ANCA-negative pauci-immune crescentic glomerulonephritis

[Vasculitides]

In everyday clinical practice, immunologically mediated systemic vasculitides are among the rare diseases, meaning that basic knowledge of major symptoms and indicative laboratory findings is crucial for the inclusion of these complex clinical entities in differential diagnostic considerations. For many years, systemic vasculitides have been classified according to the primarily affected vessel size, distinguishing large, medium-sized, and small vessels. Pain is very often one of the main complaints of these diseases, be it, for example, the temporally accentuated headache in giant cell arteritis, the early morning myalgias in the shoulder and hip girdle in polymyalgia rheumatica, or the mononeuritis multiplex in eosinophilic granulomatosis with polyangiitis. General symptoms such as fever, weight loss, and night sweats are often accompanied by greatly increased parameters of inflammation. In addition, organ-specific symptoms and/or laboratory abnormalities may provide crucial information. These include ENT symptoms, pulmonary or skin manifestations, as well as signs of renal involvement, such as peripheral edema, rise in blood pressure, hematuria, proteinuria, or a rapid loss of kidney function. If there is reasonable suspicion of disease, patients should be transferred to specialized centers with an interdisciplinary team. In most cases, an immunosuppressive therapy regimen is required, although in recent years the path towards avoiding high glucocorticoid doses with many side effects has been paved by the use of novel therapies.

Kidney Biopsy and Immuno-Rheumatological Diseases: A Retrospective and Observational Study

Renal involvement is a common occurrence in patients with immuno-rheumatological diseases (IRDs). Several instances of glomerulonephritis (GN) occur in the setting of IRD and complicate the clinical course of an underlying condition. The aim of this study was to observe the spectrum of nephropathies according to age, kidney function, history of IRD at the time of biopsy, and histopathological kidney diagnosis. We evaluated data relating to 699 consecutive kidney native biopsies (female 52.1%) with a median age of 48 years (IQR 34-62) performed in adult patients collected over 15 years. The study population was divided into three groups: patients with kidney histological findings correlated to underlying IRD (Group 1), patients with kidney histological findings not correlated to underlying IRD (Group 2), and patients with kidney histological findings compatible with "de novo" IRD (absent in personal medical history) (Group 3). Kidney involvement related to IRD was found in 25.2% of patients. Group 1 was mostly represented by lupus nephritis (76.6%), with a younger age than Group 3 (p < 0.001) and by a higher percentage of females than other groups (p < 0.001). Group 3 was the most represented by microscopic polyangiitis (50.8%) when compared with the other two groups (p < 0.001). Acute nephritic syndrome (p < 0.001), acute kidney injury (AKI), and abnormal urinalysis (p < 0.001) were more represented in Group 3 than the other groups. In conclusion, IRDs are characterized by different clinical presentations and heterogeneous histological findings. Kidney biopsy remains fundamental to achieving the correct diagnosis and starting targeted therapy.

De Novo ANCA-Negative Pauci-Immune Crescentic Glomerulonephritis After COVID-19 mRNA Vaccination: A Case Report

To prevent the spread of the coronavirus disease 2019 (COVID-19) pandemic, vaccines have been authorized for emergency use and implemented worldwide. We present a case of de novo glomerulonephritis (GN) after use of the COVID-19 mRNA vaccine BNT162b2. A 48-year-old man with no relevant medical history was referred for sudden and persistent worsening of renal insufficiency 1.5 months after the second vaccine dose. He had arthralgia and skin rash a week after vaccination. Abdominal pain and diarrhea started 2 weeks later, and he was admitted to the hospital for enteritis treatment. Colonoscopy showed multiple ulcerations and petechiae suggestive of vasculitis in the terminal ileum. After prednisolone therapy, his gastrointestinal symptoms improved, but his renal function continued to deteriorate. Based on kidney biopsy findings and nephrotic-range proteinuria (5,306 mg/24 hours), he was diagnosed with anti-neutrophil cytoplasmic autoantibody (ANCA)-negative pauci-immune crescentic GN (CrGN). He received high-dose steroid pulse therapy and oral cyclophosphamide, and then, gradually underwent steroid tapering, with improvement in proteinuria and renal function over several weeks. Several cases of GN suspected to be related to COVID-19 vaccines have been reported. To our knowledge, this is the first case report of ANCA-negative pauci-immune crescentic CrGN with extrarenal involvement after COVID-19 mRNA vaccination. Our finding expands the spectrum of COVID-19 vaccine-associated GN.

ANCA-negative microscopic polyangiitis with neuromuscular involvement: When pathology could make the difference

Microscopic polyangiitis (MPA) is a necrotizing small vessel vasculitis with little or absent immune deposits (pauci-immune vasculitis), usually associated with the presence of antineutrophil cytoplasmic autoantibodies (ANCA) and a wide spectrum of organ manifestations. In our report we describe the case of a 74-year-old Asian man, who rapidly developed lower limb weakness and impaired renal and pulmonary functions. ANCA detection remained borderline throughout the disease course. Electrophysiological and instrumental studies revealed a picture of neuromuscular involvement; renal and muscle biopsies disclosed a small vessel vasculitis. He was started on a targeted immunosuppressive combination therapy and his clinical status progressively improved. In the framework of a multi-organ disease, microscopic polyangiitis should be considered as a differential diagnosis in case of acute/subacute onset of muscle weakness, even in the absence of ANCA detection.

The complement system in antineutrophil cytoplasmic antibody-associated vasculitis: pathogenic player and therapeutic target

PURPOSE OF REVIEW

The purpose of this review is to discuss the role of the complement system in the pathogenesis of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) as well as the employment of complement inhibitors in AAV treatment.

RECENT FINDINGS

AAV has traditionally been considered a pauci-immune disease until recent findings demonstrated the pathogenic role of the complement system. The complement alternative pathway is crucial in AAV, and C5a seems to be a key molecule for AAV to develop. Avacopan, a C5a-receptor (C5aR) antagonist, proved effective in achieving AAV remission and ameliorating kidney function.

SUMMARY

The increased circulating levels of some complement components - as well as the consumption of others - in patients with AAV suggested a systemic activation of the complement system. Low C3 levels correlate with a more aggressive disease and a worse renal prognosis. In ANCA-associated glomerulonephritis, renal deposits of C3d and properdin, suggestive of local alternative pathway activation, correlate with glomerular crescents and proteinuria. The interaction between C5a and neutrophil triggers alternative pathway activation, suggesting the central role of C5a in AAV pathogenesis. Avacopan, a C5aR inhibitor, showed beneficial effects in AAV and represents a promising therapy to achieve sustained remission and to spare glucocorticoids.

