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

New and emerging therapies for systemic lupus erythematosus

Systemic Lupus Erythematosus (SLE) and lupus nephritis treatment is still based on non-specific immune suppression despite the first biological therapy for the disease having been approved more than a decade ago. Intense basic and translational research has uncovered a multitude of pathways that are actively being evaluated as treatment targets in SLE and lupus nephritis, with two new medications receiving FDA approval in the last 3 years. Herein we provide an overview of targeted therapies for SLE including medications targeting the B lymphocyte compartment, intracellular signaling, co-stimulation, and finally the interferons and other cytokines.

Bulk and single-cell transcriptome profiling identify potential cellular targets of the long noncoding RNA Gas5 in renal fibrosis

The long noncoding RNA growth arrest-specific 5 (lncRNA Gas5) is implicated in various kidney diseases. In this study, we investigated the lncRNA Gas5 expression profile and its critical role as a potential biomarker in the progression of chronic kidney disease. Subsequently, we assessed the effect of lncRNA Gas5 deletion on renal fibrosis induced by unilateral ureteral obstruction (UUO). The results indicated that loss of lncRNA Gas5 exacerbates UUO-induced renal injury and extracellular matrix deposition. Notably, the deletion of lncRNA Gas5 had a similar effect on control mice. The fibrogenic phenotype observed in mice lacking lncRNA Gas5 correlates with peroxisome proliferator-activated receptor (PPAR) signaling pathway activation and aberrant cytokine and chemokine reprogramming. Single-cell RNA sequencing analysis revealed key transcriptomic features of fibroblasts after Gas5 deletion, revealing heterogeneous cellular states suggestive of a propensity for renal fibrosis. Our findings indicate that lncRNA Gas5 regulates the differentiation and activation of immune cells and the transcription of key genes in the PPAR signaling pathway. These data offer novel insights into the involvement of lncRNA Gas5 in renal fibrosis, potentially paving the way for innovative diagnostic and therapeutic targets.

The CD318/CD6 axis limits type 1 diabetes islet autoantigen-specific human T cell activation

CD6 is a glycoprotein expressed on CD4 and CD8 T cells involved in immunoregulation. CD318 has been identified as a CD6 ligand. The role of CD318 in T cell immunity is restricted as it has only been investigated in a few mice autoimmune models but not in human diseases. CD318 expression was thought to be limited to mesenchymal-epithelial cells and, therefore, contribute to CD6-mediated T cell activation in the CD318-expressing tissue rather than through interaction with antigen-presenting cells. Here, we report CD318 expression in a subpopulation of CD318+ myeloid dendritic (mDC), whereas the other peripheral blood populations were CD318 negative. However, CD318 can be induced by activation: a subset of monocytes treated with LPS and IFNγ and in vitro monocyte derived DCs were CD318+. We also showed that recombinant CD318 inhibited T cell function. Strikingly, CD318+ DCs suppressed the proliferation of autoreactive T cells specific for GAD65, a well-known targeted self-antigen in Type 1 Diabetes (T1D). Our study provides new insight into the role of the CD318/CD6 axis in the immunopathogenesis of inflammation, suggesting a novel immunoregulatory role of CD318 in T cell-mediated autoimmune diseases and identifying a potential novel immune checkpoint inhibitor as a target for intervention in T1D which is an unmet therapeutic need.

Analysis of m6A-regulated genes and subtype classification in lupus nephritis

BACKGROUND

Lupus nephritis (LN) is the most common and severe clinical manifestation of systemic lupus erythematosus (SLE). N6-methyladenosine (m6A) is a reversible RNA modification and has been implicated in various biological processes. However, the roles of m6A regulators in LN are not fully demonstrated.

METHODS

We downloaded the kidney tissue transcriptome dataset of LN patients and normal controls from the GEO database and extracted the expression levels of m6A regulators. We constructed and compared Random Forest (RF) and Support Vector Machine (SVM) models, and subsequently selected featured genes to develop nomogram models. The m6A subtypes were identified based on significantly differentially expressed m6A regulators, and the m6A gene subtypes were identified based on m6A-associated differential genes, and the two m6A modification patterns were comprehensively evaluated.

