Anti-glomerular basement membrane antibody disease: a rare autoimmune disorder affecting the kidney and the lung

Clinical characteristics and outcome of double-seropositive patients with anti-glomerular basement membrane antibodies and anti-neutrophil cytoplasmic antibodies

OBJECTIVE

To explore the clinical characteristics of double-seropositive patients (DPPs) with anti-glomerular basement membrane (Anti-GBM) antibodies and anti-neutrophil cytoplasmic antibodies (ANCA).

METHODS

We collected patients with both ANCA and anti-GBM positive glomerulonephritis who were hospitalized in the Department of Nephrology at the First Affiliated Hospital of Nanjing Medical University from January 2010 to August 2022. Retrospective analysis of the baseline clinical characteristics of patients and follow-up to explore relevant factors affecting renal and patient survival.

RESULTS

A total of 386 patients, including 69 ANCA negative anti-GBM glomerulonephritis patients, 296 anti-GBM negative ANCA associated vasculitis (AAV) patients, and 21 DPPs were enrolled in this study. Among the 21 DPPs aged 68.0 years (59.5, 74.0), there were 11 males and 10 females. The median serum creatinine at diagnosis was 629.0 (343.85, 788.75) μmol/L, and the median eGFR (CKD-EPI) was 7.58 (4.74, 13.77) mL/min. Fifteen cases (71.4 %) underwent initial RRT. After a follow-up of 40.0 (11.0, 73.0) months, 13 out of 21 DPPs (61.9 %) received maintenance RRT, while 49 out of 69 (71.0 %) ANCA negative anti-GBM-GN patients and 124 out of 296 (41.9 %) anti-GBM negative AAV patients received maintenance RRT (P < 0.001). Kaplan-Meier survival analysis showed that DPPs and ANCA negative anti-GBM-GN patients were more likely to progress to ESRD than anti-GBM negative AAV patients (P = 0.001). Among the 21 patients with DPPs, renal survival was significantly better in patients with better initial renal function, including those who did not receive initial RRT (P = 0.003), with lower serum creatinine levels (Cr < 629.0 μmol/L, P = 0.004) and higher eGFR levels (eGFR ≥ 7.60 ml/min, P = 0.005) than those with poor initial renal function. At the end of follow-up, 14 out of 21 DPPs (66.7 %) survived. Survival analysis showed no significant difference among patients in DPPs group, ANCA negative anti-GBM-GN group, and anti-GBM negative AAV group.

CONCLUSIONS

DPPs and ANCA negative anti-GBM-GN patients were more likely to progress to ESRD than anti-GBM negative AAV patients. In DPPs, the poor renal function at diagnosis might be a risk factor associated with poor renal survival.

The RNA binding protein Arid5a drives IL-17-dependent autoantibody-induced glomerulonephritis

Autoantibody-mediated glomerulonephritis (AGN) arises from dysregulated renal inflammation, with urgent need for improved treatments. IL-17 is implicated in AGN and drives pathology in a kidney-intrinsic manner via renal tubular epithelial cells (RTECs). Nonetheless, downstream signaling mechanisms provoking kidney pathology are poorly understood. A noncanonical RNA binding protein (RBP), Arid5a, was upregulated in human and mouse AGN. Arid5a-/- mice were refractory to AGN, with attenuated myeloid infiltration and impaired expression of IL-17-dependent cytokines and transcription factors (C/EBPβ, C/EBPδ). Transcriptome-wide RIP-Seq revealed that Arid5a inducibly interacts with conventional IL-17 target mRNAs, including CEBPB and CEBPD. Unexpectedly, many Arid5a RNA targets corresponded to translational regulation and RNA processing pathways, including rRNAs. Indeed, global protein synthesis was repressed in Arid5a-deficient cells, and C/EBPs were controlled at the level of protein rather than RNA accumulation. IL-17 prompted Arid5a nuclear export and association with 18S rRNA, a 40S ribosome constituent. Accordingly, IL-17-dependent renal autoimmunity is driven by Arid5a at the level of ribosome interactions and translation.

Novel Therapies for ANCA-associated Vasculitis: Apilimod Ameliorated Endothelial Cells Injury through TLR4/NF-κB Pathway and NLRP3 Inflammasome

BACKGROUND

Antineutrophil cytoplasmic antibody-associated vasculitis (AAV) is a rapidly progressive form of glomerulonephritis for which effective therapeutic drugs are currently lacking, and its underlying mechanism remains unclear.

AIMS

This study aimed to investigate new treatment options for AAV through a combination of bioinformatics analysis and cell molecular experiments.

METHODS

The research utilized integrated bioinformatics analysis to identify genes with differential expression, conduct enrichment analysis, and pinpoint hub genes associated with AAV. Potential therapeutic compounds for AAV were identified using Connectivity Map and molecular docking techniques. In vitro experiments were then carried out to examine the impact and mechanism of apilimod on endothelial cell injury induced by MPO-ANCA-positive IgG.

RESULTS

The findings revealed a set of 374 common genes from differentially expressed genes and key modules of WGCNA, which were notably enriched in immune and inflammatory response processes. A proteinprotein interaction network was established, leading to the identification of 10 hub genes, including TYROBP, PTPRC, ITGAM, KIF20A, CD86, CCL20, GAD1, LILRB2, CD8A, and COL5A2. Analysis from Connectivity Map and molecular docking suggested that apilimod could serve as a potential therapeutic cytokine inhibitor for ANCA-GN based on the hub genes. In vitro experiments demonstrated that apilimod could mitigate tight junction disruption, endothelial cell permeability, LDH release, and endothelial activation induced by MPO-ANCA-positive IgG. Additionally, apilimod treatment led to a significant reduction in the expression of proteins involved in the TLR4/NF-κB and NLRP3 inflammasome-mediated pyroptosis pathways.

