Immune-mediated Renal Disease Research Articles

A novel flow cytometry panel to identify prognostic markers for steroid-sensitive forms of idiopathic nephrotic syndrome in childhood.

The clinical evolution of steroid-sensitive forms of pediatric idiopathic nephrotic syndrome (INS) is highly heterogeneous following the standard treatment with prednisone. To date, no prognostic marker has been identified to predict the severity of the disease course starting from the first episode. In this monocentric prospective cohort study we set up a reproducible and standardized flow cytometry panel using two sample tubes (one for B-cell and one for T-cell subsets) to extensively characterized the lymphocyte repertoire of INS pediatric patients. A total of 44 children with INS at disease onset were enrolled, sampled before and 3 months after standard induction therapy with prednisone and followed for 12 months to correctly classify their disease based on relapses. Age-matched controls with non immune-mediated renal diseases or with urological disorders were also enrolled. Demographical, clinical, laboratory and immunosuppressive treatment data were registered. We found that children with INS at disease onset had significantly higher circulating levels of total CD19+ and specific B-cell subsets (transitional, mature-naïve, plasmablasts/plasmacells, CD19+CD27+, unswitched, switched and atypical memory B cells) and reduced circulating levels of Tregs, when compared to age-matched controls. Prednisone therapy restored most B- and T-cell alterations. When patients were subdivided based on disease relapse, relapsing patients had significantly more transitional, CD19+CD27+ memory and in particular unswitched memory B cells at disease onset, which were predictive of a higher risk of relapse in steroid-sensitive patients by logistic regression analysis, irrespective of age. In accordance, B-cell dysregulations resulted mainly associated with steroid-dependence when patients were stratified in different disease severity forms. Of note, Treg levels were reduced independently from the disease subgroup and were not completely normalized by prednisone treatment. We have set up a novel, reproducible, disease-specific flow cytometry panel that allows a comprehensive characterization of circulating lymphocytes. We found that, at disease onset, relapsing patients had significantly more transitional, CD19+CD27+ memory and unswitched memory B cells and those who are at higher risk of relapse had increased circulating levels of unswitched memory B cells, independently of age. This approach can allow prediction of clinical evolution, monitoring of immunosuppression and tailored treatment in different forms of INS.

Renal Biopsy for Diagnosis in Kidney Disease: Indication, Technique, and Safety.

Renal biopsies are the gold standard for diagnosis, staging, and prognosis of underlying parenchymal kidney disease. This article provides an overview of the current indications and highlights ways to reduce bleeding complications in order to achieve optimal diagnostic yield with minimal risk to the patient. Novel indications have emerged from the increasing use of new molecularly targeted oncologic therapies in recent years, which often induce immune-mediated renal disease. On the other hand, the detection of specific antibodies against target antigens on podocytes in the sera of patients with new-onset nephrotic syndrome has now relativized the indication for biopsy in membranous nephropathy. The use of semi-automatic spring-loaded biopsy devices and real-time ultrasound considerably declined the complication rate and is the current standard. Percutaneous renal biopsies are overall a safe procedure if contraindications are considered. A coagulation disorder needs to be excluded beforehand, and an elevated blood pressure must be reduced to the normotensive range with medications. A laparoscopic approach or a radiology interventional procedure through the internal jugular vein may be considered for obtaining a kidney tissue sample if there is an urgent indication and a bleeding tendency cannot be adequately corrected. Major bleeding after a percutaneous renal biopsy can usually be managed with selective arterial embolization of the injured renal vessel. The use of a 16-gauge needle is the most reasonable compromise between diagnostic benefit and risk of complication. In the routine diagnostic, the biopsy specimen is examined with light microscopy, immunohistochemistry, and electron microscopy. Combination with modern molecular pathology techniques will contribute to more precise insights into the development and progression of kidney disease, which will likely refine future treatments in nephrology.

