Antineutrophil cytoplasmic antibodies: a still-growing class of autoantibodies in inflammatory disorders

Granulomatosis With Polyangiitis: The Complexity of Clinical Manifestations, Therapeutic Challenges, and Complications of a Severe Multisystemic Case

We report a case of a 34-year-old male with severe multisystemic involvement (including the testis, musculoskeletal system, skin, upper respiratory tract, ocular system, peripheral nerves, abdomen, and kidney) due to granulomatosis with polyangiitis (GPA) and a high proteinase 3 (PR3)-antineutrophil cytoplasmic antibodies (PR3ANCA) titer. A renal biopsy showed pauci-immune glomerulonephritis (GN). Systemic corticotherapy combined with cyclophosphamide was chosen for induction therapy. During the induction phase, clinical deterioration occurred in the form of severe alveolar hemorrhage, leading to admission to the intensive care unit (ICU). Influenza A (H1N1) was detected in the respiratory tract. Furthermore, blood sampling revealed an invasive Klebsiella pneumoniae infection that persisted despite multiple antibiotic regimens. A CT scan showed splenic vascular compromise, assumed to be the primary source of the infection, with sustained improvement after splenectomy. Maintenance therapy included a tapering dose of corticotherapy for 36 months and azathioprine 100mg daily for five years, which achieved full and sustained remission. The patient has been in full remission for nine years, with mild renal sequelae, including proteinuria and secondary hypertension.

The many roles of myeloperoxidase: From inflammation and immunity to biomarkers, drug metabolism and drug discovery

This review provides a practical guide to myeloperoxidase (MPO) and presents to the reader the diversity of its presence in biology. The review provides a historical background, from peroxidase activity to the discovery of MPO, to its role in disease and drug development. MPO is discussed in terms of its necessity, as specific individuals lack MPO expression. An underlying theme presented throughout brings up the question of the benefit and burden of MPO activity. Enzyme structure is discussed, including accurate masses and glycosylation sites. The catalytic cycle of MPO and its corresponding pathways are presented, with a discussion of the importance of the redox couples of the different states of MPO. Cell lines expressing MPO are discussed and practically summarized for the reader, and locations of MPO (primary and secondary) are provided. Useful methods of MPO detection are discussed, and how these can be used for studying disease processes are implied through the presentation of MPO as a biomarker. The presence of MPO in neutrophil extracellular traps is presented, and the activators of the former are provided. Lastly, the transition from drug metabolism to a target for drug development is where the review concludes.

Serum PR3-ANCA Is a Predictor of Primary Nonresponse to Anti-TNF-α Agents in Patients with Ulcerative Colitis

Background

Anti-tumor necrosis factor-α (TNF-α) agents are effective for moderately to severely active ulcerative colitis (UC). Nonetheless, a proportion of patients fail to respond to these agents as therapy for induction of remission. Recent studies indicated that perinuclear anti-neutrophil cytoplasmic antibody (p-ANCA) may predict response to anti-TNF-α agents in UC patients. However, whether PR3-ANCA can predict primary nonresponse (PNR) to anti-TNF-α agents has not yet been evaluated. The aim of this study was to examine whether PR3-ANCA can predict PNR to anti-TNF-α in UC patients.

Methods

This was a single-center retrospective study. Data were extracted from 50 patients with UC who had measurements of PR3-ANCA and received anti-TNF-α agents for the first time as induction therapy. The primary endpoint of this study was a proportion of patients with PNR stratified by PR3-ANCA positivity. PNR to anti-TNF-α agents was defined as failure to achieve reduction in partial Mayo score by 2 or more points and change to other therapeutics within 6 weeks.

Results

Fourteen (28%) of the 50 patients were PR3-ANCA positive. Seventeen (34%) of the 50 patients demonstrated PNR. Eleven (78.6%) of the 14 PR3-ANCA-positive patients demonstrated PNR, while 6 (16.7%) of the 36 PR3-ANCA-negative patients demonstrated PNR. Multivariate analysis demonstrated that PR3-ANCA positivity was associated with PNR to anti-TNF-α agents (odds ratio 19.29, 95% CI: 3.30-172.67; p = 0.002).

Conclusion

PR3-ANCA positivity can predict PNR to anti-TNF-α agents in UC patients.

Pulmonary granulomatosis of genetic origin

Granulomatous inflammation of the lung can be a manifestation of different conditions and can be caused by endogenous inflammation or external triggers. A multitude of different genetic mutations can either predispose patients to infections with granuloma-forming pathogens or cause autoinflammatory disorders, both leading to the phenotype of pulmonary granulomatosis. Based on a detailed patient history, physical examination and a diagnostic approach including laboratory workup, pulmonary function tests (PFTs), computed tomography (CT) scans, bronchoscopy with bronchoalveolar lavage (BAL), lung biopsies and specialised microbiological and immunological diagnostics, a correct diagnosis of an underlying cause of pulmonary granulomatosis of genetic origin can be made and appropriate therapy can be initiated. Depending on the underlying disorder, treatment approaches can include antimicrobial therapy, immunosuppression and even haematopoietic stem cell transplantation (HSCT). Patients with immunodeficiencies and autoinflammatory conditions are at the highest risk of developing pulmonary granulomatosis of genetic origin. Here we provide a review on these disorders and discuss pathogenesis, clinical presentation, diagnostic approach and treatment.

