Analyses of registry data of patients with anti-GBM and antineutrophil cytoplasmatic antibody-associated (ANCA) vasculitis treated with or without therapeutic apheresis

Therapeutic apheresis (TA) as a treatment for antibody-associated vasculitis (AAV) was questioned by the PEXIVAS although the MEPEX study favored TA. The aim of this study was to evaluate the efficacy of TA to improve renal function in patients consecutively included in the WAA-apheresis registry versus patients not treated with TA.

MATERIALS AND METHODS

Included were 192 patients that suffered from anti-glomerular basement membrane disease (anti-GBM, n = 28) and antineutrophil cytoplasmic antibody-associated vasculitis of MPO or PR3 origin. Of these 119 had performed TA and the other 73 had not performed TA for theses diagnoses (CTRL).

RESULTS

Elderly had an increased risk to die within 12 months (p = 0.002). All 28 anti-GBM had renal involvement, 21 dialysis dependent. At 3 month nine (36 %) did not need dialysis. Baseline data regarding renal function of AAV patients, subtype MPO and PR3, were worse in the TA groups than in CTRL. Recovery out of dialysis was better for the PR3-TA group compared with 1) the controls of MEPEX (RR 0.59, CI 0.43-0.80) and 2) the MPO-TA patients (RR 0.28, CI 0.12-0.68). The MPO-TA recovered similarly as the MEPEX-CTRL. Renal function improved most for TA-patients from baseline during the first 3 months (MPO-TA and PR3-TA) and stabilized thereafter and less for MPO-CTRL and PR3-CTRL.

CONCLUSION

PR3-TA patients seem to have best chances to get out of dialysis. PR3-TA and MPO-TA improved residual renal function better than CTRL. The present study recommends reconsiderations to use TA for AAV especially those with PR3-vasculitis with severe renal vasculitis.

AB0511 INTERNATIONAL CONSENSUS ON ANCA TESTING AND INTERPRETATION BEYOND SYSTEMIC VASCULITIS

Background:

ANCA can be detected in sera from patients with autoimmune, inflammatory, infectious or neoplastic diseases.

Objectives:

To issue a Consensus Statement on ANCA testing and interpretation beyond systemic vasculitis.

Methods:

This Statement was prepared by a group of experts, based on the results of a comprehensive search in PubMed.

Results:

In certain settings beyond systemic vasculitis, ANCA may have diagnostic, clinical, and/or prognostic relevance. Testing for PR3- and MPO-ANCA by specific immunoassays should be performed in any patient with clinical features suggesting ANCA-associated vasculitis and in patients with anti-GBM disease and idiopathic interstitial pneumonia. Routine ANCA testing is not recommended in patients with connective tissue diseases (CTD), autoimmune liver diseases, inflammatory bowel diseases, infections, and/or malignancy unless there is evidence for small vessel vasculitis. ANCA testing by specific immunoassays may be useful in patients with rheumatoid arthritis, systemic sclerosis or primary Sjögren’s syndrome who have kidney disease with a nephritic sediment or in patients with systemic lupus erythematosus if a kidney biopsy shows prominent necrotizing and crescentic lesions or proliferative lupus nephritis. ANCA testing may be justified in patients with suspected autoimmune hepatitis type 1, who do not have conventional disease-related autoantibodies, or in patients with inflammatory bowel diseases in case of diagnostic uncertainty to discriminate ulcerative colitis from Crohn’s disease. In these cases, ANCA should be tested by indirect immunofluorescence since target antigens are not well characterized. ANCA against bactericidal/permeability-increasing protein may be a biomarker for deteriorating lung function and a poor prognosis in patients with cystic fibrosis.

Conclusion:

ANCA testing is clinically relevant not only in patients with manifestations suggesting systemic vasculitis, but also in patients with certain other disorders, particularly in patients with anti-GBM disease or idiopathic interstitial pneumonia.

Disclosure of Interests:

Sergey Moiseev Grant/research support from: This work was supported by the 5-100 Project, Sechenov University, Moscow, Jan Willem Cohen Tervaert: None declared, Yoshihiro Arimura: None declared, Dimitrios Bogdanos: None declared, Csernok Elena: None declared, Jan Damoiseaux: None declared, Marc Ferrante: None declared, Luis Felipe Flores-Suárez: None declared, Marvin Fritzler: None declared, Pietro Invernizzi: None declared, David Jayne Grant/research support from: ChemoCentryx, GSK, Roche/Genentech, Sanofi-Genzyme, Consultant of: Astra-Zeneca, ChemoCentryx, GSK, InflaRx, Takeda, Insmed, Chugai, Boehringer-Ingelheim, J. Charles Jennette: None declared, Mark Little: None declared, Stephen P. McAdoo: None declared, Pavel Novikov Grant/research support from: This work was supported by the 5-100 Project, Sechenov University, Moscow, Charles D. Pusey: None declared, Antonella Radice: None declared, Alan D. Salama: None declared, Judith Savige: None declared, Mårten Segelmark: None declared, Yehuda Shoenfeld: None declared, Renato Alberto Sinico: None declared, Maria Jose Rego de Sousa: None declared, Ulrich Specks: None declared, Benjamin Terrier: None declared, Athanasios Tzioufas: None declared, Severine Vermeire: None declared, Ming-hui Zhao: None declared, Xavier Bossuyt: None declared

Epidemiology of primary systemic vasculitis in children: a population-based study from southern Sweden

OBJECTIVES

To estimate the annual incidence rate of paediatric primary systemic vasculitis (PSV) in a defined geographical area in southern Sweden.