RESULTS

We obtained the GSE32591 and GSE112943 datasets from the GEO database, including 78 LN samples and 36 normal control samples. We extracted the expression levels of 20 m6A regulators. By RF analysis we identified 7 characteristic m6A regulators and constructed nomogramh models with these 7 genes. We identified two m6A subtypes based on these seven important m6A regulators, and the immune cell infiltration levels of the two subtype clusters were significantly different. We identified two more m6A gene subtypes based on m6A-associated DEGs. We calculated the m6A scores using the principal component analysis (PCA) algorithm and found that the m6A scores of m6A cluster A and gene cluster A were lower than those of m6A cluster B and gene cluster B. In addition, we found that the levels of inflammatory factors were also significantly different between m6A clusters and gene clusters.

CONCLUSION

This study confirms that m6A regulators are involved in the LN process through different modes of action and provide new diagnostic and therapeutic targets for LN.

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.

Lupus Nephritis Biomarkers: A Critical Review

Lupus nephritis (LN), a major complication in individuals diagnosed with systemic lupus erythematosus, substantially increases morbidity and mortality. Despite marked improvements in the survival of patients with severe LN over the past 50 years, complete clinical remission after immunosuppressive therapy is achieved in only half of the patients. Therefore, timely detection of LN is vital for initiating prompt therapeutic interventions and improving patient outcomes. Biomarkers have emerged as valuable tools for LN detection and monitoring; however, the complex role of these biomarkers in LN pathogenesis remains unclear. Renal biopsy remains the gold standard for the identification of the histological phenotypes of LN and guides disease management. However, the molecular pathophysiology of specific renal lesions remains poorly understood. In this review, we provide a critical, up-to-date overview of the latest developments in the field of LN biomarkers.

Biomarkers for systemic lupus erythematosus - a focus on organ damage

INTRODUCTION

Systemic lupus erythematosus (SLE) is complex autoimmune disease with heterogenous manifestations, unpredictable disease course and response to treatment. One of the critical needs in SLE management is the identification of reliable biomarkers that can aid in early diagnosis, accurate monitoring of disease activity, and assessment of treatment response.

AREAS COVERED

In the current review, we focus on the commonly affected organs (skin, kidney, and nervous system) in SLE to summarize the emerging biomarkers that show promise in disease diagnosis, monitoring and treatment response assessment. The subtitles within each organ domain were determined based on the most relevant and promising biomarkers for that specific organ damage.

EXPERT OPINION

Biomarkers have the potential to significantly benefit the management of SLE by aiding in diagnosis, disease activity monitoring, prognosis, and treatment response assessment. However, despite decades of research, none has been validated and implemented for routine clinical use. Novel biomarkers could lead to the development of precision medicine for SLE, guide personalized treatment, and improve patient outcomes. Challenges in biomarker research in SLE include defining clear and clinically relevant questions, accounting for the heterogeneity of SLE, and confirming initial findings in larger, multi-center, multi-ethnic, independent cohorts that reflect real-world clinical scenarios.

Immunotherapeutic approaches for systemic lupus erythematosus: early overview and future potential

Systemic lupus erythematosus (SLE) is a complex autoimmune disease. Current SLE therapies include immunosuppressants, antimalarial drugs, non-steroidal anti-inflammatory drugs (NSAIDs), and corticosteroids, but these treatments can cause substantial toxicities to organs and may not be effective for all patients. In recent years, significant progress has been made in the treatment of SLE using immunotherapy, including Benlysta and Saphnelo. These advances in immunotherapy hold promise for SLE patients, providing new therapeutic options that may offer better clinical benefit and effectiveness. Simultaneously, several new biological therapies focusing on cytokines, peptides, targeted antibodies, and cell-based approaches are under clinical evaluation and have shown immense potential for the treatment of SLE. However, the complexity of SLE immunopathogenesis and disease heterogeneity present significant challenges in the development of effective immunological therapies. This review aims to discuss past experiences and understanding of diverse immunological targeting therapies for SLE and highlight future perspectives for the development of novel immunological therapies.

Integrative analysis of the association between circadian rhythm and lupus nephritis

Background

Lupus nephritis (LN) is an autoimmune nephropathy associated with systemic lupus erythematosus. Circadian rhythms are involved in the development of several diseases, especially inflammation-related diseases, but their relationship with LN is unclear.

