.