METHODS

Potential cases of PSV [IgA vasculitis (IgAV, Henoch-Schönlein purpura), Kawasaki disease (KD), granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), eosinophilic granulomatosis with polyangiitis (EGPA), polyarteritis nodosa (PAN), and Takayasu's arteritis (TAK)] were identified in a comprehensive regional healthcare register. The study area is Skåne, the southernmost county of Sweden (population 1.29 million; 21.4% aged <18 years). Case records for children (0-17 years) assigned a diagnosis code between M300 and M319 and/or D690 were reviewed to ascertain diagnosis. Only patients diagnosed between 2004 and 2014 were included.

RESULTS

In total, 556 patients with PSV were identified. The annual incidence rate per million children (95% confidence interval) was estimated to be 200 (183-217) for all PSV, 175.5 for IgAV (160-191), 20.1 for KD (14.9-25.4), 1.4 (0-2.8) for each of GPA and MPA, 0.7 (0-1.7) for PAN, and 0.4 (0-1.1) for each of EGPA and TAK. Among children aged <10 years, 99.5% of cases were either IgAV or KD, both exhibiting a seasonal pattern paralleling infections. There were no deaths, but three cases of end-stage renal disease were noted, all in MPA.

CONCLUSIONS

Vasculitis is relatively common during childhood. Mild cases associated with the infection season are most common in the youngest age groups, while during adolescence a substantial proportion has more severe forms of vasculitis.

EULAR/ERA-EDTA recommendations for the management of ANCA-associated vasculitis

In this article, the 2009 European League Against Rheumatism (EULAR) recommendations for the management of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) have been updated. The 2009 recommendations were on the management of primary small and medium vessel vasculitis. The 2015 update has been developed by an international task force representing EULAR, the European Renal Association and the European Vasculitis Society (EUVAS). The recommendations are based upon evidence from systematic literature reviews, as well as expert opinion where appropriate. The evidence presented was discussed and summarised by the experts in the course of a consensus-finding and voting process. Levels of evidence and grades of recommendations were derived and levels of agreement (strengths of recommendations) determined. In addition to the voting by the task force members, the relevance of the recommendations was assessed by an online voting survey among members of EUVAS. Fifteen recommendations were developed, covering general aspects, such as attaining remission and the need for shared decision making between clinicians and patients. More specific items relate to starting immunosuppressive therapy in combination with glucocorticoids to induce remission, followed by a period of remission maintenance; for remission induction in life-threatening or organ-threatening AAV, cyclophosphamide and rituximab are considered to have similar efficacy; plasma exchange which is recommended, where licensed, in the setting of rapidly progressive renal failure or severe diffuse pulmonary haemorrhage. These recommendations are intended for use by healthcare professionals, doctors in specialist training, medical students, pharmaceutical industries and drug regulatory organisations.

IgA- and SIgA anti-PR3 antibodies in serum versus organ involvement and disease activity in PR3-ANCA-associated vasculitis

Circulating immunoglobulin (Ig)A class anti-neutrophil cytoplasm antibodies (ANCA) directed against proteinase 3 (PR3) have been reported in ANCA-associated vasculitis (AAV) with mucosal involvement. However, secretory IgA (SIgA) PR3-ANCA has not been reported previously. In this study we compared serum levels of SIgA PR3-ANCA and IgA PR3-ANCA with IgG PR3-ANCA in relation to disease characteristics. Among 73 patients with AAV and PR3-ANCA at diagnosis, 84% tested positive for IgG PR3-ANCA, 47% for IgA-ANCA and 36% for SIgA PR3-ANCA at the time of sampling for the present study. IgA and IgG PR3-ANCA were represented similarly among patients with different organ manifestations, i.e. upper airway, lung or kidney at time of sampling. However, SIgA PR3-ANCA was significantly less represented among patients with upper airway involvement. During active disease, the proportions of IgA PR3-ANCA and SIgA PR3-ANCA-positive patients were significantly higher compared to inactive disease. Eight patients were sampled prospectively during 24 months from onset of active disease. In these patients, IgA PR3-ANCA and SIgA PR3-ANCA turned negative more often after remission induction compared to IgG PR3-ANCA. Our findings suggest that serum IgA PR3-ANCA and SIgA PR3-ANCA are related more closely to disease activity in AAV compared to IgG PR3-ANCA. Further studies are required to reveal if this has implications for disease activity monitoring. The mean number of PR3-ANCA isotypes increased along with disease activity, suggesting a global B cell activation during active disease.

Circulating microRNA expression pattern separates patients with anti-neutrophil cytoplasmic antibody associated vasculitis from healthy controls

OBJECTIVES

Antineutrophil cytoplasmic antibody associated vasculitis (AAV) has an unpredictable course and better biomarkers are needed. Micro-RNAs in body fluids are protected from degradation and might be used as biomarkers for diagnosis and prognosis, here we explore the potential in AAV.

METHODS

Plasma samples from two AAV cohorts (n=67 and 38) were compared with samples from healthy controls (n=27 and 45) and disease controls (n=20). A panel of 32 miRNAs was measured using a microfluidic quantitative real-time PCR system, and results were compared with clinical data.

RESULTS

Seven individual miRNAs were differently expressed compared to controls in both cohorts; miR-29a, -34a, -142-3p and -383 were up-regulated and miR-20a, -92a and -221 were down-regulated. Cluster analysis as well as principal component analysis (PCA) indicated that patterns of miRNA expression differentiate AAV patients from healthy subjects as well as from renal transplant recipients. Loadings plots indicated similar contribution of the same miRNAs in both cohorts to the PCA. Renal engagement was important for miRNA expression but consistent correlations between estimated glomerular filtration rate and miRNA levels were not found. We found no significant correlation between treatment regimens and circulating miRNA levels.