Methods

This was an integrative bioinformatics study. The expression profile from glomeruli, tubular interstitium and renal whole tissue samples was used to assess the expression levels and relevance of circadian rhythm-related genes. To screen for circadian rhythm-related signatures, we employed the LASSO and SVM-RFE algorithms. A consensus clustering algorithm was used to classify LN patients into two circadian rhythm patterns (cluster A and cluster B). We made immune cell infiltration analysis. We used the weighted gene co-expression network analysis (WGCNA) algorithm to identify cluster-specific differentially expressed genes. Nephroseq data were used to observe the relationship between genes and renal function.

Results

We found more significant differences in circadian rhythm-related gene expression in LN glomeruli compared with tubulointerstitial and whole-kidney tissues. We established a circadian rhythm-related signature consisting of eight genes that can easily distinguish LN from healthy individuals. Patients in cluster A were associated with B-cell-dominated immunity, whereas patients in cluster B were associated with T-cell-dominated immunity. As most of the patients with proliferative LN combined with membranous LN belonged to cluster B, patients in cluster B may have more severe renal pathology compared with patients in cluster A. Fifteen circadian rhythm-related genes associated with LN and LN typing were screened using the WGCNA algorithm, with COL1A2 and DOCK2 associated with renal prognosis.

Conclusions

This study found that circadian rhythms are associated with the occurrence of LN, providing new ideas for the development of new LN treatment options from the perspective of circadian rhythms.

Pathogenesis of systemic lupus erythematosus: risks, mechanisms and therapeutic targets

Research elucidating the pathogenesis of systemic lupus erythematosus (SLE) has defined two critical families of mediators, type I interferon (IFN-I) and autoantibodies targeting nucleic acids and nucleic acid-binding proteins, as fundamental contributors to the disease. On the fertile background of significant genetic risk, a triggering stimulus, perhaps microbial, induces IFN-I, autoantibody production or most likely both. When innate and adaptive immune system cells are engaged and collaborate in the autoimmune response, clinical SLE can develop. This review describes recent data from genetic analyses of patients with SLE, along with current studies of innate and adaptive immune function that contribute to sustained IFN-I pathway activation, immune activation and autoantibody production, generation of inflammatory mediators and tissue damage. The goal of these studies is to understand disease mechanisms, identify therapeutic targets and stimulate development of therapeutics that can achieve improved outcomes for patients.

Promising Experimental Treatments for Lupus Nephritis: Key Talking Points and Potential Opportunities

Lupus nephritis (LN) is a frequent and serious complication of systemic lupus erythematosus (SLE), impairing patients' quality of life and significantly increasing mortality. Despite optimizing the use of conventional immunosuppressants and other biological drugs, its management remains unsatisfactory. This is mainly due to the heterogeneity of SLE, but also to insufficiently effective treatment regimens and clinical trial limitations (strict criteria, low number of patients included, and side effects). Most clinical trials of new biological therapies have failed to meet their primary endpoints in both general SLE and LN, with only two biological drugs (belimumab and anifrolumab) being approved by the Food and Drug Administration (FDA) for the treatment of SLE. Recently, several Phase II randomized controlled trials have evaluated the efficacy and safety of new biologics in LN, and some of them have demonstrated an improvement in clinical and laboratory measures. Multi-target therapies are also being successfully developed and encourage a belief that there will be an improvement in LN outcomes.

Analytical validation of urine ALCAM ELISA as a test for lupus nephritis

OBJECTIVES

Urinary activated leukocyte cell adhesion molecule (uALCAM) is emerging as an outstanding biomarker for active lupus nephritis (ALN). This study aims to evaluate the analytic performance of the human ALCAM ELISA as an assay method to quantify uALCAM in patients with lupus nephritis.

METHODS

A commercially available human ALCAM ELISA kit was validated for its analytical performance as per Clinical & Laboratory Standards Institute guidelines.