The neutrophil: A key resourceful agent in immune‐mediated vasculitis

The term "vasculitis" refers to a group of rare immune-mediated diseases characterized by the dysregulated immune system attacking blood vessels located in any organ of the body, including the skin, lungs, and kidneys. Vasculitides are classified according to the size of the vessel that is affected. Although this observation is not specific to small-, medium-, or large-vessel vasculitides, patients show a high circulating neutrophil-to-lymphocyte ratio, suggesting the direct or indirect involvement of neutrophils in these diseases. As first responders to infection or inflammation, neutrophils release cytotoxic mediators, including reactive oxygen species, proteases, and neutrophil extracellular traps. If not controlled, this dangerous arsenal can injure the vascular system, which acts as the main transport route for neutrophils, thereby amplifying the initial inflammatory stimulus and the recruitment of immune cells. This review highlights the ability of neutrophils to "set the tone" for immune cells and other cells in the vessel wall. Considering both their long-established and newly described roles, we extend their functions far beyond their direct host-damaging potential. We also review the roles of neutrophils in various types of primary vasculitis, including immune complex vasculitis, anti-neutrophil cytoplasmic antibody-associated vasculitis, polyarteritis nodosa, Kawasaki disease, giant cell arteritis, Takayasu arteritis, and Behçet's disease.

[Update on etiopathogenesis of small vessel vasculitis]

Small vessel vasculitis is characterized by a necrotizing inflammation of the vessel wall predominantly with involvement of small intraparenchymal arteries, arterioles, capillaries and venules. Medium-sized and occasionally large vessels can also be involved. Antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (granulomatosis with polyangiitis, microscopic polyangiitis, eosinophilic granulomatosis with polyangiitis) are differentiated from immune complex vasculitides based on immunopathological and serological aspects. Immune complex vasculitides include IgA vasculitis, cryoglobulinemic vasculitis, hypocomplementemic urticarial vasculitis (anti-C1q vasculitis) and anti-glomerular basement membrane disease. Epidemiological and next-generation sequencing-based studies have significantly contributed to the identification of predisposing environmental factors and genetic risk factors in recent years. Under specific conditions ANCA and immune complexes can induce premature intravascular activation of neutrophilic granulocytes with degranulation and release of enzymes and reactive oxygen species, which leads to vascular damage. In granulomatosis with polyangiitis and eosinophilic granulomatosis with polyangiitis various factors, such as barrier dysfunction and dysbiosis of the microbiome contribute to extravascular granuloma formation predominantly affecting the respiratory tract.

Different Types of ANCA Determine Different Clinical Phenotypes and Outcome in ANCA-Associated Vasculitis (AAV)

Aim

Accumulating evidence supports the use of antineutrophil cytoplasmic antibody (ANCA) type to classify different clinical entities. We aimed to evaluate whether the presence and type of ANCA determine different diseases, based on clinical phenotypes, renal involvement, and response to treatment.

Patients and Methods

Differences in terms of clinical manifestations, disease activity, laboratory parameters, and histology were recorded between patients with focal necrotizing glomerulonephritis (FNGN) due to myeloperoxidase (MPO-), proteinase 3-ANCA(+) [PR3-ANCA(+)], and ANCA(-) disease at time of diagnosis. Patients were treated with the same protocol and followed-up for 24 months, in a scheduled basis of every month for the first year and every 3 months for the second year. Primary end points were: (i) Combined end-stage renal disease (ESRD) and/or death and (ii) The presence of major or minor relapse during follow-up and secondary endpoint was the combination of ESRD and reduction of estimated glomerular filtration rate (eGFR) ≥ 50%.

Results

A total of 92 patients (M/F 39/53, mean age 59.1 ± 15 years) diagnosed with FNGN due to ANCA-associated vasculitis (AAV), 36 (39.1%) patients diagnosed with PR3-ANCA, 39 (42.4%) patients diagnosed with MPO-ANCA, and 17 (18.5%) patients diagnosed with ANCA(-) were included. Number of involved systems differed significantly between PR3-, MPO-ANCA, and ANCA(-), with only renal involvement in 3, 25.5, and 29% of patients, two systems involved in 33, 31, and 59% of patients, and > 3 systems involved in 64, 43.5, and 12% of patients, respectively (p = 0.002). Histology classification revealed focal, crescentic, mixed, and sclerotic type in 14, 64, 19, and 3% of PR3-ANCA(+), 8, 28, 18, and 46% of MPO-ANCA, and 41, 29, 6, and 24% of ANCA(-), respectively (p < 0.0001). Primary end point of ESRD ± Death was reached in 11 (30.6%), 16 (41%), and 6 (35.5%) patients with PR3-ANCA(+), MPO-ANCA(+), and ANCA(-), respectively (p = NS); similarly, ESRD± > 50% eGFR reduction in 8 (22.2%), 15 (38.5%), and 5 (29.4%) patients, respectively (p = NS), meaning that patients with MPO-ANCA(+) showed a propensity to decline renal function. Rate of relapse was increased in the presence of patients with PR3-ANCA(+), 14 (38.9%), 4 (11.8%), and 2 (10.3%) of patients with PR3-ANCA(+), MPO-ANCA(+), and ANCA(-), had at least one relapse during the two-year follow-up (p = 0.006).

Conclusion

Clinical phenotype and renal histology differ significantly between PR3-ANCA(+), MPO-ANCA(+), and ANCA(-) disease and FNGN; however, renal function outcome is similar, despite the increased rate of relapses in patients with PR3-ANCA(+).

Nephritis-associated plasmin receptor (NAPlr)-positive glomerulonephritis in a case of ANCA-negative small vessel vasculitis

A 75-year-old man with fever was diagnosed with alveolar hemorrhage. Antineutrophil cytoplasmic antibodies for myeloperoxidase and proteinase 3 were absent. He received corticosteroid therapy, which immediately improved his symptoms and chest radiological findings. After the discontinuation of corticosteroids, fever and general fatigue relapsed, and renal function deteriorated with hematuria and proteinuria. A nerve conduction study revealed mononeuritis multiplex. Renal biopsy demonstrated focal necrotizing crescentic glomerulonephritis with endocapillary proliferative lesions, immunofluorescence C3 deposits, and electron-microscopic subepithelial hump-like deposits. Nephritis-associated plasmin receptor (NAPlr) and plasmin activity, biomarkers of infection-related glomerulonephritis, were positive in glomeruli. Although pathological findings suggested infection-related glomerulonephritis (IRGN), clinical manifestations, such as alveolar hemorrhage and mononeuritis multiplex, suggested systemic small vessel vasculitis. After corticosteroid therapy, systemic symptoms disappeared, and the gradual amelioration of hematuria and proteinuria was observed. Based on the clinical symptoms for which steroid therapy was effective, the patient was considered to have systemic small vessel vasculitis, the etiology of which may have been associated with infection.

