The combined role of galactose-deficient IgA1 and streptococcal IgA-binding M Protein in inducing IL-6 and C3 secretion from human mesangial cells: implications for IgA nephropathy

Investigating Vitamin D-Binding Protein's Role in Childhood Health and Development

Vitamin D-binding protein (DBP), also known as Gc-globulin, is a protein that affects several physiological processes, including the transport and regulation of vitamin D metabolites. Genetic polymorphisms in the DBP gene have a significant impact on vitamin D levels and may have implications for disease risk. DBP polymorphisms are linked to differential immune responses, which could influence the onset of juvenile diseases. This narrative review examines the various roles of DBP, with a focus on bone health, immunological regulation, and lipid metabolism in children. Chronic disorders affected by DBP polymorphisms include bone abnormalities, autoimmune diseases, cardiovascular issues, childhood asthma, allergies, cystic fibrosis, acute liver failure, celiac disease, inflammatory bowel disease, and chronic kidney disease. Future research should focus on identifying the processes that underpin the many roles that DBP plays and developing customized therapeutics to improve health outcomes in the juvenile population.

Small protein blockers of human IL-6 receptor alpha inhibit proliferation and migration of cancer cells

BACKGROUND

Interleukin-6 (IL-6) is a multifunctional cytokine that controls the immune response, and its role has been described in the development of autoimmune diseases. Signaling via its cognate IL-6 receptor (IL-6R) complex is critical in tumor progression and, therefore, IL-6R represents an important therapeutic target.

METHODS

An albumin-binding domain-derived highly complex combinatorial library was used to select IL-6R alpha (IL-6Rα)-targeted small protein binders using ribosome display. Large-scale screening of bacterial lysates of individual clones was performed using ELISA, and their IL-6Rα blocking potential was verified by competition ELISA. The binding of proteins to cells was monitored by flow cytometry and confocal microscopy on HEK293T-transfected cells, and inhibition of signaling function was examined using HEK-Blue IL-6 reporter cells. Protein binding kinetics to living cells was measured by LigandTracer, cell proliferation and toxicity by iCELLigence and Incucyte, cell migration by the scratch wound healing assay, and prediction of binding poses using molecular modeling by docking.

RESULTS

We demonstrated a collection of protein variants called NEF ligands, selected from an albumin-binding domain scaffold-derived combinatorial library, and showed their binding specificity to human IL-6Rα and antagonistic effect in HEK-Blue IL-6 reporter cells. The three most promising NEF108, NEF163, and NEF172 variants inhibited cell proliferation of malignant melanoma (G361 and A2058) and pancreatic (PaTu and MiaPaCa) cancer cells, and suppressed migration of malignant melanoma (A2058), pancreatic carcinoma (PaTu), and glioblastoma (GAMG) cells in vitro. The NEF binders also recognized maturation-induced IL-6Rα expression and interfered with IL-6-induced differentiation in primary human B cells.

CONCLUSION

We report on the generation of small protein blockers of human IL-6Rα using directed evolution. NEF proteins represent a promising class of non-toxic anti-tumor agents with migrastatic potential.

Sparsentan ameliorates glomerular hypercellularity and inflammatory-gene networks induced by IgA1-IgG immune complexes in a mouse model of IgA nephropathy

IgA nephropathy (IgAN) is characterized by glomerular deposition of immune complexes (ICs) consisting of IgA1 with O-glycans deficient in galactose (Gd-IgA1) and Gd-IgA1-specific IgG autoantibodies. These ICs induce kidney injury, and in the absence of disease-specific therapy, up to 40% of patients with IgAN progress to kidney failure. IgA1 with its clustered O-glycans is unique to humans, which hampered development of small-animal models of IgAN. Here, we used a model wherein engineered ICs (EICs) formed from human Gd-IgA1 and recombinant human IgG autoantibody are injected into nude mice to induce glomerular injury mimicking human IgAN. In this model, we assessed the protective effects of sparsentan, a single-molecule dual endothelin angiotensin receptor antagonist (DEARA) versus vehicle on EIC-induced glomerular proliferation and dysregulation of gene expression in the kidney. Oral administration of sparsentan (60 or 120 mg/kg daily) to mice intravenously injected with EIC attenuated the EIC-induced glomerular hypercellularity. Furthermore, analysis of changes in the whole kidney transcriptome revealed that key inflammatory and proliferative biological genes and pathways that are upregulated in this EIC model of IgAN were markedly reduced by sparsentan, including complement genes, integrin components, members of the mitogen-activated protein kinase family, and Fc receptor elements. Partial overlap between mouse and human differentially expressed genes in IgAN further supported the translational aspect of the immune and inflammatory components from our transcriptional findings. In conclusion, our data indicate that in the mouse model of IgAN, sparsentan targets immune and inflammatory processes leading to protection from mesangial hypercellularity.NEW & NOTEWORTHY The mechanisms by which deposited IgA1 immune complexes cause kidney injury during early phases of IgA nephropathy are poorly understood. We used an animal model we recently developed that involves IgA1-IgG immune complex injections and determined pathways related to the induced mesangioproliferative changes. Treatment with sparsentan, a dual inhibitor of endothelin type A and angiotensin II type 1 receptors, ameliorated the induced mesangioproliferative changes and the associated alterations in the expression of inflammatory genes and networks.

The complement system in IgAN: mechanistic context for therapeutic opportunities

The complement system plays a crucial role in innate immunity, providing essential defense against pathogens. However, uncontrolled or prolonged activation of the complement cascade can significantly contribute to kidney damage, especially in cases of glomerulonephritis. Immunoglobulin A nephropathy (IgAN), the most prevalent form of primary glomerulonephritis, has growing evidence supporting the involvement of complement alternative and lectin pathways. In fact, patients with IgAN experience complement activation within their kidney tissue, which may be involved in the development of glomerular damage and the progression of IgAN. Complement activation has emerged as a significant area of interest in IgAN, with numerous complement-targeting agents currently being explored within this field. Nevertheless, the exact mechanisms of complement activation and their role in IgAN progression require comprehensive elucidation. This review seeks to contextualize the proposed mechanisms of complement activation within the various stages ("hits") of IgAN pathogenesis, while also addressing the clinical implications and anticipated outcomes of complement inhibition in IgAN.

