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.

Duplex Vertical-Flow Rapid Tests for Point-of-Care Detection of Anti-dsDNA and Anti-Nuclear Autoantibodies.

The goal of this study is to develop a rapid diagnostic test for rheumatic disease and systemic lupus erythematosus (SLE) screening. A novel rapid vertical flow assay (VFA) was engineered and used to assay anti-nuclear (ANA) and anti-dsDNA (αDNA) autoantibodies from systemic lupus erythematosus (SLE) patients and healthy controls (HCs). Observer scores and absolute signal intensities from the VFA were validated via ELISA. The rapid point-of-care VFA test that was engineered demonstrated a limit of detection of 0.5 IU/mL for ANA and αDNA autoantibodies in human plasma with an inter-operator CV of 19% for ANA and 12% for αDNA. Storage stability was verified over a three-month period. When testing anti-dsDNA and ANA levels in SLE and HC serum samples, the duplex VFA revealed 95% sensitivity, 72% specificity and an 84% ROC AUC value in discriminating disease groups, comparable to the gold standard, ELISA. The rapid αDNA/ANA duplex VFA can potentially be used in primary care clinics for evaluating patients or at-risk subjects for rheumatic diseases and for planning follow-up testing. Given its low cost, ease, and rapid turnaround, it can also be used to assess SLE prevalence estimates.

Physiological principles underlying the kidney targeting of renal nanomedicines.

Kidney disease affects more than 10% of the global population and is associated with considerable morbidity and mortality, highlighting a need for new therapeutic options. Engineered nanoparticles for the treatment of kidney diseases (renal nanomedicines) represent one such option, enabling the delivery of targeted therapeutics to specific regions of the kidney. Although they are underdeveloped compared with nanomedicines for diseases such as cancer, findings from preclinical studies suggest that renal nanomedicines may hold promise. However, the physiological principles that govern the in vivo transport and interactions of renal nanomedicines differ from those of cancer nanomedicines, and thus a comprehensive understanding of these principles is needed to design nanomedicines that effectively and specifically target the kidney while ensuring biosafety in their future clinical translation. Herein, we summarize the current understanding of factors that influence the glomerular filtration, tubular uptake, tubular secretion and extrusion of nanoparticles, including size and charge dependency, and the role of specific transporters and processes such as endocytosis. We also describe how the transport and uptake of nanoparticles is altered by kidney disease and discuss strategic approaches by which nanoparticles may be harnessed for the detection and treatment of a variety of kidney diseases.

Proximity extension assay proteomics and renal single cell transcriptomics uncover novel urinary biomarkers for active lupus nephritis.

OBJECTIVE: To identify urinary biomarkers that can distinguish active renal involvement in Lupus Nephritis (LN), a severe manifestation of systemic lupus erythematosus (SLE). METHODS: Urine from 117 subjects, comprised of inactive SLE, active non-renal lupus, active LN, and healthy controls, were subjected to Proximity Extension Assay (PEA) based comprehensive proteomics followed by ELISA validation in an independent, ethnically diverse cohort. Proteomic data is also cross-referenced to renal transcriptomic data to elucidate cellular origins of biomarkers. RESULTS: Systems biology analyses revealed progressive activation of cytokine signaling, chemokine activity and coagulation pathways, with worsening renal disease. In addition to validating 30 previously reported biomarkers, this study uncovers several novel candidates. Following ELISA validation in an independent cohort of different ethnicity, the six most discriminatory biomarkers for active LN were urinary ICAM-2, FABP4, FASLG, IGFBP-2, SELE and TNFSF13B/BAFF, with ROC AUC ≥80%, with most correlating strongly with clinical disease activity. Transcriptomic analyses of LN kidneys mapped the likely origin of these proteins to intra-renal myeloid cells (CXCL16, IL-1RT2, TNFSF13B/BAFF), T/NK cells (FASLG), leukocytes (ICAM2) and endothelial cells (SELE). CONCLUSION: In addition to confirming the diagnostic potential of urine ALCAM, CD163, MCP1, SELL, ICAM1, VCAM1, NGAL and TWEAK for active LN, this study adds urine ICAM-2, FABP4, FASLG, IGFBP-2, SELE, and TNFSF13B/BAFF as additional markers that warrant systematic validation in larger cross-sectional and longitudinal cohorts.

Corrigendum: Urine L-selectin reflects clinical and histological renal disease activity and treatment response in lupus nephritis across multi-ethnicity.

[This corrects the article DOI: 10.3389/fimmu.2023.1200167.].

Urine L-selectin reflects clinical and histological renal disease activity and treatment response in lupus nephritis across multi-ethnicity.

