Lupus Nephritis Risk Factors and Biomarkers: An Update

Serum antineutrophil cytoplasmic antibody positivity at the time of renal biopsy is associated with disease activity of lupus nephritis

OBJECTIVE

To investigate the correlations between serum antineutrophil cytoplasmic antibody (ANCA) and clinicopathological features, induction treatment response, and prognosis of lupus nephritis (LN) patients.

METHODS

In this retrospective study, biopsy-proven LN patients from October 2010 to September 2020 were tested for serum ANCA by indirect immunofluorescence and ELISA and were divided into ANCA-positive group and ANCA-negative group. The clinicopathological data of the two groups were analyzed and compared.

RESULTS

Thirty-five of 115 patients (30.43%) were seropositive for ANCA. ANCA-positive patients had significantly higher systemic lupus erythematosus activity index and activity index scores, higher 24-h urinary protein, and lower complement three levels (p = 0.001, 0.028, 0.023, 0.009, respectively). The incidences of oral ulcers, thrombocytopenia, and leukocyturia, and the positive rates of anti-dsDNA antibody and anti-histone antibody were significantly higher in ANCA-positive group (p = 0.006, 0.019, 0.012, 0.001, 0.019, respectively). Class IV LN and fibrinoid necrosis/karyorrhexis were significantly more common in the ANCA-positive group (p = 0.027, 0.002). There was no significant difference in the total remission rate of ANCA-positive patients receiving cyclophosphamide and mycophenolate mofetil as induction therapies (83.33% vs. 66.67%, p > 0.05), while patients receiving cyclophosphamide as induction therapy had a higher total remission rate than those receiving other immunosuppressants (83.33% vs. 20%, p = 0.028).

CONCLUSIONS

LN patients with ANCA seropositivity at renal biopsy have a significantly higher disease activity, and their pathological manifestations are predominantly proliferative LN. These patients require a more active immunosuppressive therapy with cyclophosphamide or mycophenolate mofetil to improve their remission rate.

PM2.5 constituents associated with mortality and kidney failure in childhood-onset lupus nephritis: A 19-year cohort study

BACKGROUND

Childhood-onset lupus nephritis (cLN) is a severe form of systemic lupus erythematosus (SLE) with high morbidity and mortality. The impact of long-term exposure to fine particulate matter (PM2.5) on adverse outcomes in cLN remains unclear.

METHODS

We combined a 19-years cLN cohort from seven provinces in China with high-resolution PM2.5 dataset from 2001 to 2020, investigating the association between long-term exposure to PM2.5 and its constituents (sulfate, nitrate, organic matter, black carbon, ammonium) with the risk of death and kidney failure, analyzed with multiple variables Cox models. We also evaluated the association between 3-year average PM2.5 exposure before study entry and baseline SLE disease activity index (SLEDAI) scores using linear regression models.

RESULTS

Each 10 μg/m3 increase in annual average PM2.5 exposure was associated with an increased risk of death and kidney failure (HR = 1.58, 95 % CI: 1.24-2.02). Black carbon showed the strongest association (HR = 2.14, 95 % CI: 1.47-3.12). Higher 3-year average exposures to PM2.5 and its constituents were significantly associated with higher baseline SLEDAI scores.

CONCLUSIONS

These findings highlight the significant role of environmental pollutants in cLN progression and emphasize the need for strategies to mitigate exposure to harmful PM2.5 constituents, particularly in vulnerable pediatric populations.

Association between a single-nucleotide polymorphism of the angiotensin-converting enzyme gene and susceptibility to systemic lupus erythematosus in the Hainanese population of China