CONCLUSIONS

In this first study ever on circulating miRNA profiles in AAV, we find clear indication of their potential as biomarkers for diagnosis and classification, but more studies are needed to identify the best markers as well as the mechanisms responsible for variations.

Neutrophils from vasculitis patients exhibit an increased propensity for activation by anti-neutrophil cytoplasmic antibodies

Anti-neutrophil cytoplasmic antibodies (ANCA) are thought to be pathogenic in ANCA-associated vasculitis (AAV) by stimulating polymorphonuclear leucocytes (PMNs) to degranulate and produce reactive oxygen species (ROS). The aim of this study was to investigate if PMNs from AAV patients are stimulated more readily by ANCA compared with PMNs from healthy controls (HCs). Differences in ANCA characteristics that can account for different stimulation potential were also studied. PMNs from five AAV patients and five HCs were stimulated with 10 different immunoglobulins (Ig)Gs, purified from PR3-ANCA-positive patients, and ROS production, degranulation and neutrophil extracellular trap (NET) formation was measured. ANCA levels, affinity and clinical data of the AAV donors were recorded. The results show that PMNs from AAV patients produce more intracellular ROS (P = 0·019), but degranulate to a similar extent as PMNs from HCs. ROS production correlated with NET formation. Factors that may influence the ability of ANCA to activate PMNs include affinity and specificity for N-terminal epitopes. In conclusion, our results indicate that PMNs from AAV patients in remission behave quite similarly to HC PMNs, with the exception of a greater intracellular ROS production. This could contribute to more extensive NET formation and thus an increased exposure of the ANCA autoantigens to the immune system.

A myelopoiesis gene signature during remission in anti-neutrophil cytoplasm antibody-associated vasculitis does not predict relapses but seems to reflect ongoing prednisolone therapy

A myelopoiesis gene signature in circulating leucocytes, exemplified by increased myeloperoxidase (MPO) and proteinase 3 (PR3) mRNA levels, has been reported in patients with active anti-neutrophil cytoplasm antibody-associated vasculitis (AAV), and to a lesser extent during remission. We hypothesized that this signature could predict disease relapse. mRNA levels of PR3, MPO, selected myelopoiesis transcription factors [CCAAT/enhancer binding protein α (CEBP-α), CCAAT/enhancer binding protein β (CEBP-β), SPI1/PU.1-related transcription factor (SPIB), spleen focus forming virus proviral integration oncogene, PU.1 homologue (SPI1)] and microRNAs (miRNAs) from patient and control peripheral blood mononuclear cells (PBMC) and polymorphonuclear cells (PMN) were analysed and associated with clinical data. Patients in stable remission had higher mRNA levels for PR3 (PBMC, PMN) and MPO (PBMC). PR3 and SPIB mRNA correlated positively in controls but negatively in patient PBMC. Statistically significant correlations existed between PR3 mRNA and several miRNAs in controls, but not in patients. PR3/MPO mRNA levels were not associated with previous or future relapses, but correlated with steroid treatment. Prednisolone doses were negatively linked to SPIB and miR-155-5p, miR-339-5p (PBMC) and to miR-221, miR-361 and miR-505 (PMN). PR3 mRNA in PBMC correlated with time since last flare, blood leucocyte count and estimated glomerular filtration rate. Our results show that elevated leucocyte PR3 mRNA levels in AAV patients in remission do not predict relapse. The origin seems multi-factorial, but to an important extent explainable by prednisolone action. Gene signatures in patients with AAV undergoing steroid treatment should therefore be interpreted accordingly.

Primary systemic vasculitis with severe α1-antitrypsin deficiency revisited

OBJECTIVES

To study the clinical characteristics and epidemiology of the combination of primary systemic vasculitis (PSV) and severe alpha-1 antitrypsin (α1-AT) deficiency.

METHOD

Patients with PSV [granulomatosis with polyangiitis (GPA) (Wegener's), microscopic polyangiitis, eosinophilic granulomatosis with polyangiitis (EGPA) (Churg-Strauss), and polyarteritis nodosa] were identified through diagnosis registries and serological databases. Clinical and laboratory data, including the presence of severe α1-AT deficiency, were collected from the time of diagnosis. During follow-up, data on relapses and permanent organ damage were collected. Using the county of Skåne as the denominator population, we estimated the annual incidence rate and point prevalence of PSV in people with severe α1-AT deficiency.

RESULTS

Five patients (three women, median age 49 years) with PSV diagnosed between 1996 and 2008 were found to have α1-AT deficiency, all of them carrying the protease inhibitor ZZ (PiZZ) phenotype. During follow-up (median time 166 months, range 53-208), four patients experienced a total of 13 relapses. The median Vasculitis Damage Index (VDI) score for all patients was 3 (range 1-4) at year 1, and 7 (range 3-9) at the last follow-up. The incidence rate of PSV among PiZZ carriers was estimated to be 397/million [95% confidence interval (CI) 8-787]. The point prevalence on 1 January 2013 was estimated to be 4689/million (95% CI 94-9285).

CONCLUSIONS

In this study both the incidence and prevalence of PSV were elevated nearly 10-fold for individuals with severe α1-AT deficiency compared with the general population. Combined with previous publications, this indicates a dose-response relationship for the genetic risk and suggests a causal relationship between the PiZ allele and vasculitis.

