Subacute bacterial endocarditis (SBE) occasionally exhibits positive cytoplasmic anti-neutrophil cytoplasmic antibody (c-ANCA) of the anti-proteinase-3 (PR-3) type. Clinically, it mimics ANCA-associated vasculitis, such as Wegener's disease with glomerulonephritis. Lung abscesses are the most common manifestation of lung involvement. We herein report a case of culture-negative SBE strongly c-ANCA/PR3-positive accompanied by pulmonary involvement and glomerulonephritis. In this case, we took biopsies of both the lung and kidney, although renal biopsy is usually preferred over lung biopsy. The lung biopsy showed severe alveolar capillaritis, suggesting vasculitis consistent with polyangiitis. The renal biopsy revealed glomerulonephritis with a membranoproliferative pattern. To our knowledge, this is the first such reported case.
A 68-year-old Chinese male patient presented to our hospital with a fever, cough, chest pain, and recurrent peripheral edema. He had a past medical history significant for treated schistosomiasis 20 years previously. Physical examination revealed palpable purpura, mild hypertension, hepatosplenomegaly, and a holosystolic cardiac murmur (Levine 2/6). Echocardiography showed tricuspid valve vegetations with moderate to severe regurgitation. Serum c-ANCA/PR3 and cryoglobulin were strongly positive. Renal biopsy results indicated membranoproliferative glomerulonephritis with several crescents. Chest CT revealed multiple intraparenchymal and subpleural nodules, and lung biopsy showed polyangiitis. The patient’s ANCA titers, glomerulonephritis, and pulmonary injury all resolved after antibiotic therapy.
SBE may present with positive c-ANCA/PR3, multiple pulmonary nodules, pulmonary polyangiitis, and glomerulonephritis clinically mimicking granulomatosis with polyangiitis (Wegener's granulomatosis).
Subacute bacterial endocarditis; PR3/c-ANCA; Granulomatosis with polyangiitis (Wegener's granulomatosis); Glomerulonephritis
Anti-neutrophil cytoplasmic antibodies (ANCA) is autoantibodies characteristic of vasculitis diseases. A connection between ANCA and Wegener's granulomatosis was well established. The interaction of both ANCA phenotypes (PR3-ANCA and MPO-ANCA) with leukocytes provoked cell activation, which might be involved in the pathogenesis of ANCA-related Wegener's granulomatosis.
In this study, we examined whether PR3-ANCA sera and purified immunoglobulins from patients with Wegener's granulomatosis prime human monocytic cells for enhanced responses to microbial components in terms of production of proinflammatory cytokines.
Flow cytometry demonstrated that stimulation with antibodies to proteinase 3 enhanced the expression of TLR2, 3, 4, 7, and 9, NOD1, and NOD2 in human mononuclear cells. The sera and purified immunoglobulins significantly primed human mononuclear cells to secrete interleukin-8 in response to microbial components via TLRs and NODs. Priming effects were also observed for the production of interleukin-6, monocyte chemoattractant protein-1, and tumor necrosis factor-α. On the other hand, PR3-ANCA-negative sera from patients with polyarteritis nodosa which possibly related to MPO-ANCA and aortitis syndrome as well as control sera from a healthy volunteer did not have any priming effects on PBMCs.
In conclusion, PR3-ANCA prime human mononuclear cells to produce cytokines upon stimulation with various microbial components by up-regulating the TLR and NOD signaling pathway, and these mechanisms may partially participate in the inflammatory process in Wegener's granulomatosis.
The prevalence of antineutrophil cytoplasmic antibodies (ANCA)
was studied in 12 children with Wegener's granulomatosis. The serum
samples were taken in the active phase of disease and were screened for
ANCA by indirect immunofluorescence with normal neutrophils and enzyme
linked immunosorbent assay (ELISA) using crude neutrophil extract,
proteinase 3, myeloperoxidase, cathepsin G, lactoferrin, and elastase
as antigens. Of these 12 patients, 10 were positive for ANCA in the
active phase of their illness, and they showed a predominantly
cytoplasmic ANCA staining pattern on indirect immunofluorescence. There
were high titres of ANCA directed against crude neutrophil extract,
proteinase 3, myeloperoxidase, and cathepsin G. IgM isotypes occurred
as commonly as IgG isotypes. Therefore, screening for ANCA is usually
but not invariably positive in children with Wegener's granulomatosis.