Pulmonary granulomatosis of genetic origin mostly occurs in immunodeficiency disorders and autoinflammatory conditions. In addition to specific approaches in this regard, the diagnostic workup needs to cover environmental and occupational aspects.https://bit.ly/31SqdHW

2020 international consensus on ANCA testing beyond systemic vasculitis

This document follows up on a 2017 revised international consensus on anti-neutrophil cytoplasm antibodies (ANCA) testing in granulomatosis with polyangiitis and microscopic polyangiitis and focuses on the clinical and diagnostic value of ANCA detection in patients with connective tissue diseases, idiopathic interstitial pneumonia, autoimmune liver diseases, inflammatory bowel diseases, anti-glomerular basement membrane (GBM) disease, infections, malignancy, and during drug treatment. Current evidence suggests that in certain settings beyond systemic vasculitis, ANCA may have clinical, pathogenic and/or diagnostic relevance. Antigen-specific ANCA targeting proteinase-3 and myeloperoxidase should be tested by solid phase immunoassays in any patient with clinical features suggesting ANCA-associated vasculitis and in all patients with anti-GBM disease, idiopathic interstitial pneumonia, and infective endocarditis associated with nephritis, whereas in patients with other aforementioned disorders routine ANCA testing is not recommended. Among patients with autoimmune liver diseases or inflammatory bowel diseases, ANCA testing may be justified in patients with suspected autoimmune hepatitis type 1 who do not have conventional autoantibodies or in case of diagnostic uncertainty to discriminate ulcerative colitis from Crohn's disease. In these cases, ANCA should be tested by indirect immunofluorescence as the target antigens are not yet well characterized. Many questions concerning the optimal use of ANCA testing in patients without ANCA-associated vasculitis remain to be answered.

A case of extra pulmonary tuberculosis misdiagnosed as granulomatosis with polyangitis: Presenting with occipital condylar syndrome

Sri Lanka is a tuberculosis (TB) prevalent country with an incidence of 8886 cases in 2016 of which 30% were extra pulmonary tuberculosis (EPTB). These figures may be an underestimation, considering the diagnostic challenge of EPTB due to its diverse presentations and difficulty in microbiological confirmation. Here we describe a case of EPTB which was first diagnosed as granulomatosis with polyangitis when he presented with fever, anorexia, wasting, large joint pains, cervical pain, erythema nodosum, high inflammatory markers with strongly positive Mantoux reaction and, necrotizing granulomatous lymphadenitis in the cervical region. Immunosuppression with methotrexate 15 mg weekly and prednisolone 30 mg daily, achieved resolution of symptoms and the inflammatory markers. After about 4 months on tailing off prednisolone, he developed fever, anorexia, wasting and worsening occipital pain which evolved in to occipital condylar syndrome causing hypoglossal nerve palsy. With the aid of serial radiological, histopathological and bacteriological investigations, he was eventually diagnosed to have EPTB involving the left base of the skull with upper mediastinal lymphadenitis. This case highlights the importance to have a high index of suspicion to diagnose EPTB, especially in a country with a high prevalence of TB and to revise the diagnosis with a close follow up to avoid disastrous consequences associated with misdiagnosis.

Pulmonary disorders that are potentially associated with anti- neutrophilic cytoplasmic antibodies: A brief review

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis frequently manifests with involvement of the lungs and kidneys, and it also may affect other anatomic sites. This article presents the patterns of pulmonary injury in which ANCA-associated vasculitis is included in the differential diagnosis, with a discussion of antineutrophil cytoplasmic antibody testing methods. The histologic features of non-vasculitic, potentially-ANCA-associated pulmonary lesions are reviewed briefly as well.

Immunomodulatory potential of recombinant filarial protein, rWbL2, and its therapeutic implication in experimental ulcerative colitis in mouse

OBJECTIVE

Immunomodulation by helminth proteins has potential therapeutic implications in inflammatory bowel disease. In the present study, we have explored the therapeutic effect of a RAL family protein of filarial parasite Wuchereria bancrofti i.e., rWbL2 protein against DSS induced colitis in a mouse model.

MATERIALS AND METHODS

Anti-inflammatory activity of rWbL2 on mice peritoneal exudate cells was analyzed under in vitro condition. The colitis mice were treated intraperitoneally (i.p.) with rWbL2 in increasing doses (10 µg, 25 µg, and 50 µg) on days 4, 5, and 6. Disease severity was assessed by disease activity index (DAI), macroscopic and histopathological scores, and enzyme myeloperoxidase activity (MPO) in the colon. The response of the cultured splenocytes from treated mice to Con-A stimulation, in terms of ELISA-based assessment of the protein followed by the assessment of mRNA expression of cytokines, was measured by real-time PCR analysis.

RESULT

rWbL2 protein showed anti-inflammatory activity in vitro. Treatment with rWbL2 (at 25 µg/dose) effectively attenuated disease severity by reducing weight loss, DAI, mucosal edema, colon damage, and MPO activity. This therapeutic effect was found to be associated with increased release of anti-inflammatory cytokine IL-10 and decreased release of pro-inflammatory cytokine IFN-γ and TNF-α by the splenocytes of treated mice followed by stimulation with Con-A.

CONCLUSIONS

These results provide evidence of the strong immunomodulatory potential of rWbL2 protein implicating its therapeutic application against ulcerative colitis.

Differential diagnosis of granulomatous lung disease: clues and pitfalls

Granulomatous lung diseases are a heterogeneous group of disorders that have a wide spectrum of pathologies with variable clinical manifestations and outcomes. Precise clinical evaluation, laboratory testing, pulmonary function testing, radiological imaging including high-resolution computed tomography and often histopathological assessment contribute to make a confident diagnosis of granulomatous lung diseases. Differential diagnosis is challenging, and includes both infectious (mycobacteria and fungi) and noninfectious lung diseases (sarcoidosis, necrotising sarcoid granulomatosis, hypersensitivity pneumonitis, hot tub lung, berylliosis, granulomatosis with polyangiitis, eosinophilic granulomatosis with polyangiitis, rheumatoid nodules, talc granulomatosis, Langerhans cell histiocytosis and bronchocentric granulomatosis). Bronchoalveolar lavage, endobronchial ultrasound-guided transbronchial needle aspiration, transbronchial cryobiopsy, positron emission tomography and genetic evaluation are potential candidates to improve the diagnostic accuracy for granulomatous lung diseases. As granuloma alone is a nonspecific histopathological finding, the multidisciplinary approach is important for a confident diagnosis.