RESULTS

Assaying 30 sets of serial dilutions of ALCAM exhibited an average CV of 10% and 97%-105% recovery. The assay also exhibited overall acceptable imprecision (CV < 20%) in day-to-day, site-to-site, and lot-to-lot reproducibility. The assay exhibited a reportable range from 4018 pg/ml down to 62 pg/ml with an r2 of 0.999 in urine, with a limit of detection of 16-45 pg/ml. Most tested chemicals did not interfere with the assay, and no diurnal variations were observed in uALCAM levels. uALCAM was stable for at least 3 months at -20°C or -80°C.

CONCLUSION

This analytic-validated uALCAM ELISA may provide physicians with an accurate and reliable tool for use in early detection of renal involvement in lupus, routine outpatient monitoring of disease activity, and long-term prognostication.

Kunxian capsule alleviates renal damage by inhibiting the JAK1/STAT1 pathway in lupus nephritis

ETHNOPHARMACOLOGICAL RELEVANCE

Kunxian capsule (KXC) is a new traditional Chinese medicine drug included in "The key science and technology achievements" in the Ninth Five Year Plan of China. KXC has been clinically used for more than 10 years in the treatment of lupus nephritis (LN). However, the underlying role and molecular mechanism of KXC in LN remain unclear.

AIM OF THE STUDY

This study aimed to explore the efficacy and potential mechanisms of KXC through pharmacological network, in vitro and in vivo studies.

MATERIALS AND METHODS

Pharmacological network analysis of KXC treatment in LN was performed using data acquired from the Traditional Chinese Medicine System Pharmacology Database and Analysis Platform (TCMSP, https://old.tcmsp-e.com/tcmsp.php) and NCBI Gene Expression Omnibus (GEO, https://www.ncbi.nlm.nih.gov/geo/database). HK-2 cells were chosen as an in vitro model of the tubular immune response by simulation with interferon γ (IFN-γ). MRL/lpr mice were used to explore the mechanism of KXC in vivo. Finally, the specific active molecules of KXC were further analyzed by molecular docking.

RESULTS

The pharmacological network analysis showed that STAT1 is a key factor in the effects of KXC. In vitro and in vivo experiments confirmed the therapeutic effect of KXC on LN renal function and tubular inflammation. The protective effect of KXC is mediated by STAT1 blockade, which further reduces T-cell infiltration and improves the renal microenvironment in LN. Two main components of KXC, Tripterygium hypoglaucum (H.Lév.) Hutch (Shanhaitang) and Epimedium brevicornu Maxim (Yinyanghuo) could block JAK1-STAT1 activation. Furthermore, we found 8 molecules that could bind to the ATP pocket of JAK1 with high affinities by performing docking analysis.

CONCLUSIONS

KXC inhibits renal damage and T-cell infiltration in LN by blocking the JAK1-STAT1 pathway.

Optimization and Characterization of Novel ALCAM-Targeting Antibody Fragments for Transepithelial Delivery

Activated leukocyte cell adhesion molecule (ALCAM) is a cell adhesion molecule that supports T cell activation, leukocyte migration, and (lymph)angiogenesis and has been shown to contribute to the pathology of various immune-mediated disorders, including asthma and corneal graft rejection. In contrast to monoclonal antibodies (mAbs) targeting ALCAM's T cell expressed binding partner CD6, no ALCAM-targeting mAbs have thus far entered clinical development. This is likely linked with the broad expression of ALCAM on many different cell types, which increases the risk of eliciting unwanted treatment-induced side effects upon systemic mAb application. Targeting ALCAM in surface-exposed tissues, such as the lungs or the cornea, by a topical application could circumvent this issue. Here, we report the development of various stability- and affinity-improved anti-ALCAM mAb fragments with cross-species reactivity towards mouse, rat, monkey, and human ALCAM. Fragments generated in either mono- or bivalent formats potently blocked ALCAM-CD6 interactions in a competition ELISA, but only bivalent fragments efficiently inhibited ALCAM-ALCAM interactions in a leukocyte transmigration assay. The different fragments displayed a clear size-dependence in their ability to penetrate the human corneal epithelium. Furthermore, intranasal delivery of anti-ALCAM fragments reduced leukocyte infiltration in a mouse model of asthma, confirming ALCAM as a target for topical application in the lungs.

A novel technology for home monitoring of lupus nephritis that tracks the pathogenic urine biomarker ALCAM

Introduction

The gold standard for diagnosis of active lupus nephritis (ALN), a kidney biopsy, is invasive with attendant morbidity and cannot be serially repeated. Urinary ALCAM (uALCAM) has shown high diagnostic accuracy for renal pathology activity in ALN patients.