Specific diagnosis still relies on clinical and pathological features,
and the value of ANCA in the diagnosis of paediatric Wegener's
granulomatosis requires further study.
Anti-neutrophil cytoplasmic autoantibodies (ANCA) specifically associated with Wegener's granulomatosis were found to be directed against a saline-soluble glycoprotein triplet that migrates on SDS gels as distinct bands of Mr 29,000, 30,500, and 32,000 and is present in the azurophilic granules. This antigen was specifically recognized by all cytoplasmic-staining (C)-ANCA-positive sera from patients with Wegener's disease. C-ANCA antigen bound [3H]diisopropylfluorophosphate, which indicates that it is a serine protease, but it could clearly be distinguished from the serine proteases elastase and cathepsin G. Stimulation of cytochalasin B-treated neutrophils with FMLP induced release of C-ANCA antigen. This indicates that in vivo C-ANCA might interact with the C-ANCA antigen after its release upon inflammatory stimulation. We further demonstrate that in some perinuclear staining (P-ANCA) patients' sera autoantibodies against other myeloid lysosomal enzymes can be detected, such as antimyeloperoxidase and antielastase. C-ANCA and P-ANCA thus represent a novel class of autoantibodies directed against myeloid lysosomal enzymes. The originally described Wegener-specific C-ANCA show an apparently uniform specificity for the 29,000 serine protease. In contrast, P-ANCA may recognize myeloperoxidase as well as elastase and/or other antigens.
Wegener's Granulomatosis (WG) is a systemic vasculitis typically associated with antineutrophil cytoplasmic antibodies (ANCAs). A small proportion of patients are ANCA negative, however, and this is more commonly found in individuals with disease limited to the ears, nose, throat, and lungs, who do not have renal involvement. Rituximab is a monoclonal anti-CD20 antibody that has been demonstrated to be effective in the treatment of autoantibody-associated rheumatic diseases, including systemic WG. We report the case of a patient with ANCA-negative WG who responded well to rituximab, illustrating that even in the absence of detectable autoantibodies, B-cell depletion can be effective.
Cytoplasmic antineutrophil cytoplasmic antibodies (cANCA) that accompany the neutrophilic vasculitis seen in Wegener's granulomatosis (WG), are directed against proteinase-3 (PR-3), a serine proteinase which is located in azurophilic granules of neutrophils and monocytes. PR-3, when expressed on the surface of TNFalpha-primed neutrophils, can directly activate neutrophils by complexing cANCA and promoting concomitant Fcgamma receptor (FcgammaR) cross-linking. Although the neutrophil's pathogenic role in WG has been studied, the role of the monocyte has not been explored. The monocyte, with its ability to release cytokines and regulate neutrophil influx, also expresses PR-3. Therefore, the monocyte may play a significant role in WG via the interaction of surface PR-3 with cANCA, inducing cytokine release by the monocyte. To test this hypothesis, monocytes were studied for PR-3 expression and for IL-8 release in response to cANCA IgG. PBMC obtained from healthy donors displayed dramatic surface PR-3 expression as detected by immunohistochemistry and flow cytometry in response to 0. 5-h pulse with TNFalpha (2 ng/ml). Purified monoclonal anti-PR-3 IgG added to TNFalpha-primed PBMC induced 45-fold more IL-8 release than an isotype control antibody. Furthermore, alpha 1-antitrypsin (alpha1-AT), the primary PR-3 antiprotease, inhibited the anti-PR-3 induced IL-8 release by 80%. Importantly, Fab and F(ab')2 fragments of anti-PR-3 IgG, which do not result in Fcgamma receptor cross-linking, do not induce IL-8 release. As a correlate, IgG isolated from cANCA positive patients with WG induced six times as much PBMC IL-8 release as compared to IgG isolated from normal healthy volunteers. Consistent with PR-3 associated IL-8 induction, alpha1-AT significantly inhibited this effect. These observations suggest that cANCA may recruit and target neutrophils through promoting monocyte IL-8 release. This induction is mediated via Fcgamma receptor cross-linking and is regulated in part by alpha1-AT.
