Short-chain fatty acids ameliorate experimental anti-glomerular basement membrane disease

BACKGROUND

Short-chain fatty acids (SCFAs), as the link between gut microbiota and the immune system, had been reported to be protective in many autoimmune diseases by the modulation of T cell differentiation. The pathogenic role of autoreactive Th1 and Th17 cells and the protective role of Treg cells in the pathogenesis of anti-GBM disease have been fully demonstrated. Thus, the present study aimed to investigate the therapeutic effects of SCFAs in a rat model of anti-GBM disease.

MATERIALS AND METHODS

Experimental anti-GBM disease was constructed by immunizing Wistar Kyoto rats with a nephrogenic T cell epitope α3127-148, and intervened by sodium acetate, sodium propionate, or sodium butyrate, 150 mM in the drinking water from day 0 to 42. Kidney injury was accessed by the biochemical analyzer, immunofluorescence, and immunohistochemistry. Antibody response was detected by ELISA. T cell clustering and proliferation were detected by flow cytometry. Human kidney 2 (HK2) cells were stimulated in vitro and cytokines were assessed by quantitative real-time PCR.

RESULTS

Treatment with sodium acetate, sodium propionate, or sodium butyrate ameliorated the severity of kidney impairment in rats with anti-GBM glomerulonephritis. In the sodium butyrate-treated rats, the urinary protein, serum creatinine, and blood urea nitrogen levels were significantly lower; the percentage of crescent formation in glomeruli was significantly reduced; and the kidneys showed reduced IgG deposition, complement activation, T cell, and macrophage infiltration as well as the level of circulating antibodies against anti-α3(IV)NC1. The treatment of sodium butyrate reduced the α3127-148-specific T cell activation and increased the Treg cells differentiation and the intestinal beneficial bacteria flora. It also alleviated the damage of HK2 cells treated with inflammatory factors and complement.

CONCLUSION

Treatment with SCFAs, especially butyrate, alleviated anti-GBM nephritis in rat model, indicating its potential therapeutic effects in clinical usage.

Glomerulonephritis With Positive Anti-Glomerular Basement Membrane Antibodies Following Alemtuzumab Treatment

Presentation A 28 year old female presented to the emergency department with a one week history of headache, vomiting and diaphoresis. Creatinine on admission was 492 and urinalysis revealed blood and protein. This was 5 months after a second infusion of Alemtuzumab, for treatment of highly active relapsing remitting multiple sclerosis. Diagnosis Anti-glomerular basement membrane disease was diagnosed after a vasculitic screen was sent for suspected glomerulonephritis. Treatment Unfortunately despite early diagnosis and immunosuppressive treatment, the patient progressed to end stage kidney failure. Conclusion It is important to maintain a high index of suspicion and test for anti-GBM disease in patients receiving alemtuzumab who develop acute renal failure.

Inhibitory Anti-Peroxidasin Antibodies in Pulmonary-Renal Syndromes

BACKGROUND

Goodpasture syndrome (GP) is a pulmonary-renal syndrome characterized by autoantibodies directed against the NC1 domains of collagen IV in the glomerular and alveolar basement membranes. Exposure of the cryptic epitope is thought to occur via disruption of sulfilimine crosslinks in the NC1 domain that are formed by peroxidasin-dependent production of hypobromous acid. Peroxidasin, a heme peroxidase, has significant structural overlap with myeloperoxidase (MPO), and MPO-ANCA is present both before and at GP diagnosis in some patients. We determined whether autoantibodies directed against peroxidasin are also detected in GP.

METHODS

We used ELISA and competitive binding assays to assess the presence and specificity of autoantibodies in serum from patients with GP and healthy controls. Peroxidasin activity was fluorometrically measured in the presence of partially purified IgG from patients or controls. Clinical disease severity was gauged by Birmingham Vasculitis Activity Score.

RESULTS

We detected anti-peroxidasin autoantibodies in the serum of patients with GP before and at clinical presentation. Enriched anti-peroxidasin antibodies inhibited peroxidasin-mediated hypobromous acid production in vitro. The anti-peroxidasin antibodies recognized peroxidasin but not soluble MPO. However, these antibodies did crossreact with MPO coated on the polystyrene plates used for ELISAs. Finally, peroxidasin-specific antibodies were also found in serum from patients with anti-MPO vasculitis and were associated with significantly more active clinical disease.

CONCLUSIONS

Anti-peroxidasin antibodies, which would previously have been mischaracterized, are associated with pulmonary-renal syndromes, both before and during active disease, and may be involved in disease activity and pathogenesis in some patients.

Spatial and Temporal Clustering of Anti-Glomerular Basement Membrane Disease

BACKGROUND AND OBJECTIVES

An environmental trigger has been proposed as an inciting factor in the development of anti-GBM disease. This multicenter, observational study sought to define the national incidence of anti-GBM disease during an 11-year period (2003-2014) in Ireland, investigate clustering of cases in time and space, and assess the effect of spatial variability in incidence on outcome.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We ascertained cases by screening immunology laboratories for instances of positivity for anti-GBM antibody and the national renal histopathology registry for biopsy-proven cases. The population at risk was defined from national census data. We used a variable-window scan statistic to detect temporal clustering. A Bayesian spatial model was used to calculate standardized incidence ratios (SIRs) for each of the 26 counties.

