Idiopathic microscopic polyarteritis nodosa: ultrastructural observations on the renal vascular and glomerular lesions

Chemokines and Cytokines Profiles in Patients with Antineutrophil Cytoplasmic Antibodies-Associated Vasculitis: A Preliminary Study

The damage to small vessels in AAV and inflammatory reactions are accompanied by the release of various chemokines and cytokines. Using a flow cytometry technique, we assessed the levels of specific cytokines, namely IL-1β IL-6, IL-8, IL-10, IL12p70, and TNF, and chemokines, IFN-α, IP-10, and MIG in the serum from 9 healthy volunteers and 20 AAV patients, where 11 of the patients were not treated and evaluated at the time of diagnosis and 9 were already diagnosed and taking CY + GCS. The obtained results were then compared considering the activity of the disease, the type and titre of the ANCA antibodies, the inflammatory status, and the kidneys' condition. Amongst others, the IL-6, IL-8, IL-10, TNF, and MIG levels were much higher in the serum of AAV patients than in healthy controls, whereas the level of IL-1β was higher in healthy volunteers. Additionally, the levels of IL-6, IL-10, IP-10, and MIG negatively correlated with the eGFR level, while the level of IFN-α positively correlated with the titre of PR3-ANCA. As most of the molecules are implicated in trafficking primed neutrophils towards small vessels, looking for links between the levels of these cytokines/chemokines and the clinical symptoms of AAV may facilitate the diagnosis and predict the progression of the disease.

Microscopic polyangiitis: Clinical characteristics and long-term outcomes of 378 patients from the French Vasculitis Study Group Registry

OBJECTIVE

To describe characteristics and long-term outcomes of patients with microscopic polyangiitis (MPA), an antineutrophil cytoplasm antibody (ANCA)-associated small-vessel necrotizing vasculitis.

METHODS

MPA patients from the French Vasculitis Study Group Registry satisfying the European Medicines Agency algorithm were analyzed retrospectively. Characteristics at diagnosis, treatments, relapses and deaths were analyzed to identify factors predictive of death or relapse.

RESULTS

Between 1966 and 2017, 378 MPA patients (median age 63.7 years) were diagnosed and followed for a mean of 5.5 years. At diagnosis, the main clinical manifestations included renal involvement (74%), arthralgias (45%), skin (41%), lung (40%) and mononeuritis multiplex (32%), with less frequent alveolar hemorrhage (16%), cardiomyopathy (5%) and severe gastrointestinal signs (4%); mean serum creatinine was 217 μmol/L. ANCA were detected in 298/347 (86%) patients by immunofluorescence and/or enzyme-linked immunosorbent assay (ELISA). Among the 293 patients with available ELISA specificities, 272 (92.8%) recognized myeloperoxidase and 13 (4.4%) proteinase-3. During follow-up, 131 (34.7%) patients relapsed and 78 (20.6%) died, mainly from infections. Respective 5-year overall and relapse-free survival rates were 84.2% and 60.4%. Multivariable analyses retained age >65 years, creatinine >130 μmol/L, severe gastrointestinal involvement and mononeuritis multiplex as independent risk factors for death. Renal impairment was associated with a lower risk of relapse.

CONCLUSION

Non-renal manifestations and several risk factors for death or relapse were frequent in this nationwide cohort. While mortality was low, and mainly due to treatment-related complications, relapses remained frequent, suggesting that MPA management can be further improved.

Comparative Changes Noted in Renal Biopsies on Light Microscopy of ANCA Positive Vs ANCA Negative Serology

OBJECTIVES

Pauci-immune glomerulonephritis is the commonest cause of rapidly progressive glomerulonephritis (RPGN) which is associated with increased mortality and morbidity. More than 90% of these patients have serological presence of either antineutrophil cytoplasmic antibodies (ANCA), of cytoplamic (C) or perinuclear (P) type. "Immunofluoresence studies" exhibiting minimal or no fluorescence is diagnostic in all such cases. The present study aims to study the differences between renal biopsies of serologically ANCA negative versus ANCA positive individuals.

MATERIALS AND METHODS

One hundred and twenty renal biopsies (of clinically suspected cases of systemic vasculitis) were sub-divided sub-divided under the heading of serologically ANCA positive and serologically ANCA negative; and scoring them by means of a semi-quantitative scoring system devised at the beginning of the study to identify statistically significant, specific light microscopic features in the sub-components of renal biopsy.

RESULTS

Fifteen parameters were found to be statistically significantly (p-value <0.05) in ANCA positive serological cases. These were glomerular capillary loop infiltration by neutrophils, cellular crescents, fibro-cellular crescents, glomerular fibrinoid necrosis, glomerular sclerosis, peri-glomerular infiltration, interstitial oedema, interstitial eosinophils, tubular atrophy, tubular necrosis, tubulitis, arterial hyalinization, arterial necrosis, arterial vessel wall polymorpho nuclear infiltrate and myointimal hypertrophy.

CONCLUSION

The presence of above parameters in a renal biopsy report of a patient (in absence of facilities of autoimmune serology and immunofluoresence) can alert both nephrologist and nephropathologist to keep a possibility of renal symptoms arising out of systemic vasculitis.

