Epidemiological, immunological, and treatment response profile of patients with lupus nephritis in Brazil.

BACKGROUND AND HYPOTHESIS: Brazil has the largest number of individuals of African descent outside Africa and a very admixed population. Among cases of lupus nephritis (LN) in the country, there are differences in incidence, and even in severity, depending on the location and characteristics of the population studied. The aim of this study was to describe the clinical and epidemiological characteristics of LN in Brazil, as well as to determine which of those characteristics would be risk factors for a poor renal prognosis. METHODS: This was a retrospective, descriptive observational study of patients diagnosed with LN who underwent kidney biopsy between 1999 and 2015 in the Nephrology Department of the Hospital das Clínicas, in São Paulo, Brazil. Data were collected from electronic medical records. RESULTS: We evaluated 398 patients, among who 94.1% and 77.7% tested positive for antinuclear antibodies and anti-DNA antibodies, respectively, whereas 33.7% showed the full-house pattern. The time from LN symptom onset to biopsy was <6 months in 47.5% (early biopsy group) and ≥6 months in 52.5% (late biopsy group). In the early biopsy group, the chronicity index was lower and the activity index was higher. Multivariate analysis showed that a higher chronicity index was the only independent risk factor for progression to requiring kidney replacement therapy. CONCLUSION: Late biopsy seems to be associated with negative renal outcomes in LN. However, it seems that a higher chronicity index is the main predictor of a poor renal outcome among patients with LN in Brazil.

Kidney involvement in systemic lupus erythematosus: From the patient assessment to a tailored treatment.

In the last few years, several studies have provided new evidence for the diagnosis, management, and follow-up of patients with lupus nephritis. Evidence showing dissociation between clinical and histological findings has prompted reevaluation of the role of the kidney biopsy as a tool for diagnosis and follow-up. In therapeutics, four immunosuppressive schemes now have supporting evidence for use as initial therapy. Current challenges include individualized selection of the best immunosuppressive regimen, an unmet need for non-invasive biomarkers of disease activity to inform treatment responses and guide subsequent therapy, holistic patient management in this complex, multisystem disease, and ultimately the development of more targeted therapies directed at specific effector pathways driving glomerular inflammation and damage in order to improve treatment response. In this communication, we review the diagnostic and therapeutic approach to lupus nephritis, as well as evaluation of response to therapy and disease control.

Lactobacillus plantarum CQPC02 intervenes in mouse lupus nephritis by regulating the NF-κB signaling pathway.

A strain of Lactobacillus plantarum CQPC02 (LP-CQPC02) isolated from naturally fermented kimchi was utilized in this investigation. In order to construct an animal model of lupus nephritis, pristane was used. We then used a kit to identify markers in mouse blood and tissues and a quantitative polymerase chain reaction (qPCR) to measure the expression of genes associated to nuclear factor kappa-B (NF-κB) in mouse kidney tissue. According to the results of the experiments, oral administration of LP-CQPC02 LP-CQPC02 may lessen the lupus nephritis-related rise in urine protein as well as the cytokine levels that were rising in the serum and renal tissues, including IL-6, IL-12, tumor necrosis factor alpha, and interferon. Additionally, in mice with nephritis, LP-CQPC02 can lower serum creatinine (SCr), blood urea nitrogen (BUN), total cholesterol (TC), triglyceride (TG), and raise total protein (TP) and albumin (ALB) levels. In mice with nephritis, LP-CQPC02 can also reduce the positive rate of double-stranded deoxyribonucleic acid (dsDNA). Pathological sections were examined, and it was shown that LP-CQPC02 can lessen tissue damage such incomplete glomerular morphology and inflammatory infiltration brought on by nephritis. In the kidneys of mice with lupus nephritis, LP-CQPC02 can upregulate the expression of inhibitor of NF-κB (IκB-α), downregulate the expression of NF-κB, transforming growth factor-ß1 (TGF-ß1), vascular endothelial growth factor (VEGF), intercellular cell adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1). Lactobacillus plantarum CQPC02 has been confirmed to have an intervention effect on nephritis in mice and has the potential as a probiotic.

Controversies in Systemic Lupus Erythematosus 2021: Changing the Paradigm in the Management of Lupus Nephritis.