Methods

Lateral flow assays (LFA) for assaying uALCAM were engineered using persistent luminescent nanoparticles, read by a smartphone. The stability and reproducibility of the assembled LFA strips and freeze-dried conjugated nanoparticles were verified, as was analyte specificity.

Results

The LFA tests for both un-normalized uALCAM (AUC=0.93) and urine normalizer (HVEM)-normalized uALCAM (AUC=0.91) exhibited excellent accuracies in distinguishing ALN from healthy controls. The accuracies for distinguishing ALN from all other lupus patients were 0.86 and 0.74, respectively.

Conclusion

Periodic monitoring of uALCAM using this easy-to-use LFA test by the patient at home could potentially accelerate early detection of renal involvement or disease flares in lupus patients, and hence reduce morbidity and mortality.

Analysis of herpesvirus infection and genome single nucleotide polymorphism risk factors in multiple sclerosis, Volga federal district, Russia

Multiple sclerosis (MS) is a heterogeneous disease where herpesvirus infection and genetic predisposition are identified as the most consistent risk factors. Serum and blood samples were collected from 151 MS and 70 controls and used to analyze circulating antibodies for, and DNA of, Epstein Barr virus (EBV), human cytomegalovirus (HCMV), human herpes virus 6 (HHV6), and varicella zoster virus (VZV). The frequency of selected single nucleotide polymorphisms (SNPs) in MS and controls were studied. Herpesvirus DNA in blood samples were analyzed using qPCR. Anti-herpesvirus antibodies were detected by ELISA. SNPs were analyzed by the allele-specific PCR. For statistical analysis, Fisher exact test, odds ratio and Kruskall-Wallis test were used; p<0.05 values were considered as significant. We have found an association between circulating anti-HHV6 antibodies and MS diagnosis. We also confirmed higher frequency of A and C alleles in rs2300747 and rs12044852 of CD58 gene and G allele in rs929230 of CD6 gene in MS as compared to controls. Fatigue symptom was linked to AC and AA genotype in rs12044852 of CD58 gene. An interesting observation was finding higher frequency of GG genotype in rs12722489 of IL2RA and T allele in rs1535045 of CD40 genes in patient having anti-HHV6 antibodies. A link was found between having anti-VZV antibodies in MS and CC genotype in rs1883832 of CD40 gene.

The dual role of CD6 as a therapeutic target in cancer and autoimmune disease

Autoimmune disease involves loss of tolerance to self-antigen, while progression of cancer reflects insufficient recognition and response of the immune system to malignant cells. Patients with immune compromised conditions tend to be more susceptible to cancer development. On the other hand, cancer treatments, especially checkpoint inhibitor therapies, can induce severe autoimmune syndromes. There is recent evidence that autoimmunity and cancer share molecular targets and pathways that may be dysregulated in both types of diseases. Therefore, there has been an increased focus on understanding these biological pathways that link cancer and its treatment with the appearance of autoimmunity. In this review, we hope to consolidate our understanding of current and emerging molecular targets used to treat both cancer and autoimmunity, with a special focus on Cluster of Differentiation (CD) 6.

Exploring urine:serum fractional excretion ratios as potential biomarkers for lupus nephritis

Objectives

The goal of this exploratory study is to determine if urine:serum fractional excretion ratios can outperform the corresponding urinary biomarker proteins in identifying active renal disease in systemic lupus erythematosus (SLE).

Methods

Thirty-six adult SLE patients and twelve healthy controls were examined for serum and urine levels of 8 protein markers, namely ALCAM, calpastatin, hemopexin, peroxiredoxin 6 (PRDX6), platelet factor 4 (PF4), properdin, TFPI and VCAM-1, by ELISA. Fractional excretion of analyzed biomarkers was calculated after normalizing both the urine and serum biomarker levels against creatinine. A further validation cohort of fifty SLE patients was included to validate the initial findings.