Wegener’s granulomatosis (WG) is a multisystemic necrotising granulomatous vasculitis of small and medium sized vessels, that primarily involves the upper and lower respiratory tracts, lung tissues and kidneys. Serum antineutrophil cytoplasmic antibodies (ANCA) are a sensitive and specific marker of WG. Whereas the peripheral nervous system is often involved in WG, central nervous system manifestations are reported only in 2–8%, and are rarely present at onset. We report on a patient with atypical neurological presentation of ANCA negative WG in whom the diagnosis was made only after a meningeal biopsy.
Anti‐neutrophil cytoplasmic antibodies (ANCA) directed against proteinase 3 (PR3) are highly specific for Wegener's granulomatosis (WG). Evidence for a pivotal role of PR3‐ANCA in the induction of vasculitis has been demonstrated. B cell clusters have been observed within endonasal biopsy specimens.
To determine whether B cell selection and maturation take place in granulomatous lesions of WG.
Granulomatous lesions and the immunoglobulin (VH) gene repertoire from nasal tissue of six WG patients—two active and two smouldering localised WG (ANCA negative, restricted to respiratory tract), plus one active and one smouldering PR3‐ANCA positive generalised WG—were characterised by immunohistochemistry, polymerase chain reaction, cloning, DNA sequencing and database comparison.
B lymphocyte‐rich, follicle‐like areas were observed proximal to PR3 positive cells and plasma cells in granulomatous lesions; 184 VH genes from these granulomatous lesions were compared with 84 VH genes from peripheral blood of a healthy donor. The mutational pattern of VH genes from active WG resembled memory B cells. Structural homologies of VH genes from granulomatous lesions to PR3‐ANCA encoding genes were detected. Significantly more genes (55%, 45%, and 53%, respectively) from active WG compared with the healthy repertoire carried mutations to negatively charged amino acids within the binding site coding regions, favouring affinity to the positively charged PR3.
Selection and affinity maturation of potentially PR3‐ANCA producing autoreactive B cells may start in granulomatous lesions, thereby contributing to disease progression from ANCA negative localised to PR3‐ANCA positive generalised WG.
B lymphocyte; Wegener's granulomatosis; PR3; PR3‐ANCA; VH genes
A retrospective analysis was conducted of eight cases of Wegener's granulomatosis (WG), who presented with cutaneous lesions. The clinical, immunopathologic and histopathologic features of the cutaneous lesions were reviewed. Antineutrophil cytoplasmic antibody (ANCA) status of the patients was established. When possible, a comparison of immunofluorescence findings of skin biopsies was made with those of renal biopsies taken at the same time. In all except one, systemic and cutaneous disease developed concurrently. On histopathology, leukocytoclastic vasculitis was noted in five patients and features of lupus erythematosus and pyoderma gangrenosum in one case each. Four patients showed immunoglobulin deposits in subepidermal blood vessel walls, while one patient showed granular immune deposits at dermo-epidermal junction only. Immunoglobulin G was the most common immunoreactant detected. C-ANCA/proteinase 3 (PR3)-ANCA was positive in six patients, P-ANCA/myeloperoxidase (MPO)-ANCA in one patient, while one patient did not show ANCA positivity on indirect immunofluorescence. All four renal biopsies showed pauci-immune glomerulonephritis, irrespective of the presence (n=3) or absence (n=1) of immune deposits in the skin biopsy. Skin manifestations are encountered in nearly half of the patients with WG, thus it is important to be familiar with cutaneous histopathologic as well as immunofluorescence findings in WG patients.
Cutaneous biopsy; direct immunofluorescence; pauci-immune
Wegener’s granulomatosis (WG) is a multisystem vasculitic disorder which can commonly afflict various components of the eye. Here we describe some unusual ocular manifestations of the disease in one patient. A young male with history of upper respiratory tract symptoms including epistaxis, nasal stuffiness and maxillary sinus pain presented with bilateral lacrimal gland abscess and ptosis. Lacrimal gland biopsy revealed granulomatous vasculitis. Lung cavities, positive cytoplasmic-antineutrophil cytoplasmic antibodies and high titers of serine proteinase-3 antibodies confirmed the diagnosis of WG. The patient developed dry eyes after a month of first presentation. There was no dryness of mouth, suggesting the absence of salivary gland involvement, and antinuclear antibodies as well as antibodies against Ro and La antigens classical of primary Sjogren’s syndrome were absent. Granulomatous vasculitis of lacrimal gland leading to abscess formation and dryness of eyes has not been described in WG and reflects the aggressive nature of inflammatory process in this disease.