The role of the mesangium in glomerular function

When discussing glomerular function, one cell type is often left out, the mesangial cell (MC), probably since it is not a part of the filtration barrier per se. The MCs are instead found between the glomerular capillaries, embedded in their mesangial matrix. They are in direct contact with the endothelial cells and in close contact with the podocytes and together they form the glomerulus. The MCs can produce and react to a multitude of growth factors, cytokines, and other signaling molecules and are in the perfect position to be a central hub for crosstalk communication between the cells in the glomerulus. In certain glomerular diseases, for example, in diabetic kidney disease or IgA nephropathy, the MCs become activated resulting in mesangial expansion. The expansion is normally due to matrix expansion in combination with either proliferation or hypertrophy. With time, this expansion can lead to fibrosis and decreased glomerular function. In addition, signs of complement activation are often seen in biopsies from patients with glomerular disease affecting the mesangium. This review aims to give a better understanding of the MCs in health and disease and their role in glomerular crosstalk and inflammation.

Effects of modified Huangqi Chifeng decoction on the IL-17 signaling pathway in an IgA nephropathy rat model

ETHNOPHARMACOLOGICAL RELEVANCE

Immunoglobulin A nephropathy (IgAN) is an immune-related primary glomerular disease prevalent worldwide, with complicated clinical manifestations and an unclear pathogenesis. IgAN is the main cause of chronic renal failure and places a significant burden on patients and society. The modified Huangqi Chifeng decoction (MHCD) is an effective prescription for the clinical treatment of IgAN while its specific mechanism remains to be further elucidated.

AIM OF THE STUDY

Based on the findings of previous network pharmacology-related method-based studies, this study aimed to further explore the mechanism of action of MHCD for IgAN treatment.

MATERIALS AND METHODS

IgAN rat model was established by bovine serum protein + carbon tetrachloride + lipopolysaccharide. After successful modeling, the rats in the original model group were divided into 5 group: model group, telmisartan group, and MHCD high-, medium- and low-dose groups by random number table (n = 10 respectively). The corresponding drugs were applied for 8 weeks, and the experiment lasted for 21 weeks. At the end of the experiment, 24h urine protein quantification, serum biochemistry and IL-6 and IL-17A levels were measured. The pathological changes of kidney were observed by light microscope, immunofluorescence microscope and the changes of glomerular ultrastructure were observed by transmission electron microscope. The expression levels of IL-17 signaling pathway related proteins (HSP90, MMP9, NF-κB P65 and p-NF-κB P65) were detected by Western Blot and immunohistochemistry.

RESULT

Telmisartan and MHCD treatment can reduce the 24h urinary protein level and improved blood stasis states of IgAN rats, alleviate the renal pathological injury, decrease the serum levels of IL-6, IL-17A and the expression levels of HSP90, MMP9 and p-NF-κB P65 related proteins in IL-17 signaling pathway.

CONCLUSION

MHCD can down-regulate the expression of IL-17 signaling pathway-related factors in IgAN model rats, improve the state of blood stasis, and alleviate the pathological damage of kidney in rats.

Molecular insight in intrarenal inflammation affecting four main types of cells in nephrons in IgA nephropathy

Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis and the leading cause of kidney failure in the world. The current widely accepted framework for its pathogenesis is the "multi-hit hypothesis." In this review, we mainly discussed the intrarenal inflammation in IgAN, which is initiated by immune complex deposition with complement molecule activation, by focusing on four main types of cells in nephrons including mesangial cells, endothelial cells, podocytes, and tubular epithelial cells (TECs). Galactose-deficient IgA1 (Gd-IgA1)-containing immune complexes deposit in the mesangium and activate complement molecules and mesangial cells. Activation of mesangial cells by Gd-IgA1 deposition with enhanced cellular proliferation, extracellular matrix (ECM) expansion, and inflammatory response plays a central role in the pathogenesis of IgAN. Regional immune complex deposition and mesangial-endothelial crosstalk result in hyperpermeability of endothelium with loss of endothelial cells and infiltration barrier proteins, and recruitment of inflammatory cells. Podocyte damage is mainly derived from mesangial-podocyte crosstalk, in which tumor necrosis factor-α (TNF-α), transforming growth factor-β (TGF-β), renin-angiotensin-aldosterone system (RAAS), and micro-RNAs are the major players in podocyte apoptosis and disorganization of slit diaphragm (SD) related to proteinuria in patients with IgAN. In addition to filtrated proteins into tubulointerstitium and mesangial-tubular crosstalk involved in the injury of TECs, retinoic acid has been discovered innovatively participating in TEC injury.

Gut-kidney axis in IgA nephropathy: Role on mesangial cell metabolism and inflammation

IgA Nephropathy (IgAN) is the commonest primary glomerular disease around the world and represents a significant cause of end-stage renal disease. IgAN is characterized by mesangial deposition of IgA-immune complexes and mesangial expansion. The pathophysiological process includes an abnormally glycosylated IgA1, which is an antigenic target. Autoantibodies specifically recognize galactose-deficient IgA1 forming immune complexes that are amplified in size by the soluble IgA Fc receptor CD89 leading to deposition in the mesangium through interaction with non-classical IgA receptors. The local production of cytokines promotes local inflammation and complement system activation, besides the stimulation of mesangial proliferation. The spectrum of clinical manifestations is quite variable from asymptomatic microscopic hematuria to rapidly progressive glomerulonephritis. Despite all the advances, the pathophysiology of the disease is still not fully elucidated. The mucosal immune system is quoted to be a factor in triggering IgAN and a "gut-kidney axis" is proposed in its development. Furthermore, many recent studies have demonstrated that food intake interferes directly with disease prognosis. In this review, we will discuss how mucosal immunity, microbiota, and nutritional status could be interfering directly with the activation of intrinsic pathways of the mesangial cells, directly resulting in changes in their function, inflammation and development of IgAN.

IL-6 and its role in IgA nephropathy development

IL-6 is considered one of the well characterized cytokines exhibiting homeostatic, pro- and anti-inflammatory activities, depending on the receptor variant and the induced intracellular cis- or trans-signaling responses. IL-6-activated pathways are involved in the regulation of cell proliferation, survival, differentiation, and cell metabolism changes. Deviations in IL-6 levels or abnormal response to IL-6 signaling are associated with several autoimmune diseases including IgA nephropathy (IgAN), one of most frequent primary glomerulonephritis worldwide. IgAN is associated with increased plasma concentration of IL-6 and increased plasma concentration of aberrantly galactosylated IgA1 immunoglobulin (Gd-IgA1). Gd-IgA1 is specifically recognized by autoantibodies, leading to the formation of circulating immune complexes (CIC) with nephritogenic potential, since CIC deposited in the glomerular mesangium induce mesangial cells proliferation and glomerular injury. Infection of the upper respiratory or digestive tract enhances IL-6 production and in IgAN patients is often followed by the macroscopic hematuria. This review recapitulates general aspects of IL-6 signaling and summarizes experimental evidences about IL-6 involvement in the etiopathogenesis of IgA nephropathy through the production of Gd-IgA1 and regulation of mesangial cell proliferation.