RESULTS

Seventy-nine cases were included. National incidence was 1.64 (95% confidence interval [95% CI], 0.82 to 3.35) per million population per year. A temporal cluster (n=10) was identified during a 3-month period; six cases were resident in four rural counties in the southeast. Spatial analysis revealed wide regional variation in SIRs and a cluster (n=7) in the northwest (SIR, 1.71; 95% CI, 1.02 to 3.06). There were 29 deaths and 57 cases of ESRD during a mean follow-up of 2.9 years. Greater distance from diagnosis site to treating center, stratified by median distance traveled, did not significantly affect patient (hazard ratio, 1.80; 95% CI, 0.87 to 3.77) or renal (hazard ratio, 0.76; 95% CI, 0.40 to 1.13) survival.

CONCLUSIONS

To our knowledge, this is the first study to report national incidence rates of anti-GBM disease and formally investigate patterns of incidence. Clustering of cases in time and space supports the hypothesis of an environmental trigger for disease onset. The substantial variability in regional incidence highlights the need for comprehensive country-wide studies to improve our understanding of the etiology of anti-GBM disease.

Pathogenesis of rapidly progressive glomerulonephritis: what do we learn?

Rapidly progressive glomerulonephritis (RPGN) is a life-threatening disease with a poor prognosis. In this review, the pathogenesis of RPGN owing to antineutrophil cytoplasmic antibody-associated crescentic glomerulonephritis and anti-GBM diseases is discussed. By the model of nephrotoxic nephritis, T cells, dendritic cells and toll-like receptors are involved in podocyte activation and parietal epithelial cell proliferation which contribute to the crescent formation and glomerular injury. Furthermore, growth factors and Goodpasture autoantigen are also involved in the onset of the disease. In the study of ANCA-associated glomerulonephritis, the role of lysosome-associated membrane protein (LAMP)-2 and neutrophil extracellular traps is well studied. However, the role of LAMP-2 in the disease pathogenesis remains uncertain. We hope this review can help us to further understand the pathogenesis of the disease.

Extracorporeal membrane oxygenation as a platform for recovery: a case report of a child with pulmonary hemorrhage, refractory hypoxemic respiratory failure, and new onset goodpasture syndrome

We report a case of a 9-year-old female with acute pulmonary hemorrhage and refractory hypoxemic respiratory failure secondary to Goodpasture syndrome (GS). After failing treatment with high frequency oscillatory ventilation and inhaled nitric oxide, she was successfully managed with venovenous extracorporeal membrane oxygenation (VV ECMO). The patient's weight at the time of cannulation was 31 kg. A 19 French 18 cm (arterial) Biomedicus cannula was inserted in the right internal jugular vein and used as the drain. A 17 French 50 cm (venous) Biomedicus cannula was inserted in the right femoral vein and used as the return. Then the patient was anticoagulated with 100 units/kg of intravenous heparin and the circuit was primed with one unit of packed red blood cells. VV ECMO was performed with an SIII Sorin roller head pump with integrated servo regulator and a Quadrox D Bioline coated oxygenator. Despite systemic anticoagulation with heparin, the patient's pulmonary hemorrhage resolved. Extracorporeal membrane oxygenation served as a platform through which we were able to provide renal replacement therapy and plasmapheresis. The patient was successfully discharged home with normal pulmonary function.

A 25-year experience with pediatric anti-glomerular basement membrane disease

Anti-glomerular basement membrane (anti-GBM) disease, which is extremely uncommon in children, is characterized by rapidly progressive glomerulonephritis (RPGN) and autoantibodies against GBM collagen. Pulmonary hemorrhage is the third component in Goodpasture Syndrome. Cigarette smoking and exposure to hydrocarbons have been linked to anti-GBM disease in adults, but such an association has not been established in children. We reviewed renal biopsy and autopsy specimens over 25 years from a major tertiary care U.S. children's hospital, diagnosing anti-GBM by clinical RPGN, crescentic glomerulonephritis, and linear immunofluorescence (IF) immunoglobulin G staining in patients under 18 years of age. We identified four patients, with and without pulmonary manifestations. The sole autopsy case showed diagnostic IF despite undetectable serum anti-GBM antibodies and positive testing for serum anti-neutrophil cytoplasmic antibodies (ANCA). Three patients have survived 1-18 years following diagnosis, one of whom is recovering renal function. One adolescent had a history of smoking cigarettes and one had a probable hydrocarbon exposure. Anti-GBM disease is unusual in children, and the relationship to inhaled agents is incompletely understood. Serum anti-GBM antibodies are typically present, but cases with undetectable levels can occur. Some patients are anti-GBM and ANCA positive, with a small subset ANCA-positive, anti-GBM-negative. Ours is the first such described pediatric case.