Targeting Monocyte Derived CCL17 Attenuates Murine Crescentic Glomerulonephritis by Affecting Renal CCR4+ Regulatory T-Cell Recruitment

Introduction: The chemokine receptor CCR4 is expressed by diverse CD4⁺ T cell subsets including regulatory T cells (Tregs) but its functional importance for leukocyte recruitment and the relevance of its two corresponding chemokines CCL17 and CCL22 have not been studied in immune-mediated crescentic glomerulonephritis (cGN). Methods: Utilizing the single-cell RNA sequencing (scRNAseq) data in analyzing leukocytes isolated from both human and murine nephritic kidneys, we identified CCL17 as a potential therapeutic target in immune-mediated renal disease. Using a mouse model of murine cGN, we then delineated the effects of targeting CCL17 by neutralizing antibodies and in Ccl17 gene-deficient mice. Results: Unsupervised scRNAseq analyses identified the CCL17-CCR4 axis as a mechanism potentially involved in renal T-cell migration. Analyses of functional kidney impairment and histopathological kidney damage revealed an attenuation of crescentic GN in anti-CCL17 antibody-treated mice which was corroborated using in Ccl17 gene-deficient mice. Immunohistochemical analyses revealed that these changes were accompanied by an affected renal Treg recruitment in both experimental approaches. Conclusion: The chemokine receptor CCR4 and its corresponding chemokine CCL17 are expressed in human and murine cGN and targeting the CCR4-CCL17 axis by neutralizing antibodies as well as Ccl17 gene deficiency led to increased renal Treg recruitment and reduced histological and functional kidney damage in murine cGN.

Deep learning-based multi-model approach on electron microscopy image of renal biopsy classification

BackgroundElectron microscopy is important in the diagnosis of renal disease. For immune-mediated renal disease diagnosis, whether the electron-dense granule is present in the electron microscope image is of vital importance. Deep learning methods perform well at feature extraction and assessment of histologic images. However, few studies on deep learning methods for electron microscopy images of renal biopsy have been published. This study aimed to develop a deep learning-based multi-model to automatically detect whether the electron-dense granule is present in the TEM image of renal biopsy, and then help diagnose immune-mediated renal disease.MethodsThree deep learning models are trained to classify whether the electron-dense granule is present using 910 electron microscopy images of renal biopsies. We proposed two novel methods to improve the model accuracy. One model uses the pre-trained ResNet convolutional layers for feature extraction with transfer learning which was firstly improved with skip architecture, then uses Support Vector Machine as the classifier. We developed a multi-model to combine the traditional ResNet model with the improved one to further improve the accuracy.ResultsDeep learning-based multi-model has the highest model accuracy, and the average accuracy is about 88%. The improved ReseNet + SVM model performance is much better than the traditional ResNet model. The average accuracy of the improved ResNet + SVM model is 83%, while the traditional ResNet model accuracy is only 58%.ConclusionsThis study presents the first models for electron microscopy image classification of Renal Biopsy. Identifying whether the electron-dense granule is present plays an important role in the diagnosis of immune complex nephropathy. This study made it possible for Artificial Intelligence models assist to analyze complex electron microscopy images for disease diagnosis.

Rituximab as Initial Therapy in Adult Patients With Minimal Change Disease

Rituximab as Initial Therapy in Adult Patients With Minimal Change Disease

Immune-Mediated Renal Diseases: A Team-Based Learning Module for Preclinical Medical Students.

IntroductionThe underlying immune mechanisms of renal diseases are complex, and medical students benefit from learning these complexities in the setting of team-based learning (TBL), where they can apply foundational immunologic concepts to clinical problems.MethodsThis immune-mediated renal disease TBL module focusing on glomerular disease was delivered over a period of 2 consecutive years in an integrated cardiovascular, pulmonary, and renal block within the second semester of the first year of medical school. Each class consisted of 53 students, for a total of 106 students. The TBL module consisted of a seven-question individual and team readiness assurance test (iRAT and tRAT) and two clinically relevant team application activities. Following the TBL module, students completed an 18-item survey that collected information on student perspectives of engagement.ResultsFor the 2-year period, the iRAT average scores were 73% and 74%, and the tRAT average scores were 100% and 99%, respectively. The survey assessing student perceptions of engagement yielded positive feedback.DiscussionIn summary, this TBL module effectively integrates the foundational and clinical sciences to teach higher-order concepts in immunology and renal disease pathogenesis to medical students.