Antineutrophil cytoplasmic antibody; Horner’s syndrome; lacrimal gland; ptosis; Sjogren’s syndrome
Antineutrophil cytoplasmic autoantibody (ANCA) causes vascular injury that leads to small-vessel vasculitis. Patients with ANCA aberrantly express neutrophil granule–encoding genes, including 2 that encode autoantigens: proteinase 3 (PR3) and myeloperoxidase (MPO). To uncover a potential transcriptional regulatory mechanism for PR3 and MPO disrupted in patients with ANCA vasculitis, we examined the PR3 and MPO loci in neutrophils from ANCA patients and healthy control individuals for epigenetic modifications associated with gene silencing. We found that levels of the chromatin modification H3K27me3, which is associated with gene silencing, were depleted at PR3 and MPO loci in ANCA patients compared with healthy controls. Interestingly, in both patients and controls, DNA was unmethylated at a CpG island in PR3, whereas in healthy controls, DNA was methylated at a CpG island in MPO. Consistent with decreased levels of H3K27me3, JMJD3, the demethylase specific for H3K27me3, was preferentially expressed in ANCA patients versus healthy controls. In addition, we describe a mechanism for recruiting the H3K27 methyltransferase enhancer of zeste homolog 2 (EZH2) to PR3 and MPO loci mediated by RUNX3. RUNX3 message was decreased in patients compared with healthy controls, and may also be under epigenetic control. DNA methylation was increased at the RUNX3 promoter in ANCA patients. These data indicate that epigenetic modifications associated with gene silencing are perturbed at ANCA autoantigen–encoding genes, potentially contributing to inappropriate expression of PR3 and MPO in ANCA patients.
The glycosylation status of autoantigens appears to be crucial for the pathogenesis of some autoimmune diseases, since carbohydrates play a crucial role in the distinction of self from non-self. Proteinase 3 (PR3), the main target antigen for anti-neutrophil cytoplasmic antibodies (ANCA) in patients with Wegener’s granulomatosis (WG), contains two Asn-linked glycosylation sites. The present study explores the influence of the glycosylation status of PR3 on the PR3 recognition by ANCA in a well characterized population of patients with WG.
Forty-four patients with WG (459 serum samples) who participated in a multicenter randomized trial, were tested by capture ELISA for ANCA against PR3 and deglycosylated recombinant variants of PR3.
The patients were followed for a median of 27 months, and the median number of serum samples per patient was 10. At baseline, the correlation between the levels of ANCA against PR3 and against all the deglycosylated recombinant variants of PR3 were greater than 0.94 (ρ<0.001 for all the comparisons). Longitudinal analyses comparing the levels of ANCA against PR3 versus all the deglycosylated recombinant variants of PR3, using linear mixed models, showed no significant statistical differences (ρ≥0.90 in all cases).
The glycosylation status of PR3 has no impact on its recognition by ANCA in WG.
ANCA; biological markers; glycosylation; proteinase 3; Wegener’s granulomatosis
The use of serum antibodies to neutrophil cytoplasmic antigens (ANCA) as a diagnostic marker for Wegener's granulomatosis and other forms of vasculitis has been assessed. Although ANCA have been described by several groups the precise antigenic targets are unknown, and detection of ANCA still relies on an indirect immunofluorescence assay technique. Several different patterns of fluorescence have been produced by using sera from different groups of patients, and insufficient information is available on the frequency of positive results and of the patterns of immunofluorescence obtained when serum from patients with vasculitis as a part of a generalised connective tissue disease is used. A study was carried out on serum from 240 patients, including 23 patients with Wegener's granulomatosis, 12 with microscopic polyarteritis, and 30 with various connective tissue diseases. Three patterns of fluorescence were observed: bright coarsely granular cytoplasmic, bright non-granular cytoplasmic, and weak diffuse cytoplasmic. The bright, coarsely granular pattern was 86% specific for Wegener's granulomatosis in this series and was observed in 18 of 23 cases. Other patterns of fluorescence were found in various conditions and were not of diagnostic value. The technique is simple, inexpensive, rapid, and reproducible.