The angiotensin-converting enzyme (ACE) gene plays a significant role in regulating immune responses and inflammatory processes, thus impacting the susceptibility to systemic lupus erythematosus (SLE). Understanding how single-nucleotide polymorphisms (SNPs) within the ACE gene contribute to the genetic susceptibility to SLE is essential for comprehending the disease's aetiology. Therefore, exploring this relationship in the Hainan region of China is crucial for gaining insights into the pathogenesis of SLE. This study comprised 428 participants, including 214 SLE patients and 214 healthy controls. Clinical data were gathered, and blood samples were collected. Genotyping of three SNPs (rs4459609, rs4309, rs1987692) within the ACE gene was performed using SNaPshot technology. The frequencies of alleles and genotypes of these three SNPs were compared between the SLE and control groups. Combining different genetic models and haplotype analysis, the correlation between ACE gene polymorphisms and SLE was investigated. Both study groups exhibited conformity with the Hardy-Weinberg genetic equilibrium (p > .05). Significant differences were observed in the genotype frequency distributions of ACE genes rs4459609, rs4309 and rs1987692 between the SLE and control groups (p = .009, .008, .032, respectively). The frequency of allele T at rs4309 was significantly higher in the SLE group than in the control group, correlating significantly with increased SLE risk (odds ratio [OR] = 1.527, 95% confidence interval [CI] = 1.147-2.035). Associations among ACE rs4459609, rs4309 and rs1987692 polymorphisms and increased susceptibility to SLE were found under co-dominant and dominant models (p < .05, with OR values and 95% CI greater than 1). Linkage disequilibrium was observed among rs4459609, rs4309 and rs1987692, and haplotype analysis revealed a significantly higher frequency of the CCA haplotype in the control group compared to the SLE group (p < .001). The ACA and ATA haplotypes showed significantly higher frequencies in the SLE group than in the control group (p = .014, p = .013, respectively). ACE gene polymorphisms are associated with the genetic susceptibility to SLE. The AC and AA genotypes at the rs4459609 locus, the TT genotype and T allele at the rs4309 locus and the AC and CC genotypes at the rs1987692 locus may serve as risk factors for the development of SLE.

Attainment of EULAR/ERA-EDTA targets of therapy with current immunosuppressive regimens and adjustments in treatment: a multicentre, real-life observational study

OBJECTIVE

To estimate real-life European Alliance of Associations for Rheumatology (EULAR)/European Renal Association (ERA)-European Dialysis and Transplantation Association (EDTA) response rates and predictors for no response in patients with lupus nephritis (LN) managed with conventional immunosuppressive therapies.

METHODS

Ambidirectional cohort study of patients with new-onset LN (period 2014-to date). Response rates in the first year were calculated, and all treatment modifications were recorded. Univariate and multivariate regression analyses were performed to assess determinants of failure to respond at 12 months.

RESULTS

140 patients were included (81.4% women, median (IQR) age at LN diagnosis 38 (22) years). Among them, 32.1% presented with nephrotic range proteinuria, 28.6% with glomerular filtration rate <60 mL/min, 76.6% had proliferative and 19.7% class V LN. Initial treatment consisted of cyclophosphamide in 51.4% of patients (84.7% high-dose, 15.3% low-dose) and mycophenolate in 32.1%. 120 patients had available data at 12 months. EULAR/ERA-EDTA renal response rates at 3, 6 and 12 months were achieved by 72.6%, 78.5% % and 69.2% of patients, respectively. In multivariate analysis, increased Chronicity Index at baseline was associated with failure to achieve either complete or partial response at 12 months (OR 2.26, 95% CI 1.35 to 3.77). Notably, 20% of patients required treatment modifications due to suboptimal response during the first 12 months, with the addition of or switch to a different immunosuppressive drug in seven and nine patients, respectively.

CONCLUSIONS

More than two-thirds of patients with LN attain EULAR/ERA-EDTA response rates by 12 months, but 20% require therapy modifications within this time period. Patients with increased chronicity in baseline biopsy, when combined with histological activity, are at higher risk for a lack of clinical response.

[Risk factors and prognosis of pediatric silent lupus nephritis with class Ⅲ to Ⅴ]

OBJECTIVES

To study the risk factors and prognostic characteristics of pediatric silent lupus nephritis (SLN) with class Ⅲ to V.

METHODS

A retrospective study was conducted to collect clinical data from 30 children diagnosed with SLN at the Department of Pediatrics, Second Xiangya Hospital, Central South University, from May 2007 to April 2023. Based on renal pathological classification, the patients were divided into a class Ⅱ group (12 cases) and a class Ⅲ to Ⅴ group (18 cases). The risk factors for the occurrence of class Ⅲ to Ⅴ SLN were analyzed, and the prognostic characteristics were summarized.

RESULTS

Among the 30 SLN patients, the median follow-up time was 61.50 months. There were no statistically significant differences in the proportions of patients who discontinued glucocorticoids or achieved low disease activity status, nor in the annual decline rate of estimated glomerular filtration rate (eGFR) between the class Ⅱ and class Ⅲ to V groups (P>0.05). However, three patients in the class Ⅱ group progressed to stage 1 chronic kidney disease (CKD), while eight patients in the class III to V group reached stage 1 CKD, and four patients reached stage 2 CKD. Among the 26 female SLN patients, serum complement C3 levels in the class III to V group were lower than those in the class Ⅱ group (P<0.05). Serum C3 levels in SLN patients, as well as in female SLN patients, were negatively correlated with the fluorescence intensity of IgA, IgG, and C3 immune complexes in the kidneys (P<0.05). Additionally, serum C3 levels in female SLN patients were negatively correlated with the renal pathological activity index (P<0.05). Binary logistic regression analysis indicated that being female and having low serum complement C3 levels were risk factors for the occurrence of class Ⅲ to V SLN in children (P<0.05).