A multidisciplinary approach is crucial for the accurate differential diagnosis of granulomatous lung diseaseshttp://ow.ly/FxsP30cebtf

Autoimmune hepatitis and eosinophilic granulomatosis with polyangiitis: a rare association

We describe a case of 40-year-old woman who presented to our hospital with symptoms of non-radiating epigastric pain for 4-5 days associated with nausea and vomiting. Her history was significant for asthma with recurrent exacerbations, polyneuropathy and recurrent sinus infections. Liver function tests revealed cholestasis. Antinuclear antibody and antismooth muscle cell antibody were positive. Liver biopsy revealed active chronic hepatitis with cholestasis. A diagnosis of autoimmune hepatitis was made. All other causes of cholestatic jaundice were ruled out. Her history of recurrent asthma exacerbations, eosinophilia, recurrent sinus infections and positive myeloperoxidase antibodies was suggestive of eosinophilic granulomatosis with polyangiitis. She was found to have combination of autoimmune hepatitis and eosinophilic granulomatosis with polyangiitis, a rarely reported association in the medical literature. She was started on prednisone for her autoimmune hepatitis. On follow-up with her gastroenterologist, her transaminases were trending down and she was symptomatically better.

Alveolar Hemorrhage

Alveolar hemorrhage (AH) is a clinical syndrome with diverse etiologies both immune and nonimmune. The defining pathological feature of AH is the presence or absence of pulmonary capillaritis. The antineutrophil cytoplasmic antibody (ANCA) related vasculitis and systemic lupus erythematosus are the commonest causes of immune AH with pulmonary capillaritis, whereas Goodpasture's syndrome and idiopathic pulmonary hemosiderosis are common causes of immune AH without pulmonary capillaritis. The major nonimmune causes of AH are primarily drug induced, or due to hematological malignancy and disorders of coagulation. Clinical features of AH include: dyspnea, fever, hemotypsis, bilateral crackles and pallor. Hypoxemia and bilateral diffuse airspace disease on the chest radiograph with relative sparing of the bases and apices which most often clears within 48 hours after its onset further characterize this syndrome. The major clinical implications of this syndrome are its potential to cause respiratory failure in severe cases and its sequelae of pulmonary fibrosis with associated morbidity and disability. In addition, AH may be the initial manifestation of a systemic immune disorder which can be managed optimally if recognized early. The diagnosis of AH is confirmed by bronchoalveolar lavage by demonstrating a progressively bloody return on successive aliquots of instilled saline or hemosiderin laden macrophages in the bronchoalveolar lavage fluid. The open lung biopsy remains the gold standard for the diagnosis of AH but is reserved for inapparent cases in whom corticosteroids and immunosuppressive therapy may be life saving. Serologic testing and examination of the urine sediment are useful adjuncts to the diagnosis. The treatment of AH is primarily supportive while an attempt is made to determine its etiology and initiate specific therapy. Glucocorticoids and cyclophosphamide are the cornerstones of therapy in immune AH with adjunctive plasmapheresis in life-threatening cases.

Simultaneous comprehensive multiplex autoantibody analysis for rapidly progressive glomerulonephritis

Rapidly progressive glomerulonephritis (RPGN) is mainly caused by anti-glomerular basement membrane (GBM) antibody-mediated glomerulonephritis, immune-complex or anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides and leads to rapid loss of renal function. Detection of ANCA and autoantibodies (autoAbs) to GBM and dsDNA enables early diagnosis and appropriate treatment of RPGN aiding in preventing end-stage renal disease.Determination of ANCA on neutrophils (ANCA) as well as autoAbs to myeloperoxidase (MPO-ANCA), proteinase 3 (PR3-ANCA), GBM, and dsDNA was performed by the novel multiplex CytoBead technology combining cell- and microbead-based autoAb analyses by automated indirect immunofluorescence (IIF). Forty patients with granulomatosis with polyangiitis (GPA), 48 with microscopic polyangiitis (MPA), 2 with eosinophilic GPA, 42 with systemic lupus erythematosus (SLE), 43 with Goodpasture syndrome (GPS), 57 with infectious diseases (INF), and 55 healthy subjects (HS) were analyzed and findings compared with classical single testing.The CytoBead assay revealed for GPA, MPA, GPS, and SLE the following diagnostic sensitivities and for HS and INF the corresponding specificities: PR3-ANCA, 85.0% and 100.0%; MPO-ANCA, 77.1% and 99.1%; anti-GBM autoAb, 88.4% and 96.4%; anti-dsDNA autoAb, 83.3% and 97.3%; ANCA, 91.1% and 99.1%, respectively. Agreement with classical enzyme-linked immunosorbent assay and IIF was very good for anti-GBM autoAb, MPO-ANCA, PR3-ANCA, and ANCA, respectively. Anti-dsDNA autoAb comparative analysis demonstrated fair agreement only and a significant difference (P = 0.0001).The CytoBead technology provides a unique multiplex reaction environment for simultaneous RPGN-specific autoAb testing. CytoBead RPGN assay is a promising alternative to time-consuming single parameter analysis and, thus, is well suited for emergency situations.

Granulomatosis with Polyangiitis (Wegener's Granulomatosis) Accompanied by Dysuria

A 65-year-old male visited us with complaints of retarded urination, dysuria, gross hematuria, and fever. Urinalysis showed pyuria. Prostatic tumor with lung metastasis was suspected from computed tomography and magnetic resonance imaging. Transurethral prostatic biopsy and bronchoscopic biopsy only revealed fibrinoid necrosis and inflammatory infiltration. Right lateral maxillary sinusitis was also found by MRI. ANCA testing was positive with specificity for anti-PR3 (PR3-ANCA). On the basis of these results, Granulomatosis with polyangiitis (GPA) was diagnosed. GPA involving the prostate gland is unusual, and only a few cases have previously been reported.

Autoantigens as Partners in Initiation and Propagation of Autoimmune Rheumatic Diseases

Systemic autoimmune diseases are characterized by specific targeting of a limited group of ubiquitously expressed autoantigens by the immune system. This review examines the mechanisms underlying their selection as immune targets. Initiation of autoimmune responses likely reflects the presentation of antigens with a distinct structure not previously encountered by the immune system, in a proimmune context (injury, malignancy, or infection). Causes of modified structure include somatic mutation and posttranslational modifications (including citrullination and proteolysis). Many autoantigens are components of multimolecular complexes, and some of the other components may provide adjuvant activity. Propagation of autoimmune responses appears to reflect a bidirectional interaction between the immune response and the target tissues in a mutually reinforcing cycle: Immune effector pathways generate additional autoantigen, which feeds further immune response. We propose that this resonance may be a critical principle underlying disease propagation, with specific autoantigens functioning as the hubs around which amplification occurs.