Ectopic Relapse of Anti-neutrophil Cytoplasmic Antibody-associated Pituitary Vasculitis with No Elevation of Anti-neutrophil Cytoplasmic Antibodies after Renal Remission

The relationship between anti-neutrophil cytoplasmic antibody (ANCA) titer levels and relapse risk in patients with ANCA-associated vasculitis (AAV) following clinical remission remains controversial. We herein report a case showing ectopic relapse of AAV in the pituitary with no ANCA elevation after renal remission. Magnetic resonance imaging revealed an enlarged pituitary gland. A pituitary biopsy showed geographic necrosis with multinucleated giant cells. We diagnosed this case as relapse of AAV in the pituitary. One month after rituximab therapy, the pituitary gland volume had decreased. The intensification of therapy due to the possibility of vasculitis relapse may facilitate better control of AAV.

Anca negative pauci-immune crescentic glomerulonephritis and mixed connective tissue disease: a case study

One of the most common causes of rapidly progressive glomerulonephritis (RPGN) is pauci-immune crescentic glomerulonephritis (CrGN). In the majority of cases, this condition has a positive serologic marker, the anti-neutrophil cytoplasmic antibodies (ANCAs), but in approximately 10% there are no circulating ANCAs, and this subgroup has been known as the ANCA-negative pauci-immune CrGN. RPGN can be associated with systemic diseases, but there are only few case reports describing the association with mixed connective tissue disease (MCTD). The authors report a case of ANCA-negative CrGN associated with a MCTD.

Crescentic glomerulonephritis: what's different in South Asia? A single center observational cohort study

Background: The spectrum and outcomes of crescentic glomerulonephritis (Cr.GN) in South Asia is vastly different from that reported worldwide and there is a paucity of information. The aim of the study was to study the demography, clinical presentation, histology and predictors of longitudinal outcomes of Cr.GN in this population. Methods: An observational cohort study of renal biopsies was performed in the largest tertiary center in South India over a period of 10 years (January 2006 to December 2015) with ≥50% crescents on renal histology indicating Cr.GN. Results: A total of 8645 kidney biopsies were done; 200 (2.31%) were Cr.GN. Patients were categorized into three etiological groups: anti-glomerular basement membrane (type I), immune complex (type II), and pauci-immune (type III). Type II was the most common (96, 46.5%), followed by type III (73, 38%) and type I (31, 15.5%). Female preponderance was seen across all types. About half of all patients presented with recent onset hypertension. Type II had the highest median proteinuria (4.2 (2.1-6) g/day, p=0.06) and the median estimated glomerular filtration rate was lowest in type I (5 (4-8) ml/min/1.73m 2, p<0.001). Among type III, anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis was seen only in ~50% of patients. Nearly one third of patients with type I were also positive for ANCA making them 'double positive'. Acute glomerular insults like tuft necrosis and chronic changes as evidenced by moderate to severe interstitial fibrosis, was a predominant feature of type I. Conclusions: ANCA-negative pauci-immune vasculitis, as well as double positive Cr.GN, are reported for the first time in South-Asia. Renal survival was significantly worse in type I/III compared to type II. Types I/III, moderate to severe interstitial fibrosis and tubular atrophy, presence of oliguria/anuria and increasing percentage of crescents in renal biopsy were significant predictors of end stage kidney disease in our cohort.

When Anti-Neutrophil Cytoplasmic Antibody Fails: A Case of Anti-Neutrophil Cytoplasmic Antibody Negative Granulomatosis With Polyangiitis

Granulomatosis with polyangiitis (GPA) is a vasculitis of small and medium-sized vessels and presents with varying signs and symptoms. It includes upper and lower airway manifestations and glomerulonephritis with a positive antineutrophil cytoplasmic antibody (ANCA) in serology in 90% of cases. However, about 10% of cases with GPA can have negative serology, often resulting in a diagnostic delay. Obtaining a tissue pathology is needed to confirm GPA. Here we present a 77-year-old male who presented with generalized weakness and loss of appetite and was found to have glomerulonephritis and bilateral opacities in the lungs with a negative ANCA. He was diagnosed with ANCA negative granulomatosis with polyangiitis after a renal biopsy revealed necrotizing inflammation with crescent formation. He was successfully treated with systemic glucocorticoids and rituximab. In conclusion, prompt diagnosis and treatment of ANCA negative vasculitis are required to decrease mortality.

Narrative Review of Hypercoagulability in Small-Vessel Vasculitis

Pauci-immune necrotizing and crescentic glomerulonephritis (GN) is the most common etiology of rapidly progressive GN. Clinical presentation in those afflicted is usually related to rapid loss of kidney function. We report the case of a 70-year-old woman who came to medical attention for signs and symptoms related to lower-extremity deep vein thrombosis (DVT). At presentation, the patient had biochemical abnormalities consistent with active GN, which quickly progressed to rapid loss in kidney function requiring renal replacement therapy. Kidney biopsy revealed small-vessel vasculitis with glomerular crescents. Serologic studies were negative for antineutrophil cytoplasmic antibody antibodies and other causes of acute GN. Plasmapheresis, immunosuppressive, and anticoagulant therapies were prescribed. Absence of other apparent end-organ involvement with vasculitis pointed toward renal-limited small-vessel vasculitis, yet presence of unprovoked DVT argues for systemic vascular inflammation. This case illustrates that venous thrombosis can be the presenting manifestation in patients with vasculitis and silent, severe end-organ involvement. The epidemiology and pathophysiology of venous thromboembolism in small-vessel vasculitis are discussed in this report.

Unique case of ANCA-negative pauci-immune necrotizing glomerulonephritis with diffuse alveolar hemorrhage, potentially associated with midostaurin

We present a 61-year-old male with FLT3-mutated acute myeloid leukemia treated with midostaurin who developed acute kidney injury requiring hemodialysis and pulmonary renal syndrome. Antibodies to proteinase-3, myeloperoxidase, and glomerular basement membrane were negative. Renal biopsy confirmed acute pauci-immune focal necrotizing glomerulonephritis (GN) with fibrin crescents indicating rapidly progressing glomerulonephritis. He improved with pulse methylprednisolone, intravenous cyclophosphamide, and plasma exchange with resolution of hemoptysis. This case highlights the importance of prompt renal biopsy to guide early initiation of life-saving therapies. To our knowledge, this is the first reported case of ANCA-negative pauci-immune necrotizing GN likely secondary to midostaurin.

Individualised Homeopathic Therapy in ANCA Negative Rapidly Progressive Necrotising Crescentic Glomerulonephritis with Severe Renal Insufficiency - A Case Report

Anti-Neutrophil Cytoplasmic Antibody (ANCA)-negative Rapidly Progressive Glomerulonephritis (RPGN) is a severe form of autoimmune renal injury with a bleak prognosis.