OBJECTIVE—Wegener's granulomatosis (WG) is an inflammatory disorder characterised by granulomatous inflammation, vasculitis, and necrotising vasculitis and is strongly associated with anti-neutrophil cytoplasmic antibodies (ANCA). Activated monocytes/macrophages are present in renal biopsy specimens and participate in granuloma formation by synthesising and secreting a variety of chemoattractants, growth factors, and cytokines. In view of these findings, in vivo monocyte activation was evaluated in patients with WG and the findings related to parameters of clinical disease activity.
METHODS—Monocyte activation was analysed by measuring plasma concentrations of soluble products of monocyte activation, that is neopterin and interleukin 6 (IL6), by ELISA, and by quantitating the surface expression of activation markers on circulating monocytes by flow cytometry.
RESULTS—Twenty four patients with active WG were included in this study. Ten of these patients were also analysed at the time of remission. Twelve patients with sepsis served as positive controls, and 10 healthy volunteers as negative controls for monocyte activation. Patients with active disease had increased monocyte activation compared with healthy controls as shown by increased concentrations of neopterin (p <0.0001) and increased surface expression of CD11b (p < 0.05) and CD64 (p < 0.05). In those patients with increased concentrations of IL6 during active disease plasma concentrations of IL6 decreased during follow up when patients went into remission (p < 0.0001). In addition, neopterin (r = 0.37, r = 0.44), IL6 (r = 0.37, r = 0.60) and CD63 expression (r = 0.39, r = 0.45) correlated significantly with disease activity as measured by the Birmingham Vasculitis Activity Score and C reactive protein values, respectively. Compared with patients with sepsis, all markers of monocyte activation in patients with vasculitis were lower.
CONCLUSION—It is concluded that disease activity in WG correlates with the extent of activation of monocytes, compatible with their role in the pathophysiology of this disease.
Keywords: anti-neutrophil cytoplasmic antibody; monocyte activation; vasculitis; flow cytometry
Among the anti-neutrophil cytoplasmic antibodies (ANCA), those targeting proteinase 3 (PR3) have a high specificity for Wegener's granulomatosis (WG). It is known that a preceding priming of neutrophils with cytokines is a prerequisite for membrane surface expression of PR3, which is then accessible to autoantibody binding. Employing a monoclonal antibody directed against human PR3 and ANCA- positive serum from WG patients with specificity for PR3, we now investigated the role of free arachidonic acid (AA) in autoantibody- related human neutrophil activation. Priming of neutrophils with tumor necrosis factor (TNF-alpha) for 15 min or exposure to anti-PR3 antibodies or incubation with free AA (10 microM) as sole events did not provoke superoxide generation, elastase secretion or generation of 5-lipoxygenase products of AA. Similarly, the combination of TNF-alpha- priming and AA incubation was ineffective. When TNF-alpha-primed neutrophils were stimulated by anti-PR3 antibodies, superoxide and elastase secretion was provoked in the absence of lipid mediator generation. However, when free AA was additionally provided, a strong activation of the 5-lipoxygenase pathway was demasked, with the appearance of excessive quantities of leukotriene (LT)B4, LTA4, and 5- hydroxyeicosatetraenoic acid. Moreover, superoxide and elastase secretion were markedly amplified, and studies with 5-lipoxygenase inhibitors and a LTB4-antagonist demonstrated this was due to an LTB4- related autocrine loop of cell activation. In contrast, the increased synthesis of platelet-activating factor in response to TNF-alpha- priming and anti-PR3 stimulation did not contribute to the amplification loop of neutrophil activation under the given conditions. We conclude that anti-PR3 antibodies are potent inductors of the 5- lipoxygenase pathway in primed human neutrophils, and extracellular free AA, as provided at an inflammatory focus, synergizes with the autoantibodies to evoke full-blown lipid mediator generation, granule secretion and respiratory burst. Such events may be enrolled in the pathogenesis of focal necrotizing vascular injury in Wegener's granulomatosis.