New features of disease after diagnosis in 6 forms of systemic vasculitis

OBJECTIVE

To quantify the occurrence of features of vasculitis that initially present after diagnosis in 6 types of primary vasculitis.

METHODS

Standardized collection of data on 95 disease manifestations in 6 vasculitides, including granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), eosinophilic granulomatosis with polyangiitis (Churg-Strauss; EGPA), polyarteritis nodosa (PAN), giant cell arteritis (GCA), and Takayasu arteritis (TAK), was obtained within a set of multicenter longitudinal, observational cohorts. For each form of vasculitis, the frequency of disease-specific manifestations at diagnosis was compared to the cumulative frequency of each manifestation. The percentage of patients who initially developed severe manifestations after diagnosis, defined as organ- or life-threatening in the small and medium vessel vasculitides (GPA, MPA, EGPA, PAN) and as ischemic/vascular in the large vessel vasculitides (GCA, TAK), was reported.

RESULTS

Out of 838 patients with vasculitis, 490 (59%) experienced ≥ 1 new disease manifestation after diagnosis. On average, patients with vasculitis experienced 1.3 new manifestations after diagnosis (GPA = 1.9, MPA = 1.2, EGPA = 1.5, PAN = 1.2, GCA = 0.7, and TAK = 1.0). New severe manifestations occurred after diagnosis in 224 (27%) out of 838 patients (GPA = 26%, MPA = 19%, EGPA = 21%, PAN = 23%, GCA = 24%, and TAK = 44%). Timing of onset of new manifestations was not significantly associated with disease duration.

CONCLUSION

A majority of patients with vasculitis develop new disease features after diagnosis, including a substantial number of new, severe manifestations. Ongoing assessment of patients with established vasculitis should remain broad in scope.

Endothelium-neutrophil interactions in ANCA-associated diseases

The two salient features of ANCA-associated vasculitis (AAV) are the restricted microvessel localization and the mechanism of inflammatory damage, independent of vascular immune deposits. The microvessel localization of the disease is due to the ANCA antigen accessibility, which is restricted to the membrane of neutrophils engaged in β2-integrin-mediated adhesion, while these antigens are cytoplasmic and inaccessible in resting neutrophils. The inflammatory vascular damage is the consequence of maximal proinflammatory responses of neutrophils, which face cumulative stimulations by TNF-α, β2-integrin engagement, C5a, and ANCA by the FcγRII receptor. This results in the premature intravascular explosive release by adherent neutrophils of all of their available weapons, normally designed to kill IgG-opsonized bacteria after migration in infected tissues.

Diagnosis and management of pulmonary vasculitis

The pulmonary vasculitides are a heterogeneous group of disorders characterized pathologically by vascular destruction with cellular inflammation and necrosis. These disorders can affect small, medium, and large vessels and may be primary or occur secondary to a variety of conditions. Vasculitis involving the lungs is most commonly due to primary, idiopathic, small-vessel antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides, which includes granulomatosis with polyangiitis (formerly Wegener’s granulomatosis), Churg–Strauss syndrome, and microscopic polyangiitis. From a clinical perspective these remain among the most challenging of diseases both in terms of diagnosis and treatment. This review will focus on diagnosis and management of ANCA-associated vasculitides.

Clinical features and outcome of microscopic polyangiitis under a new consensus algorithm of ANCA-associated vasculitides in Korea

The classification system for antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis and polyarteritis nodosa had its limitations due to numerous overlapping features of these disease entities. The aim of this study is to investigate the clinical features and outcome of patients diagnosed with microscopic polyangiitis (MPA) according to the newly proposed consensus algorithm of ANCA-associated vasculitides and polyarteritis nodosa. Fifty-five cases of MPA, comprised of 33 men and 22 women, diagnosed according to a new consensus algorithm at a single tertiary hospital were identified for analysis. The main clinical features were constitutional symptoms (78.2%), followed by renal involvement (74.5%), musculoskeletal symptoms (67.3%), skin manifestations (50.9%), neurologic involvement (43.6%), and lung involvement (41.8%). P-ANCA and/or anti-myeloperoxidase antibody were present in 69.1%. Five Factor Score and Birmingham Vasculitis Activity Score (BVAS) at diagnosis were 1.1 ± 0.9 and 10.9 ± 4.9, respectively. Forty-four patients were available for a long-term follow-up, and six patients (13.6%) resulted in death. Mortality was associated with BVAS > 9 at the time of diagnosis, age > 60 years, and presence of cardiomyopathy and interstitial lung disease. The survival rate at 1 and 3 years was 93.9 and 89.2%, respectively. Eight patients (14.5%) required dialysis at the time of diagnosis. This is the first study to demonstrate the clinical features in patients with MPA using a new consensus algorithm. Survival rate was higher than previously reported, and interstitial lung disease was a new risk factor for death in patients with MPA.