A 60-year-old Indian woman was treated with classical homeopathy for ANCA-negative RPGN, and after one year of treatment, serum creatinine and other parameters indicating renal injury dropped steadily despite the withdrawal of immunosuppressive drugs; renal dialysis, which was conducted twice a week initially, was made rarer and stopped after one year.

Classical homeopathy may be considered a potential therapeutic modality in severe pathologies. Controlled studies are required to establish further the extent to which classical homeopathy may relieve patients from procedures such as dialysis that cause considerable physical and economic discomfort.

Crescentic glomerulonephritis with anti-GBM antibody but no glomerular deposition

Background

Anti-glomerular basement membrane (GBM) antibodies are highly specific for Goodpasture’s or anti-GBM disease, in which they are generally directed against the non-collagenous (NC1) domain of the alpha 3 chain of type IV collagen(α3(IV)), and less commonly, toward the α 4(IV) or α 5(IV) chains, which form a triple helical structure in GBM and alveolar basement membrane (ABM). Alterations in the hexameric structure of the NC1 (α3 (IV)), allows novel epitopes to be exposed and an immune response to develop, with subsequent linear antibody deposition along the GBM, leading to a crescentic glomerulonephritis. Positive anti-GBM antibodies are assumed to be pathogenic and capable of binding GBM in vivo, especially in the context of rapidly progressive glomerulonephritis.

We have investigated patients with circulating anti-GBM antibodies, reactive to α3 (IV) and human GBM by immunoassays and Western blotting respectively, with focal necrotising crescentic glomerulonephritis but no linear GBM antibody deposition on immunohistochemistry. Three out of four were also ANCA positive. Despite not binding native GBM, patients’ sera showed linear binding to primate glomeruli by indirect immunofluorescence, in the 2 cases tested. Following treatment, significant improvements in kidney function were found in 3/4 patients.

Case presentation

We present four patients with crescentic glomerulonephritis and circulating anti-GBM antibodies, but no glomerular binding.

Conclusions

These novel findings, demonstrate that in some patients anti-GBM antibodies may not bind their own GBM. This has important implications for clinical diagnosis, suggesting that histological confirmation of kidney injury by anti-GBM antibodies should be obtained, as non-binding GBM antibodies may be associated with significant renal recovery.

Electronic supplementary material

The online version of this article (10.1186/s12882-018-1027-x) contains supplementary material, which is available to authorized users.

Pulmonary renal syndrome: A case report of diffuse alveolar hemorrhage in association with ANCA negative pauci-immune glomerulonephritis

RATIONALE

Pulmonary renal syndrome (PRS) is a term most commonly used to describe a combination of glomerulonephritis and pulmonary hemorrhage as a manifestation of a multisystem autoimmune disease. It is usually associated with ANCA vasculitis and anti-GBM disease. Diffuse alveolar hemorrhage in a patient with ANCA and anti-GBM negative pauci-immune glomerulonephritis is rare and optimal management is unknown.

PATIENT CONCERNS

An 85-year-old man with hypertension, diabetes mellitus, prostate cancer and recently diagnosed pauci-immune necrotizing glomerulonephritis presented to our emergency department with worsening dyspnea and pedal edema for several days. Clinical presentation and radiological studies were suggestive of fluid overload but he developed worsening respiratory failure despite hemodialysis.

DIAGNOSES

Bronchoscopy confirmed diffuse alveolar hemorrhage. ANCA and anti-GBM antibodies were negative. The patient was diagnosed with pulmonary renal syndrome - diffuse alveolar hemorrhage in the setting of ANCA and anti-GBM negative pauci-immune glomerulonephritis.

INTERVENTIONS

Patient was started on intravenous pulse steroids, cyclophosphamide and received seven sessions of plasmapheresis.

OUTCOMES

There was an improvement in patient's respiratory status and repeat bronchoscopy at the end of treatment did not show diffuse alveolar hemorrhage.

LESSONS

Pauci-immune crescentic necrotizing glomerulonephritis is usually associated with the presence of ANCA, however, ANCA may be absent in 10% of these cases. Immunosuppression is the mainstay of treatment for ANCA and anti-GBM associated PRS. This case highlights the importance of immunosuppression and plasmapheresis in patients with ANCA negative vasculitis due to presence of unidentified serum antibodies. If left untreated, these patients can have a fulminant course with high mortality ranging from 25 to 50%.

Glucocorticoids in the Treatment of Glomerular Diseases: Pitfalls and Pearls

Glucocorticoids exert anti-inflammatory and immunosuppressive activities by genomic and nongenomic effects. The classic genomic effects are mediated by cytosolic glucocorticoid receptors that can upregulate the expression of anti-inflammatory proteins in the nucleus (transactivation) or repress the translocation of proinflammatory transcription factors from the cytosol into the nucleus (transrepression). The nongenomic effects are probably mediated by membrane glucocorticoid receptors. Glucocorticoid receptors are expressed also in podocytes and experimental data suggest that glucocorticoids may protect from podocyte injury. Glucocorticoids have a low therapeutic index and may exert a number of time-dependent and dose-dependent side effects. Measures to prevent or attenuate side effects include single-morning administration of short-acting glucocorticoids, dietetic counseling, increasing physical activity, frequent monitoring, and adapting the doses to the clinical conditions of the patient. Synthetic glucocorticoids, either given alone or in combination with other immunosuppressive drugs, are still the cornerstone therapy in multiple glomerular disorders. However, glucocorticoids are of little benefit in C3 glomerulopathy and may be potentially deleterious in patients with maladaptive focal glomerulosclerosis. Their efficacy depends not only on the type and severity of glomerular disease, but also on the timeliness of administration, the dosage, and the duration of treatment. Whereas an excessive use of glucocorticoids can be responsible for severe toxicity, too low a dosage and too short duration of glucocorticoid treatment can result in false steroid resistance.

Tuberculosis and pauci-immune crescentic glomerulonephritis

We report here a case that highlights tuberculosis (TB) as a possible cause for pauci-immune crescentic glomerulonephritis (c-GN), an important and often treatable cause of kidney injury. A 47-year-old HIV-negative man of mixed ethnicity presented with a 2-week history of cough, haemoptysis and unintentional weight loss. Chest examination revealed crepitations over the right upper zone and urinalysis demonstrated an active urinary sediment with red cell casts. Chest radiograph confirmed right upper lobe cavitation. Serum laboratory investigations revealed a serum creatinine of 632 µmol/L and were negative for antineutrophil cytoplasmic antibodies. A diagnosis of pauci-immune c-GN was made on renal biopsy. In addition, sputum PCR confirmed infection with drug-sensitive Mycobacterium tuberculosis Standard TB treatment and immunosuppression with prednisone and cyclophosphamide was commenced, and over the course of 6 months, renal function improved to an estimated glomerular filtration rate >60 mL/min.