CONCLUSIONS

Class Ⅲ to V SLN is not uncommon among SLN children, and there remains a risk of long-term renal function progression. Being female and having low serum complement C3 levels are identified as risk factors for class Ⅲ to V SLN in children.

Testosterone deficiency and chronic kidney disease

Testosterone's biological functions are extensive, influencing reproductive and systemic health. It plays a vital role in sexual functions, muscle protein synthesis, bone metabolism, fat distribution, and cardiovascular health. The hormone also affects mood, cognitive function, and erythropoiesis, underscoring its importance in both physical and mental health. Testosterone deficiency, or male male hypogonadism, is increasingly recognized as a significant health issue affecting various bodily systems, also in the context of chronic kidney disease (CKD). Recent research indicates a complex interplay between testosterone levels and renal health, suggesting that male male hypogonadism may both impact and be impacted by CKD. The latter is characterized by a gradual loss of kidney function, affects millions globally and is often associated with diabetes mellitus, arterial hypertension, and autoimmune diseases. Men with CKD frequently experience lower testosterone levels, which can exacerbate muscle wasting, reduce quality of life, and increase cardiovascular risk. Overall, low testosterone levels in CKD patients are associated with increased morbidity and mortality. Several mechanisms explain the relationship between CKD and testosterone deficiency. The uremic environment in CKD disrupts the hypothalamic-pituitary-gonadal axis, impairing hormone production. Nutritional deficiencies and chronic inflammation common in CKD patients further suppress gonadal function. The consequences of low testosterone in CKD are profound, with studies suggesting that testosterone replacement therapy (TRT) might improve clinical outcomes, though the long-term effects and causal relationships remain under investigation. The potential benefits of TRT in CKD patients might be significant. TRT can enhance muscle mass and strength, address anemia by stimulating erythropoiesis, improve bone density, and possibly offer cardiovascular benefits by improving body composition and insulin sensitivity. General symptoms of male hypogonadism, such as deteriorated psychological, sexual and physical wellbeing, can be improved by TRT. However, these benefits must be weighed against potential risks. TRT may exacerbate fluid retention, arterial hypertension, or exacerbate existing heart failure, particularly in CKD patients with pre-existing cardiovascular comorbidities. Additionally, concerns about the progression of renal disease via several testosterone affected pathways involving renal tubular integrity exist, highlighting the need for careful patient selection and monitoring. Understanding this relationship is crucial for developing comprehensive treatment strategies that address both renal and endocrine dysfunctions, highlighting the need for integrated patient care, which means good collaboration between subspecialists like nephrologists, endocrinologists, urologists and primary care providers, aiming to improve outcomes and quality of life while mitigating adverse effects.

Anti-Smith Antibodies as a Predictive Factor for Developing Lupus Nephritis in Systemic Lupus Erythematosus Patients: A Systematic Review

Lupus nephritis (LN) is the most frequent and lethal complication of systemic lupus erythematosus (SLE), often presenting with subtle or no initial symptoms. Therefore, it is crucial to identify SLE patients who are at risk of developing LN to ensure they receive timely intervention. Significant scientific efforts have been made to identify various genes and antibodies that could increase the risk of LN. Our objective is to review the role of anti-Smith antibodies in this disease and evaluate their potential as a predictive marker for LN. This review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. We searched for different study types from 2019 onwards as per our inclusion and exclusion criteria, to look for the significance of anti-Smith antibodies. The following databases were used: PubMed, PMC, Google Scholar, Science Direct, and Scopus. Twenty-two studies were checked for eligibility, of which 17 studies passed, based on the commonly used quality assessment tool for each of the corresponding studies. The study results indicated that anti-Smith antibodies are highly specific for SLE and are part of its classification criteria. In addition, we observed that positive titers correlate with disease activity. The presence of anti-Smith antibodies is influenced by ethnicity being most common among Black patients. However, the data regarding their effectiveness as a predictive marker for LN is not fully established. A more sensitive investigation and larger cohorts on diverse ethnic populations could provide a definitive answer regarding the role of anti-Smith antibodies in LN, highlighting the need for additional research.

