Antibodies to DNA

Precise Targeting of Autoantigen-Specific B Cells in Lupus Nephritis with Chimeric Autoantibody Receptor T Cells

Despite conventional therapy, lupus nephritis (LN) remains a significant contributor to short- and long-term morbidity and mortality. B cell abnormalities and the production of autoantibodies against nuclear complexes like anti-dsDNA are recognised as key players in the pathogenesis of LN. To address the challenges of chronic immunosuppression associated with current therapies, we have engineered T cells to express chimeric autoantibody receptors (DNA-CAART) for the precise targeting of B cells expressing anti-dsDNA autoantibodies. T cells from LN patients were transduced using six different CAAR vectors based on their antigen specificity, including alpha-actinin, histone-1, heparan sulphate, or C1q. The cytotoxicity, cytokine production, and cell-cell contact of DNA-CAART were thoroughly investigated in co-culture experiments with B cells isolated from patients, both with and without anti-dsDNA positivity. The therapeutic effects were further evaluated using an in vitro immune kidney LN organoid. Among the six proposed DNA-CAART, DNA4 and DNA6 demonstrated superior selectively cytotoxic activity against anti-dsDNA+ B cells. Notably, DNA4-CAART exhibited improvements in organoid morphology, apoptosis, and the inflammatory process in the presence of IFNα-stimulated anti-dsDNA+ B cells. Based on these findings, DNA4-CAART emerge as promising candidates for modulating autoimmunity and represent a novel approach for the treatment of LN.

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.

Clinical algorithm model based on cfDNA to predict SLE disease activity

BACKGROUND

Circulating cell-free DNA (cfDNA) has been widely used as a new liquid-biopsy marker. Dysregulation of cfDNA has been found in patients with systemic lupus erythematosus (SLE). However, the detailed association between cfDNA and SLE has not been thoroughly studied.

METHODS

Plasma samples were collected from 88 patients with active SLE and 39 patients with inactive SLE. The cfDNA concentration was determined, and the length and distribution of cfDNA fragments were verified.

RESULTS

cfDNA concentrations were significantly higher in patients with active SLE than in patients with inactive SLE (0.4 [0.18-0.897] ng/µL vs 0.249 [0.144-0.431] ng/µL; p = .043). cfDNA fragments were enriched in the ranges of 153-198 bp and 300-599 bp. cfDNA concentrations were associated with the reduction of the anti-double-stranded DNA (dsDNA) antibodies titer (r = -0.301, p = .034). The presence of anti-U1 ribonucleoprotein (p = .012), anti-Sjogren syndrome A (p = .024), anti-dsDNA (p = .0208), and anti-nucleosome antibodies (p = .0382) might associate to the variation of cfDNA concentration. Reduced cfDNA concentration was associated with renal damage in active SLE patients (0.31 [0.11-0.73] ng/µL vs 0.65 [0.27-1.53] ng/µL; p = .009). The Active index, a combination model including cfDNA concentration and other clinical indices, had an area of 0.886 under the receiver operating characteristics curve for distinguishing active SLE. The Active index was positively correlated with the SLE disease activity index score (r = 0.6724, p < .0001).

CONCLUSIONS

Through systematic stratified analysis and clinical algorithm model, this study found that plasma cfDNA concentration is closely related to SLE disease severity, which has guiding significance for the future clinical application of cfDNA in SLE.

Hal Holman of Stanford

Before age 35, Holman hit over 0.500 at the University of California Los Angeles (UCLA); was recruited by professional baseball; led the Association of Interns and Medical Students and the International Union of Students in Denmark; had his passport confiscated; was stripped of a prestigious internship; shadowed by the Federal Bureau of Investigation ; grilled before a Senate committee on subversive activities; made a major medical discovery; and was recruited to be the new Chief of Medicine at Stanford. Holman was involved in building a leading academic institution. He expanded what medical students and graduates learned and what they researched. Holman saw the collision course between the technological capacity to do more and the growing expectations of the public. Moreover, he anticipated the monetization of health care and how it would widen the gap between what we know and what we practice in health care. He reinvented himself in population health. In contrast to reductionist laboratory-based research, his work embraced complexity and made action researchable and research action-oriented. Some innovations did not survive as originally conceived, but their ethos became mainstream. These included evidence-based management, shared physician-patient decision-making, self-management, critical evaluation of medical technology and diagnostics, and chronic disease management. Through the rise of the twentieth century American biomedical medicine, medical education, and slow-motion health care delivery crises that still occur, Holman changed the debate in a time when the funding, the people, the technology, and the need made all things seem possible.

Comparative analysis of contemporary anti-double stranded DNA antibody assays for systemic lupus erythematosus

Objective

Elevated double-stranded DNA (dsDNA) antibody levels in blood serum are considered a disease-specific marker in systemic lupus erythematosus (SLE), correlate with disease activity and the incidence of lupus nephritis, and can be detected in up to 86% of all SLE cases. Despite the high clinical relevance, the variety of dsDNA antibody testing methods with heterogenous performance in clinical use remains challenging. This study is the first to prospectively investigate the performance of two of today's most commonly applied anti-dsDNA testing methods head-to-head under real-world conditions, as well as their correlation with other clinical and serological disease parameters in SLE patients.

Methods

In this prospective study, all SLE patients undergoing treatment at the Department of Rheumatology at the University Hospital Bonn within a 13-months period (n=41) and control patients without connective-tissue disease (n=51) were consecutively enrolled and examined. For all study participants' serum samples both anti-dsDNA-NcX enzyme-linked immunoassay testing EUROIMMUN, Luebeck, Germany) and the fluorescence immunoassay ELiA dsDNA (Thermo Fisher Scientific, Waltham, USA) were performed. In addition, demographic data, further laboratory values and disease activity parameters were recorded. Clinical disease activity was assessed by SLEDAI-2K.

Results

Both assays showed high specificity (anti-dsDNA-NcX ELISA: 0.9, ELiA dsDNA: 0.959), but there were notable differences in sensitivity (anti-dsDNA-NcX ELISA: 0.51, ELiA dsDNA: 0.38). Pearsons's correlation yielded a positive correlation between anti-dsDNA concentrations and CRP concentrations for the anti-dsDNA-NcX ELISA (R=0.22; p=0.038) and a mild-to-moderate inverse correlation between concentrations of anti-dsDNA and complement C4 for the ELiA dsDNA test (R=-0.22; p=0.045) when SLE and control patients were considered together. Other than, no significant correlation between anti-dsDNA concentrations and clinical or laboratory findings was found for either test procedure.

Conclusion

Both anti-dsDNA antibody assays represent reliable examination methods with high specificity for the diagnosis of SLE that fulfill EULAR/ACR requirements. However, the anti-dsDNA-NcX ELISA showed superior sensitivity and significant correlation with disease activity (as measured by CRP concentrations).

Fecal microbiota transplantation in the treatment of systemic lupus erythematosus: What we learnt from the explorative clinical trial

Systemic lupus erythematosus (SLE) is an autoimmune disease with the characterized presence of autoantibodies and resulting in multiple organ damage, which is incurable and can be lethal. The current treatments are limited and less progress has been made in drug discovery for the last few decades. Researches imply that gut dysbiosis exists in both patients and murine models with SLE, taking part in the pathogenesis of SLE through multiple mechanisms such as microbiota translocation and molecular mimicry. Intestinal interventions on the gut microbiome by fecal transplantations to reconstitute the gut-immunity homeostasis serve as a novel therapeutic option for SLE patients. Fecal microbiota transplantation (FMT), which is usually used in intestinal diseases, has been firstly demonstrated to be safe and efficient in recovering gut microbiota structure of SLE patients and reducing lupus activity in our recent clinical trial, which is the first trial testing FMT therapy in SLE treatment. In this paper, we reviewed the results of the single-arm clinical trial and made recommendations on FMT practice in SLE treatment including therapeutic indications, screening items and dosage regimen, trying to provide references for future study and clinical practice. We also came up with the unanswered questions that need to be solved by the ongoing randomized controlled trial as well as the future expectations for the intestinal intervention strategies of SLE patients.