Microscopic polyangiitis: Clinical presentation

Microscopic polyangiitis (MPA) is a member of the family of ANCA-associated vasculitides. Its characteristic histology shows a necrotizing small vessel vasculitis with little or absent immune deposits (pauci-immune vasculitis). In Western countries MPA shows a lower prevalence than Wegener's disease, it affects more men than women and commences at the age of > or = 50 years. The two organs most typically involved and often defining prognosis are the kidneys and the lungs. MPA may concomitantly or sequentially involve other organs such as the nervous system, the skin, the musculoskeletal system, but also the heart, the eye and the intestines. Treatment decisions should be based on severity and pattern of organ involvement and respect the five factor score (FFS). Life- or organ- threatening disease is treated with glucocorticoids and (pulse) cyclophosphamide. Plasmapheresis and i.v.immunoglobulins have been shown to be beneficial as additional measure in severe cases. If renal function is preserved, Methotrexate may be considered to induce remission, and if the FFS equals 0, remission may be induced with glucocorticoid monotherapy. Maintenance therapy is recommended with Azathioprin, mycophenolate mofetil may be used as a second line drug. Biologic agents such as monoclonal antibodies to tumor necrosis factor a and B cell depleting rituximab have been shown to bear remission-inducing quality.

Clinical features and outcomes of microscopic polyangiitis in Korea

Microscopic polyangiitis (MPA) is a systemic vasculitis affecting small vessels. To determine the clinical features and outcomes of MPA in Korean patients, we retrospectively reviewed the medical records of patients diagnosed with MPA at a single medical center in Korea between 1989 and 2006. The 18 patients who met the Chapel Hill criteria for MPA had a mean (+/-SD) age at the time of diagnosis of 62.4+/-12.7 yr. Renal manifestations and general symptoms were the most common features of MPA, with lung involvement also very common. Antineutrophil cytoplasmic antibodies (ANCA) were present in 17 of the 18 patients (94%). Of 17 patients treated with steroids and cyclophosphamide, 11 (65%) had stable or improved course. One patient treated with steroids without cyclophosphamide showed disease progression. Ten of the 18 patients (56%) died at a median follow-up of 8 months. MPA in Korean patients was distinguished by a higher rate of lung involvement, especially alveolar hemorrhage, which was the leading cause of death in our patients. Korean patients were also older at MPA onset and were more likely positive for ANCA. Other overall clinical manifestations did not differ significantly.

Antineutrophil cytoplasmic antibody-associated vasculitides

The identification of antineutrophil cytoplasmic antibodies (ANCA) proved a major breakthrough in the classification, diagnosis, monitoring, and understanding of vasculitides. Vasculitides associated with ANCA selectively affect the small vessels; they include Wegener granulomatosis, microscopic polyangiitis, and Churg-Strauss syndrome. Evidence supporting a direct pathogenic role for ANCA has accumulated over the years. The clinical, laboratory, and histological findings vary across diseases; they are discussed here based on a review of published data from over 1600 patients. The course and prognosis also vary according to the disease. New treatment strategies tailored to the type and extent of the vascular disease have improved survival and treatment safety. Induction therapy, which should be given on an emergency basis in a specialized unit, consists of glucocorticoid therapy and cyclophosphamide in Wegener granulomatosis; microscopic polyangiitis and Churg-Strauss syndrome, without poor prognostic factors, can be managed with glucocorticoid therapy alone as the first-line treatment. A full recovery or complete remission is now achieved in over 80% of patients. Maintenance therapy is mandatory to reduce the relapse rate, which varies across diseases. Among patients with Wegener granulomatosis, up to 50% relapse within the first 5 years. Azathioprine is the main maintenance drug, although methotrexate, mycophenolate mofetil, or leflunomide may be used as second-line drugs. Biotherapies such as rituximab and TNFalpha antagonists are currently under evaluation as promising rescue agents for patients with refractory disease.

Polyangéite microscopique

Microscopic polyangiitis was initially considered a "microscopic" form of polyarteritis nodosa and was not definitively distinguished from it until the Chapel Hill nomenclature (1994). Microscopic polyangiitis is a systemic necrotizing vasculitis of small vessels. Its typical clinical manifestations are rapidly progressive glomerulonephritis and alveolar hemorrhage. Other possible symptoms resemble those encountered in polyarteritis nodosa. Microscopic polyangiitis belongs to the group of ANCA-associated vasculitides, and 75-80% of patients have pANCA to myeloperoxidase (MPO). Anti-MPO ANCA pathogenicity has been established in animal models, and a recent report describes transplacental transfer of these antibodies in humans, resulting in pulmonary hemorrhage and renal involvement in the newborn. Patients with no poor prognostic factors, as defined by a five-factor score, can be treated with corticosteroids alone, with immunosuppressants added only in case of treatment failure. Patients with one or more poor prognostic factors must receive a combination of corticosteroids and immunosuppressants, mainly intravenous pulsed cyclophosphamide, with plasma exchange as an adjuvant therapy for those with severe renal involvement. Once remission is achieved, maintenance therapy can replace cyclophosphamide by azathioprine or methotrexate. Biological therapies are under evaluation. The remission rate is above 80% with these regimens, and the relapse rate is around 30% at 5 years, lower than for Wegener's granulomatosis.