A diagnostic pitfall in IgG4-related hypophysitis: infiltration of IgG4-positive cells in the pituitary of granulomatosis with polyangiitis

INTRODUCTION

Immunoglobulin (Ig) G4-related hypophysitis is an emerging clinical entity, which is characterized by an elevated serum IgG4 concentration and infiltration of IgG4-positive plasma cells in the pituitary. Although some criteria for its diagnosis have been proposed, they have not been fully established. In particular, differential diagnosis from secondary chronic inflammation including granulomatosis with polyangiitis (GPA) is difficult in some cases. We describe central diabetes insipidus with pituitary swelling exhibiting infiltration of IgG4-positive cells.

PATIENT

A 43-year-old woman in the remission stage of GPA presented with sudden-onset polyuria and polydipsia. Pituitary magnetic resonance imaging revealed swelling of the anterior and posterior pituitary and stalk, with heterogeneous gadolinium enhancement and disappearance of the high signal intensity of the posterior pituitary. Evaluation of biochemical markers for GPA suggested that the disease activity was well-controlled. Endocrinological examination revealed the presence of central diabetes insipidus and growth hormone deficiency. Pituitary biopsy specimen showed IgG4-positive cells, with a 43% IgG4(+)/IgG(+) ratio, which met the criteria for IgG4-related hypophysitis. However, substantial infiltration of polymorphonuclear neutrophils with giant cells was also noted, resulting in a final diagnosis of pituitary involvement of GPA.

CONCLUSION

These results suggest that pituitary involvement of GPA should be taken into account for the differential diagnosis of IgG4-related hypophysitis.

Systemic necrotizing vasculitis

Systemic necrotizing vasculitis may be idiopathic or associated with a variety of diseases of known etiology. A typical example is polyarteritis nodosa, which is characterized by fibrinoid necrosis and severe inflammation leading to destruction of the wall, narrowing of the lumen, and interference with blood circulation. In addition to the idiopathic form, histologically similar lesions are seen in hepatitis B, rheumatoid arthritis, Kawasaki mucocutaneous lymph node syndrome, and other diseases. Microscopic polyangitis involves mainly small vessels-venules more often than arterioles-but occasionally also small arteries. Its characteristic feature is leukocytoclasia of neutrophilic leukocytes, but fibrinoid necrosis also occurs. Churg-Strauss syndrome consists of granulomas in patients with a background of severe allergy, such as asthma, allergic rhinitis, or occasionally drug sensitization.

Proteinase 3-ANCA Vasculitis versus Myeloperoxidase-ANCA Vasculitis

In patients with GN or vasculitis, ANCAs are directed against proteinase 3 (PR3) or myeloperoxidase (MPO). The differences between PR3-ANCA-associated vasculitis (AAV) and MPO-AAV described in the past have been supplemented during the last decade. In this review, we discuss the differences between these two small-vessel vasculitides, focusing especially on possible etiologic and pathophysiologic differences. PR3-AAV is more common in northern parts of the world, whereas MPO-AAV is more common in southern regions of Europe, Asia, and the Pacific, with the exception of New Zealand and Australia. A genetic contribution has been extensively studied, and there is a high prevalence of the HLA-DPB1*04:01 allele in patients with PR3-AAV as opposed to patients with MPO-AAV and/or healthy controls. Histologically, MPO-AAV and PR3-AAV are similar but show qualitative differences when analyzed carefully. Clinically, both serotypes are difficult to distinguish, but quantitative differences are present. More organs are affected in PR3-AAV, whereas renal limited vasculitis occurs more often in patients with MPO-AAV. For future clinical trials, we advocate classifying patients by ANCA serotype as opposed to the traditional disease type classification.

High prevalence of IgA class anti-neutrophil cytoplasmic antibodies (ANCA) is associated with increased risk of bacterial infection in patients with cirrhosis

BACKGROUND & AIMS

Anti-neutrophil cytoplasmic antibodies (ANCA) are a non-uniform family of antibodies recognizing diverse components of neutrophil granulocytes. ANCA formation might be induced by protracted bacterial infections or probably reflect an abnormal immune response to commensal microorganisms. Bacterial infections are common complications in cirrhosis with high incidence of episodes caused by enteric organisms, therefore, we sought to study the presence and clinical importance of ANCA in cirrhosis.

METHODS

Sera of 385 patients with cirrhosis of different etiologies were assayed for ANCA of IgG, IgA, IgA1, IgA2, and secretory IgA subtypes by indirect immunofluorescence and ELISAs. The control group comprised 202 patients with chronic liver diseases without cirrhosis and 100 healthy subjects. In cirrhosis, a 2-year follow-up, observational study was conducted to assess a possible association between the presence of ANCA and clinically significant bacterial infections.

RESULTS

Prevalence of ANCA IgA was significantly higher in cirrhosis (52.2%) compared to chronic liver diseases (18.6%) or healthy controls (0%, p<0.001 for both). ANCA IgA subtyping assays revealed marked increase in the proportion of IgA2 subtype (46% of total ANCA IgA) and presence of the secretory component concurrently. Presence of ANCA IgA was associated with disease-specific clinical characteristics (Child-Pugh stage and presence of ascites, p<0.001). During a 2-year follow-up period, risk of infections was higher among patients with ANCA IgA compared to those without (41.8% vs. 23.4%, p<0.001). ANCA IgA positivity was associated with a shorter time to the first infectious complication (pLogRank <0.001) in Kaplan-Meier analysis and was identified as an independent predictor in multivariate Cox-regression analysis (HR:1.74, 95% CI: 1.18-2.56, p=0.006).