Interleukin-6 Downregulates the Expression of Vascular Endothelial-Cadherin and Increases Permeability in Renal Glomerular Endothelial Cells via the Trans-Signaling Pathway

The pathogenesis of IgA nephropathy (IgAN) is still unknown, but reportedly, interleukin 6 (IL-6) is involved in this process. However, its role in damaging glomerular endothelial cells is still unclear. Therefore, in this study, to clarify the mechanism of the pathogenesis of IgAN, we investigated the effect of IL-6 on the permeability of glomerular endothelial cells. A rat model of IgAN was established, and the animals divided into two groups, namely, the normal and IgAN groups. Glomerular endothelial cell injury was evaluated via electron microscopy. Furthermore, IL-6-induced changes in the permeability of human renal glomerular endothelial cells (HRGECs) were measured via trans-endothelial resistance (TEER) measurements and fluorescein isothiocyanate-dextran fluorescence. Furthermore, vascular endothelial-cadherin (VE-cadherin) was overexpressed to clarify the effect of IL-6 on HRGEC permeability, and to determine the pathway by which it acts. The classical signaling pathway was blocked by silencing IL-6R and the trans-signaling pathway was blocked by sgp30Fc. In IgAN rats, electron microscopy showed glomerular endothelial cell damage and western blotting revealed a significant increase in IL-6 expression, while VE-cadherin expression decreased significantly in the renal tissues. IL-6/IL-6R stimulation also significantly increased the permeability of HRGECs (p < 0.05). This effect was significantly reduced by VE-cadherin overexpression (p < 0.01). After IL-6R was silenced, IL-6/IL-6R still significantly reduced VE-cadherin expression and sgp30Fc blocked the trans-signaling pathway as well as the upregulation of IL-6/IL-6R-induced VE-cadherin expression. This suggests that IL-6 mainly acts via the trans-signaling pathway. IL-6 increased the permeability of HRGECs by decreasing the expression of VE-cadherin via the trans-signaling pathway.

Cytokines and Production of Aberrantly O-Glycosylated IgA1, the Main Autoantigen in IgA Nephropathy

Immunoglobulin A (IgA) nephropathy is the most common primary glomerulonephritis worldwide, with no disease-specific treatment and up to 40% of patients progressing to kidney failure. IgA nephropathy (IgAN), characterized by IgA1-containing immunodeposits in the glomeruli, is considered to be an autoimmune disease in which the kidneys are injured as innocent bystanders. Glomerular immunodeposits are thought to originate from the circulating immune complexes that contain aberrantly O-glycosylated IgA1, the main autoantigen in IgAN, bound by IgG autoantibodies. A common clinical manifestation associated with IgAN includes synpharyngitic hematuria at disease onset or during disease activity. This observation suggests a connection of disease pathogenesis with an activated mucosal immune system of the upper-respiratory and/or gastrointestinal tract and IgA1 glycosylation. In fact, some cytokines can enhance production of aberrantly O-glycosylated IgA1. This process involves abnormal cytokine signaling in IgA1-producing cells from patients with IgAN. In this article, we present our view of pathogenesis of IgAN and review how some cytokines can contribute to the disease process by enhancing production of aberrantly glycosylated IgA1. We also review current clinical trials of IgAN based on cytokine-targeting therapeutic approaches.

Collectin11 and Complement Activation in IgA Nephropathy

BACKGROUND AND OBJECTIVES

IgA nephropathy is the most common primary GN worldwide. Previous research demonstrated that collectin11, an initiator of the complement lectin pathway, was involved in both AKI and chronic tubulointerstitial fibrosis. Here, we investigated the potential role of collectin11 in the pathogenesis of IgA nephropathy.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The deposition of collectin11 and other complement proteins was detected in glomeruli of 60 participants with IgA nephropathy by immunofluorescence. In vitro, human mesangial cells were treated with IgA1-containing immune complexes derived from participants with IgA nephropathy. Then, the expression of collectin11 in mesangial cells was examined by quantitative RT-PCR and immunofluorescence. The codeposition of collectin11 with IgA1 or C3 on mesangial cells was detected by immunofluorescence and proximity ligation assays.

RESULTS

In total, 37% of participants with IgA nephropathy (22 of 60) showed codeposition of collectin11 with IgA in the glomerular mesangium. Using an injury model of mesangial cells, we demonstrated that IgA1-immune complexes derived from participants with IgA nephropathy increased the secretion of collectin11 in mesangial cells with the subsequent deposition of collectin11 on the cell surface via the interaction with deposited IgA1-immune complexes. In vitro, we found that collectin11 bound to IgA1-immune complexes in a dose-dependent but calcium-independent manner. Furthermore, deposited collectin11 initiated the activation of complement and accelerated the deposition of C3 on mesangial cells.

CONCLUSIONS

In situ-produced collectin11 by mesangial cells might play an essential role in kidney injury in a subset of patients with IgA nephropathy through the induction of complement activation.

Immunological drivers of IgA nephropathy: Exploring the mucosa-kidney link

IgA nephropathy (IgAN) is the most common pattern of primary glomerular disease reported worldwide. Up to 40% of those with IgAN progress to end-stage kidney disease within 20 years of diagnosis, with no currently available disease-specific treatment. This is likely to change rapidly, with evolving insights into the mechanisms driving this disease. IgAN is an immune-complex-mediated disease, and its pathophysiology has been framed by the 'four-hit hypothesis', which necessitates four events to occur for clinically significant disease to develop. However, this hypothesis does not explain the wide variability observed in its presentation or clinical progression. Recently, there has been great interest in exploring the role of the mucosal immune system in IgAN, especially given the well-established link between mucosal infections and disease flares. Knowledge of antigen-mucosal interactions is now being successfully leveraged for therapeutic purposes; the gut-directed drug Nefecon (targeted release formulation-budesonide) is on track to become the first medication to be approved specifically for the treatment of IgAN. In this review, we examine established immunological paradigms in IgAN, explore how antigen-mucosal immune responses drive disease, and discuss how this knowledge is being used to develop new treatments.