Objective: There is an urgent need for novel biomarkers in lupus nephritis (LN). We report a non-invasive urinary biomarker, L-selectin, in two independent multi-ethnic cohorts. Methods: uL-selectin was tested cross-sectionally in a Chinese cohort (n=255) and a US cohort (n=219) of SLE patients and controls using ELISA. A longitudinal cohort includes 20 active Chinese LN patients. Results: uL-selectin was significantly increased in active LN patients compared to active non-renal SLE, inactive LN, inactive non-renal SLE, chronic kidney disease patients, and healthy controls. uL-selectin positively correlated with global and renal disease activities as well as histological activity index and chronicity index (CI). Low uL-selectin was an independent predictor for high CI. During follow-up, uL-selectin levels decreased significantly in the complete renal remission group. Conclusion: uL-selectin is a novel biomarker of disease activity and renal histopathology in LN across multiple ethnicities. It also reflects treatment response in LN patients during follow up.

Rare case of Ralstonia mannitolilytica peritonitis in an adult peritoneal dialysis patient.

Peritonitis is a common complication of peritoneal dialysis (PD) usually caused by skin-dwelling Gram-positive bacteria and Gram-negative bacteria colonizing the gut and urinary tract. Occasionally, uncommon bacteria can cause peritonitis in PD patients. We describe a case of Ralstonia mannitolilytica peritonitis in a 67-year-old woman who has been on PD for more than 10 years with no prior episodes of peritonitis. To our knowledge, this is the first reported case of Ralstonia peritonitis in the United States. She initially presented with abdominal tenderness, right flank pain, and cloudy output from her nephrostomy tube. PD fluid and urine cultures grew E. coli which responded to treatment. However, her symptoms recurred after completion of antibiotic therapy with PD fluid growing Ralstonia species. She again responded to intraperitoneal antibiotics but had recurrence of symptoms after the completion of her second course of antibiotics. PD fluid grew Ralstonia mannitolilytica resistant to the prior antibiotic regimen. The PD catheter was removed, and she was transitioned to hemodialysis. Subsequent treatment led to the resolution of her symptoms. Ralstonia species are Gram-negative bacteria that are prevalent in water supplies and can form biofilms. They have been known to cause infection particularly in neonates, immunocompromised patients, or patients in intensive care. In our patient, prior antibiotic treatment for E. coli peritonitis is likely to have contributed to the development of Ralstonia peritonitis. Clinical improvement after removal of the PD catheter revealed that seeding from the PD catheter was the likely culprit for the recurrent infections.

V-Set Immunoglobulin Domain-Containing Protein 4 as a Novel Serum Biomarker of Lupus Nephritis and Renal Pathology Activity.

OBJECTIVE: To discover novel serum biomarkers that have diagnostic or predictive value in lupus nephritis (LN). METHODS: Using a quantitative protein microarray, we screened for high-abundant proteome expression in the serum of patients with LN compared to healthy controls. Top candidates from this screening were validated using a larger cohort of patients with LN compared to a disease control cohort (subjects with other chronic kidney diseases) and a healthy control cohort. Promising markers were then selected using a machine-learning model and further validated with a larger patient cohort. The corresponding autoantibodies and immune complexes containing these proteins were also examined. RESULTS: In total, 13 proteins were found to be significantly elevated in LN patient serum in the screening, among which 8 proteins were validated by enzyme-linked immunosorbent assay using 81 serum samples from LN patients and control subjects. Three serum markers with LN diagnostic potential were identified using feature importance analysis and further validated using 155 serum samples from LN patients and control subjects. V-set immunoglobulin domain-containing protein 4 (VSIG4) appeared to be the most promising marker in distinguishing LN from healthy controls, with an area under the curve of 0.93. VSIG4 could also discriminate active LN from inactive LN. Furthermore, serum VSIG4 levels were positively correlated with all of the following clinical parameters: the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) score (Spearman's rank correlation rs = 0.42, P < 0.001), the renal domain score of the SLEDAI (rs = 0.46, P < 0.001), the urinary protein-to-creatinine ratio (rs = 0.56, P < 0.001), and the serum creatinine level (rs = 0.41, P < 0.001). Importantly, we found that serum VSIG4 levels tracked with LN disease activity longitudinally, and that serum VSIG4 levels reflected the renal pathology activity index (AI), particularly the AI components of crescent formation and hyaline deposits. CONCLUSION: VSIG4 may be a promising novel serum biomarker and therapeutic target in patients with LN.

Late onset granulomatous interstitial nephritis after booster dose of COVID-19 vaccination: Case report and review of literature.