[Case of goodpasture syndrome associated with minimal change nephrotic syndrome (MCNS) in a patient with rheumatoid arthritis (RA)]

In early June 2004, a 50-year-old female was admitted to the hospital for slight fever, general fatigue, hemoptysis, dyspnea, and renal dysfunction (serum creatinine[Cr] : 6.05 mg/dL). She had been treated with prednisolone (PSL : 10-20 mg/day) for RA. She was diagnosed with Goodpasture syndrome based on a high titer of anti-glomerular basement membrane antibody (87 EU), and pulmonary hemorrhage. The renal and pulmonary impairments were markedly improved by the pulse therapy, plasma exchange and temporary hemodialysis. However, the Cr level remained at 2.0 mg/dL, indicating nephrotic syndrome. Light microscopy with Periodic acid-Shiff(PAS) staining demonstrated global sclerosis in three of ten glomeruli. Five glomeruli showed the formation of cellular, and fibrocellular crescents, and the formation of fibrous crescents. Tubular damage and interstitial fibrosis were severe. Immunofluorescence microscopy disclosed major depositions of IgG in a linear pattern along the glomerular basement membrane(GBM). Electron microscopy revealed foot process effacement (>50%)and no electron-dense deposits. Therefore, we diagnosed Goodpasture syndrome associated with minimal change nephrotic syndrome (MCNS). Some reports have dealt with the association of RA and Goodpasture syndrome with D-penicillamine, and of RA and antineutrophil cytoplasmic antibodies (ANCA)-related vasculitis with pulmonary hemorrhage, but none has dealt with cases complicated with RA and Goodpasture syndrome associated with MCNS. Accordingly, whether or not there is a causal relationship between RA and Goodpasture syndrome remains obscure, but since the number of reported cases is small, experience with more cases is necessary to clarify this matter.

Advances in the pathogenesis of Goodpasture's disease: from epitopes to autoantibodies to effector T cells

Goodpasture's disease, an "organ-specific" autoimmune disease is manifest by rapidly progressive glomerulonephritis and pulmonary hemorrhage. Studies into the pathogenesis of this disease have shed light on the autoantigen (the non-collagenous domain of the alpha3 chain of type IV collagen, alpha3(IV)NC1) and its epitopes, as well as the involvement of autoantibodies and cellular effectors in disease. The discovery of alpha3(IV)NC1 lead to studies that defined the structure and biology of type IV collagen and are defining B and T cell epitopes. Goodpasture autoantibody epitopes are "cryptic" in that they are structurally sequestered by adjacent non-collagenous domains of alpha4 and alpha5 type IV collagen. T cell epitope studies in rats demonstrated that a 13-mer could induce experimental autoimmune glomerulonephritis. T cells from patients with Goodpasture's recognize two epitopes, in regions which are highly susceptible in antigen processing by endosomal proteases. Goodpasture's disease is strongly associated with HLA DRB1 genes, whereby DRB1*1501 confers susceptibility and the DRB1*0701 and DRB1*0101 are dominantly protective. Experimental data implicate both autoantibodies and cell mediated immunity as disease effectors. Observations in humans suggest that regulatory T cells are associated with the development of self-immunoregulation in the convalescent phase of disease.

Crescentic transformation in primary membranous glomerulopathy: association with anti-GBM antibody

Crescentic transformation of primary membranous nephropathy (MN) associated with the development of anti-GBM antibody is a rare cause of acute renal failure in patients with MN. We report a 54-year-old lady, diagnosed to have MN four years earlier, who presented with acute deterioration of renal functions. Renal biopsy revealed circumferential crescents in all glomeruli. Serum anti-GBM antibodies were positive. Despite therapy with plasmapheresis, steroids and oral cyclophosphamide, she did not improve and continues to be dialysis dependent.

Goodpasture's syndrome in a patient using cocaine--a case report and review of the literature

Glomerulonephritis is a very rare form of cocaine-induced renal pathology. We report a 26-year-old woman having inhaled cocaine, who presented with antiglomerular basement membrane glomerulonephritis and pulmonary hemorrhage. She was treated with immunosuppressive therapy and plasmapheresis. Maintenance hemodialysis was required on discharge. We stress the importance of early detection and treatment of this renal association for the potential fatal consequences implicated.

T Cell Epitope Mimicry in Antiglomerular Basement Membrane Disease

Antiglomerular basement membrane (GBM) disease or Goodpasture's syndrome is among the earliest recognized human autoimmune diseases. Although collagen 4alpha3 NC1 (Col4alpha3NC1) has been identified as the responsible autoantigen, it remains unknown how autoimmunity to this autoantigen is provoked. We have demonstrated in our rat model that a single nephritogenic T cell epitope pCol28-40 of Col4alpha3NC1 induces glomerulonephritis. We hypothesized that microbial peptides that mimic this T cell epitope could induce the disease. Based on the critical residue motif (xxtTxNPsxx) of pCol28-40, seven peptides derived from human infection-related microbes were chosen through GenBank search and synthesized. All peptides showed cross-reactivity with pCol28-40-specific T cells at various levels. Only four peptides induced transient proteinuria and minor glomerular injury. However, the other three peptides induced severe proteinuria and modest to severe glomerulonephritis in 16-25% of the immunized rats. Unexpectedly, the most nephritogenic peptide, pCB, derived from Clostridium botulinum, also induced modest (25%) to severe (25%) pulmonary hemorrhage, another important feature of anti-GBM disease; this was not correlated with the severity of glomerulonephritis. This finding suggests that subtle variations in T cell epitope specificity may lead to different clinical manifestations of anti-GBM disease. In summary, our study raises the possibility that a single T cell epitope mimicry by microbial Ag may be sufficient to induce the anti-GBM disease.

Effects of preparations modifying Th1/Th2 ratio on the incidence of clinical variants of chronic graft-versus-host reaction

Induction of chronic graft-versus-host reaction in a semiallogenic DBA/2- (DBA/2xC57Bl/6) F1 system leads to the development of Th1- or Th2-dependent immunopathologies. Modification of the Th1/Th2 ratio during induction with preparations acting on the immune system cells via different mechanisms and shifting the Th1/Th2 balance towards Th2 (bisphenol A, pentoxifylline, muramyl dipeptide) increases the incidence of Th2-dependent autoimmune lupus-like glomerulonephritis.