ABSTRACT: Lupus nephritis (LN) affects about a third of patients with systemic lupus erythematosus. Although the use of conventional therapy has significantly improved the prognosis of LN, the response to treatment remains suboptimal, with high rates of relapse and the occurrence of end-stage kidney disease. The implementation of new diagnostic and treatment strategies aimed at improving these outcomes represents a necessary paradigm shift in the management of LN.Herein, we discuss different points of view regarding these still unresolved issues; these comments represent a debate that took place during the virtual congress of the Pan American League of Associations for Rheumatology (PANLAR) and which was organized by the PANLAR Lupus Study Group, GLADEL (Grupo Latino Americano De Estudio del Lupus) on August 15, 2021.

Lupus nephritis in children. / Nefropatía lúpica en pacientes pediátricos.

INTRODUCTION: Lupus nephritis is an early manifestation in the development of systemic lupus erythematosus that worsens the morbidity and mortality of these patients. OBJECTIVE: To study the form of presentation in patients with lupus nephritis, the clinical and immunological characteristics, and their relationship with renal histology. PATIENTS AND METHOD: Retrospective study in children under 18 years of age, with lupus nephritis, in follow-up in a third level children's hospital in Madrid, between January 2012 and May 2020. We recorded demographic, clinical, and laboratory data (blood count, renal function, liver function, protein, ionogram, blood glucose, uric acid, lactate dehydrogenase, coagulation, and urine analysis), as well as immunological data (immunoglobulins, antinuclear antibodies, comple ment, and lupus anticoagulant), and histological classification data. Descriptive analysis and analysis of associations between variables was performed, with a significant p < 0.05. RESULTS: 16 patients (11 women) were included, the median age at presentation was 10.6 ± 2.3 years (5.7-15.3). The median time between symptoms onset and renal involvement was 6.3 months ± 10.5 (range 0 - 33.6). Renal involvement was the initial manifestation in 37.5% of patients. 50% had arthralgias or arthritis prior to diagnosis, and 25% had fever and constitutional symptoms (asthenia, anorexia, and/or weight loss). The most frequent form of renal involvement was microhematuria associated with proteinuria in non-nephrotic range. In the renal anatomo-pathological study, according to the ISN/RPS 2003 classification, grades III (46.6%) and IV (33.3%) predominated. CONCLUSIONS: Six patients presented renal involvement at baseline with musculoskeletal involvement being more frequent. Most patients (86.6%) presented advanced lupus nephritis in the histological study at diagnosis. Immunologic in volvement was the only marker that correlated with systemic involvement.

The landscape of systemic lupus erythematosus in Brazil: An expert panel review and recommendations.

PURPOSE: The objective of this review is to address the barriers limiting access to diagnosis and treatment of systemic lupus erythematosus (SLE) and lupus nephritis (LN) in Brazil, specifically for patients in the public healthcare system, arguably those with the least access to innovation. DESIGN: A selected panel of Brazilian experts in SLE/LN were provided with a series of relevant questions to address in a multi-day conference. During the conference, responses were discussed and edited by the entire group through numerous drafts and rounds of discussion until a consensus was achieved. RESULTS: The authors propose specific and realistic recommendations for implementing access to innovative diagnostic tools and treatment alternatives for SLE/LN in Brazil. Moreover, in creating these recommendations, the authors strived to address barriers and impediments for technology adoption. The multidisciplinary care required for SLE/LN necessitates the collective participation of all involved stakeholders. CONCLUSION: A great need exists to expand the adoption of innovative diagnostic tools and treatments for SLE/LN not only in Brazil but also in most countries, as access issues remain an urgent demand. The recommendations presented in this article can serve as a strategy for new technology adoption in other countries in a similar situation.

Systemic lupus erythematosus diagnosis impacts clinical outcomes of arteriovenous fistulas in comparison to other end-stage renal disease etiologies.