Billions of doses of COVID-19 vaccine have been administered to combat the coronavirus pandemic. Though the vaccine is generally well tolerated, several cases of new onset or relapsing glomerulonephritis have been reported. In comparison, post-vaccination tubulointerstitial nephritis (TIN) has rarely been reported, mostly after the first or the second dose of the vaccine. Acute interstitial nephritis after booster dose of COVID-19 vaccination has not yet been reported. We report a case of acute granulomatous TIN shortly after the booster dose of Moderna vaccine. Our patient had no clinical evidence of renal injury after the first two doses of vaccine. Renal dysfunction was incidentally observed ~ 1 month after the booster dose of vaccine. The patient responded to steroids with rapid improvement in kidney function. While it is difficult to ascertain the causal relationship between the vaccination and development of TIN, it is important to be vigilant about such delayed side effects of the vaccine.

Treatment of lupus nephritis: consensus, evidence and perspectives.

Despite the continuing development of immunomodulatory agents and supportive care, the prognosis associated with lupus nephritis (LN) has not improved substantially in the past decade, with end-stage kidney disease still developing in 5-30% of patients within 10 years of LN diagnosis. Moreover, inter-ethnic variation in the tolerance of, clinical response to and level of evidence regarding various therapeutic regimens for LN has led to variation in treatment prioritization in different international recommendations. Modalities that better preserve kidney function and reduce the toxicities of concomitant glucocorticoids are unmet needs in the development of therapeutics for LN. In addition to the conventional recommended therapies for LN, there are newly approved treatments as well as investigational drugs in the pipeline, including the newer generation calcineurin inhibitors and biologic agents. In view of the heterogeneity of LN in terms of clinical presentation and prognosis, the choice of therapies depends on a number of clinical considerations. Molecular profiling, gene-signature fingerprints and urine proteomic panels might enhance the accuracy of patient stratification for treatment personalization in the future.

Comprehensive Urinomic Identification of Protein Alternatives to Creatinine Normalization for Diagnostic Assessment of Lupus Nephritis.

Introduction: The current gold standard used for urine biomarker normalization, creatinine, poses a challenge to translate to the point of care because antibodies to creatinine are difficult to develop and currently available ligands to creatinine are sub-optimal for this purpose. Hence, protein alternatives to creatinine are clearly needed. To address this need, lupus nephritis was selected as a model disease where urine protein assessment is required for diagnosis. Methods: A comprehensive proteomic screen of 1129 proteins in healthy and lupus nephritis urine was executed to identify protein alternatives to creatinine for the normalization of urine biomarkers. Urinary proteins that correlated well with creatinine but did not vary with disease were further validated by ELISA in an independent cohort of lupus nephritis subjects. Results: The comprehensive proteomic screen identified 14 urine proteins that correlated significantly with urine creatinine but did not differ significantly between SLE and controls. Of the top five proteins selected for ELISA validation, urine HVEM and RELT once again showed significant correlation with urine creatinine in independent cohorts. Normalizing a lupus nephritis biomarker candidate ALCAM using urinary HVEM demonstrated comparable diagnostic ability to creatinine normalization when distinguishing active lupus nephritis from inactive SLE patients. Conclusions: The discovery of urine HVEM as a protein alternative to creatinine for biomarker normalization has applications in the engineering of antibody-based point of care diagnostics for monitoring lupus nephritis progression.

Discovery of Novel Circulating Immune Complexes in Lupus Nephritis Using Immunoproteomics.

Objective: The goal is to discover novel circulating immune complexes (ICx) in the serum of lupus nephritis (LN) as potential biomarkers. Methods: Protein A/G magnetic beads or C1q-coated plates were used to capture ICx in the serum of LN, followed by the identification of immunoglobulin-binding proteins using liquid chromatography and tandem mass spectrometry (LC-MS/MS). Bioinformatic approaches and single-cell RNA sequencing (scRNA Seq) databases were used to select potential candidate ICx markers in LN. The selected ICx markers were further validated using ELISA. Results: A total of 300 immunoglobulin-binding proteins were discovered in the screening, among which 77 proteins were detectable only in LN samples. Bioinformatics-assisted selection allowed us to further identify 10 potential immunoglobulin-binding proteins, which form ICx as potential biomarkers in LN. In a validation cohort of 62 LN patients and 21 healthy controls (HC), we found that prolyl 3-hydroxylase 1 (P3H1), phosphatase and actin regulator 4 (PHACTR4), and regulator of G-protein signaling 12 (RGS12) ICx exhibited discriminative capability in distinguishing LN from HC, with an area under the curve (AUC) values of 0.82, 0.99, and 0.90, respectively. Furthermore, a biomarker panel comprising CD14, CD34, cystatin A, myocyte enhancer factor 2C (MEF2C), RGS12, and ubiquitin C (UBC) ICx could distinguish active LN from inactive LN with an AUC value of 0.85, which is comparable to or better than pathological parameters such as renal activity index (AI) and renal chronicity index (CI). Conclusion: Immunoproteomics-based discovery studies have enabled us to identify circulating immune complexes as potential biomarkers of LN.