Pulmonary-renal syndrome in a patient with bacterial endocarditis

Pulmonary-renal syndrome is defined as a combination of pulmonary hemorrhage and glomerulonephritis. We report an unusual case of bacterial endocarditis presenting with pulmonary hemorrhage and rapidly progressive glomerulonephritis as the initial manifestations of the disease. A 37-year-old man was admitted with fever, hemoptysis, and dyspnea. Admission examinations revealed severe renal failure requiring dialysis therapy. Chest radiograph showed extensive pulmonary reticulonodular infiltrates. Echocardiography revealed ventricular septal defect. Furthermore, blood cultures grew viridians group streptococci. The kidney and lung biopsies demonstrated diffuse cresentic glomerulonephritis and alveolar hemorrhage, respectively. Bacterial endocarditis was diagnosed according to the Duke criteria and the patient was treated with intravenous antibiotic therapy. The pulmonary infiltrates disappeared gradually. However, renal function did not improve, even after trial of a course of immunosuppressive therapy. The patient survived and remained on regular hemodialysis. We conclude that bacterial endocarditis should be included in the differential diagnosis of pulmonary-renal syndrome.

Epitope Spreading and Autoimmune Glomerulonephritis in Rats Induced by a T Cell Epitope of Goodpasture’s Antigen

An amino-terminal region of alpha3 chain of type IV collagen noncollagenous domain [alpha3(IV)NC1] that induces experimental autoimmune glomerulonephritis (EAG) in rats has been identified. Only recombinant antigens that contain a nine-amino acid (AA) span of alpha3(IV)NC1, consistent with a T cell epitope, could induce EAG. It was hypothesized that synthetic peptides of this region should induce EAG. Human and rat peptides of this region were synthesized and rats were immunized to define the nephritogenic epitope. A 13-AA rat peptide induced EAG with proteinuria, decreased renal function, and glomerular basement membrane (GBM)-bound deposits in half of the rats. This peptide induces lymph node cell proliferation and development of antibodies to epitopes of alpha3(IV)NC1 external to the peptide immunogen. Carboxy-terminal extension to 21 amino acids results in all rats' demonstrating anti-GBM antibody and severe EAG. Asparagine at position 19 is critical for EAG induction. None of the 50 rats that were immunized with peptide that contained human sequence with isoleucine at position 19 developed EAG, whereas rat sequence with asparagine 19 induced EAG. Truncation of amino terminal AA of the peptide aborts EAG induction. These studies demonstrate that a T cell epitope of alpha3(IV)NC1 induces lymph node cell proliferation, EAG, and intramolecular epitope spreading; that the length of this peptide influences the formation of anti-GBM antibody; and that the presence of asparagine at position 19 of the peptide is critical to disease induction.

Experimental autoimmune Goodpasture's disease: a pathogenetic role for both effector cells and antibody in injury

BACKGROUND

Goodpasture's disease [antiglomerular basement membrane (GBM) glomerulonephritis] is a classic autoimmune disease and the only organ-specific autoimmune renal disease in which the antigen is well described. The importance of antibodies against the non-collagenous domain of the alpha3 chain of type IV collagen [alpha3(IV)NC1] is well established. However, observational human studies and studies in experimental systems also imply a role for cell-mediated effector injury.

METHODS

Active experimental autoimmune glomerulonephritis (EAG) was induced by immunization with alpha3-alpha5(IV)NC1 heterodimers in B cell intact C57BL/6 mice and B cell (mu chain-deficient) mice. Passive disease was induced by transferring sera from B cell intact and B cell deficient mice with EAG to RAG-1-/- mice (that lack adaptive immunity). Histologic and functional injury was studied.

RESULTS

Despite the absence of B cells and immunoglobulin in B-cell-deficient mice, histologic and functional injury developed in mice immunized with alpha3-alpha5(IV)NC1, with T cells and macrophages in glomeruli. Injury occurred to a similar degree to that found in B-cell-intact mice. Transfer of sera from B-cell-intact mice with EAG containing antibodies (but not from B-cell-deficient mice with EAG) to RAG-1-/- mice induced linear immunoglobulin deposits on the glomerular basement membrane (GBM) and pathologic proteinuria.

CONCLUSION

Both cell-mediated and humoral effectors are capable of inducing renal injury in EAG. Given the similarity of the disease-initiating antigen in this model to the antigen in human anti-GBM glomerulonephritis, similar overlapping mechanisms are likely to operate in human disease.

Sequential development of perinuclear ANCA-associated vasculitis and anti-glomerular basement membrane glomerulonephritis

A 75-year-old man suffered from perinuclear antineutrophil cytoplasm antibody (p-ANCA)-associated vasculitis with mild renal involvement. Three years later, he suddenly experienced an anuric acute renal failure due to anti-glomerular basement membrane (GBM) disease. Antibodies to myeloperoxydase were continuously present at a high titer in the patient's serum while serum anti-GBM antibodies were only detected at the time of the acute renal failure. A substantial proportion of patients with anti-GBM glomerulonephritis simultaneously display ANCAs whose pathogenic role is not clear. In our case, ANCAs were supposed to be of pathogenic importance because they may have uncovered the Goodpasture antigen. This case report lends further support to the concept that p-ANCA vasculitis may trigger anti-GBM disease.