Proteinase 3 Antibody and Anti-Double-Stranded DNA in a Patient With Immunoglobin Light Chain Amyloidosis

Proteinase 3 (PR3) anti-neutrophil cytoplasmic antibodies (ANCA) and anti-double-stranded DNA (anti-dsDNA) antibodies have been associated with a variety of nephritic diseases, most recognizably granulomatosis with polyangiitis and systemic lupus erythematosus (SLE) glomerulonephritis, respectively. We report the first clinical case of positive PR3 and dsDNA in a patient with renal Immunoglobin light chain (AL) amyloidosis. A 75-year-old man presented to the hospital with chronic fatigue, weight loss, and a recent diagnosis of left ventricular infiltrative cardiomyopathy secondary to AL amyloidosis. Autoimmune serology was significant for PR3-ANCA and anti-dsDNA antibodies. A renal biopsy confirmed AL amyloidosis with diffuse Congo red stain. This case report is the first of its kind, showing atypical antibody presentation in the setting of amyloidosis.

The expression of antibodies to Z-DNA in the blood of patients with systemic lupus erythematosus: Relationship to autoantibodies to B-DNA

To explore the antibody response to Z-DNA, a DNA conformation with a zig-zag structure, blood of patients with systemic lupus erythematosus (SLE) and otherwise healthy individuals (NHS) were assayed by ELISA using brominated poly(dGdC), a synthetic Z-DNA antigen. These studies showed that SLE patients commonly express antibodies to Z-DNA; NHS also had binding in this assay. In SLE blood, levels of antibodies to Z-DNA were related to those to B-DNA using calf thymus DNA as a source of B-DNA; cross-reactivity was demonstrated by adsorption experiments using DNA cellulose. As shown by dissociation assays, antibody binding of SLE anti-Z-DNA is sensitive to the effects of ionic strength, suggesting electrostatic binding. Since Z-DNA structure can be found in bacterial DNA as well as bacterial biofilms, these findings suggest that, in SLE, anti-DNA antibody responses can result from stimulation by DNA of bacterial origin, with cross-reactivity leading to autoreactivity.

p16Ink4a, a marker of cellular senescence, is associated with renal disease in the B6.NZMSle1/Sle2/Sle3 mouse model of lupus

OBJECTIVES

Despite treatment, one-third of patients with lupus nephritis (LN) show a decline in renal function. Prognostic markers of poor outcome as well as novel therapeutic targets are therefore highly sought. We showed that p16INK4a, a marker of cellular senescence, is observed in baseline kidney biopsies from patients with LN, and is associated with renal disease. Here, we set out to assess for whether these findings are recapitulated in the B6.NZMSle1/Sle2/Sle3 (B6.Sle1.2.3) mouse model of spontaneous lupus.

METHODS

We evaluated the occurrence and time of onset of p16Ink4a staining by immunohistochemistry on kidney sections, and tested for its association with multiple renal and systemic disease parameters, fibrosis and CD8+ T cell infiltration, in two cohorts of B6.Sle1.2.3 mice.

RESULTS

The presence of p16Ink4a-positive cells in kidney was significantly associated with increased urine albumin/creatinine ratio, histopathological scores, CD8+ T cell infiltration and fibrosis, in both B6.Sle1.2.3 cohorts. In contrast, p16Ink4a staining was not associated with systemic disease parameters. A time course showed that systemic disease parameters as well as glomerular IgG deposits appeared in B6.Sle1.2.3 mice by 4 months of age; the appearance of p16Ink4a-positive cells occurred later, by 8 months of age, overlapping with renal disease.

CONCLUSION

We report, for the first time, the presence of p16Ink4a-positive cells, a marker of cellular senescence, in the B6.Sle1.2.3 kidney, and their association with renal disease severity. This provides a preclinical model in which to test for the role of cellular senescence in the pathogenesis of LN, as a potential kidney-intrinsic disease mechanism.

Autoantibodies to dsDNA in the diagnosis, classification and follow-up of patients with systemic lupus erythematosus

Autoantibodies, in particular anti-dsDNA antibodies, are increasingly used for diagnosis, classification and follow-up of patients with SLE. Since standardization of autoantibody assays is a major challenge, more attention should be paid to harmonization initiatives and better definition of required test characteristics in classification criteria. For diagnosis and follow-up separate multi-center studies are required to establish test characteristics of distinct immuno-assays for both purposes. Finally, such studies should consider not to evaluate SLE as a single disease, but as a disease with distinct subtypes.

Omega-3 fatty acids: Current insights into mechanisms of action in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is one of the autoimmune diseases characterized by the lack of self-tolerance and the formation of immune complexes and nuclear autoantigens resulting in inflammation in multiple organs. Nowadays, the major aim of SLE therapy is the control of disease activity. However, the biological heterogeneity between patients and the absence of safe and specific targeted treatments complicate the lupus management. Therefore, the potential prophylactic effects of natural therapy considering the potential side effects of classical pharmacology, also the role of diet therapy in decreasing co-morbidities and improving quality of life in SLE patients could be a promising approach to SLE disease. Omega-3 polyunsaturated fatty acids (omega-3 PUFAs) are one of the agents that are considered for their preventive and therapeutic properties in disease activity of SLE and the related complications. The intake of omega-3 PUFAs likely has a direct relationship with improvements in inflammatory, cardiovascular, depressive, and neuromotor symptoms of the patients. The current review summarizes clinical and preclinical studies with comprehensive insights into the mechanisms of action of omega-3 fatty acids (omega-3 FAs) in Systemic Lupus Erythematosus to provide an update on the negative and positive aspects of the intake of omega-3 FAs in SLE patients.

Serological, fragmentomic, and epigenetic characteristics of cell-free DNA in patients with lupus nephritis

Objectives

The biological characteristics of plasma circulating cell-free DNA (cfDNA) are related to the pathogenesis of lupus nephritis (LN). The aim of this study was to explore the biological characteristics of cfDNA in patients with LN in terms of serology, fragment omics, and epigenetics, and to discuss the possibility of liquid biopsy for cfDNA as an alternative to conventional tissue biopsy.

Methods

cfDNA was extracted from plasma samples of 127 patients with systemic lupus erythematosus (64 with LN, 63 without LN). The cfDNA concentration was determined using the Qubit method. Next-generation sequencing cfDNA methylation profiling was performed for three LN patients and six non-LN patients. The methylation panel was designed based on data from The Cancer Genome Atlas cohort. The fragmentation index, motif score, and DELFI score were calculated to explore the fragmentation profile of cfDNA in patients with LN. Statistical and machine learning methods were used to select features to calculate the methylation scores of the samples.

Results

Patients with LN had significantly lower cfDNA concentrations (P = 0.0347) than those without LN. This may be associated with the presence of anti-double-stranded DNA antibodies (r = -0.4189; P = 0.0296). The mean DELFI score (proportion of short fragments of cfDNA) in patients with LN was significantly higher than that in patients without LN (P = 0.0238). Based on the pan-cancer data, 73, 66, 8, and 10 features were selected and used to calculate the methylation scores. The mean methylation scores of these features in patients with LN differed significantly from those in patients without LN (P = 0.0238).

Conclusions

The specificity of cfDNA in patients with LN was identified using serological, fragmentomic, and epigenetic analyses. The findings may have implications for the development of new molecular markers of LN.

Predicting diagnostic gene expression profiles associated with immune infiltration in patients with lupus nephritis

Objective

To identify potential diagnostic markers of lupus nephritis (LN) based on bioinformatics and machine learning and to explore the significance of immune cell infiltration in this pathology.

Methods

Seven LN gene expression datasets were downloaded from the GEO database, and the larger sample size was used as the training group to obtain differential genes (DEGs) between LN and healthy controls, and to perform gene function, disease ontology (DO), and gene set enrichment analyses (GSEA). Two machine learning algorithms, least absolute shrinkage and selection operator (LASSO) and support vector machine-recursive feature elimination (SVM-RFE), were applied to identify candidate biomarkers. The diagnostic value of LN diagnostic gene biomarkers was further evaluated in the area under the ROC curve observed in the validation dataset. CIBERSORT was used to analyze 22 immune cell fractions from LN patients and to analyze their correlation with diagnostic markers.