Recurrent hydronephrosis and spontaneous renal rupture caused by lymphoplasmacytic inflammation in a cat

A seven-year-old male cat that was previously diagnosed with – and treated for – left hydronephrosis due to suspected idiopathic proteinaceous materials in the renal pelvis, presented with a short history of anorexia and vomiting. The abdominal ultrasound revealed bilateral hydronephrosis, and the intravenous pyelography showed a moderate amount of free fluid in the retroperitoneal space at 48 hours. After the nephrectomy, the gross examination of the right kidney revealed a very thin capsule with urine leakage, and the right renal pelvis showed small, black deposits. The histopathology of the right kidney revealed hydronephrosis with compression atrophy, necrosis of the renal cortex/medulla, and a moderate lymphoplasmacytic inflammation. The crystallographic analysis revealed that the black deposits were composed of 100% protein and no minerals. The cat was diagnosed with hydronephrosis and spontaneous renal rupture caused by proteinaceous pelvic materials, secondary to the idiopathic renal lymphoplasmacytic inflammation. In addition to revealing the possibility that immune-mediated renal disease can induce spontaneous renal rupture in cats, this case report demonstrates the utility of imaging for diagnosing and monitoring hydronephrosis, detecting urine leakage, and planning surgery.

Curcumin Attenuates Both Acute and Chronic Immune Nephritis.

Curcumin is known to have immunomodulatory potential in addition to anti-oxidant, anti-inflammatory and anti-carcinogenic effects. The aim of the present study is to investigate the therapeutic effects of curcumin on immune-mediated renal disease in an anti-glomerular basement membrane (GBM) model (representing acute kidney Injury, AKI) and murine lupus model (representing chronic kidney disease, CKD). In the AKI model, female anti-GBM 129/svj mice were administered with curcumin right before disease induction. In the CKD model, female MRL.lpr mice at the age of 8-10 weeks old were treated with curcumin or placebo via oral gavage daily for two months. After treatment, serum autoantibody levels, splenomegaly and spleen cellularity were reduced in murine lupus. Collectively, curcumin ameliorated kidney disease in the two mouse models with either acute or chronic nephritis, as marked by reduced proteinuria, blood urea nitrogen, glomerulonephritis, crescent formation, tubule-interstitial disease, and renal infiltration by lymphocytes. In addition, curcumin treatment reduced activation of the NFkB, MAPK, AKT and pBAD pathways either systemically, or within the inflamed kidneys. These findings suggest that natural food supplements could become an alternative approach to ameliorating immune-mediated kidney diseases.

Paediatric immune-mediated renal disease: an overview.

Paediatric immune-mediated renal disease: an overview.

HLA and kidney disease: from associations to mechanisms.

Since the first association between HLA and diseases of native kidneys was described almost 50 years ago, technological and conceptual advances in HLA biology and typing, together with better case ascertainment, have led to an improved understanding of HLA associations with a variety of renal diseases. A substantial body of evidence now supports the existence of HLA genetic associations in the field of renal disease beyond the role of HLA in allogeneic responses intransplant recipients. Allomorphs of HLA have emerged as important risk factors in most immune-mediated renal diseases, which, together with other genetic and environmental factors, lead to loss of tolerance and autoimmune-mediated renal inflammation. HLA associations have also been described for renal diseases that are less traditionally seen as autoimmune or immune-mediated. Here, we review essential concepts in HLA biology and the association of HLA with diseases of the native kidneys, and describe the current understanding of the epistatic and mechanistic bases of HLA-associated kidney disease. Greater understanding of the relationship between HLA and kidney function has the potential not only to further the understanding of immune renal disease at a fundamental level but also to lead to the development and application of more effective, specific and less toxic therapies for kidney diseases.