Extensive endoscopic image-guided sinus surgery decreases BPI-ANCA in patients with cystic fibrosis

Antineutrophil cytoplasm autoantibodies (ANCA) directed against bactericidal/permeability-increasing protein (BPI) are common in patients with cystic fibrosis (CF), and serum levels are correlated with lung colonization by Pseudomonas aeruginosa and the severity of lung damage. The production of BPI-ANCA may be due to the costimulation of BPI when mounting an immune response against P. aeruginosa. The effect of surgery aiming to eradicate bacteria and infected tissue on BPI-ANCA levels is sparsely described. A cohort of patients with CF were included: 53 patients having extensive image-guided sinus surgery (EIGSS) with topical postoperative antibiotic treatment, 131 non-operated controls and 36 who had double lung transplantation (LTX). In all 219 patients, serum samples before and after surgery or at similar intervals were analysed for IgG and IgA BPI-ANCA. The EIGSS group showed a highly significant decrease in both IgA and IgG BPI-ANCA levels compared with their own preoperative values and control group values (P < 0.001-0.02). The LTX patients also showed a highly significant decrease in both IgA and IgG BPI-ANCA levels (P < 0.001). EIGSS and LTX decrease IgA and IgG BPI-ANCA levels in patients with CF, indicating that extensive removal of infected tissue influences the pathogenic process of autoantibody production. The results shown herein are in favour of applying EIGSS in selected patients with CF and for using BPI-ANCA as a surrogate marker for guiding further therapeutic interventions.

Phagocytosis of apoptotic cells by macrophages in anti-neutrophil cytoplasmic antibody-associated systemic vasculitis

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a group of autoimmune diseases, including granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA). It is not known why ANCA develop, but it has been shown that they participate in pathogenesis by activating polymorphonuclear neutrophils (PMNs). In this study we hypothesize that dysregulation of phagocytosis in AAV leads to the accumulation of apoptotic neutrophils seen in association with blood vessels in AAV. These cells progress into secondary necrosis, contributing to tissue damage and autoantibody formation. Peripheral blood cells were counted, and phagocytosis was investigated using monocyte-derived macrophages (MØ) and PMNs from healthy blood donors (HBD), AAV patients and systemic lupus erythematosus (SLE) patients. Furthermore, the effect of serum was assessed. Phagocytosis was measured using flow cytometry. The results showed no deviation in monocyte subpopulations for AAV patients compared to HBDs, although there was a decrease in lymphocyte and pDC (plasmacytoid dendritic cell) populations (4·2 × 10(6) cells/l versus 10·4 × 10(6) cells/l, P < 0·001). The number of neutrophils was increased (6·0 × 10(9) cells/l versus 3·8 × 10(9) cells/l, P < 0·001). There were no differences found in the ability of MØs to engulf apoptotic cells, nor when comparing apoptotic PMNs to become engulfed. However, serum from AAV donors tended to decrease the phagocytosis ability of MØs (36%) compared to serum from HBDs (43%). In conclusion, there is no intrinsic dysfunction in the MØs or in the PMNs that have an effect on phagocytic activity, but ANCA may play a role by decreasing phagocytic ability.

Association of cigarette smoking with organ damage in primary systemic vasculitis

OBJECTIVES

To study the association between late organ damage in patients with primary systemic vasculitis (PSV) and cigarette smoking. PSV included Wegener's granulomatosis (WG), microscopic polyangiitis (MPA), Churg-Strauss syndrome (CSS), and polyarteritis nodosa (PAN).

METHODS

The pattern and extent of organ damage according to the Vasculitis Damage Index (VDI) were analysed for 86 prevalent cases with PSV retrieved from a geographically defined population in southern Sweden (46 WG, 27 MPA, four CSS, and nine PAN). Data on clinical findings, laboratory tests, and smoking habits were collected from case records from the time of diagnosis. The patients were stratified into two main groups according to their smoking habits: smokers (subdivided into active and ex-smokers) and non-smokers (patients who had never smoked).

RESULTS

Data on smoking habits were available for 77 patients (90%). Thirty-three (38%) patients were categorized as smokers and 44 (51%) were non-smokers. Smoking was more common in men (61.5% vs. 23.6% in women, p = 0.001). There were no differences in smoking habits between the main diagnostic groups (WG 40% smokers, MPA 45%). Ear, nose, and throat (ENT) damage was significantly more prevalent in non-smokers (p = 0.001). Myocardial infarction (MI) and end-stage renal disease (ESRD) were more common in the current smokers (p = 0.04) than in the non-smokers.

CONCLUSIONS

We found ENT damage to be significantly less prevalent in smokers. This is the first report of a possible modifying effect of cigarette smoking on the development of organ damage in PSV, but more studies are needed before any firm conclusions can be made.

Elevated neutrophil membrane expression of proteinase 3 is dependent upon CD177 expression

Proteinase 3 (PR3) is a major autoantigen in anti-neutrophil cytoplasmic antibodies (ANCA)-associated systemic vasculitis (AASV), and the proportion of neutrophils expressing PR3 on their membrane (mPR3+) is increased in AASV. We have shown recently that mPR3 and CD177 are expressed on the same cells in healthy individuals. In this study we try to elucidate mechanisms behind the increased mPR3 expression in AASV and its relationship to CD177. All neutrophils in all individuals were either double-positive or double-negative for mPR3 and CD177. The proportion of double-positive neutrophils was increased significantly in AASV and systemic lupus erythematosus patients. The proportion of mPR3+/CD177+ cells was not correlated to general inflammation, renal function, age, sex, drug treatment and levels of circulating PR3. AASV patients had normal levels of granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor. Pro-PR3 was found to constitute 10% of circulating PR3 but none of the mPR3. We found increased mRNA levels of both PR3 and CD177 in AASV, but they did not correlate with the proportion of double-positive cells. In cells sorted based on membrane expression, CD177-mRNA was several-fold higher in mPR3+ cells. When exogenous PR3 was added to CD177-transfected U937 cells, only CD177+ cells bound PR3 to their membrane. In conclusion, the increased membrane expression of PR3 found in AASV is not linked directly to circulating PR3 or PR3 gene transcription, but is dependent upon CD177 expression and correlated with the transcription of the CD177 gene.