CONCLUSIONS

Presence of IgA type ANCA is common in cirrhosis. Involvement of gut mucosal immune system is in center of their formation and probably reflects sustained exposure to bacterial constituents.

Antineutrophil cytoplasmic autoantibodies: how are they detected and what is their use for diagnosis, classification and follow-up?

Antineutrophil cytoplasmic antibodies (ANCA) are traditionally detected by an indirect immunofluorescence technique. According to the international consensus on ANCA testing, ANCA should also be tested by antigen-specific tests for myeloperoxidase-ANCA and proteinase 3-ANCA. The direct noncompetitive enzyme-linked immunosorbent assay (ELISA) used to be the method of choice. Nowadays, these assays are called "first-generation" assays. Second-generation tests (capture ELISA) or third-generation tests (anchor ELISA) are more sensitive and specific for ANCA testing. We postulate that ANCA as detected by these newer ANCA tests may replace the need to perform indirect immunofluorescence-based assays. For classification of patients, ANCA serotype seems more important than classifying patients according to their clinical subtype, since genetics, clinical manifestations and response to therapy are more related to ANCA serotype than to clinical subtype. Detection of ANCA to monitor disease activity is still a controversial issue. Treatment based on ANCA levels is at present only experimentally performed in those patients who are treated with B-cell depletion therapy with rituximab. Future studies are needed to establish whether this way of monitoring patients is warranted.

Autoimmune liver disorders and small-vessel vasculitis: four case reports and review of the literature

Autoimmune liver diseases (AILD) are a group of immunologically induced hepatic disorders that can lead to liver cirrhosis and end-stage liver disease. Extra-hepatic involvement and association with rheumatic diseases (such as Sjögren's syndrome, systemic sclerosis and rheumatoid arthritis) are well known, whereas the coexistence of AILD with small-vessel vasculitis in the same patients have been only occasionally reported. In the present paper we report four such cases and an extensive review of the literature. Clinical features of autoimmune-liver diseases associated with small-vessel vasculitis are discussed, as well as possible common pathogenic pathways including HLA genomics, costimulatory molecules and autoantibodies. In conclusion, knowledge about this association can help physicians in recognising and treating an aggressive disease which could otherwise result in severe and multiple organ damage, compromising the overall prognosis and the indication to liver transplantation.

Lactoferrin, a key molecule in immune and inflammatory processes

Lactoferrin (Lf) belongs to the family of antimicrobial molecules that constitute the principal defense line of nonvertebrate organisms. In human immunity, their roles are considerably extended, and actually exceed mere direct antimicrobial properties. As a result, Lf is involved in both innate and adaptive immunities where its modulating effects not only help the host fight against microbes but also protect the host against harmful effects of inflammation. Such beneficial effects have been noticed in studies using dietary Lf, without the experimenters always explaining the exact modes of action of Lf. Effects on mucosal and systemic immunities are indeed often observed, which make the roles of Lf tricky to decipher. It is now known that the immunomodulatory properties of Lf are due to its ability to interact with numerous cellular and molecular targets. At the cellular level, Lf modulates the migration, maturation, and functions of immune cells. At the molecular level, in addition to iron binding, interactions of Lf with a plethora of compounds, either soluble or cell-surface molecules, account for its modulatory properties. This paper reviews our current understanding of the mechanisms that explain the regulatory properties of Lf in immune and inflammatory processes.

Low Serum Alpha-Antitrypsin Associated with Anti-PR-3 ANCA in Autistic Children with GI Disease

AIM

To assess the possible relationship between serum alpha-1 antitrypsin (AAT) levels and anti-neutrophil cytoplasmic antibodies (ANCA) in autistic children with severe GI disease and to test the hypothesis that there is an association between low serum AAT levels, the presence of ANCA and inflammatory GI disease seen in some autistic children.

SUBJECTS AND METHODS

Serum from 40 autistic children with chronic digestive disease (many with ileo-colonic lymphoid nodular hyperplasia (LNH) and inflammation of the colorectum, small bowel and/or stomach), and 41 controls (21 age matched autistic children with no GI disease and 20 age matched children without autism or GI disease) were tested using ELISAs designed to quantitate ANCA (anti-PR3), AAT and PR3 levels.

RESULTS

We found that a significant number of autistic children with chronic digestive disease had anti-PR3 ANCA, high serum PR3 and high severity of disease when compared to controls. This same group of autistic children had low serum levels of AAT compared to controls, which also correlated with the presence of anti-PR3 ANCA, high serum PR3, as well as the severity of intestinal disease, particularly LNH and severe erythema.

DISCUSSION

These results suggest a relationship between low AAT levels, ANCA and severity of GI disease seen in a subpopulation of ASD individuals. We suggest that low AAT levels may result in high levels of PR3, which may, in turn be associated with the presence of ANCA.

Hypotheses on the etiology of antineutrophil cytoplasmic autoantibody associated vasculitis: the cause is hidden, but the result is known

The first description of what is now known as antineutrophil cytoplasmic autoantibody-associated necrotizing vasculitis appeared more than 140 yr ago. Since then, many aspects of the pathogenic pathway have been elucidated, indicating the involvement of antineutrophil cytoplasmic autoantibodies, but why antineutrophil cytoplasmic autoantibodies are produced in the first place remains unknown. Over the years, many hypotheses have emerged addressing the etiology of antineutrophil cytoplasmic antibody production, but no exclusive factor or set of factors can so far be held responsible. Herein is reviewed the most influential hypotheses regarding the causes of antineutrophil cytoplasmic antibody-associated vasculitis with the aim of placing in an epidemiologic background the different hypotheses that are centered on environmental and genetic influences.