The role of the immune system in kidney disease.

The immune system and the kidneys are closely linked. In health the kidneys contribute to immune homeostasis, while components of the immune system mediate many acute forms of renal disease and play a central role in progression of chronic kidney disease. A dysregulated immune system can have either direct or indirect renal effects. Direct immune-mediated kidney diseases are usually a consequence of autoantibodies directed against a constituent renal antigen, such as collagen IV in anti-glomerular basement membrane disease. Indirect immune-mediated renal disease often follows systemic autoimmunity with immune complex formation, but can also be due to uncontrolled activation of the complement pathways. Although the range of mechanisms of immune dysregulation leading to renal disease is broad, the pathways leading to injury are similar. Loss of immune homeostasis in renal disease results in perpetual immune cell recruitment and worsening damage to the kidney. Uncoordinated attempts at tissue repair, after immune-mediated disease or non-immune mediated injury, result in fibrosis of structures important for renal function, leading eventually to kidney failure. As renal disease often manifests clinically only when substantial damage has already occurred, new diagnostic methods and indeed treatments must be identified to inhibit further progression and promote appropriate tissue repair. Studying cases in which immune homeostasis is re-established may reveal new treatment possibilities.

MTOR Inhibition and Kidney Diseases.

Mammalian or mechanistic target of rapamycin (mTOR) is a serine-threonine kinase that plays essential roles in cell growth, proliferation, metabolism, and survival. Increased activation of the mTOR pathway is observed in patients and animal models of renal transplant rejection, autosomal dominant polycystic kidney disease, renal cell carcinoma, diabetic nephropathy, lupus nephritis, and angiomyolipoma. Agents that inhibit mTOR, such as sirolimus and everolimus, are incorporated in immunosuppressive regimens to prevent renal allograft rejection and are often used to facilitate calcineurin inhibitor minimization or to reduce the incidence of tumor recurrence. There are data from basic or animal studies to suggest that sirolimus and its analogs may also benefit patients with autosomal dominant polycystic kidney disease and metabolic- or immune-mediated renal diseases through its ability to reduce glomerular hypertrophy, renal parenchymal inflammation and fibrosis, but translation into clinical use has proved challenging. This review summarizes the current understanding of mTOR signaling pathway under physiological and pathological conditions and recent findings on mTOR inhibitors in the management of kidney transplantation and nontransplant kidney diseases.

Targeting B Cells and Plasma Cells in Glomerular Diseases: Translational Perspectives.

The unique contributions of memory B cells and plasma cells in kidney diseases remain unclear. In this review, we evaluate the clinical experience with treatments directed at B cells, such as rituximab, and at plasma cells, such as proteasome inhibition, to shed light on the role of these two B lineage compartments in glomerular diseases. Specifically, analysis of these targeted interventions in diseases such as ANCA-associated vasculitis, SLE, and antibody-mediated transplant rejection permits insight into the pathogenetic effect of these cells. Notwithstanding the limitations of preclinical models and clinical studies (heterogeneous populations, among others), the data suggest that memory B and plasma cells represent two engines of autoimmunity, with variable involvement in these diseases. Whereas memory B cells and plasma cells appear to be key in ANCA-associated vasculitis and antibody-mediated transplant rejection, respectively, SLE seems likely to be driven by both autoimmune compartments. These conclusions have implications for the future development of targeted therapeutics in immune-mediated renal disease.

T helper type 17 cells in immune-mediated glomerular disease.