Epitope shift of proteinase-3 anti-neutrophil cytoplasmic antibodies in patients with small vessel vasculitis

Anti-neutrophil cytoplasmic antibodies against proteinase 3 (PR3-ANCA) are used as diagnostic tools for patients with small vessel vasculitis (AASV). We have produced chimeric mouse/human PR3 molecules and investigate changes in reactivity over time and the possible relationship between epitope specificity and clinical course. Thirty-eight PR3-ANCA-positive patients diagnosed between 1990 and 2003 were followed until December 2005. Plasma was collected at each out-patient visit and older samples were retrieved retrospectively. Patients reacted with multiple epitopes at the time of diagnosis. At subsequent relapses 12 patients shifted reactivity, in 11 cases from epitopes located in the C-terminal towards epitopes in the N-terminal. Patients with reactivity against N-terminal parts of PR3 at diagnosis had a significantly lower relapse rate, 30% compared to 78% in the group with predominantly C-terminal reactivity (P = 0.04). The reactivity pattern did not correlate to outcome measured as death, end-stage renal disease or vasculitis activity index score (VDI) at 5 years. Further research is necessary to conclude if this is a general phenomenon.

Polyarteritis nodosa when applying the Chapel Hill nomenclature--a descriptive study on ten patients

OBJECTIVES

Polyarteritis nodosa (PAN) is a term that has been used to describe a wide variety of vasculitic conditions. In 1994, the Chapel Hill Consensus Conference on the nomenclature of systemic vasculitides proposed that the name classical PAN should be restricted to diseases where there is arteritis in small and medium-sized arteries without the involvement of smaller vessels. Our aim was to describe the symptoms and course of disease in PAN when the microscopic forms are excluded.

METHODS

All patients with a diagnosis of PAN treated in our departments during the period 1990-2002 were eligible for this study. The diagnosis had to be confirmed by biopsy, angiography or electromyography.

RESULTS

Ten patients were eligible for the study. The median age was 46 yrs. Renal involvement was seen in 70% at diagnosis. After 5 yrs, 57% had experienced a relapse, which is equivalent to the relapse rate seen in microscopic polyangiitis. Organ damage was assessed by the Vasculitis Damage Index (VDI) and after 5 yrs cardiovascular and neuropsychiatric damage dominated, followed by renal damage. During the follow-up, two patients developed end-stage renal disease. The annual incidence of PAN in our local catchment area was estimated to 1.6 per million and year.

CONCLUSIONS

When applying the Chapel Hill nomenclature, PAN is a rare but severe disease with a high incidence of renal involvement and frequent relapses.

Increased neutrophil membrane expression and plasma level of proteinase 3 in systemic vasculitis are not a consequence of the - 564 A/G promotor polymorphism

Several findings link proteinase 3 (PR3) to small vessel vasculitis. Besides being a major target of anti-neutrophil cytoplasm antibodies (ANCA), previous findings have shown increased circulating levels of PR3 in vasculitis patients, increased levels of neutrophil membrane-PR3 (mPR3) expression and a skewed distribution of the - 564 A/G polymorphism in the promotor region of the PR3 gene. In this study we elucidate how these three findings relate to each other. The plasma concentration of PR3 was measured by enzyme-linked immunosorbent assay (ELISA), mPR3 expression by fluorescence activated cell sorter (FACS) and the gene polymorphism by real-time polymerase chain reaction (PCR). We compared results from 63 patients with ANCA-associated systemic vasculitis (AASV) with 107 healthy blood donors. In accordance with previous reports, AASV patients had increased plasma concentrations of PR3 compared to healthy controls (mean 224 microg/l versus 155 microg/l, P < 0.0001). They also showed an increased number of mPR3-positive neutrophils (60%versus 42%, P < 0.001). However, contrary to a previous report, we found no skewed distribution of the polymorphism in PR3 gene. There was a weak correlation between mPR3 mean fluorescence intensity (MFI) and plasma PR3 among healthy controls and myeloperoxidase-ANCA (MPO-ANCA)-positive patients (r = 0.24, P = 0.015 and r = 0.52, P = 0.011, respectively). In conclusion, increased plasma PR3 and high expression of mPR3 are associated with small vessel vasculitis, but neither of them is a consequence of the - 564 A/G polymorphism of the PR3 gene promotor.

Alport syndrome in southern Sweden

AIM

The aim of the present investigation is to study the epidemiology of Alport syndrome in southern Sweden, to search for mutations in the COL4A5 gene and to estimate the mutation frequency.

PATIENTS AND METHODS

Patients with suspected Alport syndrome were identified in an area with a population of 1.45 million. Clinical criteria were used to establish the diagnosis and samples for mutation analysis were collected. Mutation analyses were performed with Single-Stranded Conformation Polymorphism analysis (SSCP) of PCR-amplified genomic DNA.