The Clinical Spectrum of Primary Renal Vasculitis

BACKGROUND AND OBJECTIVES

The vasculitides are potentially severe and often difficult to diagnose syndromes. Many forms of vasculitis may involve the kidneys. This review will focus on the clinical and histopathological aspects of renal involvement in the systemic vasculitides.

METHODS

We searched the MEDLINE database using as key terms the MeSH terms and textwords for different forms of vasculitis and for renal involvement, creating a database of more than 2200 relevant references.

RESULTS

The frequency of renal involvement in vasculitis varies among different syndromes. It is more frequent in Wegener's granulomatosis and microscopic polyarteritis, while it is uncommon to rare in other forms of vasculitis such as Behçet's disease and relapsing polychondritis. The vessels affected include the renal artery in Takayasu arteritis, medium-size renal parenchymal artery in classic polyarteritis nodosa, and glomerular involvement in Wegener's granulomatosis and microscopic polyarteritis. The clinical expression of renal vasculitis depends on the size of the affected vessels and includes renovascular hypertension, isolated nonnephrotic proteinuria, interstitial nephritis, and glomerulonephritis, which can be rapidly progressive. Diagnosis is established by a combination of history, clinical manifestations, laboratory findings (eg, urine sediment, urine protein, antineutrophil cytoplasmic antibodies), imaging techniques (renal angiography, especially when there is a suspicion of medium-to-large vessel disease, and chest radiograph), and finally, renal biopsy. Prognosis varies from unfavorable in the rapidly progressive glomerulonephritis of microscopic polyarteritis, which can lead to renal failure, chronic dialysis, and renal transplantation, to benign, as in the case of Henoch Schonlein purpura, in which the majority of patients recover.

CONCLUSIONS

The manifestations and prognosis of renal vasculitis range widely. Renal involvement greatly influences prognosis and dictates the need for early and prompt immunosuppressive therapy. Thus, the clinician should be alert for the timely diagnosis and treatment of renal vasculitis.

ANCA-induced neutrophil F-actin polymerization: implications for microvascular inflammation

BACKGROUND

The antineutrophil cytoplasmic antibody (ANCA)-positive vasculitides are characterized by a necrotizing vasculitis of small vessels with neutrophil infiltration. The reasons behind the selectivity for small vessels remain unclear, but may relate to the necessity for neutrophils to deform in order to pass through capillaries. The resistance to deformation of neutrophils largely arises from their actin cytoskeleton. It is hypothesized that ANCA, by inducing actin polymerization, increases neutrophil rigidity and contributes to their sequestration in capillaries.

METHODS

To test this hypothesis, neutrophils were treated with IgG-ANCA and the following characterizations: formation of filamentous F-actin (by flow cytometry); changes in morphology (by fluorescence and electron microscopy); and the potential to obstruct microvessels (by measuring entry times into micropipettes with comparable diameters to capillaries). The neutrophil signaling mechanisms activated by IgG-ANCA were investigated using blocking antibodies to Fcgamma receptors and inhibitors of tyrosine phosphorylation. Protein tyrosine phosphorylation was examined by immunoblotting of cell lysates, and calcium fluxes were measured by spectrofluorimetry of Fura-2 pentakis (acetoxymethyl) ester (Fura 2-AM) labeled neutrophils.

RESULTS

IgG-ANCA led to a significant dose-dependent actin polymerization over about 10 minutes. Over the same period, neutrophils became distorted in shape and more resistant to micropipette aspiration. Treatment with normal IgG caused less marked and delayed changes in these parameters. Actin polymerization required engagement of FcgammaRIIa receptor, tyrosine phosphorylation, and calcium fluxes.

CONCLUSION

These novel findings reveal signaling mechanisms that underlie ANCA-induced actin polymerization and might explain the predilection for small vessels in IgG-ANCA-associated vasculitis.

Microscopic Polyangiitis Presenting with Liver Dysfunction Preceding Rapidly Progressive Necrotizing Glomerulonephritis

The authors describe a 52-year-old woman diagnosed with microscopic polyangiitis. She presented with abnormal liver function tests accompanied by fever, headache, and fatigue. Two months later, rapidly progressive necrotizing glomerulonephritis developed together with seropositivity for perinuclear antineutrophil cytoplasmic antibody. Although liver dysfunction from microscopic polyangiitis is very rare, especially at presentation, this diagnostic possibility should be kept in mind to permit prompt consideration of steroid therapy.

Circulating endothelial cells as markers for ANCA-associated small-vessel vasculitis

BACKGROUND

Histological findings in small-vessel vasculitis associated with antineutrophil cytoplasmic antibodies (ANCAs) suggest that damaged endothelial cells undergo necrosis and detachment from the basement membrane. We postulated that isolation of these cells from peripheral blood might provide a novel marker of the disease and elucidate pathogenetic events.

METHODS

18 patients with active ANCA-associated vasculitis, 20 patients in remission, 20 healthy controls, 12 patients with infection, and 12 patients with glomerular disease not associated with ANCA were studied. Endothelial cells were isolated from peripheral blood by use of Dynabeads coated with antibodies against CD146, and were stained for von Willebrand factor (vWF), CD31, and Ulex Europaeus lectin 1 (UEA-1). Tissue-factor immunocytochemistry and assays for markers of apoptosis and necrosis were also done.