CD4+ T cells are important drivers of tissue damage in immune-mediated renal diseases, such as anti-glomerular basement membrane glomerulonephritis, anti-neutrophil cytoplasmic antibody-associated glomerulonephritis, and lupus nephritis. The discovery of a distinct, IL-17-producing CD4+ T-cell lineage termed T helper type 17 (TH17) cells has markedly advanced current understanding of the pathogenic mechanisms of organ-specific immunity and the pathways that lead to target organ damage. TH17 cells are characterized by the expression of the transcription factor RORγt, the production of the pro-inflammatory cytokines IL-17A, IL-17F, IL-22, and high expression of the chemokine receptor C-C-motif chemokine receptor 6 (CCR6). An emerging body of evidence from experimental models and human studies supports a key role for these cells in the development of renal damage, and has led to the identification of targets to inhibit the production of TH17 cells in the intestine, their migration, or their actions within the kidney. Here, we describe the identification, regulation, and function of TH17 cells and their associated pathways in immune-mediated kidney diseases, with a particular focus on the mechanisms underlying renal tissue injury. We also discuss the rationale for the translation of these findings into new therapeutic approaches in patients with autoimmune kidney disease.

Rituximab for immunologic renal disease: What the nephrologist needs to know.

Rituximab (RTX), a chimeric, monoclonal anti-CD20 antibody, is increasingly used in immune-mediated renal diseases. While licensed in the induction treatment of ANCA-associated vasculitis, it represents one of the most commonly prescribed off-label drugs. Much of the information regarding its safety has been drawn from experience in hematology and rheumatology. Ample evidence illustrates the safety of RTX, however, rare but serious adverse events have emerged that include progressive multifocal leucoencephalopathy and hepatitis B reactivation. Moderate to severe hypogammaglobulinemia and late-onset neutropenia following RTX therapy confer an increased infectious risk and factors predicting these side effects (i.e. a genetic basis) need to be identified. Nephrologists initiating RTX need to bear in mind that long-term risks and optimal dosing for many renal indications remain unclear. Special considerations must be given when RTX is used in women of childbearing age. We summarize practical aspects concerning the use of RTX. This review will provide nephrologists with information to guide their use of RTX alerting them to safety risks and the need for patient counselling.

Blockade of CD354 (TREM-1) Ameliorates Anti-GBM-Induced Nephritis.

CD354, Triggering Receptor of Myeloid Cells-1 (TREM-1), is a potent amplifier of myeloid immune responses. Our goal was to determine the expression and function of TREM-1 in immune-mediated nephritis. An anti-glomerular basement membrane antibody (anti-GBM)-induced nephritis model was employed, where mice were sensitized with rabbit IgG followed by anti-GBM serum to induce disease. Anti-GBM-treated 129x1/svJ mice developed severe nephritis whereas C57BL/6 (B6) mice were resistant to disease. Anti-GBM disease resulted in elevated renal TREM-1 messenger RNA (mRNA) and protein levels and increased urine TREM-1 levels in 129x1/svJ. TREM-1 blockade with an inhibitory peptide, LP17, inhibited proteinuria and renal disease as measured by glomerulonephritis class, severity of tubulointerstitial disease, crescent formation, and inflammatory cell infiltrates. In sum, TREM-1 is upregulated in renal inflammation and plays a vital role in driving disease. Thus, TREM-1 blockade emerges as a potential therapeutic avenue for immune-mediated renal diseases such as lupus nephritis.

Regulatory T cells in immune‐mediated renal disease

Regulatory T cells (Tregs) are CD4+ T cells that can suppress immune responses by effector T cells, B cells and innate immune cells. This review discusses the role that Tregs play in murine models of immune-mediated renal diseases and acute kidney injury and in human autoimmune kidney disease (such as systemic lupus erythematosus, anti-glomerular basement membrane disease, anti-neutrophil cytoplasmic antibody-associated vasculitis). Current research suggests that Tregs may be reduced in number and/or have impaired regulatory function in these diseases. Tregs possess several mechanisms by which they can limit renal and systemic inflammatory immune responses. Potential therapeutic applications involving Tregs include in vivo induction of Tregs or inducing Tregs from naïve CD4+ T cells or expanding natural Tregs ex vivo, to use as a cellular therapy. At present, the optimal method of generating a phenotypically stable pool of Tregs with long-lasting suppressive effects is not established, but human studies in renal transplantation are underway exploring the therapeutic potential of Tregs as a cellular therapy, and if successful may have a role as a novel therapy in immune-mediated renal diseases.