Anti-GBM glomerulonephritis: a T cell-mediated autoimmune disease?

Anti-glomerular basement membrane (GBM) glomerulonephritis, which was among the earliest recognized human autoimmune diseases, is characterized by the presence of anti-GBM antibody. It has been a prototypical example of autoantibody-mediated autoimmune disease. However, decades of research on this disease, based either on clinical observations or experimental models, have revealed that T cell-mediated cellular immunity may potentially be a more important mediator of glomerulonephritis. We have made several breakthroughs in understanding the T cell-mediated mechanism causing this disease in a rat model based on Goodpasture's antigen, non-collagen domain 1 of alpha3 chain of type IV collagen (Col4alpha3NC1). We demonstrated that anti-GBM glomerulonephritis was induced by either passive transfer of Col4 alpha3NC1-specific T cells or active immunization with the nephritogenic T cell epitope of Col4alpha3NC1. Immunization with the T cell epitope also triggered production of anti-GBM antibodies to diversified GBM antigens. Thus, a single nephritogenic T cell epitope alone is sufficient to induce the clinical spectrum of anti-GBM glomerulonephritis, including proteinuria, glomerular injury, and anti-GBM antibody. A possible T cell-mediated mechanism for causing human anti-GBM disease is proposed.

Point mutations of single amino acids abolish ability of alpha3 NC1 domain to elicit experimental autoimmune glomerulonephritis in rats

We previously showed concordance between Goodpasture syndrome antibody binding and production of experimental glomerulonephritis using human chimeric proteins. We now examine a more limited amino-terminal region of alpha3(IV) non-collagenous domain (NC1) and the impact of single amino acid (AA) mutations of this region on glomerulonephritis induction. Rats were immunized with collagenase-solubilized glomerular basement membrane (csGBM), D3, an alpha1(IV)NC1 chimeric protein with 69 AA of alpha3(IV)NC1 (binds Goodpasture sera), D4, the D3 construct shortened by 4 AA (non-binding), P9, P10, single AA mutants (non-binding), and S2, alpha1(IV)NC1 with 9 AA of alpha3(IV)NC1 (binding). All rats immunized with csGBM and S2 and 50% of D3 rats developed glomerulonephritis. csGBM rats had intense GBM-bound IgG deposits, but S2 and D3 rats had minimal deposits. None of the D4, P9, or P10 rats developed glomerulonephritis. Lymphocytes from nephritic rats proliferated with csGBM, S2, and D3, but not with D4, P9, or P10. Discrete segments of alpha3(IV)NC1 within the alpha1(IV)NC1 backbone can induce glomerulonephritis. Single AA mutations within that epitope render the antigen unresponsive to Goodpasture sera and incapable of inducing glomerulonephritis. These studies support the concordance of glomerulonephritis inductivity and Goodpasture serum binding. Further, they define a critical limited AA sequence within alpha3(IV)NC1 of nine or fewer AA, which confers nephritogenicity to the nonnephritogenic alpha1(IV)NC1 without in vivo antibody binding. This region may be a T-cell epitope responsible for induction of glomerulonephritis in this model in rats and Goodpasture syndrome in man.

Predominant role of FcgammaRIII in the induction of accelerated nephrotoxic glomerulonephritis

BACKGROUND

Nephrotoxic glomerulonephritis is induced by the administration of antibody against the glomerular basement membrane (GBM). We demonstrated previously that Fc receptors for immunoglobulin G (IgG) (FcgammaR) play crucial roles in the induction of accelerated nephrotoxic glomerulonephritis by using FcRgamma-deficient (-/-) mice. Since FcRgamma-/- mice lack the cell surface expression of two activating FcgammaRs, FcgammaRI and FcgammaRIII. The present study aims to identify the FcgammaR responsible for the induction of nephrotoxic glomerulonephritis.

METHODS

Accelerated anti-GBM glomerulonephritis was induced in FcgammaRI-/-, FcgammaRIII-/-, and FcRgamma-/- mice by preimmunization with rabbit IgG followed by inoculation of rabbit anti-GBM antibody. Histologic analysis and immunostaining of renal sections were performed.

RESULTS

FcgammaRI-/- mice as well as wild-type mice showed severe glomerulonephritis with hypernitremia by the administration of anti-GBM antibody. In contrast, FcgammaRIII-/- mice showed much milder renal involvement, similar to FcRgamma-/- mice. Histologically, FcgammaRI-/- mice showed intracapillary proliferation, glomerular thrombosis, and crescent formation, whereas FcgammaRIII-/- mice showed only glomerular hypercellular changes. The depositions of anti-GBM antibodies, autologous antibodies and complement C3 along the GBM were equally observed among all three FcR-/- mouse types by immunostaining.

CONCLUSIONS

Accelerated nephrotoxic glomerulonephritis is induced predominantly through FcgammaRIII but not FcgammaRI.

Characteristics and outcomes of patients with Goodpasture's syndrome

BACKGROUND

Goodpasture's syndrome is a rare disorder characterized by pulmonary hemorrhage, glomerulonephritis, and antiglomerular basement membrane antibodies.

METHODS

Case reports of Goodpasture's syndrome between 1993 and 2000 were identified using MEDLINE. Each case was reviewed for clinical manifestations, laboratory features, pathophysiology, treatment options, and outcomes.

