EULAR recommendations for the management of ANCA-associated vasculitis: 2022 update

BACKGROUND

Since the publication of the EULAR recommendations for the management of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) in 2016, several randomised clinical trials have been published that have the potential to change clinical care and support the need for an update.

METHODS

Using EULAR standardised operating procedures, the EULAR task force undertook a systematic literature review and sought opinion from 20 experts from 16 countries. We modified existing recommendations and created new recommendations.

RESULTS

Four overarching principles and 17 recommendations were formulated. We recommend biopsies and ANCA testing to assist in establishing a diagnosis of AAV. For remission induction in life-threatening or organ-threatening AAV, we recommend a combination of high-dose glucocorticoids (GCs) in combination with either rituximab or cyclophosphamide. We recommend tapering of the GC dose to a target of 5 mg prednisolone equivalent/day within 4-5 months. Avacopan may be considered as part of a strategy to reduce exposure to GC in granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA). Plasma exchange may be considered in patients with rapidly progressive glomerulonephritis. For remission maintenance of GPA/MPA, we recommend rituximab. In patients with relapsing or refractory eosinophilic GPA, we recommend the use of mepolizumab. Azathioprine and methotrexate are alternatives to biologics for remission maintenance in AAV.

CONCLUSIONS

In the light of recent advancements, these recommendations provide updated guidance on AAV management. As substantial data gaps still exist, informed decision-making between physicians and patients remains of key relevance.

Evidence-Based Guideline for the diagnosis and management of eosinophilic granulomatosis with polyangiitis

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, characterized by asthma, eosinophilia and granulomatous or vasculitic involvement of several organs. The diagnosis and management of EGPA are often challenging and require an integrated, multidisciplinary approach. Current practice relies on recommendations and guidelines addressing the management of ANCA-associated vasculitis and not specifically developed for EGPA. Here, we present evidence-based, cross-discipline guidelines for the diagnosis and management of EGPA that reflect the substantial advances that have been made in the past few years in understanding the pathogenesis, clinical subphenotypes and differential diagnosis of the disease, as well as the availability of new treatment options. Developed by a panel of European experts on the basis of literature reviews and, where appropriate, expert opinion, the 16 statements and five overarching principles cover the diagnosis and staging, treatment, outcome and follow-up of EGPA. These recommendations are primarily intended to be used by healthcare professionals, pharmaceutical industries and drug regulatory authorities, to guide clinical practice and decision-making in EGPA. These guidelines are not intended to limit access to medications by healthcare agencies, nor to impose a fixed order on medication use.

[Eosinophilia: hypereosinophilic syndrome vs. eosinophilic granulomatosis with polyangiitis]

Hypereosinophilic syndrome (HES) is defined as a peripheral eosinophil count of > 1500/μl (assessed twice at an interval of ≥ 2 weeks) and an eosinophil-induced organ damage. Idiopathic HES is differentiated from primary (clonal or neoplastic) HES and secondary (reactive) HES, depending on the etiology. Eosinophilic granulomatosis with polyangiitis (EGPA) is categorized as a secondary form of HES and is characterized by hypereosinophilia and vasculitis of small to medium-sized vessels and can be associated with an antineutrophil cytoplasmic antibody (ANCA). The treatment of HES is dependent on the etiology. Clonal HES is treated according to the respective genetic aberration, e.g. with tyrosine kinase inhibitors or chemotherapy and allogenic stem cell transplantation. Secondary forms should be treated according to the underlying cause (e.g. parasitic infection). The treatment of EGPA is carried out with immunosuppressants depending on the disease stage and disease activity. Conventional drugs, such as glucocorticoids (GC), cyclophosphamide (CYC) and methotrexate (MTX) or biologics, such as the monoclonal anti-IL5 antibody mepolizumab are commonly used. Mepolizumab is also a good option for the treatment of idiopathic HES.