Renal diseases and the role of complement: Linking complement to immune effector pathways and therapeutics

The complement system is an ancient and phylogenetically conserved key danger sensing system that is critical for host defense against pathogens. Activation of the complement system is a vital component of innate immunity required for the detection and removal of pathogens. It is also a central orchestrator of adaptive immune responses and a constituent of normal tissue homeostasis. Once complement activation occurs, this system deposits indiscriminately on any cell surface in the vicinity and has the potential to cause unwanted and excessive tissue injury. Deposition of complement components is recognized as a hallmark of a variety of kidney diseases, where it is indeed associated with damage to the self. The provenance and the pathophysiological role(s) played by complement in each kidney disease is not fully understood. However, in recent years there has been a renaissance in the study of complement, with greater appreciation of its intracellular roles as a cell-intrinsic system and its interplay with immune effector pathways. This has been paired with a profusion of novel therapeutic agents antagonizing complement components, including approved inhibitors against complement components (C)1, C3, C5 and C5aR1. A number of clinical trials have investigated the use of these more targeted approaches for the management of kidney diseases. In this review we present and summarize the evidence for the roles of complement in kidney diseases and discuss the available clinical evidence for complement inhibition.

Is complement the main accomplice in IgA nephropathy? From initial observations to potential complement-targeted therapies

IgA Nephropathy (IgAN) is the main cause of primary glomerulonephritis, globally. This disease is associated with a wide range of clinical presentations, variable prognosis and a spectrum of histological findings. More than fifty years after its first description, this heterogeneity continues to complicate efforts to understand the pathogenesis. Nevertheless, involvement of the complement system in IgAN was identified early on. Dysfunction of the immunoglobulin A (IgA) system, the principal offender in this disease, including modification of isoforms and glycoforms of IgA1, the nature of immune complexes and autoantibodies to galactose deficient IgA1 might all be responsible for complement activation in IgAN. However, the specific mechanisms engaging complement are still under examination. Research in this domain should allow for identification of patients that may benefit from complement-targeted therapy, in the foreseeable future.

Autoimmune-mediated renal disease and hypertension

Hypertension is a major risk factor for cardiovascular disease, chronic kidney disease (CKD), and mortality. Troublingly, hypertension is highly prevalent in patients with autoimmune renal disease and hastens renal functional decline. Although progress has been made over the past two decades in understanding the inflammatory contributions to essential hypertension more broadly, the mechanisms active in autoimmune-mediated renal diseases remain grossly understudied. This Review provides an overview of the pathogenesis of each of the major autoimmune diseases affecting the kidney that are associated with hypertension, and describes the current state of knowledge regarding hypertension in these diseases and their management. Specifically, discussion focuses on Systemic Lupus Erythematosus (SLE) and Lupus Nephritis (LN), Immunoglobulin A (IgA) Nephropathy, Idiopathic Membranous Nephropathy (IMN), Anti-Neutrophil Cytoplasmic Antibody (ANCA)-associated glomerulonephritis, and Thrombotic Thrombocytopenic Purpura (TTP). A summary of disease-specific animal models found to exhibit hypertension is also included to highlight opportunities for much needed further investigation of underlying mechanisms and novel therapeutic approaches.

An Update on Targeted Treatment of IgA Nephropathy: An Autoimmune Perspective

Immunoglobulin (Ig) A nephropathy (IgAN) is the commonest form of primary glomerulonephritis worldwide and is, considered a significant cause of end-stage renal disease in young adults. The precise pathogenesis of IgAN is unclear. The clinical and pathological features vary significantly between individuals and races, which makes treating IgAN difficult. Currently, the therapeutic strategies in IgAN are still optimal blood pressure control and proteinuria remission to improve the renal function in most cases. Immunosuppressive drugs such as corticosteroids can be considered in patients with persistent proteinuria and a high risk of renal function decline; however, they include a high toxicity profile. Therefore, the safety and selectivity of medications are critical concerns in the treatment of IgAN. Various pharmacological therapeutic targets have emerged based on the evolving understanding of the autoimmune pathogenesis of IgAN, which involves the immune response, mucosal immunity, renal inflammation, complement activation, and autophagy; treatments based on these mechanisms have been explored in preclinical and clinical studies. This review summarizes the progress concerning targeted therapeutic strategies and the relevant autoimmune pathogenesis in IgAN.

Mesangial cells regulate the single nephron GFR and preserve the integrity of the glomerular filtration barrier: An intravital multiphoton microscopy study

AIM

The intraglomerular mesangial cells are located between the glomerular capillaries. Here we hypothesized that mesangial cells regulate the single nephron glomerular filtration rate (snGFR) and that mesangial cells support the integrity of the glomerular filtration barrier.

METHODS

We assessed the function of mesangial cells in vivo by multiphoton microscopy. Mesangial cells were depleted in Munich Wistar Froemter rats using the Thy1.1 antibody model.

RESULTS

The Thy1.1 antibody caused the cell-specific loss of 82 ± 3% of mesangial cells. After mesangial cell depletion, the baseline snGFR was reduced to 12.0 ± 1.2 vs 32.4 ± 3.2 nL/min in controls. In control rats, the snGFR decreased after angiotensin II infusion by 61 ± 3% (P = .004), whereas it remained unchanged in Thy1.1-treated rats. The changes in the snGFR after angiotensin II infusion in control rats were accompanied by the marked rotation of the capillary loops within Bowman's space. This phenomenon was absent in anti-Thy1.1-treated rats. The glomerular sieving coefficient (GSC_A ) for albumin, used as a measure of the integrity of the glomerular filtration barrier, was low in control rats (0.00061 ± 0.00004) and increased after angiotensin II infusion (0.00121 ± 0.00015). In Thy1.1-treated rats, the GSC was elevated (0.0032 ± 0.00059) and did not change in response to angiotensin II. Electron microscopy revealed the increased thickness of the glomerular basement membrane after mesangial cell depletion.

CONCLUSION

Our data suggest that mesangial cells actively contribute to the regulation of the snGFR. Furthermore, mesangial cells are crucially involved in maintaining the integrity of the glomerular filtration barrier, in part by modulating the thickness of the glomerular basement membrane.