CONCLUSION

This study sheds light on the potential pathogenesis of AAV and highlights the protective role of apilimod in mitigating MPO-ANCA-IgG-induced vascular endothelial cell injury by modulating the TLR4/ NF-kB and NLRP3 inflammasome-mediated pyroptosis pathway. These findings suggest that apilimod may hold promise as a treatment for AAV and warrant further investigation.

Three Diseases Mediated by Different Immunopathologic Mechanisms-ANCA-Associated Vasculitis, Anti-Glomerular Basement Membrane Disease, and Immune Complex-Mediated Glomerulonephritis-A Common Clinical and Histopathologic Picture: Rapidly Progressive Crescentic Glomerulonephritis

Immune mechanisms play an important role in the pathogenesis of glomerulonephritis (GN), with autoimmunity being the main underlying pathogenetic process of both primary and secondary GN. We present three autoimmune diseases mediated by different autoimmune mechanisms: glomerulonephritis in vasculitis mediated by anti-neutrophil cytoplasmic antibodies (ANCAs), glomerulonephritis mediated by anti-glomerular basement membrane antibodies (anti-GBM antibodies), and immune complex-mediated glomerulonephritis. Some of these diseases represent a common clinical and histopathologic scenario, namely rapidly progressive crescentic glomerulonephritis. This is a severe illness requiring complex therapy, with the main role being played by therapy aimed at targeting immune mechanisms. In the absence of immune therapy, the crescents, the characteristic histopathologic lesions of this common presentation, progress toward fibrosis, which is accompanied by end-stage renal disease (ESRD). The fact that three diseases mediated by different immunopathologic mechanisms have a common clinical and histopathologic picture reveals the complexity of the relationship between immunopathologic mechanisms and their clinical expression. Whereas most glomerular diseases progress by a slow process of sclerosis and fibrosis, the glomerular diseases accompanied by glomerular crescent formation can progress, if untreated, in a couple of months into whole-nephron glomerulosclerosis and fibrosis. The outcome of different immune processes in a common clinical and histopathologic phenotype reveals the complexity of the relationship of the kidney with the immune system. The aim of this review is to present different immune processes that lead to a common clinical and histopathologic phenotype, such as rapidly progressive crescentic glomerulonephritis.

Unleashing the power of complement activation: unraveling renal damage in human anti-glomerular basement membrane disease

Anti-glomerular basement membrane (GBM) disease is a rare but life-threatening autoimmune disorder characterized by rapidly progressive glomerulonephritis with or without pulmonary hemorrhage. Renal biopsies of anti-GBM patients predominantly show linear deposition of IgG and complement component 3 (C3), indicating a close association between antigen-antibody reactions and subsequent complement activation in the pathogenesis of the disease. All three major pathways of complement activation, including the classical, lectin, and alternative pathways, are involved in human anti-GBM disease. Several complement factors, such as C3, C5b-9, and factor B, show a positive correlation with the severity of the renal injury and act as risk factors for renal outcomes. Furthermore, compared to patients with single positivity for anti-GBM antibodies, individuals who are double-seropositive for anti-neutrophil cytoplasmic antibody (ANCA) and anti-GBM antibodies exhibit a unique clinical phenotype that lies between ANCA-associated vasculitis (AAV) and anti-GBM disease. Complement activation may serve as a potential "bridge" for triggering both AAV and anti-GBM conditions. The aim of this article is to provide a comprehensive review of the latest clinical evidence regarding the role of complement activation in anti-GBM disease. Furthermore, potential therapeutic strategies targeting complement components and associated precautions are discussed, to establish a theoretical basis for complement-targeted therapies.

Renal function protection and the mechanism of ginsenosides: Current progress and future perspectives

Nephropathy is a general term for kidney diseases, which refers to changes in the structure and function of the kidney caused by various factors, resulting in pathological damage to the kidney, abnormal blood or urine components, and other diseases. The main manifestations of kidney disease include hematuria, albuminuria, edema, hypertension, anemia, lower back pain, oliguria, and other symptoms. Early detection, diagnosis, and active treatment are required to prevent chronic renal failure. The concept of nephropathy encompasses a wide range of conditions, including acute renal injury, chronic kidney disease, nephritis, renal fibrosis, and diabetic nephropathy. Some of these kidney-related diseases are interrelated and may lead to serious complications without effective control. In serious cases, it can also develop into chronic renal dysfunction and eventually end-stage renal disease. As a result, it seriously affects the quality of life of patients and places a great economic burden on society and families. Ginsenoside is one of the main active components of ginseng, with anti-inflammatory, anti-tumor, antioxidant, and other pharmacological activities. A variety of monomers in ginsenosides can play protective roles in multiple organs. According to the difference of core structure, ginsenosides can be divided into protopanaxadiol-type (including Rb1, Rb3, Rg3, Rh2, Rd and CK, etc.), and protopanaxatriol (protopanaxatriol)- type (including Rg1, Rg2 and Rh1, etc.), and other types (including Rg5, Rh4, Rh3, Rk1, and Rk3, etc.). All of these ginsenosides showed significant renal function protection, which can reduce renal damage in renal injury, nephritis, renal fibrosis, and diabetic nephropathy models. This review summarizes reports on renal function protection and the mechanisms of action of these ginsenosides in various renal injury models.

RNA N6 -methyladenosine modifications and potential targeted therapeutic strategies in kidney disease

Epigenetic modifications have received increasing attention and have been shown to be extensively involved in kidney development and disease progression. Among them, the most common RNA modification, N⁶ -methyladenosine (m⁶ A), has been shown to dynamically and reversibly exert its functions in multiple ways, including splicing, export, decay and translation initiation efficiency to regulate mRNA fate. Moreover, m⁶ A has also been reported to exert biological effects by destabilizing base pairing to modulate various functions of RNAs. Most importantly, an increasing number of kidney diseases, such as renal cell carcinoma, acute kidney injury and chronic kidney disease, have been found to be associated with aberrant m⁶ A patterns. In this review, we comprehensively review the critical roles of m⁶ A in kidney diseases and discuss the possibilities and relevance of m⁶ A-targeted epigenetic therapy, with an integrated comprehensive description of the detailed alterations in specific loci that contribute to cellular processes that are associated with kidney diseases.