[ANCA-associated vasculitis]

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) are rheumatic diseases characterized by small-to-medium vessel vasculitis. Three different entities can be distinguished: granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA) and eosinophilic granulomatosis with polyangiitis (EGPA). While lung and renal involvement are typical manifestations of both GPA and MPA, EGPA usually shows paranasal sinus and lung involvement as well as a history of bronchial asthma. Furthermore, EGPA is frequently associated with cardiac disease and peripheral neuropathy. Cyclophosphamide or rituximab, combined with glucocorticoids, are used to induce remission of severe disease. Maintenance therapy options include rituximab as the first-line treatment, as well as methotrexate or azathioprine plus low-dose glucocorticoids.

German Society of Rheumatology recommendations for management of glucocorticoid-induced osteoporosis

BACKGROUND

Glucocorticoids are of substantial therapeutic importance in the treatment of inflammatory diseases, but are also associated with bone mineral density loss, osteoporosis, and fractures, especially with long-term use.

OBJECTIVE

To develop recommendations for the management of glucocorticoid-induced osteoporosis (GIOP) in adult patients on long-term glucocorticoid (GC) treatment.

METHODS

A systematic literature search (SLR) was conducted to synthesize the evidence for GIOP prevention and treatment options. Recommendations were developed based on SLR/level of evidence and by previously defined questions and in a structured group consensus process.

RESULTS

Recommendations include supplementation with calcium and vitamin D under long-term GC therapy in adults. If specific osteologic treatment is indicated, we recommend bisphosphonates or denosumab as first-line treatment. If fracture risk is high, we recommend teriparatide as primary specific osteologic treatment. Denosumab should be used in cases of severe renal insufficiency, and specific osteologic treatment should not be given in pregnancy. For patients who have not reached the treatment goal, a switch to another class of specific osteologic drugs should be performed. We recommend re-evaluation after a treatment duration of 3-5 years or after termination of long-term GC treatment.

CONCLUSION

This work aims to provide evidence-based and consensus-based recommendations for the best possible management of GIOP in Germany and to support treatment decisions.

[ANCA-associated vasculitis]

GPA/MPA INDUCTION OF REMISSION

As demonstrated in the ADVOCATE-trial avacopan allows for a substantial reduction of glucocorticoid (GC) use during induction of remission. A future role of avacopan in the treatment of GPA and MPA is likely. Likewise, the PEXIVAS-trial showed that GC reduction of up to 60 % compared to standard dose was equal effective. The same trial proved no benefit of plasma exchange in addition to standard induction of remission. Plasma exchange therefore is now mostly obsolete.

GPA/MPA MAINTENANCE

Rituximab is well established as maintenance therapy in AAV. The optimal duration however is still unknown. The MAINRITSAN 3 study indicates that prolonged use of more than 2 years is beneficial. EGPA:  In line with earlier clinical evidence a GWAS including 534 EGPA patients indicated at last 2 distinct subgroups. The conception of a predominantly "vasculitis" and a more "eosinophilic" phenotype is supported by this genetic evidence and most likely will lead to more differentiated therapies. With the IL5-antibody mepolizumab a first principle targeting the eosinophilic component of EGPA is now available and proved to be clinically beneficial.

[German Society of Rheumatology Recommendations for the management of glucocorticoid-induced Osteoporosis. German version]

BACKGROUND

Glucocorticoids are of substantial therapeutic importance in the treatment of inflammatory diseases, but are also associated with bone mineral density loss, osteoporosis, and fractures, especially with long-term use.

OBJECTIVE

To develop recommendations for the management of glucocorticoid-induced osteoporosis (GIOP) in adult patients on long-term glucocorticoid (GC) treatment.

METHODS

A systematic literature search (SLR) was conducted to synthesize the evidence for GIOP prevention and treatment options. Recommendations were developed based on SLR/level of evidence and by previously defined questions and in a structured group consensus process.