Results

The FE ratios of all 8 proteins interrogated outperformed conventional disease activity markers such as anti-dsDNA, C3 and C4 in identifying renal disease activity. All but VCAM-1^FE were superior to the corresponding urine biomarkers levels in differentiating LN activity, exhibiting positive correlation with renal SLEDAI. ALCAM^FE, PF4^FE and properdin^FE ratios exhibited the highest accuracy (AUC>0.9) in distinguishing active LN from inactive SLE. Four of the FE ratios exhibited perfect sensitivity (calpastatin, PRDX6, PF4 and properdin), while ALCAM^FE, PF4^FE and properdin^FE exhibited the highest specificity values for active LN. In addition, several of these novel biomarkers were associated with higher renal pathology activity indices. In the validation cohort ALCAM^FE, PF4^FE and properdin^FE once again exhibited higher accuracy metrics, surpassing corresponding urine and serum biomarkers levels, with ALCAM^FE exhibiting 95% accuracy in distinguishing active LN from inactive SLE.

Conclusions

With most of the tested proteins, urine:serum fractional excretion ratios outperformed corresponding urine and serum protein measurements in identifying active renal involvement in SLE. Hence, this novel class of biomarkers in SLE ought to be systemically evaluated in larger independent cohorts for their diagnostic utility in LN assessment.

The mosaic of autoimmunity - Finally discussing in person. The 13th international congress on autoimmunity 2022 (AUTO13) Athens

While autoimmunity is a branch of medicine linked to every single organ system via direct and indirect pathways, meeting in person to discuss autoimmunity during the 13^th international congress on autoimmunity (AUTO13) with participants from all over the world had a very good reason. The mechanisms involved in autoimmune diseases are of extreme importance and in fact critical in understanding the course of diseases as well as selecting proper therapies. COVID-19 has served as a great example of how autoimmunity is deeply involved in the disease and directly correlated to severity, morbidity, and mortality. For instance, initially the term cytokine storm dominated, then COVID-19 was addressed as the new member of the hyperferritinemic syndrome, and also the use of immunosuppressants in patients with COVID-19 throughout the pandemic, all shed light on the fundamental role of autoimmunity. Unsurprisingly, SARS-CoV-2 was called the “autoimmune virus” during AUTO13. Subsequently, the correlation between autoimmunity and COVID-19 vaccines and post-COVID, all were discussed from different autoimmune aspects during the congress. In addition, updates on the mechanisms of diseases, autoantibodies, novel diagnostics and therapies in regard to autoimmune diseases such as antiphospholipid syndrome, systemic lupus erythematosus, systemic sclerosis and others, were discussed in dedicated sessions. Due to the magnificence of the topics discussed, we aimed to bring in our article hereby, the pearls of AUTO13 in terms of updates, new aspects of autoimmunity, and interesting findings. While more than 500 abstract were presented, concluding all the topics was not in reach, hence major findings were summarized.

Urine ALCAM, PF4 and VCAM-1 Surpass Conventional Metrics in Identifying Nephritis Disease Activity in Childhood-Onset Systemic Lupus Erythematosus

Objectives

Serial kidney biopsy for repeat evaluation and monitoring of lupus nephritis (LN) in childhood-onset Systemic Lupus Erythematosus (cSLE) remains challenging, thus non-invasive biomarkers are needed. Here, we evaluate the performance of ten urine protein markers of diverse nature including cytokines, chemokines, and adhesion molecules in distinguishing disease activity in cSLE.

Methods

Eighty-four pediatric patients meeting ≥4 ACR criteria for SLE were prospectively enrolled for urine assay of 10 protein markers normalized to urine creatinine, namely ALCAM, cystatin-C, hemopexin, KIM-1, MCP-1, NGAL, PF-4, Timp-1, TWEAK, and VCAM-1 by ELISA. Samples from active renal (LN) and active non-renal SLE patients were obtained prior to onset/escalation of immunosuppression. SLE disease activity was evaluated using SLEDAI-2000. 59 patients had clinically-active SLE (SLEDAI score ≥4 or having a flare), of whom 29 patients (34.5%) were classified as active renal, and 30 patients (35.7%) were active non-renal. Twenty-five healthy subjects were recruited as controls.