Clinicopathological characteristics and outcome predictors of anti-glomerular basement membrane glomerulonephritis

Objective

To explore the clinicopathological features of anti-glomerular basement membrane (anti-GBM) glomerulonephritis (anti-GBM-GN) and the prognostic values of clinical and laboratory indicators at diagnosis on renal and patient survival.

Methods

A total of 76 patients (34 males and 42 females) with anti-GBM-GN who were hospitalized in the First Affiliated Hospital of Nanjing Medical University between January 2010 and June 2021 were included in this study. The baseline clinical features, histopathological data from renal biopsies, and predictors of renal and patient survival were retrospectively analyzed.

Results

Among the 76 patients, the median serum creatinine at diagnosis was 618.0 (350.98, 888.25) μmol/L and the median estimated glomerular filtration rate (eGFR) was 6.62 (4.39, 14.41) mL/min. Of these 76 patients, 55 (72.4%) received initial kidney replacement therapy (KRT) and 39 (51.3%) received plasma exchange or double-filtered plasmapheresis (DFPP). During a median follow-up duration of 28.5 (6.0, 71.8) months, 53 (69.7%) patients progressed to kidney failure with replacement therapy (KFRT) and received maintenance dialysis. Initial KRT (HR = 3.48, 95% CI = 1.22–9.97, p = 0.020) was a significant risk factor for renal survival. During the follow-up, 49 (64.5%) of 76 patients survived. Age (≥60 years, HR = 4.13, 95% CI = 1.65–10.38, p = 0.003) and initial KRT (HR = 2.87, 95% CI = 1.01–8.14, p = 0.047) were predictive of patient survival.

Conclusions

Among patients with anti-GBM-GN, initial KRT at presentation was predictive of KFRT while older age and initial KRT were associated with higher all-cause mortality.

The m6A reader IMP2 directs autoimmune inflammation through an IL-17- and TNFα-dependent C/EBP transcription factor axis

Excessive cytokine activity underlies many autoimmune conditions, particularly through the interleukin-17 (IL-17) and tumor necrosis factor-α (TNFα) signaling axis. Both cytokines activate nuclear factor κB, but appropriate induction of downstream effector genes requires coordinated activation of other transcription factors, notably, CCAAT/enhancer binding proteins (C/EBPs). Here, we demonstrate the unexpected involvement of a posttranscriptional "epitranscriptomic" mRNA modification [N6-methyladenosine (m6A)] in regulating C/EBPβ and C/EBPδ in response to IL-17A, as well as IL-17F and TNFα. Prompted by the observation that C/EBPβ/δ-encoding transcripts contain m6A consensus sites, we show that Cebpd and Cebpb mRNAs are subject to m6A modification. Induction of C/EBPs is enhanced by an m6A methylase "writer" and suppressed by a demethylase "eraser." The only m6A "reader" found to be involved in this pathway was IGF2BP2 (IMP2), and IMP2 occupancy of Cebpd and Cebpb mRNA was enhanced by m6A modification. IMP2 facilitated IL-17-mediated Cebpd mRNA stabilization and promoted translation of C/EBPβ/δ in response to IL-17A, IL-17F, and TNFα. RNA sequencing revealed transcriptome-wide IL-17-induced transcripts that are IMP2 influenced, and RNA immunoprecipitation sequencing identified the subset of mRNAs that are directly occupied by IMP2, which included Cebpb and Cebpd Lipocalin-2 (Lcn2), a hallmark of autoimmune kidney injury, was strongly dependent on IL-17, IMP2, and C/EBPβ/δ. Imp2-/- mice were resistant to autoantibody-induced glomerulonephritis (AGN), showing impaired renal expression of C/EBPs and Lcn2 Moreover, IMP2 deletion initiated only after AGN onset ameliorated disease. Thus, posttranscriptional regulation of C/EBPs through m6A/IMP2 represents a previously unidentified paradigm of cytokine-driven autoimmune inflammation.

Glomerulonephritis in AKI: From Pathogenesis to Therapeutic Intervention

Acute kidney injury (AKI) is increasingly emerging as a global emergency. Sepsis, major surgery, and nephrotoxic drugs are the main causes of AKI in hospitalized patients. However, glomerulonephritis accounts for about 10% of AKI episodes in adults, mainly related to rapidly progressive glomerulonephritis resulting from granulomatous polyangiitis (GPA, Wegener granulomatosis), microscopic polyangiitis (MPA), and anti-glomerular basement membrane (GBM) disease. Also, diffuse proliferative lupus nephritis, immunoglobulin A nephropathy, post-streptococcal glomerulonephritis, mixed cryoglobulinemia, mesangiocapillary glomerulonephritis, membranous nephropathy, hemolytic uremic syndrome, thrombotic thrombocytopenic purpura, and scleroderma can induce acute renal failure. Early diagnosis of AKI due to glomerulonephritis is crucial for prompt, effective management to improve short- and long-term outcomes. Kidney biopsy is the gold standard for the diagnosis of glomerular disease, but it is not frequently performed in critically ill patients because of their clinical conditions. In this setting, a growing number of diagnostic assays can support the working hypothesis, including antineutrophil cytoplasmic antibodies (ANCAs), anti-double-stranded DNA antibodies, anti-GBM antibodies, antistreptolysin O and anti-DNase B antibodies, cryoglobulins, antiphospholipid antibodies, and complement levels. Therapeutic strategies in AKI patients with glomerulonephritis include high-dose corticosteroids, cyclophosphamide, and plasma exchange. This article reviews the wide spectrum of glomerulopathies associated with AKI, describing the immunological mechanisms underlying glomerular diseases and presenting an overview of the therapeutic options.