OBJECTIVES: Arteriovenous fistulas primary patency at one-year occurs in 43-85% of the patients with end-stage renal disease. The diagnosis attributable to end-stage renal disease has been suggested to impact arteriovenous fistulas outcomes. The objective was to compare primary patency at one week, 1, 3, 6, and 12 months of follow-ups, among systemic lupus erythematosus patients and two control groups; additionally, we evaluated the impact of systemic lupus erythematosus to predict early patency loss. METHODS: A retrospective review of charts from arteriovenous fistulas created between 2008 and 2017 was performed. One-hundred thirty-four patients were identified and classified according to end-stage renal disease attributable diagnosis as: systemic lupus erythematosus cases (N = 14), control-group-1 (91 patients with primarily diabetes and hypertension), and control-group-2 (29 patients with idiopathic end-stage renal disease). A case-control matched design (1:2:1) was proposed. Logistic regression analysis and Kaplan-Meier curves were used. Institutional Review Board approval was obtained. RESULTS: More systemic lupus erythematosus patients lost primary patency at 3 (28.6%) and 12 months (71.4%) than patients from control-groups-1 (vs. 3.6% and 35.7%, respectively) and -2 (vs. 0% and 14.3%, respectively), (p ≤ 0.011 for both). Days of primary patency survival were shorter in systemic lupus erythematosus patients (p = 0.003). Systemic lupus erythematosus diagnosis was the only factor associated with early patency loss, HR: 3.141, 95%CI: 1.161-8.493 (systemic lupus erythematosus diagnosis vs. control-group-1) and HR: 12.582, 95%CI: 1.582-100.035 (systemic lupus erythematosus diagnosis vs. control-group-2). CONCLUSIONS: Diagnosis attributable to end-stage renal disease has a major impact on arteriovenous fistula outcomes in patients. Systemic lupus erythematosus patients have an increased risk of arteriovenous fistulas patency loss within the first six months of follow-up. Patients with idiopathic end-stage renal disease had an excellent one year arteriovenous fistula patency survival.

Lupus Nephritis and Kidney Transplantation: Where Are We Today?

Lupus nephritis (LN) is the cause of end-stage kidney disease (ESKD) for 1.9% of the ESKD population in the United States. Although the incidence rates of ESKD from LN stopped rising in recent years, racial disparities in waiting time, pre-emptive kidney transplant, and transplant outcomes still exist. Patients with LN who progress to ESKD tend to be female, of African ancestry, and young. Kidney transplantation is safe in this population and associated with a substantial survival benefit, primarily due to reduced deaths from cardiovascular disease and infection. Transplant outcomes for patients with ESKD due to LN are similar to those without LN.

Moving Forward With Biologics in Lupus Nephritis.

The majority of patients with systemic lupus erythematosus develop lupus nephritis (LN) which significantly contributes to increased risks of hospitalizations, ESRD, and death. Unfortunately, treatments for LN have not changed over the past 15 years. Despite continued efforts to elucidate the pathogenesis of LN, no new drugs have yet replaced the standard-of-care regimens of cyclophosphamide or mycophenolate mofetil plus high-dose corticosteroids. The significant limitations of standard-of-care are low complete response rates, risk of flares, and ongoing inflammation in the kidney leading to progressive renal dysfunction. Repeat and prolonged treatments are often needed to control disease, leading to a high level of severe side effects. The development of targeted drugs with better efficacy and safety are desperately needed. The rationale for targeting key immunologic pathways in LN continues to be strongly supported by basic and translational research and has generated the hope and excitement of testing these therapies in human LN. This review provides an overview of biologics studied to date in clinical trials of LN, discusses the potential reasons for their failure, and addresses the challenges moving forward.

Is serum uric acid a predictor of long-term renal outcome in lupus nephritis?

BACKGROUND/OBJECTIVE: Recent studies observed an association between increased serum uric acid (SUA) levels and renal damage in lupus. However, the predictive value of UA for the development of long-term renal dysfunction in lupus nephritis (LN) is still unknown. The aim of this study was to evaluate if SUA may be a predictor of long-term renal outcome in LN. METHODS: Eighty biopsy-proven LN patients > 7 years of follow-up were selected. SUA levels were measured in sera stored at - 70 °C. All patients had serum stored from LN baseline, and 32 also had stored serum from 6 and 12 months after LN. Renal outcome was addressed after 7 years of follow-up to determine if SUA could be a predictor of long-term renal outcome. A good long-term renal outcome in 7 years was defined as a creatinine clearance (CrCl) ≥ 90.0 mL/min/1.73 m2, and poor if CrCl < 90 mL/min/1.73 m2. Patients were divided in two groups according to the renal outcome to assess whether SUA levels at different time points of follow-up could differentiate such groups. An ROC curve was plotted to assess accuracy. RESULTS: SUA levels at baseline and 6 months were not able to differentiate good from poor long-term renal outcomes in LN (respectively p = 0.37, p = 0.28), but at 12 months (p = 0.02), they could clearly differentiate the two groups. ROC curve (12 months) accuracy was 0.76. SUA cutoff was 6.05 mg/dL (sensitivity = 0.67, specificity = 0.89, positive predictive value = 0.85, negative predictive value = 0.73). CONCLUSION: SUA levels < 6.05 mg/dL at 12 months of follow-up is a predictor of good long-term renal outcome in lupus nephritis. KEY POINTS: • Previous studies reported an association between increased serum uric acid level and short-term renal damage in lupus patients. • The predictive value of serum uric acid for the development of long-term renal dysfunction in lupus nephritis was never assessed. • At 12 months of follow-up serum uric acid clearly differentiated good from poor long-term renal outcome in lupus nephritis. • SUA level < 6.05 mg/dL at 12 months of follow-up was a predictor of good long-term renal outcome in lupus nephritis.