There are only a few reported cases about spinal cord involvement with Wegener’s granulomatosis (WG) in the literature. In these cases, the spinal cord is usually indented or compressed by dural and meningeal masses which are characterized by necrotizing granuloma formation and vasculitis. And, it usually cannot be correctly diagnosed. A 53-year-old woman suffered from Wegener’s granulomatosis, in whom the upper thoracic spinal cord compression is the initial manifestation. The surgical biopsy and thoracic laminectomy were performed and the histologic examination was done. This patient was finally diagnosed as WG when the pathologic examination revealed as Wegener’s granulomatosis and the serum antineutrophil cytoplasmic antibodies (ANCA) were reported positive; titers of antimyeloperoxidase (MPO) antibodies were markedly elevated. After treatment with cyclophosphamide and corticosteroids this patient partially recovered from neurological involvement. In a case such as this, careful monitoring of clinical parameters is essential for assessing disease activity with repeated MRI if neurologic status changes. Serial measurement of ANCA titers may also be helpful to establish the diagnosis. Cyclophosphamide and corticosteroids are the agents of choice for induction of remission of WG.
Spinal cord; Wegener’s granulomatosis; Vasculitis
Anti–neutrophil cytoplasmic antibodies (ANCAs) targeting proteinase 3 (PR3) have a high specifity for Wegener's granulomatosis (WG), and their role in activating leukocytes is well appreciated. In this study, we investigated the influence of PR3-ANCA and murine monoclonal antibodies on human umbilical vascular endothelial cells (HUVECs). Priming of HUVECs with tumor necrosis factor α induced endothelial upregulation of PR3 message and surface expression of this antigen, as measured by Cyto-ELISA, with a maximum occurrence after 2 h. Primed cells responded to low concentrations of both antibodies (25 ng–2.5 μg/ml), but not to control immunoglobulins, with pronounced, dose-dependent phosphoinositide hydrolysis, as assessed by accumulation of inositol phosphates. The signaling response peaked after 20 min, in parallel with the appearance of marked prostacyclin and platelet-activating factor synthesis. The F(ab)2 fragment of ANCA was equally potent as ANCA itself. Disrupture of the endothelial F-actin content by botulinum C2 toxin to avoid antigen–antibody internalization did not affect the response. In addition to the metabolic events, anti-PR3 challenge, in the absence of plasma components, provoked delayed, dose-dependent increase in transendothelial protein leakage. We conclude that anti-PR3 antibodies are potent inductors of the preformed phosphoinositide hydrolysis–related signal tranduction pathway in human endothelial cells. Associated metabolic events and the loss of endothelial barrier properties suggest that anti-PR3–induced activation of endothelial cells may contribute to the pathogenetic sequelae of autoimmune vasculitis characterizing WG.
Rationale: Standard therapy for Wegener's granulomatosis is fraught with substantial toxicity and not always effective. B lymphocytes have been implicated in the pathogenesis of Wegener's granulomatosis. Their depletion has been proposed as salvage therapy for refractory disease. Earlier encouraging reports are confounded by concomitant immunosuppressive medications and include only limited available biomarker data.
Objectives: To evaluate the efficacy and safety of rituximab for remission induction in refractory Wegener's granulomatosis.
Methods: A prospective open-label pilot trial was conducted with 10 patients monitored for 1 yr. Included were patients with active severe antineutrophil cytoplasmic antibody (ANCA)–associated vasculitis, ANCA positivity, and resistance to (or intolerance of) cyclophosphamide. The remission induction regimen consisted of oral prednisone (1 mg/kg/d) and four weekly infusions of rituximab (375 mg/m2). Prednisone was tapered and discontinued over 5 mo. Failure to achieve remission, a clinical flare in the absence of B lymphocytes, and inability to complete the glucocorticoid taper were considered treatment failures.
Main Results: Three women and seven men (median age, 57 yr; range, 25–72 yr) were enrolled. All had ANCA reacting with proteinase-3. The median activity score at enrollment was 6 (range, 5–10). All patients tolerated rituximab well, achieved swift B-lymphocyte depletion and complete clinical remission (activity score, 0) by 3 mo, and were tapered off glucocorticoids by 6 mo. Five patients were retreated with rituximab alone for recurring/rising ANCA titers according to protocol. One patient experienced a clinical flare after B lymphocyte reconstitution.
Conclusion: In this cohort, rituximab was a well-tolerated and effective remission induction agent for severe refractory Wegener's granulomatosis.