Meta-analysis of myeloperoxidase G-463/A polymorphism in anti-neutrophil cytoplasmic autoantibody-positive vasculitis

Wegener's granulomatosis, microscopic polyangiitis and Churg Strauss syndrome are small-vessel vasculitides associated with anti-neutrophil cytoplasmic antibodies (ANCA) directed against proteinase 3 (PR3) and myeloperoxidase (MPO). A G to A polymorphism at position 463 in the promoter region of the MPO gene, which leads to the loss of a SP1 transcription binding site in an Alu hormone responsive element, reduces MPO expression. We hypothesized that MPO alleles may play a role in determining disease susceptibility or severity in ANCA-associated vasculitis (AASV). MPO genotypes were determined by restriction fragment length polymorphism polymerase chain reaction (RFLP/PCR) in 134 Caucasian patients (Wegener's granulomatosis, n = 69; microscopic polyangiitis, n = 65; PR3-ANCA n = 91; MPO-ANCA, n = 43) and 150 matched healthy controls. There was no difference in survival to renal failure or death in patients with the different MPO alleles (chi(2) = 0.904, P = 0.6362) or in presenting serum creatinine concentration based on MPO genotype (chi(2) = 0.389, P = 0.8232). There was no significant difference in genotype frequencies between controls (13AA, 102GG, 35GA) and patients (14AA, 97GG, 23GA: chi(2) = 1.75, P = 0.417), patients with Wegener's granulomatosis (5AA, 53GG, 11GA: chi(2) = 1.864, P = 0.3938) or patients with microscopic polyangiitis (9AA, 44GG, 12GA: chi(2) = 1.682, P = 0.4317). A meta-analysis of our study and two previous studies showed that there was no association between the myeloperoxidase G-463/A polymorphism and the risk of developing ANCA-associated vasculitis; GG versus GA plus AA (odds ratio 1.14; 95% confidence interval 0.86-1.50). The MPO G-463/A polymorphism is not a risk factor for the development or severity of AASV.

Fatal inflammatory hypophysitis

A young female patient presented as an acute medical emergency with hypoglycaemia. Investigations revealed panhypopituitarism and an inflammatory pituitary mass. An antibody screen was negative for anti-neutrophil cytoplasmic antibodies with cytoplasmic distribution (cANCA). Pituitary histology showed lymphocytic infiltration and a few Langerhan's cells. The pituitary mass rapidly expanded to involve the optic nerves and led to bilateral blindness. Later, the patient developed diarrhoea, a vasculitis rash, scleritis, and proteinuria. In subsequent investigations cANCA became positive. The patient responded to steroids and cyclophosphamide treatment and remained in partial remission for six months before dying of severe sepsis. This is the first description of Wegener's granulomatosis presenting with acute anterior pituitary failure in the absence of other organ involvement and negative serology.

Wegener's granulomatosis complicated by intestinal ulcer due to cytomegalovirus infection and by thrombotic thrombocytopenic purpura

A 61-year-old woman was admitted to our hospital because of acute kidney injury. She complained of general fatigue, appetite loss, and a high fever. Nodular lesions were observed on chest X-rays and there were >100 erythrocytes per high power field in her urinary sediment. A renal biopsy revealed necrotizing granulomatous glomerulonephritis, and her serum proteinase 3-antineutrophil cytoplasmic antibody (PR3-ANCA) titer was elevated (55 EU). Based on these findings we made a diagnosis of Wegener's granulomatosis (WG). Hemodialysis was started immediately after admission. Steroid therapy was administered and her symptoms were relieved, but her renal function did not improve. On the 50th hospital day her condition suddenly became complicated by hemoperitoneum and massive intestinal bleeding, and the descending, transverse, ascending colon and part of the ileum were surgically resected. The cytomegalovirus (CMV) antigen titer was elevated, and histologic examination of the bowel specimen showed positive staining for CMV in the ulcer lesion, suggesting that CMV infection had caused the bowel hemorrhage. After treatment with ganciclovir, the bleeding was resolved and the CMV antigens became negative. We considered that this patient was further complicated by thrombotic thrombocytopenic purpura (TTP) because of thrombocytopenia, hemolytic anemia and neurologic symptoms. She was treated by plasma exchange. We report here a case of WG complicated by acute intestinal ulcer due to CMV infection and by TTP.

Evaluation of a new fluorescent-enzyme immuno-assay for diagnosis and follow-up of ANCA-associated vasculitis

In this study we have evaluated a new, fully automated fluorescent-enzyme immuno-assay (FEIA) for detection and quantification of anti-PR3 and anti-MPO ANCA in diagnosis and follow-up of ANCA-associated small vessel vasculitis (AAV). PR3- and MPO-ANCA were determined by FEIA technology in (1) sera of 87 consecutive patients with biopsy-proven, pauci-immune necrotizing crescentic glomerulonephritis (NCGN) and 72 controls; (2) 120 sera (60 patients with Wegener's granulomatosis and 60 controls) that were previously used in a multicentre comparison of direct and capture ELISAs for PR3-ANCA; (3) in samples preceding relapse in 23 PR3-AAV patients with and 23 matched PR3-AAV patients without relapse for prediction of relapses. PR3- and/or MPO-ANCA detection in pauci-immune NCGN by FEIA revealed an overall sensitivity of 82.8%. The FEIA specificity was 96% and 100% for PR3- and MPO-ANCA, respectively. The overall sensitivity of MPO- and PR3-ANCA could be increased to 88.5% by lowering the cut-off values without affecting the specificity (ROC-curve analysis), which is similar to a multistep ANCA procedure that combines indirect immunofluorescence with direct and capture ELISAs. The sensitivity for Wegener's granulomatosis (WG) of the PR3-ANCA FEIA (60%) was more comparable to direct ELISAs (64%) than to capture ELISAs (74%). A rise of 100% in ANCA level as measured by FEIA appeared optimal (ROC-curve) for prediction of relapses and such a rise was observed in 26 patients. In 18 of these 26 patients the rise was followed by a relapse (PPV 69%), whereas in 15 of the 20 patients without a rise no relapse was observed (NPV 75%). In conclusion, detection of PR3- and MPO-ANCA by FEIA has excellent performance in terms of diagnosis of AAV patients. Furthermore, detection of rises in PR3-ANCA by FEIA for prediction of relapses gives results comparable to other techniques.