CD71 mesangial IgA1 receptor and the progression of IgA nephropathy

The transferrin receptor (CD71) is known as a receptor for IgA1 on mesangial cells, but the role of CD71 in IgA nephropathy (IgAN) is unknown. We studied clinical implication of mesangial CD71 in 282 patients with biopsy-proven IgAN (2005-2018). The transcript and protein expression of glomerular CD71 was determined by real-time polymerase chain reaction and immunohistochemistry. Ten subjects with microscopic hematuria only and no evidence of histologic abnormalities on kidney biopsy were considered as controls. Human mesangial cells (HMCs) were treated with sera from IgAN patients and expression levels of CD71 and inflammatory cytokine markers were compared according to disease status. Disease progression was defined as a ≥30% decline in estimated glomerular filtration rate from the baseline value. During a mean follow up of 53.5 (18.3-75.9) months, 80 (28.4%) patients developed disease progression. The mRNA expression of CD71 was significantly higher in progressors than in nonprogressors (P = 0.001). Among the Oxford classification scores, patients with M1 had significantly higher CD71 expression levels than those with M0. In a multivariable Cox model, elevated transcript levels of CD71 were significantly associated with 4.32-fold higher risk of disease progression (P = 0.009). Furthermore, CD71 expression levels independently predicted the increase in proteinuria of ≥50% from the baseline (P = 0.03). Finally, HMCs treated with sera from IgAN patients with the higher Oxford score (M1E1S1T0) more increased the mRNA expression of CD71 and inflammatory markers than those with sera from negative score (M0E0S0T0). However, silencing CD71 significantly reduced expression levels of the inflammatory cytokine genes. Our results show that mesangial CD71 is significantly associated with disease progression and may play a biologic role in IgAN.

New therapeutic perspectives for IgA nephropathy in children

Childhood IgA nephropathy (cIgAN) differs from the adult by having an abrupt clinical onset, often presenting as an acute attack that can progress to a chronic phase. No treatment guidelines have been established for the treatment of cIgAN. Given the severity of acute attack in children, and the number of life-years at stake, pediatricians prescribe immunosuppression in addition to renin-angiotensin system blockade. Non-specific immunosuppressors, such as corticosteroids, have systemic toxic effects, and given recent therapeutic advances in adult glomerulonephritis, new tailored strategies should be expected for children. The mucosal immune system has been highlighted as a key player in IgAN pathogenesis, and several biomarkers have been identified with a direct role in pathogenesis. In this review, we discuss current studies of conventional and novel therapeutic approaches for cIgAN.

Emerging Modes of Treatment of IgA Nephropathy

IgA nephropathy is the most common primary glomerulonephritis with potentially serious outcome leading to end stage renal disease in 30 to 50% of patients within 20 to 30 years. Renal biopsy, which might be associated with risks of complications (bleeding and others), still remains the only reliable diagnostic tool for IgA nephropathy. Therefore, the search for non-invasive diagnostic and prognostic markers for detection of subclinical types of IgA nephropathy, evaluation of disease activity, and assessment of treatment effectiveness, is of utmost importance. In this review, we summarize treatment options for patients with IgA nephropathy including the drugs currently under evaluation in randomized control trials. An early initiation of immunosupressive regimens in patients with IgA nephropathy at risk of progression should result in the slowing down of the progression of renal function to end stage renal disease.

The Role of Immune Modulation in Pathogenesis of IgA Nephropathy

IgA nephropathy (IgAN) is the most prevalent primary glomerulonephritis worldwide, with diverse clinical manifestations characterized by recurrent gross hematuria or microscopic hematuria, and pathological changes featuring poorly O-galactosylated IgA1 deposition in the glomerular mesangium. Pathogenesis has always been the focus of IgAN studies. After 50 years of research, most scholars agree that IgAN is a group of clinicopathological syndromes with certain common immunopathological characteristics, and multiple mechanisms are involved in its pathogenesis, including immunology, genetics, and environmental or nutritional factors. However, the precise pathogenetic mechanisms have not been fully determined. One hypothesis about the pathogenesis of IgAN suggests that immunological factors are engaged in all aspects of IgAN development and play a critical role. A variety of immune cells (e.g., dendritic cells, NK cells, macrophages, T-lymphocyte subsets, and B-lymphocytes, etc.) and molecules (e.g., IgA receptors, Toll-like receptors, complements, etc.) in innate and adaptive immunity are involved in the pathogenesis of IgAN. Moreover, the abnormality of mucosal immune regulation is the core of IgAN immunopathogenesis. The roles of tonsil immunity or intestinal mucosal immunity, which have received more attention in recent years, are supported by mounting evidence. In this review, we will explore the latest research insights on the role of immune modulation in the pathogenesis of IgAN. With a better understanding of immunopathogenesis of IgAN, emerging therapies will soon become realized.

Complement in IgA Nephropathy: The Role of Complement in the Pathogenesis, Diagnosis, and Future Management of IgA Nephropathy

Immunoglobulin A (IgA) nephropathy (IgAN) is an important cause of chronic and end-stage kidney disease. IgAN pathogenesis is incompletely understood. In particular, we cannot adequately explain the heterogeneity in clinical and histologic features and severities that characterizes IgAN. This limits patient stratification to appropriate and effective treatments and the development of disease-targeted therapies. Studies of the role of the alternative, lectin, and terminal complement pathways in IgAN have enhanced our understanding of disease pathogenesis and inform the development of novel diagnostic and therapeutic strategies. For example, recent genetic, serologic, and immunohistologic evidence suggests that imbalances between the main alternative complement pathway regulator protein (factor H) and competitor proteins that deregulate complement activity (factor H-related proteins 1 and 5, FHR1, and FHR5) associate with IgAN severity: a relative abundance of FHR1 and FHR5 amplifies complement-dependent inflammation and exacerbates kidney injury. Ongoing characterization of the mechanisms by which complement activity contributes to IgAN pathogenesis will facilitate the development of complement-based diagnostic techniques, biomarkers of disease activity and severity, and novel targeted therapies.

Defective gene expression of the membrane complement inhibitor CD46 in patients with progressive immunoglobulin A nephropathy

BACKGROUND

Complement is thought to play a role in immunoglobulin A nephropathy (IgAN), though the activating mechanisms are unknown. This study focused on the gene expression of CD46 and CD55, two key molecules for regulating C3 convertase activity of lectin and alternative complement pathways at a cellular level.