Targeting IL-17 and IL-23 in Immune Mediated Renal Disease.

T helper (Th) cells belong to the adaptive immune system and provide an effective and antigen-specific means of host protection. Th17 cells are a subset of Th cells, characterized by the production of the inflammatory cytokines interleukin (IL)-17A (IL-17A) and IL-17F, which bind to a receptor complex comprised of IL-17RA and IL-17RC subunits. Th17 cells combat extracellular and fungal infections, but have been implicated in autoimmune diseases. In many autoimmune conditions, the dysregulated immune response involves several parts of the immune system, including autoantibodies, B and T cells. Targeted biological therapies are appealing, as they may prevent unwanted side effects in patients. There is evolving evidence that Th17 cells are important in the kidney, mediating injury in response to vascular or chemical insults to the renal tubules, and in autoimmune diseases of the glomerulus, either through a specific attack on the glomerular basement membrane or as part of a generalized systemic inflammatory disease. Therapies targeting IL-17A, IL-12p40 and IL-17RA are being explored in clinical trials or are being utilized in clinical practice for the treatment of other IL-17 mediated diseases, such as psoriasis. This review explores the current evidence that IL-17A and Th17 cells may be pathogenic in immune kidney disease, including anti-glomerular basement membrane disease, antineutrophil cytoplasmic antibody associated vasculitis and lupus nephritis, as well as in acute kidney injury. It will discuss the place that biological agents against IL-17A, IL-12p40 and IL-17RA may have in the treatment of these conditions.

Is a legacy effect possible in IgA nephropathy?

The term 'legacy effect'--a memory of a treatment which produces benefits long after the cessation of the intervention--was adopted for the first time to describe the benefits of early and strict control of diabetes on cardiovascular complications. The search for a similar effect for early treatment of immune-mediated renal diseases, interrupting some self-amplification loops of the pathogenetical immunological mechanisms and leaving a permanent memory, is fascinating. Some recent reports suggest a long-term beneficial or legacy effect of early treatment of IgA nephropathy after a randomized controlled trial (RCT) using mycophenolate mofetil, methylprednisolone pulses or steroid/immunosuppressive multiple therapy, or prolonged steroid doses associated with tonsillectomy. Long-lasting effects of treatments are more likely to be achieved in early stages of IgA nephropathy, when mesangial proliferative or endocapillary hypercellular lesions are pre-eminent over sclerosis, and when proteinuria is not massive, above all in young patients. The long-term results considered are relevant, but have the counterpart of the risk of drug toxicity or side effects, which are particularly undesired in patients with a mild disease. Hence, there is interest for drugs targeting the intestinal mucosal immunity with a little systemic effect, aimed at interrupting the initial pathogenetical mechanism. The possibility of modulating anti-inflammatory regulatory T cells by modifying inducible enzymes is another fascinating field of future research.

A review of postinfectious glomerulonephritis cases from a tertiary care renal referral center in South India

Background: Postinfectious glomerulonephritis is an immune mediated renal disease and one of the causes for end stage renal disease in developing countries like India. The disease spectrum has changed significantly in the past few decades. The goal of this study is to review the prevalence and clinicopathological spectrum of the disease in a major tertiary care renal referral hospital. Materials and Methods: Between July 2007 and July 2012, 54 cases of postinfectious glomerulonephritis were identified at our medical center. The patients' records were retrospectively reviewed with respect to clinical presentation, laboratory, histopathology, and clinical course. Results: There were 32 males and 22 females. The mean age was 24.1 years. Twenty six percent of patients presented with acute renal failure and required dialysis support during the course of disease. Hypocomplementemia was present in about 90% of the patients. Histologically, characteristics showed distinct patterns of glomerulonephritis with predominant starry sky pattern on immunofluorescence. At the last follow-up, none of the patients were dialysis-dependent, and 53% were in complete remission. Conclusions: We hereby report cases of postinfectious glomerulonephritis with history of recurrence and cross infection to highlight the importance of treatment and awareness regarding this preventable cause of chronic renal disease.