Clinical and laboratory characteristics of early-onset and delayed-onset lupus nephritis patients: A single-center retrospective study

BACKGROUND

Lupus nephritis (LN) manifests systemic lupus erythematosus (SLE) and is characterized by various clinical and laboratory features. This study aimed to comprehensively evaluate the characteristics of LN patients according to the time of LN diagnosis: early-onset (LN diagnosed within one year from SLE diagnosis) vs. delayed-onset (LN diagnosed more than one year after SLE diagnosis).

METHODS

We conducted a retrospective analysis of medical records from all SLE patients treated at the University Hospital in Kraków, Poland, from 2012 to 2022. We collected data on demographic, clinical, and laboratory characteristics, including histological findings, treatment modalities, and disease outcomes. Statistical analyses were performed to identify factors impacting LN development and prognosis.

RESULTS

Among 331 LN patients, early-onset was diagnosed in 207 (62.54%) and delayed-onset was documented in 122 cases (36.86%). In 2 (0.6%) LN cases, the time of first kidney manifestation in the SLE course was unknown. Delayed-onset LN had a higher female-to-male ratio and younger age at SLE diagnosis. This group was associated with more severe clinical manifestations. In turn, studied subgroups did not differ in internist comorbidities, kidney histopathology, and family history regarding autoimmune diseases. Delayed-onset LN exhibited a higher frequency of anti-dsDNA, anti-Smith, anti-Ro, anti-RNP, and anti-cardiolipin IgG autoantibodies. During a 14-year follow-up period, 16 patients died. Mortality rate and causes of death were comparable in both analyzed subgroups.

CONCLUSIONS

More severe clinical manifestations in delayed-onset LN prompt strict monitoring of non-LN SLE patients to diagnose and treat kidney involvement early. Also, recognizing the higher frequency of autoantibodies such as anti-dsDNA or anti-Smith in delayed-onset LN underscores the potential value of autoantibody profiling as a diagnostic and prognostic tool.

[Update on lupus nephritis]

In addition to the butterfly rash, lupus nephritis is the most specific manifestation of systemic lupus erythematosus (SLE). The perspective on this organ manifestation has fundamentally changed as well as the manifestation of SLE itself 40 years after the first multicenter clinical study on lupus nephritis. Even if there is a faint glimpse of hope of a cure, there is still the fight against the problem of nonresponders and also the progressive loss of organ function. This update gives an overview of the current importance of lupus nephritis in the context of the whole SLE disease, of the special features and on the options provided by the new diagnostic and therapeutic developments.

Advancing Point-of-Care Diagnosis: Digitalizing Combinatorial Biomarker Signals for Lupus Nephritis

To improve the efficiency and patient coverage of the current healthcare system, user-friendly novel homecare devices are urgently needed. In this work, we developed a smartphone-based analyzing and reporting system (SBARS) for biomarker detection in lupus nephritis (LN). This system offers a cost-effective alternative to traditional, expensive large equipment in signal detection and quantification. This innovative approach involves using a portable and affordable microscopic reader to capture biomarker signals. Through smartphone-based image processing techniques, the intensity of each biomarker signal is analyzed. This system exhibited comparable performance to a commercial Genepix scanner in the detection of two potential novel biomarkers of LN, VISG4 and TNFRSF1b. Importantly, this smartphone-based analyzing and reporting system allows for discriminating LN patients with active renal disease from healthy controls with the area-under-the-curve (AUC) value = 0.9 for TNFRSF1b and 1.0 for VSIG4, respectively, indicating high predictive accuracy.

Clinico-serological associations of urinary activated leukocyte cell adhesion molecule in systemic lupus erythematosus and lupus nephritis

BACKGROUND

Lupus nephritis (LN) is one of the major complications associated with Systemic Lupus Erythematosus (SLE). Activated leukocyte cell adhesion molecule (ALCAM or CD166) is a promising urine biomarker that binds to CD6, a receptor found on lymphocytes. This binding results in T-cell activation, proliferation, and recruitment, which causes tissue inflammation and may explain the pathophysiology of LN.

AIM OF WORK

Investigate the urinary ALCAM level in SLE, study its relationship to disease activity, and clarify the association with LN activity and histopathology.