De novo or recurrent glomerulonephritis and acute tubulointerstitial nephritis after COVID-19 vaccination: A report of six cases from a single center.

Billions of COVID-19 vaccine doses have been administered to combat the ongoing global pandemic caused by severe acute respiratory syndrome coronavirus-2. While these vaccines are considered safe, with most adverse events being mild to moderate and transient, uncommon systemic side effects of the vaccines, including de novo or re-activation of various glomerular diseases have recently been observed. We report 6 patients who developed glomerular or acute tubulointerstitial disease shortly after receiving COVID-19 vaccinations. Five of these patients received mRNA vaccines (3 Moderna, 2 Pfizer-BioNTech) and 1 received adenovirus-26 vector vaccine (Johnson and Johnson/Janssen). Four of our patients developed de novo glomerulonephritis or acute tubulointerstitial nephritis (ATIN), while the other 2 had re-activation of prior glomerulonephritis. Two patients presented with acute kidney injury (AKI) characterized by severe ATIN. While both of them also had evidence of immune complex glomerular disease, ATIN was the dominant feature on the biopsies. Two other patients presented with high-grade proteinuria and AKI. Like the aforementioned patients, these patients had evidence of immune complex glomerular disease, but acute onset nephrotic syndrome was the leading clinical feature. Another patient presented with de novo myeloperoxidase-anti-neutrophil-cytoplasmic-antibody-associated pauci-immune crescentic glomerulonephritis. Yet another patient had re-activation of immunoglobulin-A glomerulonephritis that had been quiescent for several years prior to the vaccination. It is difficult to ascertain any causal relationship between COVID-19 vaccination and onset/recurrence of kidney diseases. However, vigilance about occurrence of such complications is imperative. Importantly, all our cases responded well to the immunosuppressive treatment.

The CD6/ALCAM pathway promotes lupus nephritis via T cell-mediated responses.

T cells are central to the pathogenesis of lupus nephritis (LN), a common complication of systemic lupus erythematosus (SLE). CD6 and its ligand, activated leukocyte cell adhesion molecule (ALCAM), are involved in T cell activation and trafficking. Previously, we showed that soluble ALCAM is increased in urine (uALCAM) of patients with LN, suggesting that this pathway contributes to disease. To investigate, uALCAM was examined in 1038 patients with SLE and LN from 5 ethnically diverse cohorts; CD6 and ALCAM expression was assessed in LN kidney cells; and disease contribution was tested via antibody blockade of CD6 in murine models of SLE and acute glomerulonephritis. Extended cohort analysis offered resounding validation of uALCAM as a biomarker that distinguishes active renal involvement in SLE, irrespective of ethnicity. ALCAM was expressed by renal structural cells whereas CD6 expression was exclusive to T cells, with elevated numbers of CD6+ and ALCAM+ cells in patients with LN. CD6 blockade in models of spontaneous lupus and immune-complex glomerulonephritis revealed significant decreases in immune cells, inflammatory markers, and disease measures. Our data demonstrate the contribution of the CD6/ALCAM pathway to LN and SLE, supporting its use as a disease biomarker and therapeutic target.

Physician Knowledge and Attitudes Toward the Adoption of Peritoneal Dialysis in the Treatment of Patients With End-Stage Kidney Disease.