Results

Thirty and twenty-one DEGs were screened in kidney tissue and peripheral blood, respectively. Both of which covered macrophages and interferons. The disease enrichment analysis of DEGs in kidney tissues showed that they were mainly involved in immune and renal diseases, and in peripheral blood it was mainly enriched in cardiovascular system, bone marrow, and oral cavity. The machine learning algorithm combined with external dataset validation revealed that C1QA(AUC = 0.741), C1QB(AUC = 0.758), MX1(AUC = 0.865), RORC(AUC = 0.911), CD177(AUC = 0.855), DEFA4(AUC= 0.843)and HERC5(AUC = 0.880) had high diagnostic value and could be used as diagnostic biomarkers of LN. Compared to controls, pathways such as cell adhesion molecule cam, and systemic lupus erythematosus were activated in kidney tissues; cell cycle, cytoplasmic DNA sensing pathways, NOD-like receptor signaling pathways, proteasome, and RIG-1-like receptors were activated in peripheral blood. Immune cell infiltration analysis showed that diagnostic markers in kidney tissue were associated with T cells CD8 and Dendritic cells resting, and in blood were associated with T cells CD4 memory resting, suggesting that CD4 T cells, CD8 T cells and dendritic cells are closely related to the development and progression of LN.

Conclusion

C1QA, C1QB, MX1, RORC, CD177, DEFA4 and HERC5 could be used as new candidate molecular markers for LN. It may provide new insights into the diagnosis and molecular treatment of LN in the future.

Antibody Response to HML-2 May Be Protective in Amyotrophic Lateral Sclerosis

OBJECTIVES

Reactivation of HERV-K(HML-2) has been found in subsets of individuals with amyotrophic lateral sclerosis (ALS). This study examines the antibody response against HML-2 in ALS and analyzes its clinical relevance.

METHODS

Antibodies to HML-2 envelope (env) were analyzed using a peptide array for epitope mapping and by a peptide enzyme-linked immunosorbent assay (ELISA) in 242 healthy donors, and 243 ALS and 85 multiple sclerosis (MS) individuals. Extracellular levels of HML-2 were analyzed by digital polymerase chain reaction (PCR).

RESULTS

Antibodies in the sera of ALS individuals recognized more HML-2 env peptides compared to healthy controls (p < 0.0001). ALS individuals had higher levels of HML-2 than healthy donors (p = 0.02) and higher antibody levels against a select HML-2 env peptide compared to healthy donors or individuals with multiple sclerosis (p < 0.0001). 55.14% of ALS compared to 21.16% of healthy donors and 13.10% of MS individuals had antibodies against the HML-2 peptide (AUC = 0.769, p < 0.0001). Levels of extracellular HML-2 DNA in serum (p = 0.02) and the number of HML-2 env peptides recognized by ALS sera (p = 0.02) correlated with disease duration. Among ALS individuals, lower levels of HML-2 antibodies were associated with a definite diagnosis per EL Escorial criteria (p = 0.03), and with a lower predicted (p = 0.02) and observed survival (p = 0.03).

INTERPRETATION

There is a differential antibody response against specific epitopes of HML-2 env in ALS and controls, suggesting epitope spreading, likely due to persistent antigenic exposure following reactivation of the viral genes. Low levels of antibodies to HML-2 env in ALS are associated with poor prognosis and decreased survival probability. ANN NEUROL 2022;92:782-792.

Post-genomic platform for development of oligonucleotide vaccines against RNA viruses: diamond cuts diamond

The coronavirus pandemic has starkly demonstrated the need to create highly effective vaccines against various viral diseases. The emerging new platforms for vaccine creation (adenovirus vectors and mRNA vaccines) have shown their worth in the fight against the prevention of coronavirus infection. However, adenovirus vectors and mRNA vaccines have a serious disadvantage: as a rule, only the S protein of the coronavirus is presented as an antigen. This tactic for preventing infection allows the ever-mutating virus to escape quickly from the immunity protection provided by such vaccines. Today, viral genomic databases are well-developed, which makes it possible to create new vaccines on a fundamentally new post-genomic platform. In addition, the technology for the synthesis of nucleic acids is currently experiencing an upsurge in demand in various fields of molecular biology. The accumulated experience suggests that the unique genomic sequences of viruses can act as antigens that trigger powerful humoral and cellular immunity. To achieve this effect, the following conditions must be created: the structure of the nucleic acid must be single-stranded, have a permanent 3D nanostructure, and have a unique sequence absent in the vaccinated organism. Oligonucleotide vaccines are able to resist the rapidly changing genomic sequences of RNA viruses by using conserved regions of their genomes to generate a long-term immune response, acting according to the adage that a diamond cuts a diamond. In addition, oligonucleotide vaccines will not contribute to antibody-dependent enhanced infection, since the nucleic acid of the coronavirus is inside the viral particle. It is obvious that new epidemics and pandemics caused by RNA viruses will continue to arise periodically in the human population. The creation of new, safe, and effective platforms for the production of vaccines that can flexibly change and adapt to new subtypes of viruses is very urgent and at this moment should be considered as a strategically necessary task.

The Role of B1 Cells in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by multisystemic and multi-organ involvement, recurrent relapses and remissions, and the presence of large amounts of autoantibodies in the body as the main clinical features. The mechanisms involved in this disease are complex and remain poorly understood; however, they are generally believed to be related to genetic susceptibility factors, external stimulation of the body’s immune dysfunction, and impaired immune regulation. The main immune disorders include the imbalance of T lymphocyte subsets, hyperfunction of B cells, production of large amounts of autoantibodies, and further deposition of immune complexes, which result in tissue damage. Among these, B cells play a major role as antibody-producing cells and have been studied extensively. B1 cells are a group of important innate-like immune cells, which participate in various innate and autoimmune processes. Yet the role of B1 cells in SLE remains unclear. In this review, we focus on the mechanism of B1 cells in SLE to provide new directions to explore the pathogenesis and treatment modalities of SLE.

High p16INK4a, a marker of cellular senescence, is associated with renal injury, impairment and outcome in lupus nephritis

Objectives

Because a significant fraction of patients with lupus nephritis (LN) develops renal impairment, there is a need to better understand the mechanisms underlying disease progression. Here, we assessed for cellular senescence in the LN kidney, and its association with disease severity and outcome.

Methods

We enumerated the number of cells positive for p16^INK4a protein, a marker of cellular senescence, by immunohistochemistry followed by digital quantification, on renal biopsies from 40 patients with active LN. We tested for an association of p16^INK4a with renal fibrosis, CD8⁺ T cell infiltration, systemic disease and renal function at baseline and at 5 years.

Results

The presence of p16^INK4a-positive cells was significantly associated with lower estimated glomerular filtration rate at baseline and 5 years post-treatment, independently of patient demographics and systemic disease parameters. It was also associated with higher baseline renal fibrosis and CD8⁺ T cell infiltration. Interestingly, we observed marked spatial co-distribution of glomerular p16^INK4a-positive cells with CD8⁺ T cells.

Conclusion

We demonstrate, for the first time, that LN biopsies characterised by renal impairment display increased p16^INK4a-positive cells, associated with higher fibrosis and CD8⁺ T cell infiltration. Cellular senescence may represent a kidney-intrinsic disease mechanism and potentially, a novel therapeutic target in LN.

5,6,7,8-Tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidine derivative attenuates lupus nephritis with less effect to thymocyte development

Retinoic‑acid‑receptor‑related orphan nuclear hormone receptor gamma t (RORγt), a critical transcriptional factor of Th17 cells, is a potential therapeutic target for Th17-mediated autoimmune diseases. In addition, RORγt is essential for thymocyte survival and lymph node development, and RORγt inhibition or deficiency causes abnormal thymocyte development, thymus lymphoma, and lymph node defect. Recent study demonstrated that specific regulation of Th17 differentiation related to the hinge region of RORγt. In this research, we investigated the effect of RORγt inhibitor, 5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidine derivative (TTP), in the therapy of lupus nephritis and its safety on thymocyte development. We demonstrated that TTP repressed the development of Th17 cells and ameliorated the autoimmune disease manifestation in the pristane-induced lupus nephritis mice model. The treatment of TTP in the mice did not interfere with thymocyte development, including total thymocyte number and proportion of CD4+CD8+ double-positive populations in the thymus, and had no substantial effects on the pathogenesis of thymoma. The TTP had a stronger affinity with full-length RORγt protein compared with the truncated RORγt LBD region via surface plasmon resonance, which indicated TTP binding to RORγt beyond LBD region. Molecular docking computation showed that the best binding pocket of TTP to RORγt is located in the hinge region of RORγt. In summary, as a RORγt inhibitor, TTP had a potential to develop the clinical medicine for treating Th17-mediated autoimmune diseases with low safety risk for thymocyte development.