Management of an Adult with Goodpasture's Syndrome Following Brain Trauma with Extracorporeal Membrane Oxygenation: A Case Report

A 22-year-old man suffered from acute pulmonary hemorrhage and deteriorated renal function occurred within 3 days after traumatic brain injury. Mechanical ventilation cannot correct his severe hypoxemia, therefore, venoarterial extracorporeal membrane oxygenation (VA-ECMO) support was initiated and finally resolved his hypoxemia. Concomitantly, continuous renal replacement therapy was performed to improve his kidney function. Although no anti-glomerular basement membrane (anti-GBM) antibody was detected in serum, Goodpasture's syndrome was considered. After treated with methylprednisolone pulse therapy and plasmapheresis, his renal function was significantly improved. ECMO was eventually discontinued after 60 hours of treatment and extubated on day 10. He was discharged home with normal pulmonary and renal functions.

A case of bizarre posttransplant anti-glomerular basement membrane disease

The non-collagenous (NC1) domain of α3 and α5 chains of type IV collagen are eminent targets of abnormal immune response in anti-glomerular basement membrane (anti-GBM) disease, which can be diagnosed by the presence of strong linear IgG staining along GBM detected by direct immunofluorescence. The presence of linear GBM fixation in renal allograft is a rare finding. We observed a 33-year-old male with de novo renal failure in a kidney transplant. An examination of a kidney biopsy specimen revealed, in light microscopy, mild mesangial hypercellularity together with mild focal interstitial fibrosis and sparse inflammatory infiltrate. In immunofluorescence microscopy strong linear IgG staining along the capillary walls was seen. Serum anti-GBM antibodies were negative and no mutation in exons coding NC1 domains of α3 and α5 chains of type IV collagen were detected. We described a rare case of a patient with atypical anti-GBM disease in renal allograft, caused probably by the same process which affected the native kidneys.

Falsely positive anti-glomerular basement membrane antibodies in a patient with hantavirus induced acute kidney injury - a case report

Background

Hantavirus infection is an uncommon cause of acute renal failure with massive proteinuria. Serology tests to support a presumptive diagnosis usually take a few days. During the initial work-up, autoimmune causes including anti-glomerular basement membrane (GBM) glomerulonephritis need to be excluded, because these require urgent therapy. In this case the delay in serological testing caused a dilemma in treatment initiation.

Case presentation

An 18-year-old patient was admitted to the hospital with acute renal failure, erythrocyturia and massive proteinuria. Routine blood analysis showed leucocytosis (40,5 × 109/l) and a serum creatinine of 233 μmol/l. Infectious causes, e.g. leptospirosis or hantavirus infection, or an autoimmune disease, e.g., AAV or anti-GBM glomerulonephritis was the most feasible underlying diagnosis.

Before hantavirus serology results were known, anti-GBM antibodies were positive. Treatment for anti-GBM glomerulonephritis was withheld, because of the absence of other signs and symptoms of the disease and slight improvement of renal function.

The diagnosis of acute hantavirus infection was later on confirmed, by seroconversion of a follow-up serum sample. Without further intervention renal function recovered and anti-GBM antibodies disappeared.

Conclusion

Hantavirus infection may induce anti-GBM antibodies, falsely suggestive of anti-GBM glomerulonephritis.

Anti-GBM antibodies are supposed to be 100% specific. No earlier reports of false positive anti-GBM titers were reported. Nevertheless, the anti-GBM antibodies in this case were seen as an innocent bystander effect.

Considering the need of urgent initiation of plasmapheresis and administration of immunosuppressants it may lead to diagnostic dilemmas with crucial therapeutic consequences. Knowledge of this anomaly when diagnosing acute renal failure, is very important.

Urinary podocyte and TGF-β1 mRNA as markers for disease activity and progression in anti-glomerular basement membrane nephritis

Background

Podocyte depletion causes glomerulosclerosis, with persistent podocyte loss being a major factor driving disease progression. Urinary podocyte mRNA is potentially useful for monitoring disease progression in both animal models and in humans. To determine whether the same principles apply to crescentic glomerular injury, a rat model of anti-glomerular basement membrane (anti-GBM) nephritis was studied in parallel with a patient with anti-GBM nephritis.

Methods

Podocyte loss was measured by Wilms' Tumor 1-positive podocyte nuclear counting and density, glomerular epithelial protein 1 or synaptopodin-positive podocyte tuft area and urinary podocyte mRNA excretion rate. Glomerulosclerosis was evaluated by Azan staining and urinary transforming growth factor (TGF)-β1 mRNA excretion rate.

Results

In the rat model, sequential kidney biopsies revealed that after a threshold of 30% podocyte loss, the degree of glomerulosclerosis was linearly associated with the degree of podocyte depletion, compatible with podocyte depletion driving the sclerotic process. Urinary podocyte mRNA correlated with the rate of glomerular podocyte loss. In treatment studies, steroids prevented glomerulosclerosis in the anti-GBM model in contrast to angiotensin II inhibition, which lacked a protective effect, and urinary podocyte and TGF-β1 mRNA markers more accurately reflected both the amount of podocyte depletion and the degree of glomerulosclerosis compared with proteinuria under both scenarios. In a patient successfully treated for anti-GBM nephritis, urinary podocyte and TGB-β1 mRNA reflected treatment efficacy.

Conclusion

These results emphasize the role of podocyte depletion in anti-GBM nephritis and suggest that urinary podocyte and TGF-β1 mRNA could serve as markers of disease progression and treatment efficacy.

Standardization of autoimmune testing – is it feasible?

Correct measurement of autoantibodies is essential for the diagnosis of autoimmune diseases. However, due to the variability of autoantibody results and the heterogeneity of testing, wrong diagnosis is a reality. For this and more reasons, harmonization of testing is of the outmost importance. In this review we have summarized the factors contributing to this variability. The ways with which the working group on harmonization of autoantibody testing of the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) has been trying to tackle the issue with the production and correct use of certified reference materials (CRMs), is discussed. Finally the advantages and the limitations of the use of CRMs are presented.