METHODS

The transcriptional expression in peripheral white blood cells (WBCs) of CD46 and CD55 was investigated in 157 patients enrolled by the Validation of the Oxford Classification of IgAN group, looking for correlations with clinical and pathology features and estimated glomerular filtration rate (eGFR) modifications from renal biopsy to sampling. Patients had a previous median follow-up of 6.4 (interquartile range 2.8-10.7) years and were divided into progressors and non-progressors according to the median value of their velocity of loss of renal function per year (-0.41 mL/min/1.73 m2/year).

RESULTS

CD46 and CD55 messenger RNA (mRNA) expression in WBCs was not correlated with eGFR values or proteinuria at sampling. CD46 mRNA was significantly correlated with eGFR decline rate as a continuous outcome variable (P = 0.014). A significant difference was found in CD46 gene expression between progressors and non-progressors (P = 0.013). CD46 and CD55 mRNA levels were significantly correlated (P < 0.01), although no difference between progressors and non-progressors was found for CD55 mRNA values. The prediction of progression was increased when CD46 and CD55 mRNA expressions were added to clinical data at renal biopsy (eGFR, proteinuria and mean arterial blood pressure) and Oxford MEST-C (mesangial hypercellularity, endocapillary hypercellularity, segmental glomerulosclerosis, tubular atrophy/interstitial fibrosis, presence of any crescents) score.

CONCLUSIONS

Patients with progressive IgAN showed lower expression of mRNA encoding for the complement inhibitory protein CD46, which may implicate a defective regulation of C3 convertase with uncontrolled complement activation.

Relationship between complement deposition and the Oxford classification score and their combined effects on renal outcome in immunoglobulin A nephropathy

Background

Complement activation has been highlighted in immunoglobulin (Ig) A nephropathy pathogenesis. However, whether the complement system can affect the downstream phenotype of IgA nephropathy remains unknown. Herein, we investigated the association of mesangial C3 deposition with the Oxford classification and their joint effects on worsening kidney function.

Methods

We investigated 453 patients with biopsy-proven IgA nephropathy. C3 deposition was defined as an immunofluorescence intensity of C3 ≥2+ within the mesangium. The subjects were classified according to the combination of C3 deposition and Oxford classification lesions. The primary endpoint was a composite of ≥30% decline in the estimated glomerular filtration rate or an increase in proteinuria ≥3.5 g/g during follow-up.

Results

Among the Oxford classification lesions, mesangial hypercellularity (M1), segmental glomerulosclerosis (S1) and tubulointerstitial fibrosis (T1–2) and crescentic lesion significantly correlated with C3 deposition. During a median follow-up of 33.0 months, the primary endpoint occurred more in patients with M1, S1, T1–2 and mesangial C3 deposition than in those without. In individual multivariable-adjusted Cox analyses, the presence of M1, S1, T1–2 and C3 deposition was significantly associated with higher risk of reaching primary endpoint. In the combined analyses of C3 deposition and the Oxford classification lesions, the hazard ratios for the composite outcome were significantly higher in the presence of C3/M1, C3/S1 and C3/crescent than in the presence of each lesion alone.

Conclusions

Complement deposition can strengthen the significance of the Oxford classification, and the presence of both components portends a poorer prognosis in IgA nephropathy.

Mesangial Cells Exhibit Features of Antigen-Presenting Cells and Activate CD4+ T Cell Responses

Background

Mesangial cells play a prominent role in the development of inflammatory diseases and autoimmune disorders of the kidney. Mesangial cells perform the essential functions of helping to ensure that the glomerular structure is stable and regulating capillary flow, and activated mesangial cells acquire proinflammatory activities. We investigated whether activated mesangial cells display immune properties and control the development of T cell immunity.

Methods

Flow cytometry analysis was used to study the expression of antigen-presenting cell surface markers and costimulatory molecules in mesangial cells. CD4+ T cell activation induced by mesangial cells was detected in terms of T cell proliferation and cytokine production.

Results

IFN-γ-treated mesangial cells express membrane proteins involved in antigen presentation and T cell activation, including MHC-II, ICAM-1, CD40, and CD80. This finding suggests that activated mesangial cells can take up and present antigenic peptides to initiate CD4+ T cell responses and thus act as nonprofessional antigen-presenting cells. Polarization of naïve CD4+ T cells (Th0 cells) towards the Th1 phenotype was induced by coculture with activated mesangial cells, and the resulting Th1 cells showed increased mRNA and protein expression of inflammation-associated genes.

Conclusion

Mesangial cells can present antigen and modulate CD4+ T lymphocyte proliferation and differentiation. Interactions between mesangial cells and T cells are essential for sustaining the inflammatory response in a variety of glomerulonephritides. Therefore, mesangial cells might participate in immune function in the kidney.

Recent advances in the physiopathology of IgA nephropathy

Immunoglobulin A nephropathy or Berger's disease is the most common type of primary glomerulonephritis, which is characterized by IgA1-containing immune-deposits in the glomerular mesangium. Microscopic haematuria and proteinuria are the most common presentations. Mesangial cell proliferation with IgA deposition is found on renal biopsy. Mechanims of the disease implicate at least four key molecules have been implicated in immune complex formation: galactose-deficient IgA1, autoantibodies anti-galactose-deficient-IgA1, soluble CD89 (Fc receptor for IgA) and the CD71 mesangial IgA receptor (transferrin receptor). These factors associated with environmental factors (antigens, food and microbiota) are correlated with disease progression and recurrence after transplantation. This review exploits recent data on the role of these molecular players of the disease, which may improve future therapeutic management of immunoglobulin A nephropathy.

Molecular profiling in IgA nephropathy and focal and segmental glomerulosclerosis

The aim of the study was to characterize by molecular profiling two glomerular diseases: IgA nephropathy (IgAN) and focal segmental glomerulosclerosis (FSGS) and to identify potential molecular markers of IgAN and FSGS progression. The expressions of 90 immune-related genes were compared in biopsies of patients with IgAN (n=33), FSGS (n=17) and in controls (n=11) using RT-qPCR. To identify markers of disease progression, gene expression was compared between progressors and non-progressors in 1 year follow-up. The results were verified on validation cohort of patients with IgAN (n=8) and in controls (n=6) using laser-capture microdissection, that enables to analyze gene expression separately for glomeruli and interstitium. In comparison to controls, patients with both IgAN and FSGS, had lower expression of BAX (apoptotic molecule BCL2-associated protein) and HMOX-1 (heme oxygenase 1) and higher expression of SELP (selectin P). Furthermore, in IgAN higher expression of PTPRC (protein-tyrosine phosphatase, receptor-type C) and in FSGS higher expression of BCL2L1 (regulator of apoptosis BCL2-like 1) and IL18 compared to control was observed. Validation of differentially expressed genes between IgAN and controls on another cohort using laser-capture microdissection confirmed higher expression of PTPRC in glomeruli of patients with IgAN. The risk of progression in IgAN was associated with higher expression EDN1 (endothelin 1) (AUC=0.77) and FASLG (Fas ligand) (AUC=0.82) and lower expression of VEGF (vascular endothelial growth factor) (AUC=0.8) and in FSGS with lower expression of CCL19 (chemokine (C-C motif) ligand 19) (AUC=0.86). Higher expression of EDN1 and FASLG along with lower expression of VEGF in IgAN and lower expression of CCL19 in FSGS at the time of biopsy can help to identify patients at risk of future disease progression.