Results

Urine concentrations of ALCAM, KIM-1, PF4 and VCAM-1 were significantly increased in active LN patients versus active non-renal SLE, inactive SLE and healthy controls. Five urine proteins differed significantly between 2 (hemopexin, NGAL, MCP1) or 3 (Cystatin-C, TWEAK) groups only, with the highest levels detected in active LN patients. Urine ALCAM, VCAM-1, PF4 and hemopexin correlated best with total SLEDAI as well as renal-SLEDAI scores (p < 0.05). Urine ALCAM, VCAM-1 and hemopexin outperformed conventional laboratory measures (anti-dsDNA, complement C3 and C4) in identifying concurrent SLE disease activity among patients (AUCs 0.75, 0.81, 0.81 respectively), while urine ALCAM, VCAM-1 and PF4 were the best discriminators of renal disease activity in cSLE (AUCs 0.83, 0.88, 0.78 respectively), surpassing conventional biomarkers, including proteinuria. Unsupervised Bayesian network analysis based on conditional probabilities re-affirmed urine ALCAM as being most predictive of active LN in cSLE patients.

Conclusion

Urinary ALCAM, PF4, and VCAM-1 are potential biomarkers for predicting kidney disease activity in cSLE and hold potential as surrogate markers of nephritis flares in these patients.

Exploration of the pathogenesis of Sjögren's syndrome via DNA methylation and transcriptome analyses

OBJECTIVES

Sjögren's syndrome (SS), a systemic autoimmune disorder, is characterized by dry mouth and eyes. However, SS pathogenesis is poorly understood. We performed bioinformatics analysis to investigate the potential targets and molecular pathogenesis of SS.

METHODS

Gene expression profiles (GSE157159) and methylation data (GSE110007) associated with SS patients were obtained from the Gene Expression Omnibus (GEO) database. Differentially methylated positions (DMPs) and differentially expressed genes (DEGs) were identified by the R package limma. The potential biological functions of DEGs were determined using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. Key DMPs were selected by overlap and the shrunken centroid algorithm, and corresponding genes were identified as hub genes, with their diagnostic value assessed by receiver operating characteristic (ROC) curves. The potential molecular mechanisms of hub genes were analyzed by protein-protein interaction (PPI) networks and single-gene gene set enrichment analysis (GSEA). Peripheral blood mononuclear cells (PBMCs) were collected from control and SS patients at The Affiliated Hospital of Southwest Medical University and Dazhou Central Hospital. The mRNA levels of hub genes were verified by quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

We identified 788 DMPs and 2457 DEGs between the two groups. Functional enrichment analysis suggested that the DEGs were significantly enriched in T cell activation, leukocyte cell-cell adhesion, and cytokine-cytokine receptor interaction. TSS200, TSS1500, and 1stExon were identified as highly enriched areas of differentially methylated promoter CpG islands (DMCIs). In total, 61 differentially methylated genes (DMGs) were identified by the overlap of 2457 DEGs and 507 genes related to DMPs (DMPGs), of which 21 genes located near TSS200, TSS1500, and 1stExon were selected. Then, three key DMPs and the corresponding hub genes (RUNX3, HLA-DPA1, and CD6) were screened by the shrunken centroid algorithm and calculated to have areas under the ROC curve of 1.000, 0.931, and 0.986, respectively, indicating good diagnostic value. The GSEA results suggested that all three hub genes were highly associated with the immune response. Finally, positive mRNA expression of the three hub genes in clinical SS samples was verified by qRT-PCR, consistent with the GSE157159 data.

CONCLUSIONS

The identification of three hub genes provides novel insight into molecular mechanisms and therapeutic targets for SS. Key Points • Hub genes were screened by DNA methylation and transcriptome analyses. • The relative expression of hub genes in peripheral blood samples was verified by qRT-PCR. • HLA-DPA1 was correlated with the pathogenic mechanism of SS.