[Goodpasture syndrome: ocular manifestation in a young man]

Goodpasture syndrome (GS) is a rare organ-specific autoimmune disease that may consist of glomerulonephritis and pulmonary hemorrhage. Only few case reports have been published on ocular symptoms in the context of GS. This is a case report of a 22-year-old male with GS who was referred to our practice because of visual disturbances. The anamnesis revealed pulmonary hemorrhage, acute renal failure and nephrotic syndrome, which was treated by immunosuppressive therapy with additional plasmapheresis. Ophthalmoscopically, bilateral cotton wool spots were found along the vessels and bilateral retinal hemorrhages predominantly at the posterior pole. By intensifying the existing antihypertensive therapy the eyesight showed significant improvement. Although infrequently seen in Goodpasture syndrome it is important to be aware of ocular symptoms as they may be the initial signs of GS.

Goodpasture's syndrome in early pregnancy: A case report

Goodpasture's syndrome (GPS) presenting during pregnancy is extremely rare and patients exhibiting hemoptysis and renal dysfunction in early pregnancy are uncommon. The present study reports the case of a 17-year-old diagnosed with GPS during the thirteenth week of pregnancy. Prompt recognition and immediate treatment (steroids and plasma exchange) was initiated. Renal function normalized following treatment and anti-GBM antibody became negative during hospital stay. However, due to irregular follow-up, the patient eventually succumbed. The case highlights that the current treatment plan for GPS should be revised to improve the outcome of pregnancy. In addition, it determines how important it is for obstetricians to consider whether a pregnancy should be terminated to improve the chances of survival of pregnant patients with GPS.

Therapeutic Mechanism of Glucocorticoids on Cellular Crescent Formation in Patients With Antiglomerular Basement Membrane Disease

BACKGROUND

This study aimed to explore the therapeutic mechanism of glucocorticoids (GCs) in antiglomerular basement membrane disease.

MATERIALS AND METHODS

Thirty-four patients with biopsy-proven antiglomerular basement membrane nephritis were divided into the following 2 groups: group 1 (patients treated with GCs, n = 22) and group 2 (patients who were not treated with GCs, n = 12). The expression of parietal epithelial cells (PECs), activated PECs and glucocorticoid receptors (GRs) was examined quantitatively and compared between the 2 groups. Correlations between GR expression in glomeruli and patients' clinicopathological indices were also analyzed.

RESULTS

Compared with patients in group 2, patients in group 1 showed lower levels of serum creatinine (SCr) (P = 0.03), average cellular crescent percentage (P = 0.005) and macrophages infiltrating in renal interstitium (P = 0.03). PECs (P = 0.007) and activated PECs (P = 0.03) were strongly detected in the cellular components of classic crescents, and both were significantly reduced in group 1 compared to group 2. GR expression either in glomeruli (P = 0.01) or interstitium (P = 0.009) was lower in group 1 after GCs treatment than in group 2. Additionally, GR expression in glomeruli was strongly correlated with renal function (SCr: r = 0.45, P = 0.009; eGFR: r = -0.35, P = 0.046), the proportion of cellular crescents (r = 0.67, P < 0.001), PECs (r = 0.64, P < 0.001) and activated PECs (r = 0.72, P < 0.001), and the degree of interstitial (r = 0.50, P = 0.004) and glomerular (r = 0.49, P = 0.007) macrophage infiltration.

CONCLUSIONS

GCs might exert their therapeutic effects via inhibiting the activation and proliferation of PECs, as well as macrophage infiltration, which could contribute to crescent formation and determine renal survival. GRs are involved in this process as well.

Status epilepticus as the initial presentation of antibody-negative Goodpasture's syndrome

Goodpasture's syndrome is a rare pulmonary-renal disease. It is characterised by presence of auto-antibodies directed against the glomerular basement membrane (GBM) antigen. These antibodies that bind to the GBM antigens cause rapidly progressive glomerulonephritis. The alveolar basement membrane also contains similar antigen, leading to pulmonary haemorrhage in active disease. We report a case of a young man who initially presented with status epilepticus and later was found to have rapidly progressive glomerulonephritis with pulmonary haemorrhage. Serum anti-GBM antibody was negative but the renal biopsy confirmed the diagnosis by showing typical linear IgG along the GBM on immunofluorescent study. He was treated with plasmapheresis and high-dose steroid in combination with oral cyclophosphamide. His renal function normalised after treatment.

Pneumonia, Acute Respiratory Distress Syndrome, and Early Immune-Modulator Therapy

Acute respiratory distress syndrome (ARDS) is caused by infectious insults, such as pneumonia from various pathogens or related to other noninfectious events. Clinical and histopathologic characteristics are similar across severely affected patients, suggesting that a common mode of immune reaction may be involved in the immunopathogenesis of ARDS. There may be etiologic substances that have an affinity for respiratory cells and induce lung cell injury in cases of ARDS. These substances originate not only from pathogens, but also from injured host cells. At the molecular level, these substances have various sizes and biochemical characteristics, classifying them as protein substances and non-protein substances. Immune cells and immune proteins may recognize and act on these substances, including pathogenic proteins and peptides, depending upon the size and biochemical properties of the substances (this theory is known as the protein-homeostasis-system hypothesis). The severity or chronicity of ARDS depends on the amount of etiologic substances with corresponding immune reactions, the duration of the appearance of specific immune cells, or the repertoire of specific immune cells that control the substances. Therefore, treatment with early systemic immune modulators (corticosteroids and/or intravenous immunoglobulin) as soon as possible may reduce aberrant immune responses in the potential stage of ARDS.