FINDINGS

Few circulating endothelial cells were seen in healthy controls (0-20 cells/mL, median 5 cells/mL), patients with infection (0-16 cells/mL, median 8 cells/mL), and patients with non-ANCA glomerulonephritis (0-21 cells/mL, median 4 cells/mL). By contrast, large numbers of circulating endothelial cells were detected in patients with active vasculitis (20-5700 cells/mL, median 136 cells/mL, p<0.0001 when compared with healthy controls). Cell numbers fell substantially during 6 months of successful immunosuppressive treatment among those with active disease. Patients in remission had moderately raised cell numbers (0-60 cells/mL, median 16 cells/mL). 84% of cells obtained from patients with active disease stained positive for annexin/propidium iodide and 86% stained tissue factor positive, indicating a necrotic and procoagulant phenotype.

INTERPRETATION

Circulating endothelial cells are a novel marker of active ANCA-associated small-vessel vasculitis. The clinical use of this tool and the pathogenic mechanisms leading to these findings require further investigation.

Vasculitis: Wegener granulomatosis, Churg-Strauss syndrome, microscopic polyangiitis, polyarteritis nodosa, and Takayasu arteritis

Identification, diagnosis, and management of the primary vasculitides and their attendant complications is a challenging task for the critical care physician. However, with appropriate therapy, the morbidity and mortality of these diseases can be markedly improved and allow the individual patient to return to their previous functional state.

Polyarteritis nodosa and microscopic polyangiitis: etiologic and diagnostic considerations

Polyarteritis nodosa (PAN) is a systemic necrotizing vasculitis of medium-sized vessels with clinical manifestations resulting from ischemia and infarction of affected tissues and organs. Although the cause of most cases of PAN and the related disorder microscopic polyangiitis (MPA) remains largely unknown, there has been significant progress in understanding the pathogenesis of vascular inflammation. The diagnostic approach to PAN and MPA should be individualized and based on specific organ involvement. Because no test or clinical finding reliably indicates the presence or absence of PAN or MPA, diagnosis requires integration of clinical findings, angiography, and biopsy data.

Renal histopathology and clinical course in 94 patients with Wegener's granulomatosis

BACKGROUND

The main purpose of this study was to examine histopathological changes seen in renal biopsies from patients with Wegener's granulomatosis (WG) with varying degrees of renal involvement and to study possible correlations between the morphological variables and the severity of the disease.

METHODS

Ninety-four patients with WG and active renal disease were included in this retrospective study. All patients had a percutaneous renal biopsy taken on their first admission to the hospital and 14 patients had a second biopsy. The patients were followed for a median of 42.5 months (range 0.5-184).

RESULTS

Segmental necrotizing glomerulonephritis and extracapillary proliferation were present in 85.1 and 91.5% respectively. Of seven patients (7.4%) with normal serum creatinine and urinary protein excretion <0.5 g/day, all had crescents and six had segmental glomerular necrosis. Serum creatinine at biopsy correlated significantly with the percentage of glomeruli with crescents (rho=0.52, P=0.0004), with necrosis (rho=0.36, P=0.002) and with the percentage of normal glomeruli (rho=-0.55, P=0.0003). On a multivariate analysis, only the percentage of normal glomeruli was significantly associated with renal function and development of end-stage renal disease. In 14 second biopsies after a mean of 41.2 (+/-26) months, chronicity scores had increased significantly in 13 biopsies in spite of full immunosuppressive treatment.

CONCLUSION

Although renal biopsy is of value in defining renal involvement in WG, it is of limited help in the early stage of the disease in predicting renal outcome for the individual patient. A follow-up biopsy can be useful in revealing the degree of activity and chronicity and hence be of importance for the choice of further therapy.

Pulmonary capillaritis

Vasculitis, inflammation, and necrosis of blood vessels can involve any size or type of vessel in the pulmonary vasculature, including the capillaries, so-called capillaritis. Although pulmonary capillaritis is a histopathologic diagnosis that is not pathognomonic of a specific disorder, it usually signals the presence of an underlying systemic vasculitis or collagen vascular disease. Patients with pulmonary capillaritis usually present with bilateral infiltrates on chest radiographs and can be acutely ill with diffuse alveolar hemorrhage that may be life threatening. Therapy depends on diagnosis of the underlying disease that gave rise to the capillaritis. Since many of the disorders leading to capillaritis are treated by immunosuppression with corticosteroids and cyclophosphamide or azathioprine, infection must be excluded early in the course of therapy.