Myeloperoxidase-antineutrophil cytoplasmic antibody (ANCA)-associated systemic vasculitis developed from ANCA negative renal limited vasculitis: A case report

RATIONALE

The relationship between antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) and ANCA-negative vasculitis has not been elucidated.

PATIENT CONCERNS

A 64-year-old female with edema and proteinuria was admitted. A kidney biopsy indicated focal proliferative nephritis with crescents in 25% of glomeruli. Serum ANCA was negative. Eighteen months later, systemic symptoms emerged and acute kidney injury occurred. Serum ANCA against myeloperoxidase (MPO) turned positive. Repeated kidney biopsy showed more severe lesion than last time. Immunoglobulin (Ig)G was purified from serum obtained before the first kidney biopsy. Weak ANCA which could not be detected in serum was found in IgG.

DIAGNOSES

MPO-ANCA-associated AAV developed from ANCA-negative renal-limited AAV.

INTERVENTIONS

The patient was treated with glucocorticoid.

OUTCOMES

The serum creatinine decreased to 2.17 mg/dL a week later. MPO-ANCA turned negative when re-examined 3 weeks later. No relapse has been observed during follow-up for 6 months.

LESSONS

This is the first reported case about the spontaneous transformation from ANCA-negative renal-limited AAV to ANCA-positive systemic vasculitis. There might be a slow process of epitope spreading in the pathogenesis of disease. Physicians should try their best to detect the ANCA in the diagnose and treatment of ANCA-negative AAV.

Complement activation in pauci-immune necrotizing and crescentic glomerulonephritis: results of a proteomic analysis

Background

Complement activation plays an important role in the pathophysiology of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), although it remains unclear which pathway is activated. Whether pauci-immune necrotizing crescentic glomerulonephritis (pauci-immune GN) with negative ANCA serology is part of the spectrum of AAV or a different disease entity is essentially unknown.

Methods

We used proteomic analysis to delineate the complement profile in a series of 13 kidney biopsies of patients with pauci-immune GN, with either proteinase 3 (PR3) (five patients) or myeloperoxidase (MPO) antibodies (four patients) or with consistently negative ANCA serology (four patients). Immunofluorescence staining of glomeruli was essentially negative in the PR3-ANCA and MPO-ANCA groups, while a mild staining for C3 was seen in the ANCA-negative cases. No electron-dense deposits were found in the PR3-ANCA and MPO-ANCA groups, but mesangial and few subepithelial deposits were clearly present in the ANCA-negative specimens.

Results

Mass spectrometry revealed low spectra numbers for C3 and immunoglobulins in both PR3-positive and MPO-positive patients with minimal or no C4 and C9. In contrast, larger spectra numbers for C3, moderate spectra numbers for C9, complement factor H-related protein-1 and low spectra numbers for C4, C5 and immunoglobulins were found in the ANCA-negative cases.

Conclusion

While complement activation is noted in AAV, the complement activation appears to be more prominent in the ANCA-negative glomerulonephritis. The larger amount of C3 and moderate amount of C9 in the ANCA-negative glomerulonephritis implies activation of the alternate and terminal pathway of complement, suggesting that this entity may be caused or promoted by a genetic or acquired defect in the alternative pathway.

Pauci-immune lupus nephritis: possibility or co-incidence?

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized with immune complex formation and renal involvement of lupus and may include several kinds of pathological conditions, but mostly, it is associated with immune complex-induced glomerular disease. Pauci-immune lupus nephritis is a very rare condition. We describe a 45-year-old female patient with pauci-immune crescentic necrotizing lupus nephritis and briefly discuss the possible mechanism and pathogenesis.

Seasonal Influence on the Risk of Relapse at a Rise of Antineutrophil Cytoplasmic Antibodies in Vasculitis Patients with Renal Involvement

Objective.

The objective of this study was to identify risk factors for a relapse at the time of an increase in antineutrophil cytoplasmic antibodies (ANCA) in patients with renal ANCA-associated vasculitis (AAV).

Methods.

All patients between January 2000 and November 2011 with renal AAV having an ANCA rise during remission were included. Differences in time to relapse since the ANCA rise were assessed using a Cox regression model. The level of 25-hydroxy Vitamin D (25(OH)D) was assessed at the ANCA rise and at a subsequent relapse or time-matched during remission.

Results.

Sixty patients had an ANCA rise, of whom 36 patients relapsed. Three risk factors were associated with a relapse at the time of the ANCA increase: previous disease activity not treated with cyclophosphamide or rituximab (HR 3.48, 95% CI 1.60–7.59), an ANCA rise during the fall season (HR 4.37, 95% CI 1.60–11.90), and an extended ANCA rise (HR 3.57, 95% CI 1.50–8.48). Levels of 25(OH)D significantly decreased during followup in relapsing patients, but not in patients who remained in remission (difference −6.3 ± 14.4, p = 0.017 vs 2.7 ± 16.3, p = 0.430).

Conclusion.

ANCA rises occurring during the fall season are more frequently followed by a relapse than ANCA rises occurring during other seasons. Although it is tempting to speculate that decreasing Vitamin D levels following the ANCA rise can be held responsible for the subsequent relapse, this remains to be determined.

The functional activities of complement factor H are impaired in patients with ANCA-positive vasculitis

Increasing evidences have demonstrated that the activation of the alternative complement pathway is crucial for the pathogenesis of anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV). Our recent study found that circulating levels of complement factor H (FH), a key regulator of the alternative pathway, were associated with disease activity. In the current study, functional activities of FH were assessed to further explore the potential role of FH in the pathogenesis of AAV. We found that the two patients with ANCA-negative pauci-immune necrotizing crescentic glomerulonephritis exhibited relatively normal functional activities of FH. However, patients with ANCA-positive vasculitis exhibited deficient functional activities of FH, in terms of interaction with and the regulation of C3b, binding to mCRP and endothelial cells, and the protection of host cells against complement attack. Our findings indicate that functional activities of FH are deficient in patients with ANCA-positive vasculitis, potentially contributing to the disease development.