Management of Small Vessel Vasculitides

Inflammation mediated by cells of the immune system and necrosis are the most striking features observed at the histologic level in patients with vasculitides, clinical entities classified according to pathologic findings involving different organs, to etiology, or to size of vessels involved. Small vessel vasculitides (SVV) are a peculiar group of systemic disorders electively involving small intraparenchymal arteries, arterioles, capillaries, or venules and leading to different levels of vascular obstruction, tissue ischemia and risk of infarction; they can be divided into anti-neutrophil cytoplasmic antibody-associated vasculitides and immune complex vasculitides. Despite the significant advances in understanding the whole disease process and pathophysiology of SVV, strong efforts are still needed to draft, share and spread guidelines in the therapeutic management of these protean disorders. After an accurate evaluation of different open or double-blind trials and cohort studies in this review, we analyze the actual medical tools suggested for treating granulomatosis with polyangiitis, microscopic polyangiitis, eosinophilic granulomatosis with polyangiitis, Henoch-Schönlein purpura, cryoglobulinemic vasculitis, anti-glomerular basement membrane disease and hypocomplementemic urticarial vasculitis.

Cell therapy for basement membrane-linked diseases

For most disorders caused by mutations in genes encoding basement membrane (BM) proteins, there are at present only limited treatment options available. Genetic BM-linked disorders can be viewed as especially suited for treatment with cell-based therapy approaches because the proteins that need to be restored are located in the extracellular space. In consequence, complete and permanent engraftment of cells does not necessarily have to occur to achieve substantial causal therapeutic effects. For these disorders cells can be used as transient vehicles for protein replacement. In addition, it is becoming evident that BM-linked genetic disorders are modified by secondary diseases mechanisms. Cell-based therapies have also the ability to target such disease modifying mechanisms. Thus, cell therapies can simultaneously provide causal treatment and symptomatic relief, and accordingly hold great potential for treatment of BM-linked disorders. However, this potential has for most applications and diseases so far not been realized. Here, we will present the state of cell therapies for BM-linked diseases. We will discuss use of both pluripotent and differentiated cells, the limitation of the approaches, their challenges, and the way forward to potential wider implementation of cell therapies in the clinics.

Goodpasture's syndrome with absence of circulating anti-glomerular basement membrane antibodies: a case report

Background

Goodpasture’s syndrome, a rare disease, is an organ-specific autoimmune disease mediated by anti-glomerular basement membrane antibodies. Its pathology is characterized by crescentic glomerulonephritis with linear immunofluorescent staining for immunoglobulin G on the glomerular basement membrane. Although rare, a few cases with absence of circulating anti-glomerular membrane antibodies have been described.

Case presentation

The objective of this clinical case report is to describe and discuss a case of a 27-year-old white man who was hospitalized with a 1-year history of weight loss and a 1-month history of hemoptysis, with aggravation  the day before, having developed dyspnea and cough in the previous 24 hours. An analytical study showed normocytic normochromic anemia with a hemoglobin level of 7.2 g/dL and leukocytosis with normal renal function and coagulation times. A blood transfusion was performed without complications. Chest computed tomography revealed a reticulonodular infiltrate of both lungs. Bronchoscopy showed no apparent lesions. Sputum cultures, rapid urine antigens for Legionella pneumophila and Streptococcus pneumoniae, studies for Influenza, virologic markers and serologic studies for autoimmunity were all negative. At the end of the tenth day his general state deteriorated with fatigue, hematuria, and in 3 days he developed aggravation of renal function with recurrent hemoptysis and anemia. Immunosuppression with daily prednisolone 1 g administered intravenously was initiated. An urgent bronchoscopy showed no lesions. A kidney biopsy showed fibrinoid necrosis and cellular crescents. Immunofluorescence revealed a linear immunoglobulin G deposition compatible with Goodpasture’s syndrome. Immunosuppressive therapy with daily cyclophosphamide 120 mg orally was added. Subsequently he was transferred to a referral center at which 21 sessions of plasmapheresis and four sessions of hemodialysis were performed with good response; he currently has no need of hemodialysis.

Conclusions

The absence of circulating anti-glomerular basement membrane antibodies in Goodpasture’s syndrome adds complexity to the diagnosis creating an unusual setting in a rare disease. In our case a kidney biopsy was essential for diagnosis and clinical approach. Studies have shown that early aggressive therapy leads to an improved prognosis. Physicians should consider tissue diagnoses such as bronchoscopy and kidney biopsy in pulmonary renal syndrome.

Novel therapy for anti-glomerular basement membrane disease with IgA nephropathy: A case report

Anti-glomerular basement membrane (GBM) disease is characterized by circulating anti-GBM antibodies and deposition of these antibodies in the renal GBM. Renal involvement in anti-GBM is more severe when compared with other types of immune-mediated glomerulonephritis, and the majority of patients manifest progressive renal failure, leading to end-stage renal disease. In a limited number of cases, anti-GBM disease has been shown to be accompanied with other immune-mediated glomerulonephritis. The present study reported the case of a 50-year-old female patient presenting with rapidly progressive glomerulonephritis, who was diagnosed with anti-GBM disease with IgA nephropathy. The patient achieved a relatively good therapeutic outcome with administration of corticosteroids plus mycophenolate mofetil (MMF), which may prove to be a novel treatment option for this rare disease; however, the exact underlying mechanism requires further in-depth investigation.

Atypical anti-glomerular basement membrane disease

Background

Anti-glomerular basement membrane (anti-GBM) disease classically presents with aggressive necrotizing and crescentic glomerulonephritis, often with pulmonary hemorrhage. The pathologic hallmark is linear staining of GBMs for deposited immunoglobulin G (IgG), usually accompanied by serum autoantibodies to the collagen IV alpha-3 constituents of GBMs.

Methods

Renal pathology files were searched for cases with linear anti-GBM to identify cases with atypical or indolent course. Histopathology, laboratory studies, treatment and outcome of those cases was reviewed in detail.