Microscopic polyangiitis with alveolar hemorrhage. A study of 29 cases and review of the literature. Groupe d'Etudes et de Recherche sur les Maladies "Orphelines" Pulmonaires (GERM"O"P)

Microscopic polyangiitis (MPA) is a systemic small-vessel vasculitis primarily associated with necrotizing glomerulonephritis and pulmonary capillaritis. In this retrospective study of 29 patients with MPA and alveolar hemorrhage (AH), we characterized the pulmonary manifestations at presentation and assessed the short- and long-term outcome. AH was diagnosed when bronchoalveolar lavage was macroscopically bloody, or contained hemosiderin-laden macrophages, in the absence of lung infection or pulmonary edema. MPA was diagnosed when AH was associated with focal segmental necrotizing glomerulonephritis at kidney biopsy or pathologically proved small-vessel vasculitis. There were 17 women and 12 men, with a mean age of 55.8 +/- 16.7 years. The onset was rapidly progressive, but in 8 (28%) patients, symptoms preceded the diagnosis for more than 1 year. The most constant systemic findings associated with AH were glomerulonephritis in 28 (97%) patients; fever (62%); myalgia and arthralgia (52%); weight loss (45%); ear, nose, and throat symptoms (31%); and skin involvement (17%). Lung opacities were bilateral in 26 (90%) patients, most frequently involving the lower part of the lungs. Bronchoalveolar lavage, performed in 27 patients, was hemorrhagic in 25 (93%), and contained numerous siderophages in others. Most patients were severely anemic (mean hemoglobin, 8.1 +/- 1.8 g/dL). ANCA, present in 27 (93%) patients, gave a perinuclear (14), cytoplasmic (11), or mixed (1) pattern. Mean serum creatinine level was 407 +/- 415 mumol/L. Renal biopsy confirmed the presence of necrotizing glomerulonephritis in 27 patients. Patients were treated with corticosteroids (100%), cyclophosphamide (79%), plasmapheresis (24%), dialysis (28%), and mechanical ventilation (10%). The overall mortality rate was 31% (9 patients). Deaths were related to vasculitis (5 patients) or side effects of treatment (4). Deaths were more frequent in aged or mechanically ventilated patients. The 5-year survival rate was 68%. The recovery of respiratory function among survivors was clinically considered complete in 20 (69%) patients. However, 7 patients (24%) had persistent alterations on pulmonary function tests. Of the 11 patients who had relapses, 2 died from AH.

Interleukin-8: A pathogenetic role in antineutrophil cytoplasmic autoantibody-associated glomerulonephritis

BACKGROUND

In neutrophil trafficking, the role of interleukin-8 (IL-8) is location dependent. Tissue IL-8 directs transmigration, whereas intravascular IL-8 frustrates this process. The bystander damage of glomerular endothelium by antineutrophil cytoplasmic autoantibody (ANCA)-activated neutrophils is believed to be an early event in the pathogenesis of ANCA-associated glomerulonephritis. We have studied the role of IL-8 in this process.

METHODS

Intraglomerular expression of IL-8 in patients with ANCA-associated glomerulonephritis was studied by in situ hybridization and immunohistochemistry and location of neutrophils by serial section immunohistochemistry. In vitro, we analyzed ANCA-stimulated neutrophil IL-8 production by enzyme-linked immunosorbent assay, and the IL-8 attributable effect of ANCA-stimulated neutrophil supernatant by chemotactic and transendothelial assays.

RESULTS

There was intraglomerular expression of IL-8 at segmental, crescentic, and parietal epithelial sites. IL-8 protein expression colocalized to intraglomerular neutrophils; many localized within glomerular capillary loops, suggesting failed trafficking to tissue IL-8. ANCAs differentially stimulated time- and dose-dependent neutrophil IL-8 production, and ANCA-stimulated neutrophil supernatant demonstrated potent IL-8-dependent chemotactic activity and inhibited transendothelial migration of normal human neutrophils toward an IL-8 gradient.

CONCLUSION

Despite heavy tissue expression of IL-8 in ANCA-associated GN, the production of IL-8 by ANCA-stimulated neutrophils within the intravascular compartment may frustrate neutrophil transmigration, encourage intravascular stasis, and contribute to bystander damage of glomerular endothelial cells.

Polyarteritis nodosa, microscopic polyangiitis and Churg-Strauss syndrome

Polyarteritis nodosa (PAN), first described by Küssmaul and Maier, is a well-known form of necrotizing angiitis whose manifestations are weight loss, fever, asthenia, peripheral neuropathy, renal involvement, musculoskeletal and cutaneous manifestations, hypertension, gastrointestinal tract involvement, and cardiac failure. Recently individualized from PAN, microscopic polyangiitis (MPA) is a systemic vasculitis of small-size vessels whose clinical manifestations are very similar to those of PAN, but it is characterized by the presence of rapidly progressive glomerulonephritis (RPGN), which is nearly constant, and pulmonary involvement usually absent in PAN. Churg Strauss syndrome (CSS) is a disorder characterized by hypereosinophilia and systemic vasculitis similar to that of PAN and occurring in individuals with asthma and allergic rhinitis. Considering the etiologies of PAN, primary and secondary vasculitides can also be distinguished because PAN can be the consequence of hepatitis B virus (HBV) infection and sometimes of other etiologic agents. The prognosis of systemic vasculitides has been transformed by corticosteroids that are, except in HBV-related PAN, the basic treatment. Immunosuppressive drugs, especially cyclophophamide, have also contributed to improving the prognosis, but their precise role in the management of these vasculitides is still being elucidated.