RESULTS

Recommendations include supplementation with calcium and vitamin D under long-term GC therapy in adults. If specific osteologic treatment is indicated, we recommend bisphosphonates or denosumab as first-line treatment. If fracture risk is high, we recommend teriparatide as primary specific osteologic treatment. Denosumab should be used in cases of severe renal insufficiency, and specific osteologic treatment should not be given in pregnancy. For patients who have not reached the treatment goal, a switch to another class of specific osteologic drugs should be performed. We recommend re-evaluation after a treatment duration of 3-5 years or after termination of long-term GC treatment.

CONCLUSION

This work aims to provide evidence-based and consensus-based recommendations for the best possible management of GIOP in Germany and to support treatment decisions.

Genome-wide association study of eosinophilic granulomatosis with polyangiitis reveals genomic loci stratified by ANCA status

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare inflammatory disease of unknown cause. 30% of patients have anti-neutrophil cytoplasmic antibodies (ANCA) specific for myeloperoxidase (MPO). Here, we describe a genome-wide association study in 676 EGPA cases and 6809 controls, that identifies 4 EGPA-associated loci through conventional case-control analysis, and 4 additional associations through a conditional false discovery rate approach. Many variants are also associated with asthma and six are associated with eosinophil count in the general population. Through Mendelian randomisation, we show that a primary tendency to eosinophilia contributes to EGPA susceptibility. Stratification by ANCA reveals that EGPA comprises two genetically and clinically distinct syndromes. MPO+ ANCA EGPA is an eosinophilic autoimmune disease sharing certain clinical features and an HLA-DQ association with MPO+ ANCA-associated vasculitis, while ANCA-negative EGPA may instead have a mucosal/barrier dysfunction origin. Four candidate genes are targets of therapies in development, supporting their exploration in EGPA.

Update Therapie der ANCA-assoziierten Vaskulitiden

Dieser Artikel gibt eine Übersicht über die aktuellen deutschen und europäischen Therapieempfehlungen zu den ANCA-assoziierten Vaskulitiden (AAV) sowie ein Update zu seither publizierten wichtigen Therapiestudien. Nach den deutschen und europäischen Empfehlungen erfolgt die Remissionsinduktion bei GPA/MPA mit organbedrohender Erkrankung mit Glucocorticoiden und Cycloposphamid oder Rituximab, bei nicht organbedrohender Erkrankung mit Glucocorticoiden und Methotrexat (MTX) oder Mycophenolat-Mofetil (MMF). Die kürzlich publizierte MYCYC-Studie unterstützt die Empfehlungen; sie zeigte eine Nicht-Unterlegenheit gegenüber i. v. Cyclosphamid bei GPA/MPA-Patienten mit nicht-organbedrohender und organbedrohender Erkrankung auf. Die remissionserhaltende Therapie soll mit niedrig-dosierten Glucocorticoiden sowie Azathioprin, MTX und Rituximab durchgeführt werden. Rituximab wurde Ende 2018 auf der Basis der MAINRITSAN-Studie als remissionserhaltende Therapie zugelassen und ist damit nun die formal einzige zur Remissionserhaltung zugelassene Therapie. Mehrere Studien zur untersuchten zudem die kurze Anwendung von Glucocorticoiden (z. B. durch additive Therapie mit Avacopan) in der Remissionsinduktion und das komplette Ausschleichen von Glucocorticoiden in der Remissionserhaltung. Die ersten Ergebnisse hierzu sind vielversprechend; Langzeitdaten stehen allerdings aus. Für die sehr viel seltenere EGPA liegen insgesamt deutlich weniger Studiendaten vor. Die Therapie wird jedoch im Wesentlichen nach den gleichen Prinzipien wie bei den anderen AAV durchgeführt. Neuerdings steht, in Deutschland für diese Indikation aber noch nicht zugelassen, eine Biologikatherapie mit dem Anti-IL-5-Antikörper Mepolizumab zur Verfügung.

Immune stimulatory effects of neutrophil extracellular traps in granulomatosis with polyangiitis

OBJECTIVES

The aim of this study was to analyse the role of netting neutrophils in the pathogenesis of granulomatosis with polyangiitis (GPA), especially their interplay with peripheral blood mononuclear cells (PBMCs).