Introduction Hemodialysis (HD) is a significant contributor to Medicare spending. Peritoneal dialysis (PD) is a lower-cost dialysis modality with non-inferior clinical outcomes. Recent initiatives at the federal level have emphasized shifting dialysis from in-center to home modalities, namely, PD. Such policy has been slow to impact the distribution of HD and PD due to multiple barriers, including at the provider level. Previous research has characterized the role of patient knowledge gaps and preferences in the under-utilization of PD. We sought to understand physician knowledge and attitudes toward PD to elucidate provider-level barriers to PD adoption. Methods We conducted a 10-question survey assessing physician comfort level, perceived knowledge, and objective knowledge of HD and PD that was distributed among the internal medicine faculty at the University of Texas Southwestern Medical Center, Dallas, TX. The survey respondents included nephrologists and non-nephrologists. Demographic information of respondents was collected. Survey responses were summarized and stratified by medical specialty. All statistical tests used 0.05 as the statistical significance level. Results Among 391 survey recipients, there were 83 respondents (21.2%). The mean age of respondents was 43 and 54% were women. With regard to specialty, 88% of respondents were non-nephrologists and 12% were nephrologists. All respondents reported an increased level of comfort and experience caring for patients receiving HD compared to PD. Regardless of specialty, respondents had a high incorrect response rate with regard to contraindications to PD. While nephrologists reported high perceived knowledge regarding PD, objective assessments revealed knowledge gaps with regard to PD candidacy. Non-nephrologists reported lower perceived knowledge but scored better on objective knowledge assessments regarding medical contraindications to PD. Both specialty groups held misconceptions regarding psychosocial barriers to PD. Discussion This physician survey demonstrated overall decreased confidence in knowledge and experience in the care of patients receiving PD compared to HD. Knowledge assessments revealed discordance between perceived knowledge and objective knowledge with regard to contraindications to PD. These findings highlight ongoing misconceptions across medical specialties regarding the applicability of PD. These findings demonstrate the need for increased training on PD candidacy among nephrologists and non-nephrologists alike. These findings demonstrate the need for education and advocacy around PD for providers to effectively meet federal priorities advocating for shifting dialysis to the home. Conclusion This study demonstrates the impact of physician knowledge and attitudes toward PD in the under-utilization of PD as a dialysis modality. These findings demonstrate a need for increased provider education around PD candidacy and the benefits of shifting dialysis care to the home. Novel models of dissemination are needed to increase the adoption of PD and meet federal policy goals of shifting dialysis care to home-based modalities.

Peritoneal Dialysis Use in Patients With Ascites: A Review.

The past few decades have seen steady increase in the prevalence of kidney failure needing kidney replacement therapy. Concomitantly, there has been progressive growth of heart failure and chronic liver disease, and many such patients develop ascites. Therefore, it is not uncommon to encounter patients with kidney failure who concurrently have ascites. The presence of ascites adds many challenges in the management of kidney failure. Poor hemodynamics make volume management difficult. The presence of coagulopathy, malnutrition, and encephalopathy compounds the complexity of the management. Such patients do not tolerate hemodialysis well. However, several concerns have limited the use of peritoneal dialysis (PD), so hemodialysis remains the predominant dialysis modality in these patients. However, observational studies have illustrated that PD provides hemodynamic stability and facilitates better volume management compared with hemodialysis. Moreover, PD obviates the need for therapeutic paracentesis by facilitating continuous drainage of ascites. PD potentially reduces hemorrhagic complications by avoiding routine anticoagulation use. Moreover, small studies have suggested that outcomes such as peritonitis and mechanical complications are comparable to those in PD patients without ascites. PD does not affect transplant candidacy, and these patients can successfully receive combined liver and kidney transplants. Hence, PD should be considered a viable dialysis option in kidney failure patients with ascites.

Ewingella americana Peritonitis in a Patient on Peritoneal Dialysis: A Case Report and Review of the Literature.

Most episodes of peritoneal dialysis (PD)-associated peritonitis are caused by skin-dwelling gram-positive bacteria and gram-negative bacteria colonizing gut and urinary tract. Occasionally, however, uncommon bacteria can cause peritonitis in PD patients. We describe a case of Ewingella americana peritonitis, the first such case reported from the United States. A 68-year-old woman with end-stage kidney disease due to hypertension was initiated on PD 2 years prior to the present event. She presented with abdominal pain associated with nausea and vomiting. She was afebrile and hemodynamically stable. Abdomen was diffusely tender with guarding and rebound. No obvious root cause was apparent. Initial PD fluid white count was 502/mm3 with 87% neutrophils. Gram stain was negative. Culture grew gram-negative rods, which were later identified as Ewingella americana, resistant to ampicillin and cefazolin but sensitive to gentamicin, ceftazidime, and cefepime. After empiric intraperitoneal vancomycin and gentamicin, she was continued on intraperitoneal gentamicin for a total period of 21 days. She responded to the treatment rapidly with complete recovery. PD fluid on day four showed 40 nucleated cells with 12% neutrophils. Patient remained on PD without consequences. Ewingella americana is a gram-negative facultative anaerobic bacillus that can survive in water, including domestic water. Inadequate hand hygiene is a potential root cause of infection. Although rare, Ewingella peritonitis can be observed in PD patients and is treatable. Clinicians should be aware of Ewingella as a potential cause of PD peritonitis.