ANCA-associated vasculitis - clinical utility of using ANCA specificity to classify patients

The anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) are a heterogeneous group of rare syndromes characterized by necrotizing inflammation of small and medium-sized blood vessels and the presence of ANCAs. Several clinicopathological classification systems exist that aim to define homogeneous groups among patients with AAV, the main syndromes being microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA) and eosinophilic GPA (EGPA). Two main types of ANCA can be detected in patients with AAV. These ANCAs are defined according to their autoantigen target, namely leukocyte proteinase 3 (PR3) and myeloperoxidase (MPO). Patients with GPA are predominantly PR3-ANCA-positive, whereas those with MPA are predominantly MPO-ANCA-positive, although ANCA specificity overlaps only partially with these clinical syndromes. Accumulating evidence suggests that ANCA specificity could be better than clinical diagnosis for defining homogeneous groups of patients, as PR3-ANCA and MPO-ANCA are associated with different genetic backgrounds and epidemiology. ANCA specificity affects the phenotype of clinical disease, as well as the patient's initial response to remission-inducing therapy, relapse risk and long-term prognosis. Thus, the classification of AAV by ANCA specificity rather than by clinical diagnosis could convey clinically useful information at the time of diagnosis.

Clinical presentation and outcome prediction of clinical, serological, and histopathological classification schemes in ANCA-associated vasculitis with renal involvement

Several classification schemes have been developed for anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), with actual debate focusing on their clinical and prognostic performance. Sixty-two patients with renal biopsy-proven AAV from a single center in Mexico City diagnosed between 2004 and 2013 were analyzed and classified under clinical (granulomatosis with polyangiitis [GPA], microscopic polyangiitis [MPA], renal limited vasculitis [RLV]), serological (proteinase 3 anti-neutrophil cytoplasmic antibodies [PR3-ANCA], myeloperoxidase anti-neutrophil cytoplasmic antibodies [MPO-ANCA], ANCA negative), and histopathological (focal, crescenteric, mixed-type, sclerosing) categories. Clinical presentation parameters were compared at baseline between classification groups, and the predictive value of different classification categories for disease and renal remission, relapse, renal, and patient survival was analyzed. Serological classification predicted relapse rate (PR3-ANCA hazard ratio for relapse 2.93, 1.20-7.17, p = 0.019). There were no differences in disease or renal remission, renal, or patient survival between clinical and serological categories. Histopathological classification predicted response to therapy, with a poorer renal remission rate for sclerosing group and those with less than 25 % normal glomeruli; in addition, it adequately delimited 24-month glomerular filtration rate (eGFR) evolution, but it did not predict renal nor patient survival. On multivariate models, renal replacement therapy (RRT) requirement (HR 8.07, CI 1.75-37.4, p = 0.008) and proteinuria (HR 1.49, CI 1.03-2.14, p = 0.034) at presentation predicted renal survival, while age (HR 1.10, CI 1.01-1.21, p = 0.041) and infective events during the induction phase (HR 4.72, 1.01-22.1, p = 0.049) negatively influenced patient survival. At present, ANCA-based serological classification may predict AAV relapses, but neither clinical nor serological categories predict renal or patient survival. Age, renal function and proteinuria at presentation, histopathology, and infectious complications constitute the main outcome predictors and should be considered for individualized management.

Mayo Clinic/Renal Pathology Society Consensus Report on Pathologic Classification, Diagnosis, and Reporting of GN

Renal pathologists and nephrologists met on February 20, 2015 to establish an etiology/pathogenesis-based system for classification and diagnosis of GN, with a major aim of standardizing the kidney biopsy report of GN. On the basis of etiology/pathogenesis, GN is classified into the following five pathogenic types, each with specific disease entities: immune-complex GN, pauci-immune GN, antiglomerular basement membrane GN, monoclonal Ig GN, and C3 glomerulopathy. The pathogenesis-based classification forms the basis of the kidney biopsy report. To standardize the report, the diagnosis consists of a primary diagnosis and a secondary diagnosis. The primary diagnosis should include the disease entity/pathogenic type (if disease entity is not known) followed in order by pattern of injury (mixed patterns may be present); score/grade/class for disease entities, such as IgA nephropathy, lupus nephritis, and ANCA GN; and additional features as detailed herein. A pattern diagnosis as the sole primary diagnosis is not recommended. Secondary diagnoses should be reported separately and include coexisting lesions that do not form the primary diagnosis. Guidelines for the report format, light microscopy, immunofluorescence microscopy, electron microscopy, and ancillary studies are also provided. In summary, this consensus report emphasizes a pathogenesis-based classification of GN and provides guidelines for the standardized reporting of GN.

Mayo Clinic/Renal Pathology Society Consensus Report on Pathologic Classification, Diagnosis, and Reporting of GN

Renal pathologists and nephrologists met on February 20, 2015 to establish an etiology/pathogenesis-based system for classification and diagnosis of GN, with a major aim of standardizing the kidney biopsy report of GN. On the basis of etiology/pathogenesis, GN is classified into the following five pathogenic types, each with specific disease entities: immune-complex GN, pauci-immune GN, antiglomerular basement membrane GN, monoclonal Ig GN, and C3 glomerulopathy. The pathogenesis-based classification forms the basis of the kidney biopsy report. To standardize the report, the diagnosis consists of a primary diagnosis and a secondary diagnosis. The primary diagnosis should include the disease entity/pathogenic type (if disease entity is not known) followed in order by pattern of injury (mixed patterns may be present); score/grade/class for disease entities, such as IgA nephropathy, lupus nephritis, and ANCA GN; and additional features as detailed herein. A pattern diagnosis as the sole primary diagnosis is not recommended. Secondary diagnoses should be reported separately and include coexisting lesions that do not form the primary diagnosis. Guidelines for the report format, light microscopy, immunofluorescence microscopy, electron microscopy, and ancillary studies are also provided. In summary, this consensus report emphasizes a pathogenesis-based classification of GN and provides guidelines for the standardized reporting of GN.

ANCA-Negative Pauci-Immune Crescentic Glomerulonephritis Linked with Non-Small Cell Carcinoma of the Lung

The association between malignancy and glomerular disease has been appreciated for decades [Baschinsky et al., Am J Kidney Dis 2000;36:E24]. Several types of glomerular injury in patients with cancer have been recognized [Morikawa et al., CEN Case Rep 2013;2:158-164; Baschinsky et al., Am J Kidney Dis 2000;36:E24]. The most common association is between nephrotic syndrome and carcinoma [Baschinsky et al., Am J Kidney Dis 2000;36:E24]. We report a case of anti-neutrophil cytoplasmic antibody-negative crescentic glomerulonephritis associated with lung cancer. To the best of our knowledge, only 1 other case of ANCA-negative pauci-immune crescentic glomerulonephritis associated with lung cancer has been reported [Baschinsky et al., Am J Kidney Dis 2000;36:E24].

Urinary thrombin: a novel marker of glomerular inflammation for the diagnosis of crescentic glomerulonephritis (prospective observational study)

Background

Crescentic glomerulonephritis (CresGN), an uncommon rapidly progressive disease, is characterized by severe glomerular inflammation with fibrin deposition. The lack of specific CresGN biomarkers delays diagnosis and threatens life. Because fibrin deposits in CresGN glomeruli indicate thrombin generation, we hypothesized that thrombin is excreted in urine and is a specific CresGN biomarker.