Neonatal Fc receptor in human immunity: Function and role in therapeutic intervention

The humoral immune response provides specific, long-lived protection against invading pathogens, via immunoglobulin production and other memory functions. IgG, the most abundant immunoglobulin isotype, has the longest half-life and protects against bacterial and viral infections. The neonatal Fc receptor (FcRn) transports IgG across barriers, for example, the placenta, enhancing fetal humoral immunity to levels similar to their mothers'. Importantly, FcRn, by protecting IgG from intracellular degradation, results in an approximately 21-day circulating IgG half-life and high plasma levels; similarly, FcRn recycles albumin and is the portal of entry for enteric cytopathic human orphan (echo) virus infection. Dysregulated immune responses may lead to antibodies against self-antigens (autoantibodies), resulting in organ-specific or systemic autoimmune diseases. Autoantibody-mediated diseases have been treated by nonspecific immunoglobulin-lowering/modulating therapies, including immunoadsorption, plasma exchange, and high-dose intravenous immunoglobulin. However, targeting FcRn with specific inhibitors results in reduction in only IgG levels. The effectiveness of FcRn inhibitors in autoimmune diseases, including myasthenia gravis and immune thrombocytopenia, provides further evidence that IgG is a primary driver in these autoantibody-mediated diseases. We describe the role of FcRn in human biology, including insights that clinical testing of FcRn inhibitors have provided into FcRn biology and autoimmune disease mechanisms, allowing fact-based speculation on their therapeutic potential.

Management of Lupus Nephritis

Lupus nephritis (LN) is a frequent and severe manifestation of systemic lupus erythematosus. The main goal of the management of LN is to avoid chronic kidney disease (CKD). Current treatment strategies remain unsatisfactory in terms of complete renal response, prevention of relapses, CKD, and progression to end-stage kidney disease. To improve the prognosis of LN, recent data suggest that we should (i) modify our treat-to-target approach by including, in addition to a clinical target, a pathological target and (ii) switch from conventional sequential therapy to combination therapy. Here, we also review the results of recent controlled randomized trials.

B Cell Aberrance in Lupus: the Ringleader and the Solution

Systemic lupus erythematosus (SLE) is a prototypical autoimmune disease with high heterogeneity but the common characterization of numerous autoantibodies and systemic inflammation which lead to the damage of multiple organs. Aberrance of B cells plays a pivotal role in the immunopathogenesis of SLE via both antibody-dependent and antibody-independent manners. Escape of autoreactive B cells from the central and peripheral tolerance checkpoints, over-activation of B cells and their excessive cytokines release which drive T cells and dendritic cells stimulation, and dysregulated surface molecules, as well as intracellular signal pathways involved in B cell biology, are all contributing to B cell aberrance and participating in the pathogenesis of SLE. Based on that rationale, targeting aberrance of B cells and relevant molecules and pathways is expected to be a promising strategy for lupus control. Multiple approaches targeting B cells through different mechanisms have been attempted, including B-cell depletion via monoclonal antibodies against B-cell-specific molecules, blockade of B-cell survival and activation factors, suppressing T-B crosstalk by interrupting costimulatory molecules and inhibiting intracellular activation signaling cascade by targeting pathway molecules in B cells. Though most attempts ended in failure, the efficacy of B-cell targeting has been encouraged by the FDA approval of belimumab that blocks B cell-activating factor (BAFF) and the recommended use of anti-CD20 as a remedial therapy in refractory lupus. Still, quantities of clinical trials targeting B cells or relevant molecules are ongoing and some of them have displayed promising preliminary results. Additionally, advances in multi-omics studies help deepen our understandings of B cell biology in lupus and may promote the discovery of novel potential therapeutic targets. The combination of real-world data with basic research achievements may pave the road to conquering lupus.

Relationship between natural and infection-induced antibodies in systemic autoimmune diseases (SAD): SLE, SSc and RA

Infection or vaccine-induced T cell-dependent immune response and the subsequent high-affinity neutralizing antibody production have been extensively studied, while the connection between natural autoantibodies (nAAbs) and disease-specific antibodies has not been thoroughly investigated. Our goal was to find the relationship between immunoglobulin (Ig)M and IgG isotype nAAbs and infection or vaccine-induced and disease-related autoantibody levels in systemic autoimmune diseases (SAD). A previously described indirect enzyme-linked immunosorbent assay (ELISA) test was used for detection of IgM/IgG nAAbs against citrate synthase (anti-CS) and F4 fragment (anti-F4) of DNA topoisomerase I in 374 SAD samples, with a special focus on systemic lupus erythematosus (SLE) (n = 92), rheumatoid arthritis (n = 73) and systemic sclerosis (n = 157) disease groups. Anti-measles IgG and anti-dsDNA IgG/IgM autoantibodies were measured using commercial and in-house indirect ELISA tests. In all SAD groups the anti-measles IgG-seropositive cases showed significantly higher anti-CS IgG titers (P = 0·011). In anti-dsDNA IgG-positive SLE patients, we detected significantly higher levels of anti-CS and anti-F4 IgG nAAbs (P = 0·001 and < 0·001, respectively). Additionally, we found increased levels of IgM isotypes of anti-CS and anti-F4 nAAbs in anti-dsDNA IgM-positive SLE patients (P = 0·002 and 0·016, respectively). The association between IgG isotypes of pathogen- or autoimmune disease-related antibodies and the IgG nAAbs may underscore the immune response-inducible nature of the diseases investigated. The relationship between protective anti-dsDNA IgM and the IgM isotype of anti-F4 and anti-CS may provide immunoserological evidence for the beneficial roles of nAAbs in SLE patients.

Intermittent Fasting Aggravates Lupus Nephritis through Increasing Survival and Autophagy of Antibody Secreting Cells in MRL/lpr Mice

Systemic lupus erythematosus (SLE) is an autoimmune disease in which the main contributors to organ damage are antibodies against autoantigens, such as double-stranded DNA (dsDNA). Calorie restriction and intermittent fasting (IF) have been shown to improve autoimmune disease symptoms in patients and animal models. Here, we tested the hypothesis that IF might improve symptoms in MRL/lpr mice, which spontaneously develop an SLE-like disease. Groups of mice were fed every other day (IF) or provided food ad libitum (controls), and various lupus-associated clinicopathological parameters were analyzed for up to 28 weeks. Contrary to expectations, anti-dsDNA antibody levels, immune complex deposition in the kidney, and glomerular injury were higher in the IF group than the control group, although there were no differences in spleen and lymph node weights between groups. Proteinuria was also worsened in the IF group. IF also increased the abundance of B cells, plasmablasts, and plasma cells and elevated autophagy in plasma cells in the spleen and lymph nodes. Secretion of anti-dsDNA antibody by splenocytes in vitro was reduced by chloroquine-induced inhibition of autophagy. These results suggest that IF exacerbates lupus nephritis in MRL/lpr mice by increasing autoantibody immune complex formation.

Autoimmunity and SLE: Factual and Semantic Evidence-Based Critical Analyses of Definitions, Etiology, and Pathogenesis

One cannot discuss anti-dsDNA antibodies and lupus nephritis without discussing the nature of Systemic lupus erythematosus (SLE). SLE is insistently described as a prototype autoimmune syndrome, with anti-dsDNA antibodies as a central biomarker and a pathogenic factor. The two entities, "SLE" and "The Anti-dsDNA Antibody," have been linked in previous and contemporary studies although serious criticism to this mutual linkage have been raised: Anti-dsDNA antibodies were first described in bacterial infections and not in SLE; later in SLE, viral and parasitic infections and in malignancies. An increasing number of studies on classification criteria for SLE have been published in the aftermath of the canonical 1982 American College of Rheumatology SLE classification sets of criteria. Considering these studies, it is surprising to observe a nearby complete absence of fundamental critical/theoretical discussions aimed to explain how and why the classification criteria are linked in context of etiology, pathogenicity, or biology. This study is an attempt to prioritize critical comments on the contemporary definition and classification of SLE and of anti-dsDNA antibodies in context of lupus nephritis. Epidemiology, etiology, pathogenesis, and measures of therapy efficacy are implemented as problems in the present discussion. In order to understand whether or not disparate clinical SLE phenotypes are useful to determine its basic biological processes accounting for the syndrome is problematic. A central problem is discussed on whether the clinical role of anti-dsDNA antibodies from principal reasons can be accepted as a biomarker for SLE without clarifying what we define as an anti-dsDNA antibody, and in which biologic contexts the antibodies appear. In sum, this study is an attempt to bring to the forum critical comments on the contemporary definition and classification of SLE, lupus nephritis and anti-dsDNA antibodies. Four concise hypotheses are suggested for future science at the end of this analytical study.