Antineutrophil cytoplasmic antibodies (ANCAs) constitute a new class of autoantibodies that seem to recognise myeloid lysosomal enzymes. The occurrence of ANCAs with specificity for human leucocyte elastase (HLE) was assessed in serum samples that were routinely submitted for ANCA determination. During a study period of more than six years anti-HLE was found in only six out of 1102 serum samples that produced a perinuclear or an atypical cytoplasmic staining pattern on ethanol fixed granulocytes. These six serum samples were from four patients with a clinical diagnosis of Wegener's granulomatosis but without a definite histological diagnosis, one patient with systemic vasculitis, and one patient with Cogan's syndrome. To further evaluate the prevalence of anti-HLE we tested 315 serum samples from patients with different forms of vasculitis and related disorders. Anti-HLE was detected in two patients only. Thus autoantibodies to HLE are rarely found in serum samples from patients with vasculitic or related disorders.
Antineutrophil cytoplasmic autoantibodies (ANCAs) directed to proteinase 3 (PR3-ANCA) or myeloperoxidase (MPO-ANCA) are strongly associated with the ANCA-associated vasculitides—Wegener’s granulomatosis, microscopic polyangiitis, and Churg-Strauss syndrome. Clinical observations, including the efficacy of B-cell depletion via rituximab treatment, support—but do not prove—a pathogenic role for ANCA in the ANCA-associated vasculitides. In vitro experimental studies show that the interplay of ANCA, neutrophils, the alternative pathway of the complement system, and endothelial cells could result in lysis of the endothelium. A pathogenic role for MPO-ANCA is strongly supported by in vivo experimental studies in mice and rats, which also elucidate the pathogenic mechanisms involved in lesion development. Unfortunately, an animal model for PR3-ANCA–associated Wegener’s granulomatosis is not yet available. Here, cellular immunity appears to play a major role as well, particularly via interleukin-17–producing T cells, in line with granulomatous inflammation in the lesions. Finally, microbial factors, in particular Staphylococcus aureus and gram-negative bacteria, seem to be involved in disease induction and expression, but further studies are needed to define their precise role in disease development.
Wegener’s granulomatosis; MPO-ANCA; Microscopic polyangiitis; hLAMP-2 autoantibodies; Churg-Strauss syndrome; Staphylococcus aureus; Necrotizing crescentic glomerulonephritis; FimH; ANCA-associated vasculitis; Animal models; Antineutrophil cytoplasmic autoantibodies; Th17 cells; ANCA; T-regulatory cells; Proteinase 3; PR3-ANCA; Myeloperoxidase
Antineutrophil cytoplasmic antibodies (ANCA) are autoantibodies, the detection of which in serum can be used in the diagnosis of Wegener's granulomatosis (WG). Proteinase 3 (PR3) is a major target antigen of ANCA in WG patients, and the interaction of PR3 ANCA with leukocytes causes a debilitating autoimmune disease. The first signs and symptoms in WG patients are observed in the oral cavity, lungs, and kidneys. Human epithelial cells generally do not secrete proinflammatory cytokines upon stimulation with pathogen-associated molecular patterns (PAMPs). In this study, anti-PR3 antibodies (Abs) and PR3 ANCA-containing sera from WG patients endowed human oral, lung, and kidney epithelial cells with responsiveness to PAMPs in terms of the production of proinflammatory cytokines, such as interleukin-6 (IL-6), IL-8, monocyte chemoattractant protein-1, and tumor necrosis factor alpha. Protease-activated receptor-2 (PAR-2) agonist peptides mimicked the priming effects of PR3 ANCA against PAMPs. Furthermore, the anti-PR3 Ab-mediated cell activation was significantly abolished by RNA interference targeting PAR-2 and NF-κB. This is the first report of priming effects of anti-PR3 Abs (PR3 ANCA) on epithelial cells. The results suggest that anti-PR3 Abs (PR3 ANCA) prime human epithelial cells to produce cytokines upon stimulation with various PAMPs, and these mechanisms may be involved in severe chronic inflammation in WG.
Wegener’s granulomatosis (WG) is a necrotizing granulomatous vasculitis characterized by the involvement of the upper or lower airways, lungs, and kidneys, but it can affect almost any organ including the orbit. WG is rare in childhood. This case report describes a 7-year-old girl who presented bilateral idiophatic orbital inflammation and antineutrophil cytoplasmic antibodies-negative titres. Computed tomography scan and magnetic resonance imaging showed enlargement of both lacrimal glands with infiltration. Treatment with corticosteroids achieved remission of the disease. Three years later, she developed a systemic affectation with tracheal stenosis, pulmonary affectation, renal failure, and respiratory tract mucosa inflammation. Lacrimal gland biopsy showed perivascular nonspecific granulomas and ANCA titres remain negative. Treatment with corticosteroids and cyclophosphamide was done. A relapse occurred 2 years later, with complete remission with antitumor necrosis factor-alpha. No other symptoms have appeared after 9 years of follow-up. Early diagnosis and treatment is crucial to increase the survival rate in these patients.