Participation of endothelial cells in the development of glomerulosclerosis: a study on murine serum sickness nephritis with mitomycin C

To investigate the participation of endothelial cells in glomerulosclerosis, the study was performed in serum sickness nephritis (SSN) with administration of mitomycin C (MMC). SSN was induced in 8 week male Fisher rats by sensitizing them with albumin, chicken egg (EA). Then MMC (0.5 mg/kg bodyweight) was injected daily for 3 days and they were killed at 1, 2, 4 and 6 week intervals. Significant mesangial expansion and sclerosis were observed in the experimental mixed SSN-MMC group in comparison to the SSN or MMC control group from 1 week to 6 weeks (P < 0.05). Moreover at 1 week, double contour appearance of the glomerular capillary wall, basement membrane splitting and disruption were observed light microscopically in the mixed SSN-MMC group. Electron microscopy revealed peripheral capillary basement membrane disruption with huge subepithelial, mesangial osmiophilic deposits and epithelial foot process effacement. At 6 weeks, disappearance of the endothelial cell fenestration and subepithelial basement membrane-like material formation were observed in the MMC group. Based on these results, it is suggested that MMC induced assault on the glomerular endothelial cell produces prominent glomerular capillary basement membrane disruption at the early phase of SSN, resulting in the accumulation of huge subepithelial and mesangial deposits, mesangial cell proliferation, production of the extracelluar matrix component and initiation of glomerulosclerosis.

Crescentic glomerulonephritis and eosinophilic interstitial infiltrates in a patient with hypereosinophilic syndrome

Crescentic glomerulonephritis with immune complex deposition and acute eosinophilic interstitial nephritis developed in a patient with the hypereosinophilic syndrome. Acute renal failure ensued but was rapidly reversed by high-dose oral prednisone. Confounding factors and unusual findings are described with a review of recent literature. This mode of presentation has not previously been reported.

Systemic polyarteritis nodosa as the initial manifestation of a gastric adenocarcinoma

We report a case of systemic polyarteritis nodosa (PAN) leading to the discovery of an as yet asymptomatic, surgically curable gastric adenocarcinoma. PAN is rarely associated with malignancies and in such cases these are more often malignant haematological diseases than solid neoplasms. The immunopathological findings, the temporal relationship between both conditions, and the spontaneous resolution of vasculitis after tumour removal suggest a paraneoplastic origin of the systemic angitis.

Mechanisms of endothelial cell injury in vasculitis

The aetiology of the primary systemic vasculitides remains obscure. Recent years have seen significant advances in our understanding of inflammation and in particular the role of and interaction between the vascular endothelium, mediators and immune effector cells. This has helped to further elucidate those specific processes relevant to vasculitis which result in endothelial cell damage. In Wegener's granulomatosis and microscopic polyarteritis the evidence favours an autoimmune inflammatory response characterised by specific mediators in which the endothelium is both target and active participant. Current treatment of these disorders with combinations of corticosteroids and cytotoxics is highly effective in inducing remission. However, long-term use of this therapy is potentially toxic and there remains also a significant risk of relapse. It is hoped that increased understanding of the pathogenesis of systemic vasculitis will enable more specific, less toxic and more effective therapies to be defined. Jayne et al. have suggested a beneficial effect of intravenous pooled normal human immunoglobulin (IVIG) in patients with ANCA-positive vasculitis. In vitro studies have shown that IVIG contains antiidiotypic antibodies to ANCA and AECA, capable of inhibiting the binding of these autoantibodies to their autoantigens. In vivo, IVIG may also provide the immunoregulatory elements needed for the idiotype network and control of the autoimmune repertoire. Mathieson et al. successfully used monoclonal antibodies to T cells (Campath-H directed against CDw52) in a patient with ANCA-negative dermal lymphocytic vasculitis. Monoclonal antibodies to CAMs have been used in human renal transplant rejection and reduced the inflammation and proteinuria in animal models of anti-glomerular basement membrane disease. In vasculitis, the therapeutic use of specific anti-CAM antibodies may result from further definition of the role of CAMs. Increased understanding of the pathogenesis of systemic vasculitis is likely to provide the basis for the use of more specific immunotherapies in the future.

The pathology of vasculitis involving the kidney

The kidneys are frequently affected by systemic vasculitides. This is not surprising given the numerous vessels within the renal parenchyma. The kidneys are most often involved by small vessel vasculitides, such as microscopic polyangiitis (microscopic polyarteritis), Wegener's granulomatosis, Henoch-Schönlein purpura, and cryoglobulinemic vasculitis. These vasculitides cause renal dysfunction predominantly by inducing glomerular inflammation with resultant nephritis and renal failure. Microscopic polyangiitis (microscopic polyarteritis) and Wegener's granulomatosis are associated with and may be caused by antineutrophil cytoplasmic autoantibodies. Henoch-Schönlein purpura is caused by immunoglobulin (Ig) A-dominant immune complex localization in small vessels. Cryoglobulinemic vasculitis is sometimes induced by hepatitis C infection. Necrotizing medium-sized vessel vasculitides, such as classic polyarteritis nodosa and Kawasaki's disease, are less frequent causes of renal disease. They cause infarction secondary to thrombosis of inflamed major extrarenal and intrarenal arteries, and may lead to life-threatening hemorrhage from rupture of aneurysms. Large vessel vasculitides, such as giant cell (temporal) arteritis and Takayasu arteritis, only rarely injure the kidneys, usually by ischemia secondary to vasculitic involvement of the renal arteries or abdominal aorta. This ischemia can cause renovascular hypertension.