RESULTS

Eighty-five cases of Goodpasture's syndrome were reported in the English language literature. The mean age of patients in this review was 44 years. Most patients had multiple risk factors. Smoking was strongly associated with pulmonary hemorrhage. Most patients presented with hemoptysis and crackles. More than 90% had antiglomerular basement membrane antibodies, and 80% had crescenteric glomerulonephritis on renal biopsy.

CONCLUSION

Most patients were treated with immunosuppression and plasma exchange and were alive at follow-up. Patients with either pulmonary or renal signs and symptoms should be evaluated for Goodpasture's syndrome, since early diagnosis allows prompt treatment and improved outcome.

Goodpasture syndrome during the course of a Schönlein-Henoch purpura

Two months after surgical resection of a bronchogenic carcinoma, a 69-year-old patient presented with Schönlein-Henoch purpura with kidney involvement followed by pulmonary hemorrhage. The presence of an IgA linear pattern on the kidney biopsy specimen and circulating anti-glomerular basement membrane (GBM) IgA antibodies led to the diagnosis of Goodpasture syndrome, which implies the possibility that the well-known pulmonary involvement during the course of Schönlein-Henoch purpura could be caused by Goodpasture syndrome in certain cases. In cases of glomerulonephropathy with lung involvement, clinicians should not limit their investigations to anti-GBM IgG.

Glomerulonephritis induced by recombinant collagen IV alpha 3 chain noncollagen domain 1 is not associated with glomerular basement membrane antibody: a potential T cell-mediated mechanism

Glomerulonephritis is believed to result commonly from Ab-mediated glomerular injury. However, Ab-associated mechanisms alone cannot explain many cases of human glomerulonephritis. We developed a rat model of human anti-glomerular basement membrane (GBM) disease to investigate T cell and Ab response, and their associations with the disease. A single immunization of highly denatured recombinant mouse collagen IV alpha3 chain noncollagen domain 1 (rCol4alpha3NC1) induced severe glomerulonephritis in 100% of Wistar Kyoto rats, 33% of which died of this disease around day 35 postimmunization. The renal pathology demonstrated widespread glomerular damage and a mononuclear cell infiltration within the interstitial tissue. T cells from immunized rats responded not only to rCol4alpha3NC1, but also to isolated rat GBM. Sera Abs to rCol4alpha3NC1 were detectable in 100% of the rats, but only 20% of the rats had low levels of Ab to isolated rat GBM by Western blot, and none by immunofluorescence. Furthermore, IgG/M binding to or C3 deposition on endogenous GBM in immunized rats were not detected in most of the experimental rats, and showed no statistical correlation with disease severity. Additionally, no electronic dense deposition in the glomeruli was detected in all rats. Those data revealed a disassociation between the disease and anti-GBM Ab. T cell-mediated mechanisms, which are currently under our investigation, may be responsible for the glomerular disease.

IL-12-dependent, INF-gamma-independent experimental glomerulonephritis

There is evidence that crescentic glomerulonephritis initiated in rodents by heterologous antibodies against the glomerular basement membrane (anti-GBM glomerulonephritis) depends on a Th1-type immune reaction. Interleukin 12 (IL-12) is crucial for the development of Th1 helper cells, and interferon gamma (IFN-gamma) is a major proinflammatory product of these cells. In order to test the role of the two cytokines in anti-GBM glomerulonephritis we used mice lacking either the p40 chain of IL-12 (IL-12-/-) or the IFN-gamma receptor (IFN-gammaR-/-). Glomerulonephritis was induced by injecting a rabbit anti-GBM serum in mice preimmunized against rabbit IgG. Glomerulonephritis was assessed on the basis of proteinuria, immunofluorescence findings and histology. IL-12-/- mice were completely protected against glomerulonephritis. In contrast, IFN-gammaR-/- mice were more severely affected than wild-type mice. Similarly, cutaneous delayed-type hypersensitivity, a typical Th1 response, was abolished in the IL-12-/-, mice but increased in the IFN-gammaR-/- mice. The data obtained in IL-12-/- mice support the view that crescentic glomerulonephritis in this model represents a Th1 response. Since IFN-gamma is not required, other products of Th1 cells are likely to mediate glomerulonephritis.

Goodpasture syndrome: pathophysiology, diagnosis, and management

Goodpasture syndrome is an autoimmune disease characterized by glomerulonephritis, pulmonary hemorrhage, and autoantibodies to the glomerular and alveolar basement membranes. The cause is unknown, and if untreated, Goodpasture syndrome usually is fatal. Early diagnosis and prompt initiation of therapy can decrease disease progression and increase chances of survival. Treatment modalities remain controversial and vary among practitioners.

Matrix metalloproteinase 9 protects mice from anti-glomerular basement membrane nephritis through its fibrinolytic activity

Matrix metalloproteinase (MMP)9/gelatinase B is increased in various nephropathies. To investigate its role, we used a genetic approach. Adult MMP9-deficient (MMP9(-/)-) mice showed normal renal histology and function at 3 mo. We investigated the susceptibility of 3-mo-old mice to the accelerated model of anti-glomerular basement membrane nephritis, in which fibrin is an important mediator of glomerular injury and renal impairment. Unexpectedly, nephritis was more severe in MMP9(-/)- than in control mice, as attested by levels of serum creatinine and albuminuria, and the extent of crescents and fibrin deposits. Circulating or deposited immunoglobulin G, interleukin (IL)-1beta, or IL-10 were the same in MMP9(-/-) and MMP9(+/+) mice. However, we found that fibrin is a critical substrate for MMP9, and in its absence fibrin accumulated in the glomeruli. These data indicate that MMP9 is required for a novel protective effect on the development of fibrin-induced glomerular lesions.