ANCA; children; idiopathic orbital inflammation; exophthalmos; vasculitis; Wegener’s granulomatosis
BACKGROUND—Wegener's granulomatosis (WG) is considered a pauci-immune systemic vasculitis based on the absence of immune deposits in renal biopsies of patients with active disease. In animal models of antineutrophil cytoplasmic antibody (ANCA) associated glomerulonephritis, immune deposits along the glomerular capillary wall are present at early stages of lesion development. These deposits are degraded rapidly, resulting in "pauci-immune" lesions.
OBJECTIVE—To test the hypothesis that immune deposits can also be detected in early lesions of patients with WG, thereby initiating an inflammatory reaction that, in time, is augmented in the presence of ANCA, resulting in pauci-immune lesions later on.
METHODS—The presence of immune deposits in skin biopsies taken within 48 hours of lesion development was investigated. Direct immunofluorescence was used to examine 32 skin biopsies for the presence of immune deposits (IgG, IgA, IgM, C3c). When possible, a comparison was made between the immunofluorescence findings in renal and skin biopsies taken at the same time.
RESULTS—Four of 11 biopsies taken at initial presentation and four of 21 biopsies taken at the onset of a relapse of WG showed IgG and/or IgA containing immune deposits in the subepidermal blood vessels. All nine renal biopsies showed pauci-immune glomerulonephritis, irrespective of the presence (n=5) or absence (n=4) of immune deposits in the skin biopsy.
CONCLUSION—A substantial number of skin biopsies showed immune deposits during active disease. These results could support the hypothesis that immune complexes may trigger vasculitic lesions in WG.
Antibodies to neutrophil cytoplasmic antigens (ANCA) are good serological markers for patients with mainly vasculitic conditions. Two main types of ANCAs have been detected, the first termed cytoplasmic antineutrophil cytoplasmic antibody (cANCA) are mainly associated with patients with Wegener's granulomatosis, the other termed perinuclear antineutrophil cytoplasmic antibody (pANCA) are mainly associated with patients with renal vasculitis, rheumatic and collagen disorders. These antibodies are against various constituents of neutrophil granules. In patients with myelodysplasia, defects in normal granulocyte development are seen. We report a series of twelve patients with myelodysplasia of whom at least four showed a low titre and one a high titre of pANCA. Two of these patients also had demonstrable activity against myeloperoxidase (MPO). None of these patients had any evidence of systemic or cutaneous vasculitis or of any autoimmune disorder. There was no pANCA positivity in an age matched control group.
Dysregulated release of neutrophil azurophilic granules causes increased tissue damage and amplified inflammation during autoimmune disease. Antineutrophil cytoplasmic antibodies (ANCAs) are implicated in the pathogenesis of small vessel vasculitis and promote adhesion and exocytosis in neutrophils. ANCAs activate specific signal transduction pathways in neutrophils that have the potential to be modulated therapeutically to prevent neutrophil activation by ANCAs. We have investigated a role for diacylglycerol kinase (DGK) and its downstream product phosphatidic acid (PA) in ANCA-induced neutrophil exocytosis. Neutrophils incubated with the DGK inhibitor R59022, before treatment with ANCAs, exhibited a reduced capacity to release their azurophilic granules, demonstrated by a component release assay and flow cytometry. PA restored azurophilic granule release in DGK-inhibited neutrophils. Confocal microscopy revealed that R59022 did not inhibit translocation of granules, indicating a role for DGK during the process of granule fusion at the plasma membrane. In investigating possible mechanisms by which PA promotes neutrophil exocytosis, we demonstrated that exocytosis can only be restored in R59022-treated cells through simultaneous modulation of membrane fusion and increasing cytosolic calcium. PA and its associated pathways may represent viable drug targets to reduce tissue injury associated with ANCA-associated vasculitic diseases and other neutrophilic inflammatory disorders.