Autoantibody-dependent amplification of inflammation in SLE

Anti-double stranded DNA antibodies (anti-dsDNA) are a hallmark of SLE but their role in disease pathogenesis is not fully resolved. Anti-dsDNA in serum are highly heterogeneous therefore in this study, we aimed to dissect the functional specificities of anti-dsDNA using a panel of human monoclonal antibodies (humAbs) generated from patients with active lupus nephritis. A total of 46 ANA reactive humAbs were isolated and divided into four broad classes based on their reactivity to histones, DNA and Crithidia. Functional analysis indicated that one subclass of antibodies bound strongly to decondensed DNA areas in neutrophil extracellular traps (NETs) and protected NETs from nuclease digestion, similar to the sera from active SLE patients. In addition, these anti-dsDNA antibodies could stimulate type I interferon responses in mononuclear phagocytic cells, or NF-kB activity in endothelial cells, by uptake of NETs-anti-NETs immune complexes and subsequently trigging inflammatory responses in an Fc-gamma receptor (Fcg-R)-dependant manner. Together our data suggest that only a subset of anti-dsDNA antibodies is capable to amplify inflammatory responses by deposit in the nephritic kidney in vivo, protecting NETs digestion as well as uptake of NETs immune complexes into Fcg-R-expressing cells in vitro.

The Detection of Serum IgMs to Thyroglobulin in Subacute Thyroiditis Suggests a Protective Role of IgMs in Thyroid Autoimmunity

CONTEXT

The role of serum immunoglobulin (Ig)Ms in autoimmune thyroid diseases is uncertain.

OBJECTIVE

We looked for IgMs to thyroglobulin (Tg) in patients with subacute thyroiditis (SAT), which is characterized by high serum Tg levels, the possible de novo appearance of IgGs to Tg (TgAb-IgGs), and no autoimmune sequelae.

MAIN OUTCOME MEASURES

TgAb-IgMs and TgAb-IgGs were detected by binding to Tg using the enzyme-linked immunosorbent assay (ELISA). The upper reference limit of TgAb-IgMs and TgAb-IgGs was established in 40 normal subjects. We looked for TgAb-IgMs in 16 patients with SAT, 11 with Hashimoto's thyroiditis (HT), and 8 with Graves' disease (GD) who were all positive for TgAb-IgGs. IgM binding to bovine serum albumin (BSA), keyhole limpet hemocyanin (KLH), and glucagon in ELISA was measured. Inhibition of TgAb-IgMs binding to coated Tg was evaluated by preincubating serum samples or IgG-depleted samples with soluble Tg.

RESULTS

TgAb-IgMs were positive in 10/16 patients with SAT, 2/11 with HT, and 1/8 with GD. TgAb-IgMs were higher in SAT (0.95; 0.42-1.13) (median; 25th-75th percentiles) than in HT (0.47; 0.45-0.51) and GD patients (0.35; 0.33-0.40) (P < .005 for both). IgM binding of SAT sera to BSA, KLH, and glucagon was significantly lower than Tg. Preincubation with soluble Tg reduced the binding of IgMs to coated Tg by 18.2% for serum samples and by 35.0% and 42.1% for 2 IgG-depleted samples. TgAb-IgM levels were inversely, although nonsignificantly, correlated with Tg concentrations.

CONCLUSIONS

Tg leak associated with thyroid injury induces the production of specific TgAb-IgMs, which, in turn, increases the clearance of Tg and might prevent the establishment of a persistent thyroid autoimmune response.

Evolving story of autoantibodies in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease characterized by antinuclear antibody (ANA) production. ANAs bind to DNA, RNA and complexes of proteins and nucleic acids and are important markers for diagnosis and activity. According to current models, ANAs originate from antigen-driven processes; nevertheless, antibody responses to both DNA and RNA binding proteins display features unexpected in terms of current paradigms for antigenicity. These differences may reflect disturbances in both B and T cells critical for autoreactivity. Clinically, ANA testing has new uses for determining classification as well as assessing eligibility for clinical trials. Studies of patients with established disease show frequent seronegativity. In this setting, seronegativity may indicate a stage of disease called post-autoimmunity in which the natural history of disease or effects of immunosuppressive therapies modifies responses. The new uses of ANA testing highlight the importance of understanding autoantigenicity and developing sensitive and informative assays for clinical assessments.

Reduction of circulating innate lymphoid cell progenitors results in impaired cytokine production by innate lymphoid cells in patients with lupus nephritis

Background

Innate lymphoid cells (ILCs) play an essential role in maintaining homeostasis; however, they can also cause chronic inflammation and autoimmune disease. This study aimed to identify the role of ILCs in the pathogenesis of lupus nephritis (LN).

Methods

The percentage of ILCs within the peripheral blood mononuclear cell (PBMC) population and urine of patients with LN (n = 16), healthy controls (HC; n = 8), and disease controls (ANCA-associated vasculitis (AAV; n = 6), IgA nephropathy (IgAN; n = 9), and other glomerular diseases (n = 5)) was determined by flow cytometry analysis. In addition, ILCs were sorted and cultured with plasma from LN patients or HC to elucidate whether the reduced population of CD117⁺ ILCs observed in LN was due to changes in the ILC progenitor population.

Results

The percentage of total ILCs and CD117⁺ ILCs in LN was significantly lower than that in HC. The percentage of cytokine-secreting ILCs was also lower in LN; however, when the disease stabilized, cytokine production was restored to levels similar to those in HC. The increase in the number of exhausted ILCs (cells unable to secrete cytokines) correlated positively with disease activity. When CD117⁺ ILCs were cultured with LN plasma, the number of CD117⁺ ILCs fell, but that of other ILC subsets increased.

Conclusions

The percentage of CD117⁺ ILCs and the capacity of ILCs to secrete cytokines fell as LN severity increased, suggesting that an inflammatory environment of LN induces persistent differentiation and exhaustion of ILCs.

Autoantigens in the trabecular meshwork and glaucoma-specific alterations in the natural autoantibody repertoire

OBJECTIVES

Primary open-angle glaucoma (POAG) is a neurodegenerative disorder leading to a gradual vision loss caused by progressive damage to the optic nerve. Immunological processes are proposed to be involved in POAG pathogenesis. Altered serological autoantibody levels have been frequently reported, but complete analyses of the natural autoantibodies with respect to disease-related alterations are scarce. Here, we provide an explorative analysis of pathways and biological processes that may involve naturally immunogenic proteins and highlight POAG-specific alterations.

METHODS

Mass spectrometry-based antibody-mediated identification of autoantigens (MS-AMIDA) was carried out in healthy and glaucomatous trabecular meshwork (TM) cell lines, using antibody pools purified from serum samples of 30 POAG patients and 30 non-glaucomatous subjects. Selected antigens were validated by protein microarray (n = 120). Bioinformatic assessment of identified autoantigens, including Gene Ontology (GO) enrichment analysis and protein-protein interaction networks, was applied.

RESULTS

Overall, we identified 106 potential autoantigens [false discovery rate (FDR) < 0.01], from which we considered 66 as physiological targets of natural autoantibodies. Twenty-one autoantigens appeared to be related to POAG. Bioinformatic analysis revealed that the platelet-derived growth factor receptor beta (PDGFRB) pathway involved in TM fibrosis was particularly rich in POAG-related antigens. Antibodies to threonine-tRNA ligase (TARS), component 1 Q subcomponent-binding protein (C1QBP) and paraneoplastic antigen Ma2 (PNMA2) showed significantly (P < 0.05) higher levels in POAG patients as validated by protein microarray.

CONCLUSION

This study provides new insights into autoimmunity in health and glaucoma. Bioinformatic analysis of POAG-related autoantigens showed a strong association with the PDGFRB pathway and also increased levels of PNMA2, TARS, and C1QBP autoantibodies in the serum of POAG patients as potential glaucoma biomarkers.

