Necrotizing And Crescentic Glomerulonephritis Research Articles

Membranous Glomerulonephritis With Crescents

IntroductionMembranous glomerulonephritis (MGN) is rarely associated with necrotizing and crescentic glomerulonephritis (NCGN).MethodsWe report the clinical and pathologic findings in 15 patients with MGN and NCGN associated with anti-neutrophil cytoplasm antibodies (ANCAs), anti–glomerular basement membrane (GBM), or anti–phospholipase A2 receptor (PLA2R) antibodies.ResultsThe cohort consisted of 15 patients: 7 males and 8 females with a median age of 63 years (range: 18–79). In 12 of 15 patients, MGN and NCGN were diagnosed at the time of the biopsy, and in 3 cases, MGN predated the NCGN. ANCA was positive in 7 cases (6 MPO myeloperoxidase (MPO)-ANCA and 1 PR3–ANCA), anti-GBM antibodies were detected in 5 cases, and anti-PLA2R antibodies were found in 2 cases. One case was negative for all antibodies. Microscopic hematuria was present in all but one patient who was anuric, and median urinary protein-to-creatinine ratio was 819.5 mg/mmol (range: 88–5600). Pathologic evaluation revealed MGN and NCGN with crescents involving 28% of glomeruli (median; range: 5%–100%). Follow-up was available for all 15 patients; all were treated with steroids; 10 with cyclophosphamide, and 6 also received rituximab. At a median follow-up of 72 months, 9 had stabilization or improvement of renal function, 6 had progressed to end-stage renal disease, and 4 died during the follow-up period.ConclusionMGN with crescents associated with ANCAs or anti-GBM antibodies is a rare dual glomerulopathy. Patients present with heavy proteinuria, microscopic hematuria, and acute kidney injury and should be treated for a rapidly progressive glomerulonephritis. Prognosis is variable, and 40% of patients progress to end-stage renal disease.

Pauci-Immune Necrotizing and Crescentic Glomerulonephritis with Membranous Lupus Nephritis, Fifteen Years after Initial Diagnosis of Secondary Membranous Nephropathy.

Renal involvement in systemic lupus erythematosus (SLE) is usually immune complex mediated and may have multiple different presentations. Pauci-immune necrotizing and crescentic glomerulonephritis (NCGN) refers to extensive glomerular inflammation with few or no immune deposits that may result in rapid decline in renal function. We report a case of a 79-year-old Hispanic male with a history of secondary membranous nephropathy (diagnosed by renal biopsy 15 years previously) who was admitted with acute kidney injury and active urinary sediment. P-ANCA titers and anti-myeloperoxidase antibodies were positive. The renal biopsy was diagnostic for NCGN superimposed on a secondary membranous nephropathy. A previous diagnosis of SLE based on American College of Rheumatology criteria was discovered via Veteran's Administration records review after the completion of treatment for pauci-immune NCGN. ANCAs are detected in 20–31% of patients with SLE. There may be an association between SLE and ANCA seropositivity. In patients with lupus nephritis and biopsy findings of necrotizing and crescentic glomerulonephritis, without significant immune complex deposition, ANCA testing should be performed. In patients with secondary membranous nephropathy SLE should be excluded.

Membranous glomerulonephritis with crescents

The coexistence of membranous glomerulonephritis (MGN) and necrotizing and crescentic glomerulonephritis (NCGN) is an unusual finding in a renal biopsy except in lupus nephritis. Little is known about whether these lesions are causally related in any clinical setting. We reviewed the pathology, presentation, and clinical course of 13 non-lupus patients with combined MGN and NCGN in native kidney biopsies (nine females, four males; median age 69 years), with particular attention to evidence of secondary MGN. Additional IgG subclass and phospholipase A2 receptor (PLA2R) immunofluorescence studies were conducted in seven cases. Eight biopsies were pauci-immune other than the capillary wall deposits of MGN; one patient had a non-lupus immune complex disease, and four had mesangial deposits, including one with rare subendothelial deposits. None had anti-glomerular basement membrane disease. IgG4 was dominant or codominant in the capillary wall deposits in three cases and virtually absent in four; PLA2R was positive in two cases, and negative in five. Seven patients were judged to have secondary MGN, including five of eight ANCA+ patients. Twelve patients were treated with combinations of steroids, cyclophosphamide, rituximab, followed by durable response in seven and relentless progression to end stage renal disease in four. Secondary MGN occurs with higher frequency in ANCA-positive NCGN than in the general MGN population. A causal relationship between MGN and NCGN was not established in any patient, but circumstances suggest a common cause in several, including immune complex disease, drug reaction and paraneoplastic syndrome.