Presentation and outcome of gastrointestinal involvement in systemic necrotizing vasculitides: analysis of 62 patients with polyarteritis nodosa, microscopic polyangiitis, Wegener granulomatosis, Churg-Strauss syndrome, or rheumatoid arthritis-associated vasculitis

We reviewed the medical records of 62 patients with systemic small and medium-sized vessel vasculitides and gastrointestinal tract involvement followed at our institution between 1981 and 2002. This group included 46 men and 16 women (male:female ratio, 2.9), with a mean age of 48 +/- 18 years. Vasculitides were distributed as follows: 38 polyarteritis nodosa (21 related to hepatitis B virus), 11 Churg-Strauss syndrome, 6 Wegener granulomatosis, 4 microscopic polyangiitis, and 3 rheumatoid arthritis-associated vasculitis. Gastrointestinal manifestations were present at or occurred within 3 months of diagnosis in 50 (81%) patients and were mainly abdominal pain in 61 (97%), nausea or vomiting in 21 (34%), diarrhea in 17 (27%), hematochezia or melena in 10 (16%), and hematemesis in 4 (6%). Gastroduodenal ulcerations were detected endoscopically in 17 (27 %) patients, esophageal in 7 (11%), and colorectal in 6 (10%), but histologic signs of vasculitis were found in only 3 colon biopsies. Twenty-one (34%) patients had a surgical abdomen; 11 (18%) developed peritonitis, 9 (15%) had bowel perforations, 10 (16%) bowel ischemia/infarction, 4 (6%) intestinal occlusion, 6 (10%) acute appendicitis, 5 (8%) cholecystitis, and 3 (5%) acute pancreatitis. (Some patients had more than 1 condition.) Sixteen (26%) patients died.The respective 10-month and 5-year survival rates were 71% (95% confidence interval [CI], 52-90) and 56% (95% CI, 35-77) for the 21 surgical patients; and 94% (95% CI, 87-101) and 82% (95% CI, 70-94) for the 41 patients without surgical abdomen (p = 0.08). Peritonitis (hazard ratio [HR] = 4.3, p < 0.01), bowel perforations (HR = 5.7, p < 0.01), gastrointestinal ischemia or infarctions (HR = 4.1, p < 0.01), and intestinal occlusion (HR = 5.5, p < 0.01) were the only gastrointestinal manifestations significantly associated with increased mortality in multivariate analysis. For this subgroup of 15 patients, 6-month and 5-year survival rates were 60% (95% CI, 35-85) and 46% (95% CI, 19-73), respectively (p = 0.003). None of the other gastrointestinal or extraintestinal vasculitis-related symptoms, or angiographic abnormalities (seen in 67% of the 39 patients who underwent angiography), was predictive of surgical complications or poor outcome. However, prognosis has dramatically improved during the past 30 years, probably owing to better management of these more severely ill patients, with prompt surgical intervention when indicated, and the combined use of steroids and immunosuppressants.

Antineutrophil cytoplasmic antibody-associated neutropenia

BACKGROUND: Antineutrophil cytoplasmic antibodies (ANCA) can be associated with various disorders. However, their association with neutropenia has never been reported. METHODS: Nine patients with chronic unexplained neutropenia and ANCA were studied. Clinical charts were extensively analyzed and all patients underwent hematological and immunological investigations. RESULTS: All patients (6 women and 3 men) were Caucasian and had a mean age of 49 years (range 16-67 years). All presented with a neutropenia below 1.5x10(9)/L for more than 6 months. The neutropenia was <0.5x10(9)/L in six cases and moderate in three. There was no evidence of toxic- or drug-related neutropenia or of a hematological malignancy. Autoimmune anemia and/or thrombocytopenia were present in five patients. ANCA, with various specificities, were present in all patients. ANCA were associated with various other autoantibodies in eight patients, including antisurface-neutrophil antibodies in three cases. Four of the six patients with severe neutropenia experienced infections. Five patients were treated with hematopoietic growth factors, steroids, intravenous immunoglobulins, splenectomy, methotrexate and/or cyclophosphamide, allowing the neutrophil count to be restored transiently or permanently. CONCLUSIONS: A subset of patients with neutropenia of possible autoimmune origin may develop ANCA. Their detection would provide strong evidence of an autoimmune mechanism. Neutropenia should be added to the list of ANCA-associated diseases.

Mixed connective tissue disease associated with antineutrophil cytoplasmic antibodies against proteinase-3 and systemic atherosclerosis: a case report

A 47-year-old woman presented with facial spasm, swollen fingers and Raynaud's phenomenon due to cerebrovascular disorder and mixed connective tissue disease (MCTD). Although she was positive for both antineutrophil cytoplasmic antibodies against proteinase-3 (PR3-ANCA) and anti-U1 RNP antibodies, she did not meet the American College of Rheumatology classification criteria for Wegener's granulomatosis (WG). Physical and histopathological examinations revealed severe systemic atherosclerosis without any of the traditional risk factors. Elevated levels of malondialdehyde-modified LDL and antioxidized LDL autoantibodies, which are considered to be key factors in the pathogenesis of atherosclerosis, were also detected in the serum of this patient. In this case, systemic atherosclerosis might have been linked to these autoimmune reactions.

Nodular pulmonary vasculitis in a twelve-year-old boy

A 12-year-old boy presented with left shoulder pain during physical exercise and complained of uncommon sweating and fatigue. Diagnostic evaluation revealed a solitary pulmonary nodule in the left upper lobe. All laboratory values were within normal limits, except for an elevated level of antineutrophil cytoplasmic antibodies directed against myeloperoxidase (p-ANCA). Surgery was performed, and pathological examination showed a localized granulomatous vasculitis. Antineutrophil cytoplasmic antibodies directed against affinity purified proteinase 3 (p-ANCA) concentrations returned to baseline within 6 months, and the patient has done well during a follow-up period of 2 years. While nodular vasculitis is known to occur in Wegener's granulomatosis, to the best of our knowledge, this case represents the first c-ANCA negative primary pulmonary vasculitis in childhood.