Results

Five anti-GBM cases with atypical clinicopathologic features were identified (accounting for ∼8% of anti-GBM cases in our laboratory). Kidney biopsies showed minimal glomerular changes by light microscopy; one patient had monoclonal IgG deposits in an allograft (likely recurrent). Three patients did not have detectable serum anti-GBM by conventional assays. Three patients had indolent clinical courses after immunosuppressive treatment. One patient, untreated after presenting with brief mild hematuria, re-presented after a short interval with necrotizing and crescentic glomerulonephritis.

Conclusions

Thorough clinicopathologic characterization and close follow-up of patients with findings of atypical anti-GBM on renal biopsy are needed. Review of the literature reveals only rare well-documented atypical anti-GBM cases to date, only one of which progressed to end-stage kidney disease.

Severe Uncompensated Metabolic Alkalosis due to Plasma Exchange in a Patient with Pulmonary-Renal Syndrome: A Clinician's Challenge

Metabolic alkalosis secondary to citrate toxicity from plasma exchange is very uncommon in patients with normal renal function. In patients with advanced renal disease this can be a fatal event. We describe a case of middle-aged woman with Goodpasture's syndrome treated with plasma exchange who developed severe metabolic alkalosis. High citrate load in plasma exchange fluid is the underlying etiology. Citrate metabolism generates bicarbonate and once its level exceeds the excretory capacity of kidneys, the severe metabolic alkalosis ensues. Our patient presented with generalized weakness, fever, and oliguria and developed rapidly progressive renal failure. Patient had positive serology for antineutrophilic cytoplasmic antibodies myeloperoxidase (ANCA-MPO) and anti-glomerular basement membrane antibodies (anti-GBM). Renal biopsy showed diffuse necrotizing and crescentic glomerulonephritis with linear glomerular basement membrane staining. Patient did not respond to intravenous steroids. Plasma exchange was started with fresh frozen plasma but patient developed severe metabolic alkalosis. This metabolic alkalosis normalized with cessation of plasma exchange and initiation of low bicarbonate hemodialysis. ANCA-MPO and anti-GBM antibodies levels normalized within 2 weeks and remained undetectable at 3 months. Patient still required maintenance hemodialysis.

Natural and disease-specific autoantibodies in chronic obstructive pulmonary disease

Autoimmunity may contribute to the pathogenesis of chronic obstructive pulmonary disease (COPD). Studies have identified disease-specific autoantibodies (DSAAbs) in COPD patients, but natural autoantibodies (NAAbs) may also play a role. Previous studies have concentrated on circulating autoantibodies, but lung-associated autoantibodies may be most important. Our aim was to investigate NAAbs and DSAAbs in the circulation and lungs of COPD smoking (CS) patients compared to smokers (S) without airway obstruction and subjects who have never smoked (NS). Immunoglobulin (Ig)G antibodies that bind to lung tissue components were significantly lower in the circulation of CS patients than NS (with intermediate levels in S), as detected by enzyme-linked immunosorbent assay (ELISA). The levels of antibodies to collagen-1 (the major lung collagen) detected by ELISA were also reduced significantly in CS patients’ sera compared to NS. The detection of these antibodies in NS subjects indicates that they are NAAbs. The occurrence of DSAAbs in some CS patients and S subjects was indicated by high levels of serum IgG antibodies to cytokeratin-18 and collagen-5; furthermore, antibodies to collagen-5 eluted from homogenized lung tissue exposed to low pH (0·1 M glycine, pH 2·8) were raised significantly in CS compared to S and NS. Thus, this study supports a role in COPD for both NAAbs and DSAAbs.

A common immunopathogenesis mechanism for infectious diseases: the protein-homeostasis-system hypothesis

It was once believed that host cell injury in various infectious diseases is caused solely by pathogens themselves; however, it is now known that host immune reactions to the substances from the infectious agents and/or from the injured host cells by infectious insults are also involved. All biological phenomena in living organisms, including biochemical, physiological and pathological processes, are performed by the proteins that have various sizes and shapes, which in turn are controlled by an interacting network within the living organisms. The author proposes that this network is controlled by the protein homeostasis system (PHS), and that the immune system is one part of the PHS of the host. Each immune cell in the host may recognize and respond to substances, including pathogenic proteins (PPs) that are toxic to target cells of the host, in ways that depend on the size and property of the PPs. Every infectious disease has its own set of toxic substances, including PPs, associated with disease onset, and the PPs and the corresponding immune cells may be responsible for the inflammatory processes that develop in those infectious diseases.

Autoantibodies 2015: From diagnostic biomarkers toward prediction, prognosis and prevention

At the 12th International Workshop on Autoantibodies and Autoimmunity (IWAA), organized in August 2014 in Sao Paulo, Brazil, more than 300 autoimmunologists gathered to discuss the status of many novel autoantibodies in clinical practice, and to envisage additional value of autoantibodies in terms of prediction, prognosis and prevention of autoimmune diseases. Two separate workshops were dedicated to standardization and harmonization of autoantibody testing and nomenclature: International Autoantibody Standardization (IAS) and International Consensus on ANA Patterns (ICAP). It was apparent to all in attendance that the discovery and elucidation of novel autoantibodies did not slow down, but that multiple challenges lay ahead of us in order to apply these discoveries to effective and efficient clinical practice. Importantly, this requires optimal bidirectional communication between clinicians and laboratory specialists, as well as close collaboration with the diagnostic industry. This paper is a report on the 12th IWAA in combination with a review of the recent developments in the field of autoantibodies.