Renal artery stenosis modifies glomerular injury in antineutrophil cytoplasmic antibody-associated disease

A 68-year-old man presented with renal failure, heart failure, gastrointestinal bleeding, and a pulmonary infiltrate. Serologic evaluation revealed a perinuclear antineutrophil cytoplasmic antibody (ANCA) at a titer of 1:1280, which on immunoblot and enzyme immunoassay showed antimyeloperoxidase specificity. Autopsy showed microscopic polyarteritis based on the presence of necrotizing alveolitis and crescentic glomerulonephritis. The extent and activity of the glomerular disease was modified by a right renal artery stenosis (RAS). Twenty percent of glomeruli on the right and 82% glomeruli on the left contained crescentic lesions. Furthermore, predominantly active lesions were associated with renal artery stenosis, while the contralateral kidney contained mostly organized crescents. This observation suggests that hemodynamic factors or its sequelae can influence the onset and severity of ANCA-associated disease.

New horizons in renal vasculitis

After a long period during which few new data on the vasculitides emerged, the past decade has seen a real explosion of data on the subject. This began with basic clinical descriptions and the delineation of long term outcome as survival improved to a major extent under the influence of improved treatment regimes. In parallel, better understanding of the immunopathology has emerged. Of particular interest have been descriptions of autoantibody systems in vasculitis which seem to be specific to vasculitis and therefore diagnostically useful: the antineutrophil cytoplasmic antibodies (ANCA). Whether or not these are pathogenetically significant as well as useful remains a matter for debate. In parallel, anti endothelial cell antibodies have been described, but their role (if any), in pathogenesis remains equally obscure. There are some suggestions that vasculitis is becoming more common, but increased awareness and the availability of ANCA have undoubtedly increased awareness of the subject.

Nomenclature of vasculitic syndromes: a historical perspective

Since the original description of periarteritis nodosa (PAN) in 1866, the number of recognized forms of so-called idiopathic vasculitis has risen to about a dozen. Their relation to each other and their nature remain unclear, although the recent discovery of antineutrophil cytoplasmic autoantibodies (ANCA) promises a clue to the origin of at least some of them, particularly Wegener's granulomatosis (WG) and perhaps also Churg-Strauss syndrome (CSS). On the other hand, PAN appears to be a nonspecific syndrome of various etiologies.

Pulmonary fibrosis as an unusual clinical manifestation of a pulmonary-renal vasculitis in elderly patients

Between 1978 and 1988, three patients at our institution had an initial diagnosis of idiopathic pulmonary fibrosis but later were correctly diagnosed as having pulmonary-renal syndrome and microscopic polyarteritis. These cases involved elderly patients with progressive dyspnea and nonproductive cough, bilateral dry crackling rales, bilateral interstitial infiltrates evident on a chest roentgenogram, and restrictive findings on pulmonary function testing. In two patients, lung biopsy specimens were obtained, and an initial diagnosis of nonspecific pulmonary fibrosis was made. All three patients eventually had microhematuria and renal insufficiency. A revised diagnosis of small-vessel pulmonary-renal vasculitis was based on the demonstration of segmental necrotizing glomerulonephritis in renal biopsy specimens in two patients, thrombotic microangiopathy consistent with healed vasculitis on postmortem examination of the kidney in one patient, and subsequent detection of small-vessel vasculitis on review of the two lung biopsy specimens. Anti-neutrophil cytoplasmic antibodies with perinuclear staining on indirect immunofluorescence microscopy were positive in the two patients in whom determinations were performed. The clinical manifestations of vasculitis were notably scarce--no involvement of the skin, nervous system, or gastrointestinal tract; no episodes of fever; and minimal or absent musculoskeletal symptoms. These cases illustrate the importance of a high index of suspicion for the diagnosis of systemic vasculitis in elderly patients and the need to consider a vasculitis in the differential diagnosis of idiopathic pulmonary fibrosis, especially if an active urinary sediment is present.

Renal disease and vasculitis

Vasculitis is rare in childhood, apart from Henoch-Schönlein purpura, and paediatric nephrologists see few cases of Wegener's granuloma or microscopic polyarteritis. In contrast, this pattern is reversed in adults. Recently much information about the presentation and longer-term course of both these conditions has been described in adults, and more aggressive treatment of severe cases with renal failure has improved the outlook from a 5-year survival of about 5%-80% or more. In parallel, it has become evident that the abundant immune complexes in the circulation of patients with vasculitis may play little or no role in the pathogenesis of the vasculitic lesions. Current interest centres both on the possible role of cell-mediated immunity and the recent finding of antibodies which react with antigens in the cytoplasm of leucocytes. These antibodies seem to be of clinical use in defining patients with vasculitis, especially when only the kidney is involved at a clinical level. The nature of this leucocyte antigen (or antigens) and the possible role of antibodies directed against them in the pathogenesis of the disease are subjects of current work in many laboratories.