Genetically Determined Severity of Anti-Myeloperoxidase Glomerulonephritis

Myeloperoxidase (MPO) is a target antigen for antineutrophil cytoplasmic autoantibodies (ANCA). There is evidence that MPO-ANCA cause necrotizing and crescentic glomerulonephritis (NCGN) and vasculitis. NCGN severity varies among patients with ANCA disease, and genetic factors influence disease severity. The role of genetics in MPO-ANCA NCGN severity was investigated using 13 inbred mouse strains, F1 and F2 hybrids, bone marrow chimeras, and neutrophil function assays. Mouse strains include founders of the Collaborative Cross. Intravenous injection of anti-MPO IgG induced glomerular crescents in >60% of glomeruli in 129S6/SvEv and CAST/EiJ mice, but <1% in A/J, DBA/1J, DBA/2J, NOD/LtJ, and PWK/PhJ mice. C57BL6J, 129S1/SvImJ, LP/J, WSB/EiJ, NZO/HILtJ, and C3H mice had intermediate severity. High-density genotypes at 542,190 single nucleotide polymorphisms were used to identify candidate loci for disease severity by identifying genomic regions that are different between 129S6/SvEv and 129S1/SvImJ mice, which are genetically similar but phenotypically distinct. C57BL/6 × 129S6 F2 mice were genotyped at 76 SNPs to capture quantitative trait loci for disease severity. The absence of a dominant quantitative trait locus suggests that differences in severity are the result of multiple gene interactions. Invivo studies using bone marrow chimeric mice and invitro studies of neutrophil activation by anti-MPO IgG indicated that severity of NCGN is mediated by genetically determined differences in the function of neutrophils.

IgG Glycan Hydrolysis Attenuates ANCA-Mediated Glomerulonephritis

Anti-neutrophil cytoplasmic autoantibodies (ANCA) directed against myeloperoxidase (MPO) and proteinase 3 (Pr3) are considered pathogenic in ANCA-associated necrotizing and crescentic glomerulonephritis (NCGN) and vasculitis. Modulation of ANCA IgG glycosylation may potentially reduce its pathogenicity by abolishing Fc receptor-mediated activation of leukocytes and complement. Here, we investigated whether IgG hydrolysis by the bacterial enzyme endoglycosidase S (EndoS) attenuates ANCA-mediated NCGN. In vitro, treatment of ANCA IgG with EndoS significantly attenuated ANCA-mediated neutrophil activation without affecting antigen-binding capacity. In a mouse model of anti-MPO IgG/LPS-induced NCGN, we induced disease with either unmodified or EndoS-treated (deglycosylated) anti-MPO IgG. In separate experiments, we administered EndoS systemically after disease induction with unmodified anti-MPO IgG. Pretreatment of anti-MPO IgG with EndoS reduced hematuria, leukocyturia, and albuminuria and attenuated both neutrophil influx and formation of glomerular crescents. After inducing disease with unmodified anti-MPO IgG, systemic treatment with EndoS reduced albuminuria and glomerular crescent formation when initiated after 3 but not 24 hours. In conclusion, IgG glycan hydrolysis by EndoS attenuates ANCA-induced neutrophil activation in vitro and prevents induction of anti-MPO IgG/LPS-mediated NCGN in vivo. Systemic treatment with EndoS early after disease induction attenuates the development of disease. Thus, modulation of IgG glycosylation is a promising strategy to interfere with ANCA-mediated inflammatory processes.

Membranous Glomerulonephritis with ANCA-Associated Necrotizing and Crescentic Glomerulonephritis

Only rare cases of concurrent membranous glomerulonephritis (MGN) and antineutrophil cytoplasmic antibody (ANCA)-associated necrotizing and crescentic glomerulonephritis (NCGN) have been reported. The authors report the clinical and pathologic findings in 14 patients with MGN and ANCA-associated NCGN. The cohort consisted of eight men and six women with a mean age of 58.7 yr. ANCA positivity was documented by indirect immunofluorescence or ELISA in all patients. Indirect immunofluorescence was positive in 13 patients (seven P-ANCA, five C-ANCA, one atypical ANCA). ELISA was positive in nine of 10 patients (five MPO-ANCA, three PR3-ANCA, one MPO- and PR3-ANCA). Clinical presentation included heavy proteinuria (mean 24-hr urine protein 6.5 g/d), hematuria, and acute renal failure (mean creatinine 4.4 mg/dl). Pathologic evaluation revealed MGN and NCGN, with crescents involving a mean of 32% of glomeruli. On ultrastructural evaluation, the majority of cases showed stage I or II membranous changes. Follow-up was available for 13 patients, 12 of whom were treated with steroids and cyclophosphamide. At a mean follow-up of 24.3 mo, five patients progressed to ESRD, seven had stabilization or improvement in renal function, and one had worsening renal function. Five patients, including three with ESRD, died during the follow-up period. The only independent predictor of progression to ESRD was serum creatinine at biopsy. MGN with ANCA-associated NCGN is a rare dual glomerulopathy seen in patients with heavy proteinuria, acute renal failure, and active urine sediment. Prognosis is variable, with 50% of patients reaching endpoints of ESRD or death.