Goodpasture's Syndrome and p-ANCA Associated Vasculitis in a Patient of Silicosiderosis: An Unusual Association

Introduction. Goodpasture's syndrome is a rare clinical entity and is characterized by circulating autoantibodies which are principally directed against the glomerular/alveolar basement membrane. The etiology of Goodpasture's syndrome is still unknown. Lung involvement occurs as a result of lung injury and the exposure of new epitopes to the immune system. Recently, several studies have suggested the role of silica as one of etiological factors in ANCA associated vasculitis and glomerulonephritis. Materials and Methods. We present a case of a 40-year-old welder with silicosiderosis, who developed anti-GBM disease with p-ANCA positivity. Case Report. Patient presented to an emergency with gradually increasing breathlessness along with renal failure and died after short hospital stay. Autopsy pathology findings revealed crescentic glomerulonephritis with linear glomerular basement membrane antibody deposition, splenic vasculitis, pulmonary haemorrhage, and pulmonary silicosiderosis. Conclusion. This case reinforces the role of environmental triggers like exposure to silica, metal dust, and tobacco in pathogenesis of Goodpasture's syndrome and p-ANCA associated vasculitis.

Comparison of double filtration plasmapheresis with immunoadsorption therapy in patients with anti-glomerular basement membrane nephritis

Background

Double filtration plasmapheresis (DFPP) and (IA) are both used to clear antibody. However, the clinical efficacy and safety of DFPP in patients with anti-glomerular basement membrane (anti-GBM) disease are unclear.

Methods

The 28 enrolled patients diagnosed serologically and pathologically with anti-GBM disease from 2003 to 2013 included 16 treated with DFPP and 12 with IA, with all patients administered immunosuppressive agents. DFPP consisted of an EC50W filter for plasma separation and an EC20W filter for plasma fractionation. A double volume of plasma was processed, and each patient received a 30–40 g human albumin supplement during each session. IA consisted of 10 cycles per session, with 8–10 sessions performed daily or every other day and each session regenerating 30–60 L of plasma. Serum anti-GBM antibodies and IgG were measured, and urinary and blood tests were performed, before and after each procedure. Renal function and outcome were determined.

Results

The 28 patients consisted of 13 males and 15 females, of median age 44.5 years (range, 22.5–57 years). Six patients had pulmonary hemorrhage and 18 had serum creatinine concentrations >500 umol/L. The average serum creatinine concentration at early onset of disease was 525 umol/L while the peak concentration was 813 umol/L. All patients showed progressive increases in serum creatinine and required CRRT during the course of disease. Pathological examination showed an average 73.9% of crescents (range, 54.6–95.4%).The clinical and pathological features of the DPPP and IA groups were similar. Efficacy of clearing anti-GBM antibody was similar in the two groups (59.0 vs. 71.2%, P = 1.00), although fewer patients in the DFPP group experienced reduced IgG (62.7 vs. 83.5%, p = 0.002). One patient each had a pulmonary hemorrhage and a subcutaneous hemorrhage during treatment, but there were no other serious complications. At the end of follow-up, patient survival and renal survival were similar in the DFPP and IA groups.

Conclusion

DPPP plus immunosuppressive therapy efficiently and safely removed anti-GBM antibodies. The fewer plasma-associated side effects and reduced loss of IgG suggest that DFPP may be a better treatment choice for anti-GBM disease, especially in patients with insufficient plasma.

An Unusual Case of Anti-GBM Antibody Elevation in HIV-Associated Nephropathy

Introduction. The most commonly seen glomerular disease in HIV infected patients is HIV-associated nephropathy (HIVAN); however, a multitude of other nephropathies can occur in HIV infection with an almost equal cumulative frequency. We report an unusual case of a patient with clinical and histological evidence of HIVAN in which the diagnosis was initially confounded by the finding of an elevated serum anti-glomerular basement membrane (anti-GBM) antibody. Case Presentation. We present a case of a 27-year-old African American female with a history of schizophrenia, cocaine abuse, and HIV infection who upon admission to our hospital was found to have severe acute kidney injury requiring hemodialysis. Urine studies revealed nephrotic range proteinuria and a serological workup was positive for anti-GBM antibody elevation with a value of 91 units (normal: 0–20 units). A renal biopsy revealed HIVAN with no evidence of crescentic glomerulonephritis or anti-GBM disease. Conclusion. This case highlights the need for careful interpretation of anti-GBM antibody tests in HIV infected patients with kidney disease and, in particular, the need for biopsy confirmation of the diagnosis prior to starting therapy. More research is needed to study the prognostic correlation between the degree of anti-GBM antibody elevation in HIVAN and disease severity.

Serologic autoimmunologic parameters in women with primary ovarian insufficiency

Background

Primary ovarian insufficiency (POI) is heterogeneous disease defined by amenorrhea or premature depletion of ovarian follicles before the age of 40 years. The etiology of POI is still unclear. The purpose of this study is to evaluate whether women with POI have an elevated serum levels of autoimmunologic parameters.

Methods

The serum from peripheral blood samples which come from 96 POI patients and 100 age-matched health women were analyzed for a series of autoimmune antibodies using protein microarray. The antibodies to double-stranded DNA (ds-DNA), histone (HIS), nuclear ribonucleoprotein (RNP), Sjogren’s syndrome A (SSA/Ro), Sjogren’s syndrome B (SSB/La) and Smith antigen, Jo-1, scleroderma-associated antigen (Scl-70) and centromere (CEN), zona pellucid (ZP), adrenocortical antibodies (ACA),Rheumatoid factor (RF), glomerular basement membrane (GBM), proliferating cell nuclear antigen (PCNA), myeloperoxidase (MPO), proteinase 3 (PR3), thyroid microsomal antibody and antinuclear antibody (ANA)were analyzed.

Results

Among the 96 women with POI and 100 age-matched health controls, women with POI had significantly elevated circulation levels of Jo-1 and PR3 (p = 0.010 and p = 0.001) whereas circulation levels of ANAs, dsDNA, histone, RNP, Sm, Scl-70, SSA, SSB, CEN, ZP, ACA, RF, GBM, PCNA, MPO and TM antibodies were similar between the two groups.

Conclusions

This study shows that the autoimmune antibodies JO-1 and PR3 were significantly higher in POI women group which suggested that these antibodies may have played special role in POI, but the evaluation of the exact pathways of them remains to be determined.