Biomarkers and targeted new therapies for IgA nephropathy

IgA nephropathy (IgAN) has variable clinical presentation and outcome. There is a need to identify children who have the potential to progress to end stage renal disease (ESRD). Biomarkers related to the pathogenetic process of IgAN can detect risk factors and identify targets for new therapies. Galactose-deficient IgA1 (Gd-IgA1) is a specific biomarker of IgAN and could be the first treatment target. In experimental mice, reduction of IgA1 deposits and hematuria was observed after treatment with a bacterial protease that selectively cleaves human IgA1. Glycan-targeted drugs that may act to neutralize Gd-IgA1 inhibit abnormal enzymatic glycosylation of IgA1 or deplete cells producing Gd-IgA1. The autoimmune response to Gd-IgA1 produces autoantibodies that are sensitive and specific biomarkers of IgAN development and progression and suggests the possible benefits of anti-B cell therapies directed against CD20, B-cell activating factor (BAFF), or B cell receptor, and also proteasome inhibitors. The activation of complement in IgAN offers new biomarkers and the rationale for using complement inhibitors, including eculizumab. Renal pathological features represent sensitive biomarkers of added value over clinical data and may drive steroid therapy in selected cases. Finally, the hypothesis of the involvement of intestinal mucosal immunity in the pathogenesis of IgAN suggests the possibility of avoiding the systemic effect of steroid. Enteric budesonide targeting Peyer's patches at the ileocecal junction is an interesting option that has provided some preliminary favorable results in IgAN. In conclusion, the identification of new biomarkers is a promising area for therapies targeting IgAN in patients at risk of progression.

Interleukin-6 Signaling Pathway and Its Role in Kidney Disease: An Update

Interleukin-6 (IL-6) is a pleiotropic cytokine that not only regulates the immune and inflammatory response but also affects hematopoiesis, metabolism, and organ development. IL-6 can simultaneously elicit distinct or even contradictory physiopathological processes, which is likely discriminated by the cascades of signaling pathway, termed classic and trans-signaling. Besides playing several important physiological roles, dysregulated IL-6 has been demonstrated to underlie a number of autoimmune and inflammatory diseases, metabolic abnormalities, and malignancies. This review provides an overview of basic concept of IL-6 signaling pathway as well as the interplay between IL-6 and renal-resident cells, including podocytes, mesangial cells, endothelial cells, and tubular epithelial cells. Additionally, we summarize the roles of IL-6 in several renal diseases, such as IgA nephropathy, lupus nephritis, diabetic nephropathy, acute kidney injury, and chronic kidney disease.

Proteomic approach for identification of IgA nephropathy-related biomarkers in urine

Proteinuria is often used as a surrogate marker in monitoring and predicting outcome in patients with chronic kidney diseases, but it is non-specific. IgAN belongs to the most common primary glomerulonephritis worldwide with serious prognosis. The main aim of this work was to assess differences in urine proteins in patients with IgA nephropathy and to identify abnormal proteins as potential biomarkers of IgA nephropathy or the renal disease. In our pilot project, we selected 20 patients and compared them with 20 healthy volunteers. Protein quantification was performed using iTRAQ (isobaric tag for relative and absolute quantitation) labeling method. The peptides were separated by the isoelectric focusing method (IEF) and nano-LC with C18 column and identified by mass spectrometry using MALDI-TOF/TOF MS. Proteins´ lists obtained from IEF-LC-MS-MS/MS analysis were combined and contained 201 proteins. It was found out that 113 proteins were common in both experiments. 30 urinary proteins were significantly up- or down-regulated in patients with IgA nephropathy. We characterized potential biomarkers such as alpha-1-antitrypsin, apolipoprotein A-I, CD44 antigen or kininogen. Potential biomarkers of IgAN should be validated in further studies.

Th1, Th2 and Treg/T17 cytokines in two types of proliferative glomerulonephritis

IgA nephropathy (IgAN) and focal segmental necrotizing glomerulonephritis (FSNGN) are characterized by proliferation of native glomerular cells and infiltration by inflammatory cells. Several cytokines act as mediators of kidney damage in both diseases. The aim of the present study was to investigate the role of Th1, Th2 and Treg/T17 cytokines in these types of proliferative glomerulonephritis. Simultaneous measurement of Th1 interleukin (IL-2, IL-12, tumor necrosis factor-alpha [TNF-α], interferon-gamma [INF-γ]), Th2 (IL-4, IL-5, IL-6, IL-10, IL-13), Treg/T17 transforming growth factor-beta 1 (TGF-β1, granulocyte-macrophage colony-stimulating factor [GM-CSF], IL-17) cytokines and C-C chemokines Monocyte chemoattractant protein-1 (MCP-1, macrophage inflammatory protein-1 [MIP-1] β) was performed in first-morning urine samples, at the day of renal biopsy, using a multiplex cytokine assay. Cytokine concentrations were correlated with histological findings and renal function outcome. Urinary excretion of Th1, Th2 and Treg/Th17 cytokines were significantly higher in FSNGN compared to IgAN patients. In IgAN patients (n = 50, M/F: 36/14, M age: 40.7 [17–67] years), Th1, Th2 and T17 cytokines correlated significantly with the presence of endocapillary proliferation, while in FSNGN patients (n = 40, M/F: 24/16, M age: 56.5 [25–80] years), MCP-1 and TGF-β1 had a positive correlation with severe extracapillary proliferation (P = 0.001 and P = 0.002, respectively). Urinary IL-17 was the only independent parameter associated with endocapillary proliferation in IgAN and with MCP-1 urinary excretion in FSNGN. Response to treatment was mainly predicted by IL-6 in IgAN, and by Th2 (IL-4, IL-6), Treg (GM-CSF) cytokines and MIP-1 β in FSNGN. Th1, Th2 and T17 cytokines were directly implicated in renal pathology in IgAN and possibly through MCP-1 production in FSNGN. IL-17 and IL-6 seem to have a central role in inflammation and progression of kidney injury.