[Lung involvement in rapidly progressive glomerulonephritis]

The purpose of this study is to evaluate pulmonary involvement in rapidly progressive glomerulonephritis (RPGN). Of 71 patients in whom RPGN was diagnosed, 32 (45.1%) had pulmonary involvement: 12, alveolar hemorrhage (AH) (16.9%); 10, interstitial pneumonia (IP) (14.1%); four, chronic bronchial lesions (5.6%); two, consolidation (2.8%), and four, old inflammatory lesions (5.6%). Investigation of which organ of the twelve AH patients, the kidney or the lung, was the first to be involved, showed that the lung preceded in one patient, the kidney was first in three, and the lung and kidney occurred at the same time in the other eight. Of the ten IP patients, the lung preceded in eight, the kidney was ahead in two, and lung and kidney were simultaneous in one. Three patients had a history of pneumoconiosis, and two had acute progressive IP. Seventeen (45.9%) of 37 patients who tested positive for antineutrophil cytoplasmic autoantibodies (MPO-ANCA) had lung involvement, and three (30.0%) of the ten patients who tested negative for MPO-ANCA, PR 3-ANCA and anti-GBM antibody also had lung involvement.

Oral administration of glomerular basement membrane prevents the development of experimental autoimmune glomerulonephritis in the WKY rat

Experimental autoimmune glomerulonephritis (EAG), an animal model of Goodpasture's disease, can be induced in Wistar Kyoto (WKY) rats by a single injection of collagenase-solubilized rat glomerular basement membrane (GBM) in adjuvant. EAG is characterized by circulating and deposited anti-GBM antibodies, accompanied by focal necrotizing glomerulonephritis with crescent formation. The inhibitory effect of orally administered antigens has been reported in various animal models of autoimmunity but not in EAG in the rat. The effects of feeding rat GBM by gavage, at total doses of 0.5, 2.5, or 5 mg, before immunization were examined. A dose-dependent effect was observed on the development of EAG. A dose of 0.5 mg of GBM had no effect on disease, 2.5 mg resulted in a moderate reduction in the severity of nephritis but no change in anti-GBM antibody production, and 5 mg resulted in a marked reduction in circulating and deposited anti-GBM antibodies, albuminuria, deposits of fibrin in the glomeruli, severity of glomerular abnormalities, and numbers of infiltrating T cells and macrophages. Animals that were fed 5 mg of GBM showed a significant reduction in IgG2a but not IgG1, anti-GBM antibody levels, suggesting downregulation of Th1 responses. There was also a dose-dependent reduction in the proliferative responses of splenic T cells from treated animals to GBM antigen in vitro. These results clearly demonstrate that mucosal tolerance can be induced by oral administration of GBM antigen and that this approach is effective in preventing EAG.

Anti-glomerular basement membrane nephritis after extracorporeal shock wave lithotripsy

Rapidly progressive glomerulonephritis was observed in a 37-year-old woman following the administration of extracorporeal shock wave lithotripsy (ESWL) for a single stone in her right kidney. The renal biopsy specimen showed diffuse cellular crescents in all glomeruli, with linear deposits of immunoglobulin G and complement component C3 along the glomerular basement membrane (GBM). Circulating anti-GBM antibodies were detected by enzyme-linked immunosorbent assay. Thus, the patient was diagnosed with anti-GBM nephritis. It is suggested that ESWL produced an alteration in the GBM leading to the production of anti-GBM antibodies.

[Anti glomerular basement membrane disease in a renal transplant patient with Alport syndrome]

We report a case of anti GBM disease that developed in the renal graft of a patient with Alport syndrome. After reaching abnormal values of creatinine, the patient presented with deteriorating renal function three months after a cadaver transplant and the biopsy showed crescent formation, and linear IF deposits. Circulating antibodies against alpha 5 chain of type IV collagen were found and plasmaphereses stabilized the condition for one year until a lung infection led to withdrawal of the immunosuppressive drugs and the patient returned to dialysis. We discuss the possible mechanisms underlying the specificity of the circulating antibodies in this case, which differs from the target characteristic of the idiopathic form of anti GBM disease, the alpha 3 (IV) chain.

The goodpasture autoantigen. Identification of multiple cryptic epitopes on the NC1 domain of the alpha3(IV) collagen chain