Increased levels of anti-dsDNA antibodies in immune complexes before treatment with belimumab associate with clinical response in patients with systemic lupus erythematosus

INTRODUCTION

Immune complexes are of importance in systemic lupus erythematosus pathogenesis, and autoantibodies are believed to participate in immune complex formation. Quantification of autoantibody levels in circulating IC might be of prognostic value.

METHODS

A C1q-binding-eluting technique was applied to purify immune complexes from 55 belimumab-treated systemic lupus erythematosus patients during a 24-month follow-up. Autoantibodies in serum and in solubilized immune complexes were quantified using addressable laser bead immunoassay. We investigated whether levels of autoantibodies in immune complexes associate with disease activity and response to belimumab treatment.

RESULTS

High baseline anti-double-stranded DNA and anti-histone levels in immune complexes associated with attainment of zero scores in clinical systemic lupus erythematosus disease activity index 2000 during the 24-month follow-up (p = 0.003 and p = 0.048, respectively). Low complement levels associated with high serum anti-double-stranded DNA and anti-ribosomal P levels (p = 0.003 and p = 0.008, respectively) and high anti-double-stranded DNA (p = 0.002) but not anti-ribosomal P levels in immune complexes. Anti-SSA/SSB serum levels were lower in patients attaining lupus low disease activity state at month 6; these associations were stronger for corresponding immune complex levels. Serum levels of most autoantibodies had declined at month 3, whereas autoantibody levels in immune complexes, except for anti-double-stranded DNA, showed a more gradual decline over 1-2 years. Serum anti-double-stranded DNA levels decreased in all patients irrespective of systemic lupus erythematosus disease activity index 2000=0 attainment, whereas immune complex levels decreased only in achievers.

CONCLUSION

Immune complex levels of autoantibodies against double-stranded DNA and the SSA/SSB complex show more specific associations with treatment outcome compared with serum levels in belimumab-treated systemic lupus erythematosus patients. Characterization of autoantibody content in circulating immune complexes could prove useful in treatment evaluation in systemic lupus erythematosus and other immune complex-associated diseases.

Pattern recognition receptors as potential drug targets in inflammatory disorders

Pattern recognition receptors (PRRs) are a key part of the innate immune system, the body's first line of defense against infection and tissue damage. This superfamily of receptors including Toll-like receptors (TLRs), NOD-like receptors (NLRs), C-type lectin-like receptors (CLRs) and RIG-like receptors (RLRs) are responsible for initiation of the inflammatory response by their recognition of molecular patterns present in invading microorganisms (such as bacteria, viruses or fungi) during infection or in molecules released following tissue damage during acute or chronic disease states (such as sepsis or arthritis). These receptors are widely expressed and located on the cell surface, in intracellular compartments or in the cytoplasm can detect a single or subset of molecules including lipoproteins, carbohydrates or nucleic acids. In response, they initiate an intracellular signaling cascade that culminates in the synthesis and release of cytokines, chemokines and vasoactive molecules. These steps are necessary to maintain tissue homeostasis and remove potentially dangerous pathogens. However, during extreme or acute responses or during chronic disease, this can be damaging and even lead to death. Therefore, it is thought that targeting such receptors may offer a therapeutic approach in chronic inflammatory diseases or in cases of acute infection leading to sepsis. Herein, the current knowledge on the molecular biology of PRRs is reviewed along with their association with inflammatory and infectious diseases. Finally, the testing of therapeutic compounds and their future merit as targets is discussed.

Anti-Smith antibody is associated with disease activity in patients with new-onset systemic lupus erythematosus

Although anti-Smith (Sm) antibody is a highly specific antibody for systemic lupus erythematosus (SLE), the significance of anti-Sm antibody in patients with SLE is unclear. This study aimed to evaluate the association between anti-Sm antibodies and disease activity in patients with new-onset SLE. We included patients who were tested for anti-Sm antibodies at SLE diagnosis and within 12 months after diagnosis. SLE disease activity index (SLEDAI) was obtained at the time of the anti-Sm antibody test. The baseline disease activity was compared between patients with and without anti-Sm antibodies. The longitudinal association between disease activity and anti-Sm antibodies was also evaluated in total patients and in those with anti-Sm antibodies. Among 92 patients who were tested for anti-Sm antibodies at SLE diagnosis, 67 and another 67 patients were followed up for the presence of anti-Sm antibodies at 6 and 12 months, respectively. Although the baseline SLEDAI was comparable in patients with and without anti-Sm antibodies, the serum level of anti-Sm antibody was significantly correlated with SLEDAI (P = 0.003). At 12 months, anti-Sm antibody positivity was associated with higher SLEDAI and anti-dsDNA titer (P = 0.002, both). In addition, the changes in anti-Sm antibody titer over 12 months were correlated with the alterations in SLEDAI (P = 0.029).Anti-Sm antibody was associated with the baseline disease activity and the alteration of disease activity in patients with new-onset SLE. Monitoring of anti-Sm antibody titer may help assess the disease activity in SLE.

Glucocorticoids-All-Rounders Tackling the Versatile Players of the Immune System

Glucocorticoids regulate fundamental processes of the human body and control cellular functions such as cell metabolism, growth, differentiation, and apoptosis. Moreover, endogenous glucocorticoids link the endocrine and immune system and ensure the correct function of inflammatory events during tissue repair, regeneration, and pathogen elimination via genomic and rapid non-genomic pathways. Due to their strong immunosuppressive, anti-inflammatory and anti-allergic effects on immune cells, tissues and organs, glucocorticoids significantly improve the quality of life of many patients suffering from diseases caused by a dysregulated immune system. Despite the multitude and seriousness of glucocorticoid-related adverse events including diabetes mellitus, osteoporosis and infections, these agents remain indispensable, representing the most powerful, and cost-effective drugs in the treatment of a wide range of rheumatic diseases. These include rheumatoid arthritis, vasculitis, and connective tissue diseases, as well as many other pathological conditions of the immune system. Depending on the therapeutically affected cell type, glucocorticoid actions strongly vary among different diseases. While immune responses always represent complex reactions involving different cells and cellular processes, specific immune cell populations with key responsibilities driving the pathological mechanisms can be identified for certain autoimmune diseases. In this review, we will focus on the mechanisms of action of glucocorticoids on various leukocyte populations, exemplarily portraying different autoimmune diseases as heterogeneous targets of glucocorticoid actions: (i) Abnormalities in the innate immune response play a crucial role in the initiation and perpetuation of giant cell arteritis (GCA). (ii) Specific types of CD4+ T helper (Th) lymphocytes, namely Th1 and Th17 cells, represent important players in the establishment and course of rheumatoid arthritis (RA), whereas (iii) B cells have emerged as central players in systemic lupus erythematosus (SLE). (iv) Allergic reactions are mainly triggered by several different cytokines released by activated Th2 lymphocytes. Using these examples, we aim to illustrate the versatile modulating effects of glucocorticoids on the immune system. In contrast, in the treatment of lymphoproliferative disorders the pro-apoptotic action of glucocorticoids prevails, but their mechanisms differ depending on the type of cancer. Therefore, we will also give a brief insight into the current knowledge of the mode of glucocorticoid action in oncological treatment focusing on leukemia.