METHODS

The amount of cell-free DNA (cfDNA) was determined in sera from GPA patients (pairs active/inactive state of disease, n=18) and from healthy controls (HCs, n=10). Furthermore, we performed in vitro incubation experiments using PBMCs and NETs from patients and HCs for accessing the effect of NETs on PBMC behaviour. We determined proliferation of T- and B-cells (CSFE assay), B-cell maturation (CD38 staining and flow cytometry), production of IgG (ELISpot, ELISA), and secretion of the cytokines IFN-γ, IL-4, IL-10, IL-17A (ELISA).

RESULTS

We detected a significant increase in serum cfDNA levels of GPA patients compared to HCs. The concentration of cfDNA was associated with disease activity. NETs of patients and HCs induced proliferation of CD4+ T- cells and CD19+ B-cells and maturation of B-cells. Furthermore, we detected an increase in IL-17A secretion after stimulating PBMCs with NETs. A significant difference between PBMCs from GPA patients and HCs was not detectable.

CONCLUSIONS

NETs activate PBMCs of HCs and GPA patients. Our findings give supportive evidence that NETosis plays a role in the pathogenesis of GPA.

Serum immunoglobulin G4 in giant cell arteritis and polymyalgia rheumatica

OBJECTIVES

To date, no specific serum marker for giant cell arteritis and polymyalgia rheumatica has been established in routine practice. Therefore, the aim of this study was to examine whether immunoglobulin G4 serum concentrations could be a potential biomarker for the differentiation of both diseases.

METHODS

Serum immunoglobulin G4 (IgG4) concentrations were measured in patients with giant cell arteritis (n=41) and polymyalgia rheumatica (n=27) by an in-house enzyme-linked immunosorbent assay. In the subgroup of untreated patients with disease activity (polymyalgia rheumatica n=27, giant cell arteritis n=19) additional parameters of T-helper 2 cell inflammatory responses were analysed.

RESULTS

IgG4-values above the prior determined cut-off value of 1400 μg/ml in giant cell arteritis were rare and also significantly less frequent in giant cell arteritis than in polymyalgia rheumatica patients (7.3% vs. 44.4%; p<0.001). The relative risk that patients with clinical features of PMR, presenting without elevated IgG4 levels, have simultaneously GCA was 5.8 compared to those patients with elevated IgG4 levels. In untreated patients absolute counts of eosinophilic leukocytes were lower in giant cell arteritis than in polymyalgia rheumatica (p=0.002) and the cytokines interleukin-4 (p=0.013) and interleukin-10 (p=0.033) were less frequently detectable in giant cell arteritis than in polymyalgia rheumatica.

CONCLUSIONS

In giant cell arteritis serum levels of IgG4 usually are within the normal range. In polymyalgia rheumatica however, increased IgG4 serum levels are frequently found. Normal IgG4 serum levels in polymyalgia rheumatica may have predictive value in identifying patients with additional, clinically non-apparent giant cell arteritis.

[Clinical spectrum of IgG4-related diseases and the connection to rheumatology]

Rheumatologist should be familiar with the concept of IgG4-related disease (IgG4-RD). Due to the clinical spectrum IgG4-RD can fall directly within the scope of rheumatology and are often diagnosed primarily by rheumatologists. Furthermore, IgG4RD are relevant differential diagnoses for many other rheumatic conditions. Finally, there are an increasing amount of data suggesting an important role of immunological processes observed in IgG4-RD for other rheumatic diseases.

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.

Diagnostic Value of Procalcitonin in ANCA-Associated Vasculitis (AAV) to Differentiate Between Disease Activity, Infection and Drug Hypersensitivity

Objective:

Procalcitonin (PCT) is considered to be a specific marker for severe bacterial infections and sepsis. Elevated PCT levels have been reported in active autoimmune diseases without infection.

The aim of this study was to assess the diagnostic value of PCT serum levels in ANCA-associated vasculitis (AAV) patients with respect to infection, disease activity and drug fever using a high sensitive PCT detection method.