Goodpasture (GP) disease is an autoimmune disorder in which autoantibodies against the alpha3(IV) chain of type IV collagen bind to the glomerular and alveolar basement membranes, causing progressive glomerulonephritis and pulmonary hemorrhage. Two major conformational epitope regions have been identified on the noncollagenous domain of type IV collagen (NC1 domain) of the alpha3(IV) chain as residues 17-31 (E(A)) and 127-141 (E(B)) (Netzer, K.-O. et al. (1999) J. Biol. Chem. 274, 11267-11274). To determine whether these regions are two distinct epitopes or form a single epitope, three GP sera were fractionated by affinity chromatography on immobilized NC1 chimeras containing the E(A) and/or the E(B) region. Four subpopulations of GP antibodies with distinct epitope specificity for the alpha3(IV)NC1 domain were thus separated and characterized. They were designated GP(A), GP(B), GP(AB), and GP(X), to reflect their reactivity with E(A) only, E(B) only, both regions, and neither, respectively. Hence, regions E(A) and E(B) encompass critical amino acids that constitute three distinct epitopes for GP(A), GP(B), and GP(AB) antibodies, respectively, whereas the epitope for GP(X) antibodies is located in a different unknown region. The GP(A) antibodies were consistently immunodominant, accounting for 60-65% of the total immunoreactivity to alpha3(IV)NC1; thus, they probably play a major role in pathogenesis. Regions E(A) and E(B) are held in close proximity because they jointly form the epitope for Mab3, a monoclonal antibody that competes for binding with GP autoantibodies. All GP epitopes are sequestered in the hexamer configuration of the NC1 domain found in tissues and are inaccessible for antibody binding unless dissociation of the hexamer occurs, suggesting a possible mechanism for etiology of GP disease. GP antibodies have the capacity to extract alpha3(IV)NC1 monomers, but not dimers, from native human glomerular basement membrane hexamers, a property that may be of fundamental importance for the pathogenesis of the disease.

Idiotypic network dysregulation: a common etiopathogenesis of diverse autoimmune diseases

The pathogenesis of autoimmune disease is still an enigma. Whereas the diverse clinical manifestations of many autoimmune diseases cannot be explained by the existence of autoantibodies, idiotypic dysregulation may provide an alternative explanation. Experimental models, serum level changes of pathogenic idiotypes during exacerbation and remission, and the increased expression of pathogenic idiotypes following common infections all support this notion. In this article we review experimental models of autoimmune disease induction (systemic lupus erythematosus, antiphospholipid syndrome, Goodpasture's syndrome, autoimmune thyroiditis, and vasculitis) by manipulation of the idiotypic network, and discuss the utilization of idiotypes for the immunotherapy of autoimmune diseases and other conditions that involve the immune system (e.g., atherosclerosis).

Glomerular epithelial-myofibroblast transdifferentiation in the evolution of glomerular crescent formation

BACKGROUND

Glomerular cellular crescents consist of epithelial cells and macrophages, which can undergo an irreversible process of fibrous organization. However, the origin of the fibroblast-type cells that mediate this fibrous organization is unclear.

METHODS

This study examined glomerular epithelial- myofibroblast transdifferentiation (GEMT) in the formation and evolution of glomerular crescents in two distinct rat models of glomerulonephritis: 5/6 nephrectomy and antiglomerular basement membrane (GBM) disease.

RESULTS

Early in the course of both disease models, and prior to crescent formation, immunohistochemistry staining and in-situ hybridization demonstrated de novo expression of alpha-smooth-muscle actin (alpha-SMA), a marker of smooth muscle cells and myofibroblasts, by glomerular parietal epithelial cells (GPEC). The expression of alpha-SMA by GPEC was accompanied by a loss of E-cadherin staining, a marker of epithelial cells. At this early stage of GEMT, ultrastructural studies identified the presence of characteristic actin microfilaments and dense bodies within GPEC which retained a normal epithelial morphology with apical-basal polarity and microvilli. A late stage of transdifferentiation was seen in fibrocellular crescents. In this case, GPEC attached to intact segments of the capsular basement membrane contained large bundles of actin microfilaments throughout the cell, and this was accompanied by a loss of polarity, microvilli, and tight junctions. There was a significant correlation between the presence of alpha-SMA(+) GPEC and glomerular crescent formation. Cellular crescents contained small numbers of alpha-SMA(+) myofibroblasts. These cells become the dominant population in fibrocellular crescents, which was associated with marked local proliferation. Relatively few alpha-SMA(+) myofibroblasts remained in fibrotic/organizing crescents. Most cells within cellular and fibrocellular crescents expressed transforming growth factor-beta (TGF-beta) and basic fibroblast growth factor (FGF-2), suggesting that these growth factors may regulate this GEMT process during the evolution of glomerular crescents.

CONCLUSIONS

This study provides the first phenotypic and morphological evidence that glomerular epithelial-myofibroblast transdifferentiation participates in the formation and evolution of glomerular crescents.

Goodpasture's syndrome: a nursing challenge

Goodpasture's syndrome is an uncommon occurring disorder that causes hemorrhage in the basement membrane lining of the kidneys and the lungs. By recognizing early signs and symptoms of pulmonary-renal syndromes that may lead to a diagnosis of Goodpasture's syndrome, critical care and advanced practice nurses can play a key role in ensuring successful patient outcomes and preventing complications. Expert nursing care and emotional support is essential for the patient and family to cope with this usually fatal disease.

Anti-glomerular basement membrane glomerulonephritis after extracorporeal shock wave lithotripsy

Extracorporeal shock wave lithotripsy (ESWL) is a common noninvasive procedure for removal of upper urinary tract stones. We present a case of a man who developed anti-glomerular basement membrane (anti-GBM) disease after ESWL and review the two other cases described in the medical literature. In all cases, the affected individuals expressed the HLA DR2/HLA DR15 major histocompatibility antigen and developed a rapidly progressive anti-GBM-induced glomerulonephritis 3 to 7 months after ESWL. Anti-GBM disease may be a rare complication of ESWL in susceptible individuals and should be considered in patients who develop acute renal failure after lithotripsy.