Opposite Profiles of Complement in Antiphospholipid Syndrome (APS) and Systemic Lupus Erythematosus (SLE) Among Patients With Antiphospholipid Antibodies (aPL)

APS is the association of antiphospholipid antibodies (aPL) with thromboses and/or recurrent pregnancy loss (RPL). Among patients with SLE, one-third have aPL and 10–15% have a manifestation of secondary APS. Animal studies suggested that complement activation plays an important role in the pathogenesis of thrombosis and pregnancy loss in APS. We performed a cross-sectional study on complement proteins and genes in 525 patients with aPL. Among them, 237 experienced thromboses and 293 had SLE; 111 had both SLE and thromboses, and 106 had neither SLE nor thrombosis. Complement protein levels were determined by radial immunodiffusion for C4, C3 and factor H; and by functional ELISA for mannan binding lectin (MBL). Total C4, C4A and C4B gene copy numbers (GCN) were measured by TaqMan-based realtime PCR. Two to six copies of C4 genes are frequently present in a diploid genome, and each copy may code for an acidic C4A or a basic C4B protein. We observed significantly (a) higher protein levels of total C4, C4A, C4B, C3, and anticardiolipin (ACLA) IgG, (b) increased frequencies of lupus anticoagulant and males, and (c) decreased levels of complement factor H, MBL and ACLA-IgM among patients with thrombosis than those without thrombosis (N = 288). We also observed significantly lower GCNs of total C4 and C4A among aPL-positive patients with both SLE and thrombosis than others. By contrast, aPL-positive subjects with SLE had significantly reduced protein levels of C3, total C4, C4A, C4B and ACLA-IgG, and higher frequency of females than those without SLE. Patients with thrombosis but without SLE (N = 126), and patients with SLE but without thrombosis (N = 182) had the greatest differences in mean protein levels of C3 (p = 2.6 × 10⁻⁶), C4 (p = 2.2 × 10⁻⁹) and ACLA-IgG (p = 1.2 × 10⁻⁵). RPL occurred in 23.7% of female patients and thrombotic SLE patients had the highest frequency of RPL (41.0%; p = 3.8 × 10⁻¹⁰). Compared with non-RPL females, RPL had significantly higher frequency of thrombosis and elevated C4 protein levels. Female patients with homozygous C4A deficiency all experienced RPL (p = 0.0001) but the opposite was true for patients with homozygous C4B deficiency (p = 0.017). These results provide new insights and biomarkers for diagnosis and management of APS and SLE.

In the Right Place, at the Right Time: Spatiotemporal Conditions Determining Plasma Cell Survival and Function

Plasma cells (PCs), the B lineage cells responsible for producing and secreting antibodies (Abs), are critical cellular components of the humoral immune system. While most of the antibody-secreting cells in the body have a rather short lifetime of a few days, some of them can become long-lived and persist in the body over the entire life span of an individual. The majority of these long-lived plasma cells secretes protective antibodies against pathogens, and are thereby crucial for the humoral component of immunological memory. The generation of these protective antibody-secreting cells can be triggered by an exposure to pathogens, and also by vaccination. Although the majority of plasma cells are protective, sometimes long-lived plasma cells produce autoreactive antibodies, which contribute to the pathogenesis and perpetuation of chronic autoimmune diseases, including lupus erythematosus, rheumatoid arthritis, or multiple sclerosis. In order to promote the formation of protective antibody-secreting cells and to target pathogenic plasma cells, it is crucial to understand the signals which promote their longevity and allow them to exert their function. In recent years, it has become clear that plasma cells depend on extrinsic factors for their survival, leading to the concept that certain tissue microenvironments promote plasma cell retention and longevity. However, these niches are not static structures, but also have dynamic features with respect to their cellular composition. Here, we review what is known about the molecular and cellular composition of the niches, and discuss the impact of dynamic changes within these microenvironments on plasma cell function. As plasma cell metabolism is tightly linked to their function, we present new tools, which will allow us to analyze metabolic parameters in the plasma cell niches in vivo over time.

Parvovirus B19V Nonstructural Protein NS1 Induces Double-Stranded Deoxyribonucleic Acid Autoantibodies and End-Organ Damage in Nonautoimmune Mice

BACKGROUND

Viral infection is implicated in development of autoimmunity. Parvovirus B19 (B19V) nonstructural protein, NS1, a helicase, covalently modifies self double-stranded deoxyribonucleic acid (dsDNA) and induces apoptosis. This study tested whether resulting apoptotic bodies (ApoBods) containing virally modified dsDNA could induce autoimmunity in an animal model.

METHODS

BALB/c mice were inoculated with (1) pristane-induced, (2) B19V NS1-induced, or (3) staurosporine-induced ApoBods. Serum was tested for dsDNA autoantibodies by Crithidia luciliae staining and enzyme-linked immunosorbent assay. Brain, heart, liver, and kidney pathology was examined. Deposition of self-antigens in glomeruli was examined by staining with antibodies to dsDNA, histones H1 and H4, and TATA-binding protein.

RESULTS

The B19V NS1-induced ApoBod inoculation induced dsDNA autoantibodies in a dose-dependent fashion. Histopathological features of immune-mediated organ damage were evident in pristane-induced and NS1-induced ApoBod groups; severity scores were higher in these groups than in staurosporine-treated groups. Tissue damage was dependent on NS1-induced ApoBod dose. Nucleosomal antigens were deposited in target tissue from pristane-induced and NS1-induced ApoBod inoculated groups, but not in the staurosporine-induced ApoBod inoculated group.

CONCLUSIONS

This study demonstrated proof of principle in an animal model that virally modified dsDNA in apoptotic bodies could break tolerance to self dsDNA and induce dsDNA autoantibodies and end-organ damage.

The Impact of Autoantibodies on IVF Treatment and Outcome: A Systematic Review

The role of autoantibodies in in vitro fertilization (IVF) has been discussed for almost three decades. Nonetheless, studies are still scarce and widely controversial. The aim of this study is to provide a comprehensive systematic review on the possible complications associated to autoantibodies (AA) impeding the chances of a successful IVF cycle. An Embase, PubMed/Medline and Cochrane Central Database search was performed on 1 December 2018, from 2006 until that date. From the 598 articles yielded in the search only 44 relevant articles ultimately fulfilled the inclusion criteria and were qualitatively analyzed. Five subsets of results were identified, namely, thyroid related AA, anti-phospholipid antibodies, anti-nuclear antibodies, AA affecting the reproductive system and AA related to celiac disease. It may be implied that the majority of auto-antibodies exert a statistically significant effect on miscarriage rates, whereas the effects on clinical pregnancy and live birth rates differ according to the type of auto-antibodies. While significant research is performed in the field, the quality of evidence provided is still low. The conduction of well-designed prospective cohort studies is an absolute necessity in order to define the impact of the different types of autoantibodies on IVF outcome.

Th17 cells in renal inflammation and autoimmunity

Th17 cells are a distinct lineage of T-cells. These T-cells express IL-17A and the lineage-defining transcription factor RORγt. Th17 cells have a pivotal, physiological role in host defense against pathogens. These pro-inflammatory T-cells are also key players in autoimmunity and a pathogenic role has been demonstrated in several diseases such as rheumatoid arthritis or psoriasis. Recently, there is evidence that Th17 cells may drive renal inflammation and renal autoimmunity in anti-neutrophil-cytoplasmic-antibody-(ANCA)-vasculitis and systemic lupus erythematosus. The aim of this review is to discuss the possible involvement of Th17 cells in renal autoimmunity and its value for future therapeutic approaches.

In lupus nephritis, how do extracellular DNAs trigger type I interferon secretion: Under the assistance of HMGB1-cGAS?

Systemic lupus erythematosus (SLE) is an autoimmune disease with multiple organs involved. Kidney damage is common among SLE patients. In lupus nephritis, extracellular DNA accumulation from necrosis cells and activated cells is perceived as initial step of inflammation. The up-regulated type I IFN is one pivotal cytokine causing downstream inflammation enlargement. Currently, intracellular DNA sensor cGAS signaling has been found to be related to lupus nephritis and the aberrant up-regulation of type I IFN. However, how extracellular accumulated DNA activates intracellular cGAS is still unknown. It was reported that nuclear protein HMGB1 takes part in multiple autoimmune diseases and inflammation induction. When HMGB1 is secreted to extracellular environment under certain conditions, it combines with DNA and triggers IFN-I secretion. It has been reported that HMGB1 level in renal tissue and cGAS level in peripheral blood mononuclear cells were both significantly up-regulated in SLE patients. Hence, we present a hypothesis that in lupus nephritis, the released HMGB1 helps extracellular accumulated DNA endocytosis and cGAS signaling pathway activation, followed by IFN-I secretion. We infer this is one pivotal pro-inflammation pathway in lupus nephritis progression.

Intrarenal activation of adaptive immune effectors is associated with tubular damage and impaired renal function in lupus nephritis

Objectives

Chronic renal impairment remains a feared complication of lupus nephritis (LN). The present work aimed at identifying mechanisms and markers of disease severity in renal tissue samples from patients with LN.

Methods

We performed high-throughput transcriptomic studies (Illumina HumanHT-12 v4 Expression BeadChip) on archived kidney biopsies from 32 patients with LN and eight controls (pretransplant donors). Histological staging (glomerular and tubular scores) and immunohistochemistry experiments were performed on the same and on a replication set of 37 LN kidney biopsy samples.