Methods:

In 53 AAV patients with elevated C-reactive protein (CRP) PCT was determined by the Thermo Scientific BRAHMS PCT sensitive KRYPTOR assay. Patients underwent standardized diagnostic procedures for evaluation of disease activity and infection.

Results:

53 patients with AAV and elevated CRP (7.7±6.9 mg/dl, PCT 0.34±1.02 ng/ml) were assessed, 10 had infection with elevated CRP levels of 11.2±10.2 mg/dl and PCT levels of 1.06±2.07 ng/dl. 43 patients had no evidence of infection, 36 of them were presented with AAV with normal or only slightly positive PCT levels in active disease (n=36) (PCT 0.06±0.06 ng/ml). 7 patients had increased PCT levels due to azathioprine hypersensitivity (0.76±1.01 ng/ml). For discrimination between infection and vasculitis activity PCT was more useful than CRP with the best cut-off at 0.1 ng/ml (sensitivity 60%, specificity 92%).

Conclusion:

In contrast to previous studies using semiquantitative PCT assays, the KRYPTOR performs better with respect to discrimination of infection from active AAV. In all patients assessed with active AAV (and without infection) PCT levels remained below the PCT reference limit (0.5 ng/ml) for infections. Drug hypersensitivity seems to be an important differential diagnosis in the setting of elevated CRP and PCT in patients who receive azathioprine.

Clinical presentation and long-term outcome of 144 patients with microscopic polyangiitis in a monocentric German cohort

OBJECTIVE

To evaluate the clinical presentation and long-term outcome of a vasculitis centre cohort of patients with microscopic polyangiitis (MPA) with respect to organ manifestations, treatment, chronic damage and mortality.

METHODS

We performed a retrospective chart review at our vasculitis referral centre. MPA patients admitted between 1991 and 2013 classified by a modified European Medicines Agency algorithm were diagnosed and treated according to a standardized interdisciplinary approach.

RESULTS

Comprehensive data from standardized interdisciplinary workups was available for 144 patients (median follow-up 72 months). The overall standardized mortality ratio was 1.40 (95% CI 0.91, 2.07; P = 0.13). We observed a higher mortality [hazard ratio (HR) 4.04 (95% CI 1.21, 13.45), P = 0.02] in 17 patients with MPA-associated fibrosing interstitial lung disease (ILD) and 56 patients with peripheral nervous system involvement [HR 5.26 (95% CI 1.10, 25.14), P = 0.04] at disease onset. One hundred and fifteen patients (79.9%) responded to the initial treatment. Sixty-one (42.3%) achieved complete remission and 54 (37.5%) achieved partial remission. Twenty (13.9%) showed a refractory disease course.

CONCLUSION

MPA patients at our tertiary rheumatology referral centre seemed to have a less severe phenotype resulting in a less severe disease course and better outcome than reported in other cohorts. Fibrosing ILD was significantly associated with mortality in this cohort.

[Genetic risk factors for vasculitis]

Among the vasculitides, genome-wide association studies (GWAS) have so far been performed for Behçet's disease, Kawasaki disease, granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA). These studies delivered valuable information with respect to the pathogenesis and therapeutic targets: Apart from HLA-B51 and HLA-A26, distinct polymorphisms in cytokine (IL-10) or cytokine receptor (IL-12R/IL-23R) genes, transcription factors (STAT4) and genes encoding for proteins involved in antigen presentation (ERAP-1) have been identified as risk factors for Behçet's disease. The results of two GWAS performed for antineutrophil cytoplasmic antibody (ANCA) associated vasculitis GPA and MPA in Europe and the USA confirmed that the HLA-DP locus is the most relevant risk factor for GPA. Furthermore, the European GWAS confirmed SERPINA-1, a deficiency allele of the α-1-antitrypsin gene, as a genetic risk factor in GPA and identified a polymorphism in the proteinase 3 gene (PR3), one of the target antigens of ANCA, as a risk factor for GPA and PR3-ANCA-associated vasculitis.