PATIENTS AND METHODS

A case-control study was performed on 60 patients with SLE and 20 matched controls. The SLE disease activity index (SLEDAI) and the activity of renal disease (rSLEDAI) were evaluated. Renal biopsy and uALCAM levels were also investigated.

RESULTS

Urinary ALCAM levels were higher significantly in active LN patients than inactive LN patients, active and inactive non-LN SLE, and the control group (p < 0.001). The cut-off value for identifying active and inactive LN was above 270 ng/mg (p < 0.001). ALCAM levels were greater in proliferative (class III, IV, and IV/V) than in non-proliferative (class II and V) LN (p < 0.001). ALCAM exhibited high positive correlations with SLEDAI and rSLEDAI (p < 0.001 each) and negative significant correlations with C3 (p < 0.001) and C4 (p = 0.005).

CONCLUSION

Urinary ALCAM is a sensitive biomarker evaluating LN in SLE patients. Levels above 270 ng/mg can help distinguish between active and inactive LN. ALCAM levels are correlated positively with SLEDAI and rSLEDAI but have a negative correlation with C3 and C4. Key Points • Urinary ALCAM shows promise as a biomarker for evaluating kidney dysfunction in SLE patients. • It is a non-invasive marker that can differentiate between proliferative and non-proliferative LN. • A urinary ALCAM level above 270 ng/mg can indicate active LN, while lower levels indicate inactive LN. • Urinary ALCAM levels are correlated positively with SLEDAI and rSLEDAI scores but correlated negatively with C3 and C4.

Immune and molecular landscape behind non-response to Mycophenolate Mofetil and Azathioprine in lupus nephritis therapy

Lupus nephritis (LN) represents one of the most severe complications of systemic lupus erythematosus, leading to end-stage kidney disease in worst cases. Current first-line therapies for LN, including mycophenolate mofetil (MMF) and azathioprine (AZA), fail to induce long-term remission in 60-70% of the patients, evidencing the urgent need to delve into the molecular knowledge-gap behind the non-response to these therapies. A longitudinal cohort of treated LN patients including clinical, cellular and transcriptomic data, was analyzed. Gene-expression signatures behind non-response to different drugs were revealed by differential expression analysis. Drug-specific non-response mechanisms and cell proportion differences were identified. Blood cell subsets mediating non-response were described using single-cell RNASeq data. We show that AZA and MMF non-response implicates different cells and regulatory functions. Mechanistic models were used to suggest add-on therapies to improve their current performance. Our results provide new insights into the molecular mechanisms associated with treatment failures in LN.

Impact of imlifidase treatment on immunoglobulins in an HLA-hypersensitized lupus nephritis patient with anti-SSA/SSB antibodies after kidney transplantation: A case report

Bacterial recombinant cysteine protease Ides (imlifidase, Idefirix®, Hansa Biopharma) is used to prevent humoral transplant rejection in highly HLA-sensitized recipients, and to control IgG-mediated autoimmune diseases. We report the case of a 51 years old woman suffering from lupus nephritis with end stage kidney disease, grafted for the second time and pre-treated with imlifidase. The patient was HLA-hypersensitized (calculated Panel Reactive Antibodies [Abs], cPRA>99 %) and has three preformed Donor Specific Antibodies (DSA). Circulating immunoglobulins were monitored at initiation (0, 6, 36, 72 and 96 h), and at Ab recovery one and two months following imlifidase injection. From baseline, the higher depletion was reported after 36h for total IgG (-75 %) and IgG subclasses (-87 % for IgG1, IgG2 and IgG3, -78 % for IgG4), while no significant impact on IgA and IgM was observed. Anti-SSA 60 kDa and anti-SSB auto-Abs quickly decreased after imlifidase injection (-96 % for both after 36 h) as well as post-vaccinal specific IgG (-95 % for tetanus toxoid, -97 % for pneumococcus and -91 % for Haemophilus influenzae Abs after 36 h). At the Ab recovery phase, total IgG and anti-SSA60/SSB Abs reached their initial level at two months. Regarding alloreactive Abs, anti-HLA Abs including the three DSA showed a dramatic decrease after injection with 100 % depletion from baseline after 36 h as assessed by multiplex single bead antigen assay, leading to negative crossmatches using both lymphocytotoxicity (LCT) and flow cell techniques. DSA rebound at recovery was absent and remained under the positivity threshold (MFI = 1000) after 6 months. The findings from this case report are that imlifidase exerts an early depleting effect on all circulating IgG, while IgG recovery may depend in part from imlifidase's capacity to target memory B cells.