Recent progress in the pharmacotherapy of Churg-Strauss syndrome

Churg-Strauss syndrome (CSS) is a primary systemic vasculitis occurring primarily in patients with asthma. Unlike other small vessel vasculitides, CSS is characterised by blood and tissue eosinophilia. Corticosteroids are the therapy of first choice for all stages of the disease when active vasculitis needs to be treated rapidly. In patients with severe disease and organ- or life-threatening manifestation, the addition of cyclophosphamide appears to improve the outcome and reduces the incidence of relapses. In cases with an apparently better prognosis and less severe disease, methotrexate can be given as a corticosteroid-sparing agent in order to reduce the cumulative dose of corticosteroids, which is generally high in most cases as long-term administration of corticosteroids is often inevitable in order to control asthma, even if the vasculitis is inactive. In very severe cases of CSS, cyclophosphamide and corticosteroids may be insufficient to induce remission. In these cases, anti-TNF blocking agents such as infliximab or etanercept, may be added for a limited period of time. As this intense immunosuppression increases the risk for infections, a prophylaxis with sulfamethoxazole/trimethoprim is advised. Alternatively, the administration of recombinant IFN-alpha can be a effective when given on a short-term basis in otherwise refractory cases. Whether a continuous administration of immunosuppressive agents in addition to corticosteroids can reduce the frequency of relapses in CSS who are in remission is still unknown. As relapses occur in > 25% of all patients, studies addressing the prevention of relapses in CSS are highly desirable in the future.

IgM and IgG autoantibodies from microscopic polyangiitis patients but not those with other small- and medium-sized vessel vasculitides recognize multiple endothelial cell antigens

Using a quantitative immunoblotting technique on extracts of macrovascular and microvascular endothelial cells (EC), we analyzed serum IgM and IgG reactivities of patients with active disease fulfilling the ACR and Chapel Hill criteria for the diagnosis of polyarteritis nodosa (PAN) (n = 8), PAN related to hepatitis B virus (HBV) infection (HBV-PAN) (n = 5), Wegener's granulomatosis (n = 6), microscopic polyangiitis (MPA) (n = 18), Churg-Strauss syndrome (n = 8), and patients with chronic HBV infection without PAN (n = 5) and age- and gender-matched healthy individuals (n = 45). MPA patients' IgM bound to 200-, 105-, 80-, 65-, 45-, 35-, and 33-kDa major bands, whereas IgM from controls and other patients bound predominantly to the 65-kDa band in EC extracts. MPA patients' IgG reacted mainly with 105-, 70-, 55-, and 38-kDa protein bands, whereas IgG from controls and other patients did not. Our results provide evidence that IgM and to a lesser degree IgG from MPA patients specifically recognize multiple EC antigens.

Head and neck manifestations of Wegener's granulomatosis

Wegener's granulomatosis is an idiopathic, granulomatous disease with the potential for multiple head and neck manifestations. The otolarygologist is an essential part of the multidisciplinary team involved in establishing the diagnosis and providing ongoing care for patients with Wegener's granulomatosis. Diagnostic difficulties abound in Wegener's granulomatosis, making repeat biopsies and the use of ANCA imperative. Medical therapy consisting of corticosteroids and immunosuppressive agents is the mainstay of treatment in Wegener's granulomatosis, whereas surgery is reserved for selected head and neck manifestations. With appropriate medical and surgical treatment, many patients living with Wegener's granulomatosis can enjoy a good quality of life.

ANCA and anti-GBM antibodies in diagnosis and follow-up of vasculitic disease

In the last decade, serological detection of anti-neutrophil cytoplasmic antibodies (ANCA) and of anti-glomerular basement membrane (GBM) antibodies has tremendously facilitated the diagnosis of small vessel vasculitides. Once diagnosed, these diseases have proven to be treatable. However, in contrast to anti-GBM disease, ANCA-associated vasculitides are chronic diseases with a high relapse rate. Since morbidity in ANCA-associated vasculitides is dictated by the frequency and severity of relapses, much health benefit would be achieved if a relapse could be prevented or early treatment started. Increases in ANCA titers and persistently high ANCA levels indicate a high risk of relapse and warrant clinical evaluation of the patient for signs of relapse. This review will focus on the value of ANCA and anti-GBM antibody testing in diagnosis and on the importance of these tests in follow-up of disease.

Neutrophil-activating potential of antineutrophil cytoplasm autoantibodies

Accumulating in vivo and in vitro evidence supports the hypothesis that antineutrophil cytoplasm autoantibodies (ANCA) with specificity for proteinase 3 (PR3) and myeloperoxidase (MPO) are involved in the pathophysiology of small-vessel vasculitis. The best-described effector function of these autoantibodies is stimulation of neutrophils to produce reactive oxygen species and to release proteolytic enzymes. Neutrophil activation requires interaction of monomeric ANCA with PR3/MPO and Fcgamma receptors, but also other mechanisms--for instance, stimulation by ANCA-containing immune complexes--cannot be excluded. This review focuses on the mechanisms of neutrophil activation by ANCA. We discuss the molecules involved in ANCA binding to the neutrophil surface and in triggering the functional responses. We summarize current knowledge on the signal-transduction pathways initiated by ANCA and on the factors determining susceptibility of neutrophils to activation by these autoantibodies.

Wegener's granulomatosis: an analysis of 33 patients seen over a 10-year period

This retrospective study examined 33 patients with Wegener's granuloma seen between 1990 and 1999 in the Ayrshire and Arran region of Scotland. There was an estimated annual incidence of 10/million/year. The diagnosis in this series was based on the presence of one or more of the following: a positive histology, a positive c-ANCA or a typical clinical course. Twenty-eight patients were diagnosed based on either a positive histology and/or c-ANCA, whereas the remaining five were diagnosed based on the clinical course. c-ANCA was positive in 79.3% but correlated poorly with disease activity. Nasal biopsies were positive in 40%, whereas 94% of renal biopsies were positive, thereby making nasal biopsies unreliable in the diagnosis. Significantly elevated levels of erythrocyte sedimentation rate (ESR) averaging 77 mm/h were found in 32 patients at diagnosis. This showed fluctuation with disease activity. Thirteen patients died, 12 within 5 years. The best prognostic indicator statistically was age.