Markers for the progression of IgA nephropathy

We have summarized the latest findings on markers for progression of immunoglobulin A (IgA) nephropathy (IgAN), the most common primary glomerulonephritis with a high prevalence among end-stage renal disease (ESRD) patients. The clinical predictors of renal outcome in IgAN nephropathy, such as proteinuria, hypertension, and decreased estimated glomerular filtration rate (eGFR) at the time of the diagnosis, are well known. The Oxford classification of IgAN identified four types of histological lesions (known as the MEST score) associated with the development of ESRD and/or a 50 % reduction in eGFR. In addition, the role of genetic risk factors associated with IgAN is being elucidated by genome-wide association studies, with multiple risk alleles described. Recently, biomarkers in serum (galactose-deficient IgA1, IgA/IgG autoantibodies against galactose-deficient IgA1, and soluble CD 89-IgA complexes) and urine (soluble transferrin receptor, interleukin-6/epidermal growth factor ratio, fractalkine, laminin G-like 3 peptide, κ light chains, and mannan-binding lectin) have been identified. Some of these biomarkers may represent candidates for the development of noninvasive diagnostic tests, that would be useful for detection of subclinical disease activity, monitoring disease progression, assessment of treatment, and at the same time circumventing the complications associated with renal biopsies. These advances, along with future disease-specific therapy, will be helpful in improving the treatment effectiveness, prognosis, and the quality of life in connection with IgAN.

The Origin and Activities of IgA1-Containing Immune Complexes in IgA Nephropathy

IgA nephropathy (IgAN) is the most common primary glomerulonephritis, frequently leading to end-stage renal disease, as there is no disease-specific therapy. IgAN is diagnosed from pathological assessment of a renal biopsy specimen based on predominant or codominant IgA-containing immunodeposits, usually with complement C3 co-deposits and with variable presence of IgG and/or IgM. The IgA in these renal deposits is galactose-deficient IgA1, with less than a full complement of galactose residues on the O-glycans in the hinge region of the heavy chains. Research from the past decade led to the definition of IgAN as an autoimmune disease with a multi-hit pathogenetic process with contributing genetic and environmental components. In this process, circulating galactose-deficient IgA1 (autoantigen) is bound by antiglycan IgG or IgA (autoantibodies) to form immune complexes. Some of these circulating complexes deposit in glomeruli, and thereby activate mesangial cells and induce renal injury through cellular proliferation and overproduction of extracellular matrix components and cytokines/chemokines. Glycosylation pathways associated with production of the autoantigen and the unique characteristics of the corresponding autoantibodies in patients with IgAN have been uncovered. Complement likely plays a significant role in the formation and the nephritogenic activities of these complexes. Complement activation is mediated through the alternative and lectin pathways and probably occurs systemically on IgA1-containing circulating immune complexes as well as locally in glomeruli. Incidence of IgAN varies greatly by geographical location; the disease is rare in central Africa but accounts for up to 40% of native-kidney biopsies in eastern Asia. Some of this variation may be explained by genetically determined influences on the pathogenesis of the disease. Genome-wide association studies to date have identified several loci associated with IgAN. Some of these loci are associated with the increased prevalence of IgAN, whereas others, such as deletion of complement factor H-related genes 1 and 3, are protective against the disease. Understanding the molecular mechanisms and genetic and biochemical factors involved in formation and activities of pathogenic IgA1-containing immune complexes will enable the development of future disease-specific therapies as well as identification of non-invasive disease-specific biomarkers.

Current Understanding of the Role of Complement in IgA Nephropathy

Complement activation has a role in the pathogenesis of IgA nephropathy, an autoimmune disease mediated by pathogenic immune complexes consisting of galactose-deficient IgA1 bound by antiglycan antibodies. Of three complement-activation pathways, the alternative and lectin pathways are involved in IgA nephropathy. IgA1 can activate both pathways in vitro, and pathway components are present in the mesangial immunodeposits, including properdin and factor H in the alternative pathway and mannan-binding lectin, mannan-binding lectin-associated serine proteases 1 and 2, and C4d in the lectin pathway. Genome-wide association studies identified deletion of complement factor H-related genes 1 and 3 as protective against the disease. Because the corresponding gene products compete with factor H in the regulation of the alternative pathway, it has been hypothesized that the absence of these genes could lead to more potent inhibition of complement by factor H. Complement activation can take place directly on IgA1-containing immune complexes in circulation and/or after their deposition in the mesangium. Notably, complement factors and their fragments may serve as biomarkers of IgA nephropathy in serum, urine, or renal tissue. A better understanding of the role of complement in IgA nephropathy may provide potential targets and rationale for development of complement-targeting therapy of the disease.

Tubulointerstitial nephritis and uveitis syndrome complicated by IgA nephropathy and Graves' disease: a case report

Introduction

Tubulointerstitial nephritis and uveitis syndrome is a disorder characterized by a combination of acute tubulointerstitial nephritis and uveitis. Immunoglobulin A nephropathy is defined by the presence of immunoglobulin A deposits in glomerular mesangial areas. In this report, we describe a rare case of tubulointerstitial nephritis and uveitis syndrome complicated by immunoglobulin A nephropathy and Graves’ disease, which was successfully treated with corticosteroids. To the best of our knowledge, this is the first time such a case has been documented since tubulointerstitial nephritis and uveitis syndrome was first described.

Case presentation

A 64-year-old Japanese woman presented with tubulointerstitial nephritis and uveitis syndrome accompanied by immunoglobulin A nephropathy and Graves’ disease. She had renal dysfunction, proteinuria, and hematuria. Two weeks after her admission, she developed anterior chamber uveitis. She received corticosteroids, resulting in significant clinical improvement.

Conclusion

Tubulointerstitial nephritis and uveitis syndrome is a relatively uncommon cause of tubulointerstitial nephritis. Clinicians should recognize that tubulointerstitial nephritis and uveitis syndrome with immunoglobulin A nephropathy can occur in the presence of Graves’ disease. Additionally, this report may provide important clues in terms of the management of a concomitant case of these diseases.