Long-term survival of kidney grafts in lupus nephritis: a Mexican cohort.

Kidney transplant for patients with lupus nephritis (LN) has satisfactory outcomes in studies with short-term or mid-term follow up. Nevertheless, information about long-term outcomes is scarce. We performed a retrospective matched-pair cohort study in 74 LN recipients compared with 148 non-LN controls matched by age, sex, immunosuppressive treatment, human leukocyte antigen (HLA) matches, and transplant period in order to evaluate long-term outcomes of kidney transplant in LN recipients. Matched pairs were predominantly females (83%), median age at transplant surgery of 32 years (interquartile range 23-38 years), and 66% received a graft from a living related donor. Among LN recipients, 5-, 10-, 15-, and 20-year graft survival was 81%, 79%, 57% and 51%, respectively, and it was similar to that observed in controls (89%, 78%, 64%, and 56%, respectively). Graft loss (27% vs. 21%, p = 0.24) and overall survival ( p = 0.15) were not different between LN recipients and controls. Also, there was no difference in episodes of immunological rejection, thrombosis, or infection. Only six LN recipients had biopsy-proven lupus recurrence and three of them had graft loss. In a cohort with a long follow up of kidney transplant recipients, LN recipients had similar long-term graft survival and overall outcomes compared with non-lupus recipients when predictors are matched between groups.

The prevalence of HLA alleles in a lupus nephritis population.

BACKGROUND: Systemic lupus erythematosus (SLE) is a severe autoimmune disease that involves multiple organ systems. Lupus nephritis (LN) is a complication of SLE and is associated with poor survival and high morbidity. Many genomic studies have been performed worldwide, and several histocompatibility leukocyte antigen (HLA) loci are linked to lupus susceptibility. OBJECTIVE: The present study evaluated the association of HLA alleles in a lupus patient population, LN group and control group. The second objective evaluated whether HLA allele match or mismatch influenced kidney graft survival in a kidney transplanted lupus population. METHODS: This study was a retrospective study of 2 major groups: general lupus patients (GSLE - n = 108) and a control group (GControl - n = 216). Both groups were also divided into subgroups. RESULTS: The control group was divided into two subgroups: a healthy control group (HeCTRL) and transplant control group (TxCTRL). The GSLE group was composed of transplanted lupus patients (TxSLE) and non-transplanted lupus patients (nTxSLE). Comparison of the demographics between groups did not reveal differences between ethnicity and gender. A difference in the prevalence of three alleles, B*08, DRB1*08 and DRB1*15, was observed. These alleles were more prevalent in the lupus subgroups compared to the control groups. Five-year survival was not different between patients carrying the allele DRB1*15 in either group (overall p = 0.075; TxSLE p = 0.419; TxCTRL = 0.309). The presence of the match with this allele in the receptor was evaluated and did not demonstrate any difference in graft survival in both groups (p = 0.146) or when analyzed separately in each group (TxCTRL p = 0.739; TxSLE = 0.297). CONCLUSION: This study demonstrated that the presence of HLA-DRB1*15 was a strong factor that predisposed patients to the development of SLE and LN, but did not influence kidney graft survival.

Worse renal outcome of subclass IV-G lupus nephritis patients over IV-S.