Caveolin-1 single nucleotide polymorphism in antineutrophil cytoplasmic antibody associated vasculitis

Objective

Immunosuppression is cornerstone treatment of antineutrophil cytoplasmic antibody associated vasculitis (AAV) but is later complicated by infection, cancer, cardiovascular and chronic kidney disease. Caveolin-1 is an essential structural protein for small cell membrane invaginations known as caveolae. Its functional role has been associated with these complications. For the first time, caveolin-1 (CAV1) gene variation is studied in AAV.

Methods

CAV1 single nucleotide polymorphism rs4730751 was analysed in genomic DNA from 187 white patients with AAV from Birmingham, United Kingdom. The primary outcome measure was the composite endpoint of time to all-cause mortality or renal replacement therapy. Secondary endpoints included time to all-cause mortality, death from sepsis or vascular disease, cancer and renal replacement therapy. Validation of results was sought from 589 white AAV patients, from two European cohorts.

Results

The primary outcome occurred in 41.7% of Birmingham patients. In a multivariate model, non-CC genotype variation at the studied single nucleotide polymorphism was associated with increased risk from: the primary outcome measure [HR 1.86; 95% CI: 1.14-3.04; p=0.013], all-cause mortality [HR:1.83; 95% CI: 1.02-3.27; p=0.042], death from infection [HR:3.71; 95% CI: 1.28-10.77; p=0.016], death from vascular disease [HR:3.13; 95% CI: 1.07-9.10; p=0.037], and cancer [HR:5.55; 95% CI: 1.59-19.31; p=0.007]. In the validation cohort, the primary outcome rate was far lower (10.4%); no association between genotype and the studied endpoints was evident.

Conclusions

The presence of a CC genotype in Birmingham is associated with protection from adverse outcomes of immunosuppression treated AAV. Lack of replication in the European cohort may have resulted from low clinical event rates. These findings are worthy of further study in larger cohorts.

Genetics of toll like receptor 9 in ANCA associated vasculitides

OBJECTIVES

To investigate the contribution of genetic polymorphisms of toll like receptor (TLR) 9 and related genes on the susceptibility and clinical manifestation of anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitides (AAV).

METHODS

Four single nucleotide polymorphisms (SNPs) in TLR9 were genotyped in 863 German AAV cases and 1344 healthy controls. Significant results were replicated in a cohort of 426 Dutch and British AAV cases. 11 polymorphisms in TLR9 related genes were studied concomitantly.

RESULTS

A strong association of TLR9 genotypes and haplotypes with granulomatosis with polyangiitis was observed as well as a contrariwise association with microscopic polyangiitis. The association was confirmed when cases were compared according to ANCA status rather than to clinical entity. This was partly replicated in the second cohort leading to a striking overall difference in TLR9 allele/haplotype frequencies between proteinase 3 (PR3) ANCA+ and myeloperoxidase (MPO) ANCA+ cases (p=0.00000398, pc=0.000016, OR 1.68 (95% CI 1.35 to 2.1) for rs352140; p=0.000011, pc=0.000044, OR 1.64 (95% CI 1.31 to 2.04) for a 3-SNP haplotype). No significant association or epistatic effect was detected for TLR9 related genes: interleukin 6, interleukin 23 receptor, myeloid differentiation primary response 88, TNF receptor-associated factor 6, interleukin-1 receptor-associated kinase 4, discs large homolog 5 and nucleotide-binding oligomerisation domain containing 2.

CONCLUSIONS

We provide further evidence that PR3-ANCA+ AAV differs genetically from MPO-ANCA+ AAV. TLR9 signalling may be involved in disease pathology, favouring models of infectious agents triggering AAV development.

Toll-like receptor TLR2 and TLR9 ligation triggers neutrophil activation in granulomatosis with polyangiitis

OBJECTIVE

The aim of the study was to characterize the expression of TLR2, TLR4 and TLR9 in PMNs of patients with granulomatosis with polyangiitis (GPA) and to elucidate the role of these receptors in GPA with respect to neutrophil activation.