RESULTS

Altogether 25 families with hereditary nephritis were identified. Alport syndrome with X-linked transmission was evident in 14 families, with juvenile (< 31 years) progression to end-stage renal failure (ESRF) in ten, and adult (> or = 31 years) in four families.

CONCLUSION

The frequency of males with X-linked disease was calculated to one in 17,000 male births (95% confidence interval (CI) 1/10,500-1/28,600), and the prevalence to one in 40,000. A total of seven females with ESRF were identified, with a median age at ESRF of 45 years. The male to female ratio of cases with ESRF was 4.9 to 1. The risk of developing ESRF among females was from the expected incidence roughly estimated to 12%. Patients with X-linked disease constituted 1.8% of patients with ESRF in the examined area. A mutation was identified positive in 10 of 14 families with X-linked disease, but never in families not fulfilling the clinical criteria for Alport syndrome. In families with juvenile phenotype and positive mutation analysis, the mutation frequency was calculated to between 1/78,000 and 1/198,000 (95% CI 1/42,000-1/177,000) if the effective fertility was estimated to be between 0 and 0.2.

Increased monocyte transcription of the proteinase 3 gene in small vessel vasculitis

Proteinase 3 (PR3) is a pleiotropic and destructive serine protease and it is also a major target for autoantibodies in systemic small vessel vasculitis. We have shown recently that patients in stable remission have increased circulating levels of PR3, independent of autoantibody titre, inflammation, neutrophil degranulation and renal function. Here we explore the possibility of increased PR3 gene transcription. RNA was purified from peripheral blood monocytes from vasculitis patients and controls. Specific mRNA was measured by TaqMan real-time polymerase chain reaction (PCR). The monocyte-like cell lines THP-1 and U937 and human peripheral blod monocytes from healthy controls were stimulated with cytokines and lipopolysaccharide (LPS) for different time periods. PR3 protein was measured in plasma with enzyme-linked immunosorbent assay (ELISA). The median result for PR3 mRNA was 9.6 (1.8-680) for 22 patients, compared to 1 (0.1-2.8) for the 15 healthy controls. Elastase expression was also significantly increased, whereas myeloperoxidase and interleukin-8 were not. Stimulation of monocytes with tumour necrosis factor (TNF)-alpha, interferon (IFN)-gamma or LPS did not result in any increase of PR3 or elastase transcription, whereas interleukin (IL)-8 transcription was increased 10-fold. Circulating monocytes from patients with systemic vasculitis display increased PR3 gene transcription compared to healthy controls and patients with sytemic lupus erythematosus (SLE). This may be important for the development of vasculitis. Our results do not favour a role for cytokines, antineutrophil cytoplasmic antibodies (ANCA) or immunosuppressive medication in the upregulation of PR3 transcription in vasculitis.

Deficiency of the mannan-binding lectin pathway of complement and poor outcome in cystic fibrosis: bacterial colonization may be decisive for a relationship

In cystic fibrosis (CF) prognosis concerning lung damage development is highly variable and difficult to predict. Mannan-binding lectin (MBL) deficiency has been reported to be associated with poor outcome in CF lung disease. MBL is a recognition molecule of the MBL pathway of the complement system and is encoded by a gene characterized by a high degree of polymorphism. Some genotypes result in low serum concentrations of MBL. MBL-associated serine protease 2 (MASP-2) is another protein belonging to the MBL pathway. A mutation resulting in low levels of MASP-2 in serum has been described recently. In the present study, 112 CF patients aged 4-54 years were investigated for MBL and MASP-2 genotypes, serum levels of MBL and MASP-2 and the MBL pathway function in serum. No correlation to reduced lung function or need for lung transplantation was seen, either for MBL deficiency, MASP-2 gene mutation or reduced MBL pathway function. However, in the 27 patients colonized with Staphylococcus aureus, MBL-deficient genotypes were associated with decreased lung function. As expected, MBL pathway function in serum was reduced both in MBL-deficient patients and in patients carrying a mutant MASP-2 allele. An unexpected finding was that CF patients had higher serum levels of MBL than healthy controls when corrected for MBL genotype. In conclusion, MBL pathway function was affected both by MBL and by MASP-2 genotypes. However, MBL or MASP-2 levels in serum did not affect the clinical outcome in the cohort of CF patients studied.

Prevalences of polyarteritis nodosa, microscopic polyangiitis, Wegener's granulomatosis, and Churg-Strauss syndrome in a French urban multiethnic population in 2000: a capture-recapture estimate

OBJECTIVE

To estimate the prevalences of polyarteritis nodosa (PAN), microscopic polyangiitis (MPA), Wegener's granulomatosis (WG), and Churg-Strauss syndrome (CSS).

METHODS

Cases were collected in Seine-St. Denis County, a northeastern suburb of Paris, which has 1,093,515 adults (> or =15 years), 28% of whom are of non-European ancestry. The study period encompassed the entire calendar year 2000. Cases were identified by general practitioners, the departments of all the public hospitals and 2 large private clinics, and the National Health Insurance System. The Chapel Hill nomenclature was used to define MPA, and American College of Rheumatology criteria to define WG and CSS; PAN was diagnosed based on clinical laboratory, histological and/or angiographic findings. Three-source capture-recapture analysis was performed to correct for incomplete case ascertainment.

RESULTS

A total of 75 cases were retained and capture-recapture analysis estimated that 23.8 cases had been missed by any 1 of the 3 sources. Accordingly, prevalences per 1,000,000 adults (95% confidence interval [95% CI]) were estimated to be 30.7 (95% CI 21-40) for PAN, 25.1 (95% CI 16-34) for MPA, 23.7 (95% CI 16-31) for WG, and 10.7 (95% CI 5-17) for CSS. The overall prevalence was 2.0 times higher for subjects of European ancestry than for non-Europeans (P = 0.01).