Background International Society of Nephrology/ Renal Pathology Society (ISN/RPS) consensus on the classification of lupus nephritis (LN) subdivided class IV into diffuse segmental (IV-S) and diffuse global (IV-G). Nephrologists and nephropathologists believe that this subclassification would be clinically relevant based on hypothetical distinct immunopathogenesis of those subclasses guiding therapy as well as judging prognosis. Methods All adult patients with a renal biopsy-confirmed diagnosis of LN class IV undergoing regular follow-up in the Nephrology Division between January 2004 and December 2014 were enrolled excluding those with diabetes, hepatitis B, hepatitis C, HIV as well as those with insufficient clinical and hystopathological data. Biopsies were reviewed and reclassified according to ISN/RPS 2003 classification by two experienced pathologists and were examined by light microscopy and direct immunofluorescence. Results On baseline subclass IV-G compared to IV-S showed higher frequency of males and histologically higher activity (7.5 ± 2.8 vs 5.1 ± 2.3, p = 0.004) and chronicity index (3.4 ± 1.6 vs 2.4 ± 1.8, p = 0.016) as well as a higher percentage of epithelial crescents (12.9 vs 5.1, p = 0.0001) and vessel abnormalities (72% vs 42%, p = 0.017). Although renal function on baseline was not different between subclasses, IV-G showed lower levels, although not significant, of estimated glomerular filtration based on CKD-EPI formula (91.0 ± 34.8 vs 64.4 ± 44.5, p = 0.059) at the end of follow-up. In addition, we observed a higher rate of patients reaching CKD-EPI under 60 mL/min/1.73 m2 in subclass IV-G over IV-S on last follow-up. Conclusion Subclasses IV-S and IV-G patients show some clinical and pathological differences that might represent distinct stages of the same disease and they should thus be treated the same.

CD4+ T helper cells and regulatory T cells in active lupus nephritis: an imbalance towards a predominant Th1 response?

The objective of this study was to evaluate the frequency of CD4+ T cell subsets in peripheral blood mononuclear cells (PBMC), urine and renal tissue from patients with lupus nephritis (LN). PBMC and urinary cells were collected from 17 patients with active LN, 20 disease controls (DC) with primary glomerulonephritis and 10 healthy controls (HC) and were analysed by flow cytometry with markers for T helper type 1 (Th1), Th2, Th17 and regulatory T cells (Treg ) cells. T cell subsets were assessed by immunohistochemistry from LN biopsy specimens from 12 LN patients. T cell subtypes in PBMC were re-evaluated at 6 months of therapy. CD4+ T cells were decreased in PBMC in LN compared with DC and HC (P = 0·0001). No differences were observed in urinary CD4+ T cell subsets between LN and DC. The frequency of urinary Th17 cells was higher in patients with non-proliferative than in proliferative LN (P = 0·041). CD3+ and T-box 21 ( Tbet+) cells were found in glomeruli and interstitium of LN patients, while forkhead box protein 3 (FoxP3), retinoid-related orphan receptor gamma (ROR-γ) and GATA binding protein 3 (GATA-3) were present only in glomeruli. Th1 cells in PBMC were correlated negatively with urinary Th1 cells (Rho = -0·531; P = 0·028) and with Tbet in renal interstitium (Rho = -0·782; P = 0·004). At 6 months, LN patients showed an increase in Th17 cells in PBMC. In conclusion, the inverse association between Th1 cells from PBMC and urinary/renal tissue indicate a role for Th1 in LN pathophysiology. Urinary Th17 cells were associated with less severe LN, and Th17 increased in PBMC during therapy. Urinary CD4+ T cells were not different between LN and DC.

Uso de tacrolimus na nefrite lúpica / Use of tacrolimus in lupus nephritis

O lúpus eritematoso sistêmico é uma doença multissistêmica, de etiologia autoimune, que apresenta comprometimento renal em até 50% dos portadores. A nefrite lúpica é uma das mais sérias e comuns complicações do lúpus eritematoso sistêmico, especialmente nos pacientes não caucasianos. Drogas como ciclofosfamida (que faz a terapia de indução convencional, junto de corticosteroides), azatioprina, micofenolato de mofetila e hidroxicloroquina são essenciais para o tratamento desta complicação, porém ainda são necessárias outras opções terapêuticas em casos resistentes. O tacrolimus vem sendo utilizado recentemente no tratamento da nefrite lúpica, com escassas publicações a este respeito. Apresentamos revisão sobre o papel do tacrolimus na nefrite lúpica, utilizando artigos publicados nas principais bases de dados da literatura nacional e internacional, nos idiomas espanhol e inglês.(AU)

Systemic lupus erythematosus (SLE) is a multisystemic disease of autoimmune etiology that involves renal impairment in up to 50% of patients. Lupus nephritis (LN) is one of the most serious and common complications of systemic lupus erythematosus, especially in non-Caucasian patients. Drugs such as cyclophosphamide (which performs the conventional induction therapy along with corticosteroids), azathioprine, mycophenolate mofetil, and hydroxychloroquine are essential for the treatment of this complication, but other therapeutic options in resistant cases are also necessary. Tacrolimus has recently been used in the treatment of lupus nephritis, with few publications in this regard. We present a review of the role of tacrolimus in lupus nephritis using articles published in the main databases of national and international literature, in Spanish and English languages.(AU)

Histologic versus clinical remission in proliferative lupus nephritis.