Methods

We measured urinary thrombin activity in 200 untreated patients (17 with CresGN, 183 with primary glomerulonephritis) and controls (8 patients with healed CresGN, 11 with nephrosclerosis, and 10 with tubulointerstitial nephritis, and 66 healthy volunteers). CresGN types included 15 pauci-immune and 2 immune complex. We assessed the diagnostic accuracy of thrombinuria in 169 patients with hematuria and proteinuria. Renal biopsy tissues were immunostained for tissue factor and fibrin. We analyzed the relationship of thrombinuria to plasma thrombin-antithrombin complex, hematuria, proteinuria, glomerular filtration rate, glomerular fibrin deposition, antineutrophil cytoplasmic antibodies (ANCAs), and C-reactive protein (CRP). We studied changes in thrombin activities after glucocorticoid treatment in 12 patients with thrombinuria.

Results

The highest thrombinuria occurrence was in CresGN (70.6%), followed by membranoproliferative glomerulonephritis (41.7%), IgA nephropathy (9.2%), and acute glomerulonephritis (0%). More than 75% of patients with nonproliferative glomerulonephritis manifested no thrombinuria. No controls had thrombinuria. Thrombinuria showed high CresGN specificity (90.1%) and moderate sensitivity (70.6%) and was detected in 4 of 7 patients with ANCA-negative CresGN. In CresGN, thrombinuria was associated with fibrin deposition in glomerular extracapillary tissue, where monocytes/macrophages expressed tissue factor. Thrombinuria in CresGN was unrelated to plasma thrombin-antithrombin complex, hematuria, proteinuria, glomerular filtration rate, and CRP. After glucocorticoid treatment, thrombinuria in patients with CresGN rapidly disappeared but proteinuria and hematuria persisted.

Conclusions

Thrombinuria was specific for glomerular inflammation, was unaffected by systemic inflammation or coagulation, and demonstrated good diagnostic accuracy for CresGN including ANCA-negative cases. Thrombinuria measurement may provide risk-free diagnosis and screening for CresGN.

Granulomatosis with polyangiitis presenting as a renal tumor

Inflammatory tumors of the kidney are uncommon and include primary inflammatory processes and systemic diseases such as sarcoidosis, IgG4 disease, and granulomatosis with polyangiitis (GPA). There are approximately 15 cases of the latter in the literature. Tumors in GPA are well described and have been reported in several organs including breast, orbit, mediastinum, central nervous system, and especially the lung. We report the case of a 48-year-old woman who presented with diffuse frontal headaches. Imaging showed both a cranial/sinus and renal mass. The pathology of the dura and nasal sinus biopsies were unrevealing. A nephrectomy was performed that demonstrated a discrete lesion with extensive necrosis, granulomatous inflammation, and crescentic pauci-immune glomerulonephritis, findings consistent with GPA.

Key advances in the clinical approach to ANCA-associated vasculitis

The updated nomenclature for vasculitis defines this varied group of disorders by aetiology, specific features of pathogenesis and clinical symptoms; diagnostic and classification criteria for clinical practice are in development. Here, I review some important advances in the management of vasculitis within the category of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), which encompasses microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA) and eosinophilic granulomatosis with polyangiitis (EGPA). The clinical approach to the management of the patient with AAV should include testing for ANCA specificity; proteinase 3 (PR3)-specific ANCAs are most often associated with GPA, whereas myeloperoxidase (MPO)-ANCAs are usually associated with MPA. Also important to the management of AAV is an assessment of the disease stage and severity, to enable tailored treatment based on an algorithm derived from controlled-trial data. Remaining questions pertain to the dosage and duration of corticosteroid treatment, the selection of patients for, and duration of, maintenance treatment after induction of remission, and the identification of safer and more effective therapies than are currently in use. Outcome measures should assess not only disease activity, but also damage and quality of life. Infections, cardiovascular events and malignancies also contribute to outcome, and their prevention should therefore be part of the clinical approach to managing patients with AAV.

Clinical research in a modern Chinese peritoneal dialysis center

A prerequisite for enhancing the quality of peritoneal dialysis is the continuous review and analysis of clinical data from routine clinical care and research. Here, we describe our strategy (Peking University First Hospital, Beijing, China) to achieve that objective.

Granulomatosis with polyangiitis: rapidly progressive necrotizing glomerulonephritis in a pediatric patient

Granulomatosis with polyangiitis (GPA) is associated with a broad range of clinical manifestations including renal disease. It is a systemic vasculitis that is rarely encountered in children. We present a 14-year-old girl who suffered from pharyngitis 1 week before admittance to hospital. She was admitted for macroscopic hematuria and oliguria, under the possibility of nephritic syndrome. Renal failure with rapidly progressive glomerulonephritis occurred within 24 hours. Immunologic tests showed the presence of type-C anti-neutrophil cytoplasmic antibodies (c-ANCA with antiproteinase 3 specificity) and renal biopsy revealed pauci-immune crescentic focal necrotizing glomerulonephritis. Treatment including methylprednisolone and cyclophosphamide intravenous pulses allowed renal recovery after 3 weeks. The clinical, hematological, and biochemical parameters improved substantially, achieving remission. Granulomatosis with polyangiitis, although rare in children, should be considered in the above clinical scenario. This case underlines that knowledge of renal histology diagnosis and early aggressive immunosuppressive therapy are essential for the management of these patients.

Membranous nephropathy with crescents: a series of 19 cases

BACKGROUND

Membranous nephropathy (MN) with crescents is rare and, in the absence of lupus, usually is associated with anti-glomerular basement membrane (anti-GBM) nephritis or antineutrophil cytoplasmic antibody (ANCA)-positive glomerulonephritis. Only rare cases of crescentic MN without ANCA or anti-GBM have been reported.

STUDY DESIGN

Case series.

SETTING & PARTICIPANTS

19 patients with ANCA- and anti-GBM-negative crescentic MN and no clinical evidence of systemic lupus.

OUTCOMES

Clinical features, kidney biopsy findings, laboratory results, treatment, and follow-up of patients with crescentic MN.