CONCLUSIONS

This study provides the first prevalence estimates for these 4 vasculitides for a multiethnic, urban population. The significantly higher prevalence observed for Europeans may infer a genetic susceptibility of Caucasians. Compared with previous estimates based mostly on rural populations, the higher frequency of PAN and the lower frequency of WG might suggest specific environmental etiologic factors.

Epitope mapping of anti-PR3 antibodies using chimeric human/mouse PR3 recombinant proteins

Autoantibodies against proteinase 3 (PR3) and myeloperoxidase (MPO) (ANCA = anti-neutrophil cytoplasmic antibodies) are used as diagnostic tools for patients with small vessel vasculitis. ANCA are detected by different assays, but the correlation between the results of these assays is generally poor. The overall aim of the study was to provide a framework for the future development of new assays with an increased diagnostic yield. In order to express discrete epitopes of human PR3 (hPR3), the nonantigenic molecules murine PR3 (mPR3) and human leucocyte elastase (HLE) were used as a framework. We constructed recombinant chimeric vectors and were able to produce 6 hPR3/mPR3 proteins and 3 hPR3/HLE proteins. Anti-PR3 monoclonal antibodies differed in their binding pattern to the chimeras, but no distinct binding region could be identified for any monoclonal antibody. The recombinant hPR3/mPR3 were also tested in ELISA with sera from patients with Wegener's granulomatosis with renal involvement. The results show that patients have antibodies to different constructs, indicating that the patients vary in their antibody repertoire from the beginning of the disease, and that patients may have antibodies from a broad range of clones early in the course of the disease. Recombinant hPR3/mPR3 chimeric proteins have a potential to be used as antigens in future ANCA assays.

Pseudomonas-induced lung damage in cystic fibrosis correlates to bactericidal-permeability increasing protein (BPI)-autoantibodies

OBJECTIVE

Lung damage is the most common cause of death in cystic fibrosis (CF). It is induced by bacterial colonization and inflammatory activity perpetuates its course. Autoantibodies directed against BPI (bactericidal permeability increasing protein), called BPI-ANCA, have recently been associated with cystic fibrosis. Here we confirm this association and evaluate the relation between ANCA and total IgG level as they relate to bacterial colonization, pulmonary function, and musculoskeletal symptoms.

METHODS

BPI-ANCA, MPO-ANCA, and PR3-ANCA were measured with ELISA in 46 adult patients with CF. Total IgG was determined by immunoturbidimetry. Results were correlated to bacterial colonization, lung function and musculoskeletal symptoms.

RESULTS

BPI-ANCA was found in 33 patients. In the whole group, both BPI-ANCA and total IgG were inversely correlated to lung function, but in patients chronically colonized with Pseudomonas aeruginosa (P. aeruginosa), BPI-ANCA alone was correlated to lung damage (p = 0.01). Median lung function, measured as forced expiratory volume in 1 second, in P. aeruginosa colonized patients with high levels of BPI-ANCA was 43% of the predicted value. In BPI-ANCA negative, the corresponding figure was 83%. In patients not colonized with P. aeruginosa, this relation was less evident. No correlation between ANCA and musculoskeletal symptoms was seen.

CONCLUSION

P. aeruginosa induced lung damage in CF patients is associated with the presence of BPI-ANCA. P. aeruginosa colonized patients without BPI-ANCA have almost normal lung function. We suggest that BPI-ANCA discriminate P. aeruginosa colonized CF patients with severe lung damage from those whose disease is less destructive. Vasculitis like symptoms in CF are not ANCA associated.

Increased circulating levels of proteinase 3 in patients with anti-neutrophilic cytoplasmic autoantibodies-associated systemic vasculitis in remission

In systemic small vessel vasculitides, patients form autoantibodies against neutrophil granular proteins, anti-neutrophilic cytoplasmic autoantibodies (ANCA). Some correlation is seen between ANCA titre and disease activity, but whether this is cause or effect is still unknown. It has been reported that levels of proteinase 3 (PR3), one of the main ANCA antigens, are increased in patients with active disease. An increased level of circulating antigen could mean a predisposition to autoimmunity. In order to explore this we measured PR3 levels in patients with stable disease. In addition we measured neutrophil gelatinase-associated lipocalin (NGAL) as a specific marker of neutrophil degranulation, cystatin C as a marker of renal function as well as C-reactive protein (CRP), IL-6 and sTNFr1 as markers of inflammation. PR3, NGAL, IL-6 and sTNFr1 were measured in plasma by the ELISA technique. In the PR3 ELISA, we used anti-PR3 monoclonal antibodies as capture-antibodies and affinity-purified rabbit-anti-PR3 antibodies for detection. PR3-ANCA, myeloperoxidase (MPO)-ANCA, CRP and cystatin C were measured by routine methods. PR3 was significantly raised (P < 0.0001) in vasculitis patients (median 560 micro g/l, range 110-3,940, n = 59) compared with healthy blood donors (350 micro g/l, 110-580, n = 30) as well as disease controls (360, 110-580, n = 46). No correlation was seen with disease activity, inflammation or renal function. The raised NGAL levels correlated strongly with decreased renal function (r = 0.8, P < 0.001). After correcting for this, slightly increased levels (110, 42-340, n = 59) were observed compared with healthy blood donors (81, 38-130, n = 25), but not compared with the disease controls (120, 57-260, n = 48). In the disease controls, there was a significant correlation between NGAL and proteinase 3 (r = 0.3, p < 0.05), but this was not the case in the vasculitis patients. Whether patients had PR3-ANCA or MPO-ANCA was of no significance. In our measurements, we found significantly raised levels of PR3 in plasma from patients with small vessel vasculitis, regardless of ANCA specificity. This was not due to decreased renal function, ongoing inflammation or neutrophil activation. Plausible mechanisms for this include defects in the reticuloendothelial system, genetic factors and selective neutrophil degranulation or leakage.