BACKGROUND: Treatment response in lupus nephritis (LN) is defined clinically, without consideration of renal histology. Few studies have systematically examined histologic responses to induction therapy. In LN patients who underwent protocol kidney biopsies after induction immunosuppression, we describe the renal histology of the second biopsy and correlate histologic activity and damage with short- and long-term kidney outcomes. METHODS: Patients with suspected LN were biopsied for diagnosis (Biopsy 1), and those with proliferative LN were rebiopsied after induction (Biopsy 2). Histologic activity and damage at each biopsy were calculated as the National Institutes of Health activity and chronicity indices. Complete and partial renal responses after induction and after long-term follow-up were determined clinically. RESULTS: One-third of patients who achieved a complete clinical response after induction had persistently high histologic activity, and 62% of patients who had complete histologic remission on rebiopsy were still clinically active. Chronic renal damage increased after induction even in complete clinical responders. Chronicity at Biopsy 2 associated with long-term kidney function and development of chronic kidney disease. CONCLUSIONS: Early clinical and histologic outcomes are discordant in proliferative LN, and neither correlates with long-term renal outcome. The kidney accrues chronic damage rapidly and despite clinical response in LN. Preservation of kidney function may require therapeutic targeting of both chronic damage and inflammation during LN induction treatment.

Renal Thrombotic Microangiopathy in Proliferative Lupus Nephritis: Risk Factors and Clinical Outcomes: A Case-Control Study.

BACKGROUND: Renal thrombotic microangiopathy (TMA) may be associated with lupus nephritis. Its relationship to other disease factors and its specific effect on prognosis are not precisely known. Evidence regarding these aspects is controversial, and information focusing on kidney-limited TMA in systemic lupus erythematosus (SLE) patients is scarce. OBJECTIVES: The aims of this study were to identify risk factors for renal TMA in patients with lupus nephritis and to determine its impact on clinical outcomes. METHODS: A case-control study was performed. We studied 245 renal biopsies from SLE patients. We included patients with renal TMA, as well as control subjects adjusted for glomerulonephritis class, estimated glomerular filtration rate, activity and chronicity indices, and follow-up time. Serological and clinical features were measured at the time of the biopsy and during follow-up. RESULTS: Twenty-three patients with renal TMA and 21 control subjects were included. There were no differences in Systemic Lupus Erythematosus Disease Activity Index score, end-stage renal disease, or mortality between groups during follow-up. After multivariate analysis, lymphopenia (odds ratio, 10.69; 95% CI, 1.35-84.74) and anti-Ro antibody positivity (odds ratio, 8.96; 95% CI, 1.49-53.57) remained significantly associated with renal TMA. CONCLUSIONS: Lymphopenia and anti-Ro positivity are independent risk factors for renal TMA in SLE patients. This increased risk could be a consequence of the potential role of these factors in endothelial dysfunction and damage. Outcomes were similar for patients with the same estimated glomerular filtration rate and biopsy characteristics, regardless of the presence of TMA.

Pathogenesis and treatment of glomerulonephritis-an update.

This review updates current concepts of the genetic risk factors, etiologic events, nephtitogenic responses and treatment of the major immunologically mediated types of glomerulonephritis (GN). These include post-infectious GN, IgA nephropathy, anti-glomerular basement membrane (GBM) antibody disease, ANCA-associated vasculitis (AAV) and lupus nephritis. Although the etiology(s) of most GNs remain undefined, many are now believed to be initiated by environmental insults, particularly infectious processes, that trigger host responses in genetically susceptible individuals which lead to GN. Mechanistic concepts of these diseases have evolved from earlier views that most were consequent to glomerular trapping of preformed immune complexes to the current view that most of these diseases are auto-immune in nature mediated by both antibodies and T cells reactive with self-antigens. Therapy of GN has lagged behind advances in understanding pathogenesis. Newly appreciated roles for older mediators like complement and complement regulatory proteins offer new therapeutic targets.