Bone Marrow–Derived Cells Are Sufficient and Necessary Targets to Mediate Glomerulonephritis and Vasculitis Induced by Anti-Myeloperoxidase Antibodies

Clinical and experimental evidence indicate that ANCA cause pauci-immune necrotizing and crescentic glomerulonephritis (NCGN) and systemic small vessel vasculitis in humans. One of the major target antigens for ANCA is myeloperoxidase (MPO). An animal model that closely resembles the human disease is induced by intravenous injection of anti-MPO IgG into mice. The likely primary pathogenic targets for the anti-MPO IgG are circulating neutrophils and monocytes, although other cells have been implicated, including endothelial cells and epithelial cells. Herein is reported a new model for anti-MPO-mediated glomerulonephritis and vasculitis that further documents the pathogenic potential of ANCA and demonstrates that bone marrow (BM)-derived cells are sufficient targets to cause anti-MPO disease in the absence of MPO in other cell type. MPO knockout (Mpo-/-) mice that were immunized with mouse MPO were exposed to irradiation and received a transplant of Mpo+/+ or Mpo-/- BM. Engraftment in mice with circulating anti-MPO resulted in development of pauci-immune NCGN in all mice and pulmonary capillaritis and splenic necrotizing arteritis in some. Anti-MPO IgG also was introduced intravenously into chimeric mice by transplantation of Mpo+/+ BM into irradiated Mpo-/- mice or Mpo-/- BM into irradiated Mpo+/+ mice. Chimeric Mpo-/- mice with circulating MPO-positive neutrophils developed NCGN, whereas chimeric Mpo+/+ mice with circulating MPO-negative neutrophils did not, thereby indicating that BM-derived cells are not only sufficient but also necessary for induction of anti-MPO disease. This novel animal model further documents ANCA IgG interactions with neutrophils as a cause of ANCA-associated glomerulonephritis and vasculitis.

The Role of Neutrophils in the Induction of Glomerulonephritis by Anti-Myeloperoxidase Antibodies

In humans, circulating anti-neutrophil cytoplasm autoantibodies (ANCAs) with specificity for myeloperoxidase (MPO) are strongly associated with the development of pauci-immune necrotizing and crescentic glomerulonephritis (NCGN). In mice, we have demonstrated that intravenous injection of mouse antibodies specific for mouse MPO induces NCGN that closely mimics the human disease. We now report that the development of NCGN in this experimental model is accompanied by glomerular accumulation of neutrophils and macrophages. Neutrophil infiltration was most conspicuous at sites of glomerular necrosis and crescent formation, with macrophages also most numerous in crescents. Lymphocytes, however, were sparse in acute lesions. Importantly, mice that were depleted of circulating neutrophils with NIMP-R14 rat monoclonal antibodies were completely protected from anti-MPO IgG-induced NCGN. These findings provide direct evidence that neutrophils play a major role in the pathogenesis of anti-MPO-induced NCGN in this animal model and implicate neutrophils in the induction of human ANCA disease. This raises the possibility that therapeutic strategies to reduce circulating neutrophils could be beneficial to patients with ANCA-induced NCGN.

A novel class of autoantigens of anti-neutrophil cytoplasmic antibodies in necrotizing and crescentic glomerulonephritis: the lysosomal membrane glycoprotein h-lamp-2 in neutrophil granulocytes and a related membrane protein in glomerular endothelial cells.

Necrotizing and crescentic glomerulonephritis (NCGN) is frequently associated with circulating antineutrophil cytoplasmic autoantibodies (ANCA). It is established that ANCA are specific for soluble enzymes of granules of polymorphonuclear neutrophil granulocytes (PMN), such as myeloperoxidase (MPO) or protease 3 (PR3). The purpose of this study was to identify membrane proteins of PMNs, and/or glomerular cells, as additional autoantigenic ANCA targets. When membrane protein fractions were prepared from PMNs and isolated human glomeruli, and immunoblotted with ANCA sera of NCGN patients, two bands with apparent molecular masses of 170 and 80-110 kD (gp170/80-110) were labeled in PMNs, and a 130-kD glycoprotein (gp130) in glomeruli. Gp130 was purified, and monoclonal and rabbit antibodies (Abs) were produced which showed the same double specificity as the patient's ANCA. Using these probes, evidence was provided that gp170/80-110 is identical with human lysosomal-associated membrane protein 2 (h-lamp-2), because both proteins were immunologically cross-reactive and screening of a cDNA expression library from human promyelocytic leukemia cells with anti-gp130 Ab yielded a clone derived from h-lamp-2. Gp170/80-110 was localized primarily in granule membranes of resting PMNs, and was translocated to the cell surfaces by activation with FMLP. By contrast, gp130 was localized in the surface membranes of endothelial cells of human glomerular and renal interstitial capillaries, rather than in lysosomes, as found for h-lamp-2. Potential clinical relevance of autoantibodies to gp170/80-110 and gp130 was assessed in a preliminary trial, in which ANCA sera of patients (n = 16) with NCGN were probed with purified or recombinant antigens. Specific reactivity was detected in approximately 90% of cases with active phases of NCGN, and frequently also in combination with autoantibodies specific for PR3 or MPO. Collectively, these data provide evidence that h-lamp-2 in PMNs and a different, structurally related 130-kD membrane protein on the cell surface of renal microvascular endothelial cells are autoantigenic targets for ANCA in patients with active NCGN.