Gene Variation at Immunomodulatory and Cell Adhesion Molecules Loci Impacts Primary Sjögren's Syndrome

Primary Sjögren's syndrome (pSS) is an autoimmune disease triggered by a combination of environmental and host genetic factors, which results in the focal lymphocytic infiltration of exocrine glands causing eye and mouth dryness. Glandular infiltrates include T and B cell subsets positive for CD5 and/or CD6, two surface scavenger receptors involved in the fine-tuning of intracellular signals mediated by the antigen-specific receptor complex of T (TCR) and B (BCR) cells. Moreover, the epithelial cells of inflamed glands overexpress CD166/ALCAM, a CD6 ligand involved in homo and heterotypic cell adhesion interactions. All this, together with the reported association of functionally relevant single nucleotide polymorphisms (SNPs) of CD5, CD6, and CD166/ALCAM with the risk or prognosis of some immune-mediated inflammatory disorders, led us to investigate similar associations in a local cohort of patients with pSS. The logistic regression analyses of individual SNPs showed the association of CD5 rs2241002^T with anti-Ro/La positivity, CD6 rs17824933^C with neutropenia, and CD6 rs11230563^T with increased leukopenia and neutropenia but decreased peripheral nervous system EULAR Sjögren's syndrome disease activity index (ESSDAI). Further analyses showed the association of haplotypes from CD5 (rs2241002^T-rs2229177^C) with anemia and thrombocytopenia, CD6 (rs17824933^G-rs11230563^C-rs12360861^G) with cutaneous ESSDAI, and CD166/ALCAM (rs6437585^C-rs579565^A-rs1044243^C and rs6437585^C-rs579565^G-rs1044243^T) with disease susceptibility and several analytical parameters (anti-nuclear antibodies, neurological ESSDAI, and hematologic cytopenias). These results support the relevance of gene variation at loci coding for cell surface receptors involved in the modulation of T and B lymphocyte activation (CD5, CD6) and epithelial-immune cell adhesion (CD166/ALCAM) in modulating the clinical and analytical outcomes in patients with pSS.

Diagnostic, predictive and prognostic biomarkers in systemic lupus erythematosus: current insights

PURPOSE OF REVIEW

Biomarkers for diagnosis, monitoring and prognosis still constitute an unmet need for systemic lupus erythematosus (SLE). Focusing on recent findings, this review summarises the current landscape of biomarkers in lupus.

RECENT FINDINGS

Urine activated leukocyte cell adhesion molecule (ALCAM) exhibited good diagnostic ability in SLE and lupus nephritis (LN) whereas cerebrospinal fluid neutrophil gelatinase-associated lipocalin (NGAL) showed promise in neuropsychiatric SLE. Urine ALCAM, CD163 and vascular cell adhesion molecule 1 (VCAM-1) may be useful in surveillance of LN. Urine monocyte chemoattractant protein 1 was found to predict treatment response in SLE, and urine CD163 and NGAL treatment response in LN. Serum complement component 3 (C3) and urinary VCAM-1 have been reported to portend long-term renal prognosis in LN.

SUMMARY

NGAL holds promise as a versatile biomarker in SLE whereas urine ALCAM, CD163 and VCAM-1 displayed good performance as biomarkers in LN. The overall lack of concerted corroboration of leading candidates across multiple cohorts and diverse populations leaves the current biomarker landscape in SLE in an urgent need for further survey and systematic validation.

Treat-to-Target in Lupus Nephritis. What is the Role of the Repeat Kidney Biopsy?

Kidney involvement, termed lupus nephritis (LN), develops in 35-60% of patients with systemic lupus erythematosus, often early during the disease course. When not treated promptly and efficiently, LN may lead to rapid and severe loss of kidney function, being the reason why it is considered one of the most severe lupus manifestations. Despite improved pharmacotherapy, 5-20% of LN patients develop end-stage kidney disease within ten years from the LN diagnosis. While the principal ground of LN therapy is prevention of renal function worsening, resembling a race against nephron loss, consensual agreement upon outcome measures and clinically meaningful short- and long-term targets of LN therapy have yet to be determined. Literature points to the importance of inclusion of tissue-based approaches in the determination of those targets, and evidence accumulates regarding the importance of per-protocol repeat kidney biopsies in the evaluation of the initial phase of therapy and prediction of long-term renal prognosis. The latter leads to the hypothesis that the information gleaned from repeat biopsies may contribute to optimised therapeutic decision making, and, therefore, increased probability to attain complete renal response in the short term, and a more favourable renal prognosis within a longer prospect. The multinational project ReBioLup was recently designed to serve as a key contributor to form evidence about the role of per-protocol repeat biopsies in a randomised fashion and aspires to unify the global LN community towards improved kidney and patient survival.