RESULTS

Mean age was 55 (range, 5-86) years. All patients presented with proteinuria (mean protein excretion, 11.5 [range, 3.3-29] g/d) and nearly all had hematuria; 16 of 19 (84%) patients had decreased estimated glomerular filtration rates (eGFRs; mean serum creatinine, 2.9 [range, 0.4-10] mg/dL; mean eGFR, 39.7 [range, 4 to >100] mL/min/1.73 m2). Glomeruli showed on average 25% (range, 2%-73%) involvement by crescents. All showed a membranous pattern; 7 showed mesangial and 2 showed segmental endocapillary proliferation. By immunofluorescence, all cases showed granular subepithelial immunoglobulin G (IgG) and κ and λ light chains, and all but one showed C3; 5 showed C1q or IgA. Electron microscopy revealed stages I-III MN; 38% of cases were M-type phospholipase A2 receptor (PLA2R) associated, indicating that at least some were primary MN. Follow-up clinical data were available for all patients (mean, 22 [range, 1.5-138] months). 14 patients received immunosuppressive therapy, and 2, only angiotensin-converting enzyme inhibitor/angiotensin receptor blocker therapy. 4 patients (21%) progressed to end-stage renal disease, at 0-9 months postbiopsy. Mean serum creatinine level of those without end-stage renal disease at follow-up was 1.7 (range, 0.5-4.1) mg/dL; mean eGFR was 53.3 (range, 16-103) mL/min/1.73 m2. 67% of patients had proteinuria with protein excretion≥1 (mean, 3.2) g/d at follow-up.

LIMITATIONS

Retrospective study.

CONCLUSIONS

Crescentic MN is a rare variant of MN that usually presents with heavy proteinuria, hematuria, and decline in GFR. The prognosis is variable and the disease may respond to therapy, but most patients develop a long-term decline in GFR.

Autoantibodies to hLAMP-2 in ANCA-negative pauci-immune focal necrotizing GN

Pauci-immune focal necrotizing GN (piFNGN) is usually associated with ANCAs that are thought to be pathogenic. However, 10%-15% of patients are ANCA negative and the cause of their injury is unknown. We previously reported a high frequency of autoantibodies to human lysosome-associated membrane protein-2 (hLAMP-2) in ANCA-associated piFNGN, and have now investigated whether the same is true in ANCA-negative patients. Of 11 patients, 8 (73%) had anti-hLAMP-2 antibodies detected by ELISA and confirmed by immunoblotting and indirect immunofluorescence. The autoantibodies from all 8 patients bound to native LAMP-2 purified from human glomeruli and recombinant hLAMP-2 expressed in ldlD cells, both with molecular masses of 110 kD. However, in contrast to anti-LAMP-2 antibodies from ANCA-positive patients, these antibodies from ANCA-negative patients failed to bind the more complexly glycosylated native neutrophil hLAMP-2 (190 kD). Treatment with the deglycosylating enzyme, endo-β-galactosidase, reduced the mass of neutrophil hLAMP-2 to 110 kD and enabled autoantibody binding. Similarly, pretreating neutrophils with endo-β-galactosidase or neuraminidase converted ANCA assay results from negative to positive. Finally, IgG from LAMP-2-positive ANCA-negative patients bound specifically to normal human kidney sections and to human glomerular endothelial cells in culture. In conclusion, in patients with ANCA-negative piFNGN, we have identified autoantibodies to hLAMP-2 that bind native glomerular but not neutrophil hLAMP-2, suggesting a role in pathogenesis.

AP-VAS 2012 case report: a case of ANCA-negative crescentic glomerulonephritis complicating multiple opportunistic infections in the digestive tract

Crescentic glomerulonephritis (GN) is one of the common causes of rapidly progressive glomerulonephritis (RPGN). Pauci-immune crescentic GN is usually associated with anti-neutrophil cytoplasmic antibody (ANCA). However, patients with pauci-immune crescentic GN who lack ANCAs have recently been reported. Approximately 10-30 % of patients with pauci-immune crescentic GN lack ANCAs. The clinical characteristics of patients with ANCA-negative pauci-immune crescentic GN are not entirely the same as patients with ANCA-positive GN, and this suggests that ANCA-negative and ANCA-positive pauci-immune crescentic GN might be different disease entities. We report a patient with ANCA-negative crescentic GN complicated with multiple opportunistic infections (Candida albicans, herpes simplex virus, and Cytomegalovirus) in the digestive tract during the course of immunosuppressive therapy. After antifungal and antiviral therapies including itraconazole, valaciclovir, and ganciclovir, she recovered from multiple opportunistic infections. The occurrence of comorbid opportunistic infections during the course of immunosuppressive therapy may not be rare in the elderly. However, a case of multiple opportunistic infections limited to the digestive tract is very rare.

Recurrence of ANCA-negative renal-limited pauci-immune glomerulonephritis in the renal allograft

Renal transplantation is the treatment of choice for end-stage renal disease (ESRD) due to pauci-immune crescentic glomerulonephritis (PICGN). A small subgroup of patients with PICGN are anti-neutrophil cytoplasmic antibody (ANCA) negative. We report a case of a patient with ANCA-negative renal-limited form of PICGN who developed ESRD despite treatment. He underwent live-related renal allograft transplantation after 12 months on haemodialysis. In the eighth post-transplant month, he developed graft dysfunction, which on evaluation turned out to be a graft recurrence of the basic disease in the form of PICGN. He received treatment with methylprednisolone, cyclophosphamide and plasmapheresis. However, his renal functions did not improve and he developed graft loss in the 11th post-transplant month and was started on continuous ambulatory peritoneal dialysis. We report a rare recurrence of renal-limited PICGN in the allograft. Patients with PICGN undergoing renal transplantation should be followed up carefully, and an early biopsy should be performed in the case of graft dysfunction to deal with this potentially graft-threatening complication.

Epitope specificity determines pathogenicity and detectability in ANCA-associated vasculitis

Anti-neutrophil cytoplasmic antibody-associated (ANCA-associated) small vessel necrotizing vasculitis is caused by immune-mediated inflammation of the vessel wall and is diagnosed in some cases by the presence of myeloperoxidase-specific antibodies (MPO-ANCA). This multicenter study sought to determine whether differences in ANCA epitope specificity explain why, in some cases, conventional serologic assays do not correlate with disease activity, why naturally occurring anti-MPO autoantibodies can exist in disease-free individuals, and why ANCA are undetected in patients with ANCA-negative disease. Autoantibodies from human and murine samples were epitope mapped using a highly sensitive epitope excision/mass spectrometry approach. Data indicated that MPO autoantibodies from healthy individuals had epitope specificities different from those present in ANCA disease. Importantly, this methodology led to the discovery of MPO-ANCA in ANCA-negative disease that reacted against a sole linear sequence. Autoantibodies against this epitope had pathogenic properties, as demonstrated by their capacity to activate neutrophils in vitro and to induce nephritis in mice. The confounder for serological detection of these autoantibodies was the presence of a fragment of ceruloplasmin in serum, which was eliminated in purified IgG, allowing detection. These findings implicate immunodominant epitopes in the pathology of ANCA-associated vasculitis and suggest that autoantibody diversity may be common to other autoimmune diseases.