Results

A group of LN samples was identified by unsupervised clustering studies based on their gene expression features, that is, the overexpression of transcripts involved in antigen presentation, T and B cell activation. These samples were characterised by a significantly lower estimated glomerular filtration rate (eGFR) at the time of biopsy (T0) compared with the other systemic lupus erythematosus samples. Yet, apparent disease duration at T0, double-stranded DNA antibody titres at T0 and other relevant characteristics (serum C3, proteinuria, histological scores, numbers of previous flares) were not different between groups.

Immunohistochemistry studies confirmed the association between interstitial infiltration by adaptive immune effectors and decreased renal function in the same and in a replication group of LN kidney biopsies. This was associated with transcriptomic, histological and immunohistochemical evidence of renal tubular cell involvement.

Conclusion

Interstitial infiltration of LN kidney biopsies by adaptive immune effectors is associated with impaired renal tubular cell function and decreased eGFR. These results open new perspectives in evaluating and treating patients with LN, focusing on intrarenal mechanisms of immune cell activation.

Prozone-like phenomenon found in chemiluminescent enzyme immunoassay using magnetic particles for measurement of serum anti-single stranded DNA antibody titers: Definition and management

BACKGROUND

Serum anti-single stranded DNA antibody (anti-ssDNAab) is used as a marker for systemic lupus erythematosus. We found a 'prozone-like phenomenon,' which was different from an original prozone phenomenon, in chemiluminescent enzyme immunoassay using magnetic particles for the measurement of serum anti-ssDNAab titers. We investigated mechanisms of the prozone-like phenomenon and countermeasures to prevent it from being overlooked.

METHODS

This study examined 679 samples from patients tested for anti-ssDNAab titer at our hospital. In addition, the BF photometry OD value 2 (OD2), an index of optical density, was monitored simultaneously.

RESULTS

The undiluted samples with a prozone-like phenomenon showed extremely lower OD2. Those samples were able to be distinguished from other samples by setting OD2 criteria based on the 95% prediction interval. Significant differences (p < 0.05) were found in the titer ratios (ten-fold diluted against undiluted) between groups with >1.5 and other groups with <1.5 for the ratios of OD2.

CONCLUSIONS

We proposed two valuable methods to find a prozone-like phenomenon: one by setting OD2 criteria based on the 95% prediction interval and the other by analyzing the ratios both in titers and OD2 between undiluted and 10-fold diluted samples.

Systemic Lupus Erythematosus: Definitions, Contexts, Conflicts, Enigmas

Systemic lupus erythematosus (SLE) is an inadequately defined syndrome. Etiology and pathogenesis remain largely unknown. SLE is on the other hand a seminal syndrome that has challenged immunologists, biologists, genetics, and clinicians to solve its nature. The syndrome is characterized by multiple, etiologically unlinked manifestations. Unexpectedly, they seem to occur in different stochastically linked clusters, although single gene defects may promote a smaller spectrum of symptoms/criteria typical for SLE. There is no known inner coherence of parameters (criteria) making up the disease. These parameters are, nevertheless, implemented in The American College of Rheumatology (ACR) and The Systemic Lupus Collaborating Clinics (SLICC) criteria to classify SLE. Still, SLE is an abstraction since the ACR or SLICC criteria allow us to define hundreds of different clinical SLE phenotypes. This is a major point of the present discussion and uses "The anti-dsDNA antibody" as an example related to the problematic search for biomarkers for SLE. The following discussion will show how problematic this is: the disease is defined through non-coherent classification criteria, its complexity is recognized and accepted, its pathogenesis is plural and poorly understood. Therapy is focused on dominant symptoms or organ manifestations, and not on the syndrome itself. From basic scientific evidences, we can add substantial amount of data that are not sufficiently considered in clinical medicine, which may change the paradigms linked to what "The Anti-DNA antibody" is-and is not-in context of the imperfectly defined syndrome SLE.

Two Distinct Pathways in Mice Generate Antinuclear Antigen-Reactive B Cell Repertoires

The escape of anti-self B cells from tolerance mechanisms like clonal deletion, receptor editing, and anergy results in the production of autoantibodies, which is a hallmark of many autoimmune disorders. In this study, we demonstrate that both germline sequences and somatic mutations contribute to autospecificity of B cell clones. For this issue, we investigated the development of antinuclear autoantibodies (ANAs) and their repertoire in two different mouse models. First, in aging mice that were shown to gain several autoimmune features over time including ANAs. Second, in mice undergoing a chronic graft-versus-host disease (GVHD), thereby developing systemic lupus erythematosus-like symptoms. Detailed repertoire analysis revealed that somatic hypermutations (SHM) were present in all Vh and practically all Vl regions of ANAs generated in these two models. The ANA B cell repertoire in aging mice was restricted, dominated by clonally related Vh1-26/Vk4-74 antibodies. In the collection of GVHD-derived ANAs, the repertoire was less restricted, but the usage of the Vh1-26/Vk4-74 combination was still apparent. Germline conversion showed that the SHM in the 4-74 light chain are deterministic for autoreactivity. Detailed analysis revealed that antinuclear reactivity of these antibodies could be induced by a single amino acid substitution in the CDR1 of the Vk4-74. In both aging B6 and young GVHD mice, conversion of the somatic mutations in the Vh and Vl regions of non Vh1-26/Vk4-74 using antibodies showed that B cells with a germline-encoded V gene could also contribute to the ANA-reactive B cell repertoire. These findings indicate that two distinct pathways generate ANA-producing B cells in both model systems. In one pathway, they are generated by Vh1-26/Vk4-74 expressing B cells in the course of immune responses to an antigen that is neither a nuclear antigen nor any other self-antigen. In the other pathway, ANA-producing B cells are derived from progenitors in the bone marrow that express B cell receptors (BCRs), which bind to nuclear antigens and that escape tolerance induction, possibly as a result of crosslinking of their BCRs by multivalent determinants of nuclear antigens.

Biomarkers in connective tissue diseases

Autoimmune connective tissue diseases are clinically variable, making biomarkers desirable for assessing future disease risk, supporting early and accurate diagnosis, monitoring disease activity and progression, selecting therapeutics, and assessing treatment response. Because of their correlations with specific clinical characteristics and often with disease progression, autoantibodies and other soluble mediators are considered potential biomarkers. Additional biomarkers might reflect downstream pathologic processes or appear because of ongoing inflammation and damage. Because of overlap between diseases, some biomarkers have limited specificity for a single autoimmune connective tissue disease. This review describes select current biomarkers that aid in the diagnosis and treatment of several major systemic autoimmune connective tissue disorders: systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis, and anti-neutrophil cytoplasmic antibody-associated vasculitides. Newly proposed biomarkers that target various stages in disease onset or progression are also discussed. Newer approaches to overcome the diversity observed in patients with these diseases and to facilitate personalized disease monitoring and treatment are also addressed.

Transcriptomic profiling in human mesangial cells using patient-derived lupus autoantibodies identified miR-10a as a potential regulator of IL8

Autoantibody-mediated inflammation directed at resident kidney cells mediates lupus nephritis (LN) pathogenesis. This study investigated the role of miRNA in human mesangial cells (HMCs) stimulated with auto anti-dsDNA immunoglobulin (Ig)G antibodies. HMCs were treated with antibodies purified from active LN patients or non-specific IgG controls in the presence of normal serum. Aberrant miRNA was screened using high throughput sequencing. Anti-dsDNA IgG up-regulated 103 miRNAs and down-regulated 30 miRNAs. The miRNAs regulated genes in the cell cycle, catabolic processes, regulation of transcription and apoptosis signalling. miR-10a was highly abundant in HMCs but was specifically downregulated upon anti-dsDNA IgG induction. Interestingly, the expression of miR-10a in kidney biopsies from class III and IV LN patients (n = 26) was downregulated compared with cadaveric donor kidneys (n = 6). Functional studies highlighted the downstream regulator of miR-10a in the chemokine signalling and cell proliferation or apoptosis pathways. Luciferase assay confirmed for the first time that IL8 was a direct target of miR-10a in HMCs. In conclusion, anti-dsDNA IgG Ab down-regulated miR-10a expression in HMCs resulting in the induction of various target genes involved in HMC proliferation and chemokine expression.