Increased expression of the secretory leukocyte proteinase inhibitor in Wegener's granulomatosis

The secretory leucocyte proteinase inhibitor (SLPI) is a low molecular weight, tissue-specific inhibitor of proteases, such as elastase and cathepsin G. It is the major local protease inhibitor in the upper airways. Proteinase 3, the main autoantigen in Wegener's granulomatosis (WG), can degrade SLPI proteolytically. In addition, SLPI is sensitive to oxidative inactivation by myeloperoxidase-generated free oxygen radicals. SLPI also has an antimicrobial capacity that can be of interest, as infection is considered to play a role in the pathogenesis of WG. This study focuses on SLPI expression in patients suffering from WG, something that to our knowledge has not been explored hitherto. Serum samples and nasal biopsies were obtained from 12 Swedish WG patients, while buffy coats were obtained from 33 American WG patients. SLPI levels in serum were measured by means of ELISA and the protein was detected by means of immunohistochemistry in nasal biopsies. mRNA expression was studied by means of in situ hybridization on nasal biopsies and RT-PCR on leucocytes. IL-6 or ESR were measured as markers of inflammatory activity. Cystatin C or creatinine was measured as a marker of renal filtration. White blood cell counts were registered. In serum, we found close to normal SLPI levels, without any correlation to IL-6. Two patients had greatly elevated values, both of them suffering from severe renal engagement. Strong SLPI mRNA expression was found in nasal biopsies. RT-PCR on leucocyte mRNA showed normal or greatly elevated expression of SLPI mRNA, correlating with disease activity. Leukocyte SLPI expression seems to be up-regulated in active WG. Serum levels were measured in a small number of patients and were found to be close to normal. Lack of correlation to the acute phase response indicates a specific regulation. This might be linked to an altered protease/antiprotease balance. These findings could indicate that SLPI locally participates in the anti-inflammatory and perhaps antimicrobial response in WG.

Novel distribution of the secretory leucocyte proteinase inhibitor in kidney

The secretory leucocyte proteinase inhibitor (SLPI) is a low molecular weight, tissue-specific inhibitor of, for example, elastase and cathepsin G, which also have antimicrobial capacity. SLPI has been localised to the respiratory, gastrointestinal and genital tracts, but so far not to the kidney. The presence of SLPI in renal tubuli cells was demonstrated using immunohistochemistry and, by means of in situ hybridisation on human renal biopsies, we were able to demonstrate SLPI production. In various inflammatory conditions in the kidneys, the protease-antiprotease balance is disturbed. For this reason, as well as the possible role in the defence against ascending urinary tract infections, it is interesting to establish a source of SLPI in renal tubuli cells.

Internalization of proteinase 3 is concomitant with endothelial cell apoptosis and internalization of myeloperoxidase with generation of intracellular oxidants

The important issue addressed by the studies presented here is the mechanism of neutrophil-mediated damage to endothelial and epithelial cells during inflammation. Binding of neutrophil-released granule proteins to endothelial cells may be involved in vascular damage in patients with inflammatory vascular diseases. We have determined whether granule proteins proteinase 3(PR3) and/or myeloperoxidase (MPO) are internalized into endothelial cells, as examined by UV light, confocal, and electron microscopy. Coincident induction of apoptosis and/or the generation of intracellular oxidants were monitored. The results indicate that human endothelial cells (human umbilical vein endothelial cells, human umbilical arterial endothelial cells, human lung microvascular endothelial cells) internalize both PR3 and MPO, which are detected on the cell surface, in the cytoplasm, and possibly nuclear. Epithelial cells (small airway epithelial cells) internalized MPO but not PR3, implying that the mechanism of PR3 internalization may be cell-type specific and different from that of MPO. Internalization of PR3, but not MPO, correlated with activation of apoptosis. Internalization of MPO correlated with an increase in intracellular oxidant radicals. The requirement for the proteolytic activity of PR3 for the induction of apoptosis was examined by generating PR3-truncated fragments that did not contain the components of the catalytic triad. An apoptotic function was localized to the C-terminal portion of PR3. These studies reveal novel mechanisms by which the neutrophil granule proteins PR3 and MPO contribute to tissue injury at sites of inflammation.

How and why should we detect ANCA?

Antineutrophil cytoplasmic antibodies (ANCA) have become an established tool for the diagnosis of systemic vasculitis. The major role for ANCA testing is in diagnosing renal insufficiency of unknown origin, where a positive test indicates whether the patient will benefit from immunosuppressive treatment or not. A negative test result almost completely rules out the presence of systemic vasculitis. In this clinical setting the major antigens for ANCA are proteinase 3 and myeloperoxidase, and antibodies to these antigens can best be tested by ELISA. In other clinical settings like inflammatory bowel disease, arthritis and so on, several other ANCA specificities have been described and the IIF test is preferred. However, the clinical value of these somewhat more esoteric specificities is doubtful. New developments in assay techniques and better knowledge of specific epitopes will lead to tools for the improved diagnosis as well as follow up of patients during treatment, as has already been seen with the capture assay for PR3-ANCA.