METHODS

The expression of TLR2, TLR4 and TLR9 was determined on ex vivo PMNs in whole blood samples of GPA patients (n = 35) and healthy controls (HCs) (n = 24). Isolated PMNs were stimulated in vitro with TLR agonists and assessed for degranulation, membrane proteinase 3 (mPR3) expression, soluble l-selectin shedding and cytokine production (IL-8) in five GPA patients and five HCs. The priming effects of TLR2 and TLR9 ligation were assessed by measurement of serine protease activity after stimulation with PR3-ANCA.

RESULTS

There were no significant differences in the ex vivo expression of TLRs on PMNs in HCs and GPA patients. Stimulation of TLR4 and TLR9 induced MPO release, stimulation with TLR2, TLR4 and TLR9 ligands elicited IL-8 production and stimulation of TLR2 and TLR9 led to an upregulation in mPR3 expression on PMNs with no significant differences between GPA and HC after 1 or 24 h stimulation. Priming of PMNs with TLR2 and TLR9 ligands induced degranulation after subsequent stimulation with PR3-ANCA, which was comparable to priming with TNF-α.

CONCLUSION

Expression of TLR2, TLR4 and TLR9 in PMNs and the TLR-induced activation of PMNs was comparable in GPA and HC. mPR3 upregulation by TLR2 and TLR9 stimulation and the priming effect of TLR ligands on PMNs may have a potential implication for triggering disease activity during infection in GPA.

[Update on granulomatosis with polyangitis (GPA, Wegener's granulomatosis)]

Granulomatosis with polyangitis (GPA, Wegener's granulomatosis) is characterized by a granulomatous inflammation of the respiratory tract and a necrotizing ANCA-associated small to medium-size vessel vasculitis with a predilection for the lungs (pulmonary capillaritis) and kidneys (necrotizing glomerulonephritis). The disease evolves stage-wise and typically starts as inflammation of the respiratory tract followed by development of systemic vasculitis manifestations. Today, treatment is evidence-based and adapted according to activity and disease stage which has resulted in a significant improvement in long-term outcome. Early mortality during the first year of treatment poses one of the main problems and is a result of infections under immunosuppressive treatment. Furthermore, treatment of refractory disease activity which is often represented by granulomatous manifestations is still a challenge and may result in significant organ damage if not treated successfully.

Genetically distinct subsets within ANCA-associated vasculitis

BACKGROUND

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis is a severe condition encompassing two major syndromes: granulomatosis with polyangiitis (formerly known as Wegener's granulomatosis) and microscopic polyangiitis. Its cause is unknown, and there is debate about whether it is a single disease entity and what role ANCA plays in its pathogenesis. We investigated its genetic basis.

METHODS

A genomewide association study was performed in a discovery cohort of 1233 U.K. patients with ANCA-associated vasculitis and 5884 controls and was replicated in 1454 Northern European case patients and 1666 controls. Quality control, population stratification, and statistical analyses were performed according to standard criteria.

RESULTS

We found both major-histocompatibility-complex (MHC) and non-MHC associations with ANCA-associated vasculitis and also that granulomatosis with polyangiitis and microscopic polyangiitis were genetically distinct. The strongest genetic associations were with the antigenic specificity of ANCA, not with the clinical syndrome. Anti-proteinase 3 ANCA was associated with HLA-DP and the genes encoding α(1)-antitrypsin (SERPINA1) and proteinase 3 (PRTN3) (P=6.2×10(-89), P=5.6×10(-12,) and P=2.6×10(-7), respectively). Anti-myeloperoxidase ANCA was associated with HLA-DQ (P=2.1×10(-8)).

CONCLUSIONS

This study confirms that the pathogenesis of ANCA-associated vasculitis has a genetic component, shows genetic distinctions between granulomatosis with polyangiitis and microscopic polyangiitis that are associated with ANCA specificity, and suggests that the response against the autoantigen proteinase 3 is a central pathogenic feature of proteinase 3 ANCA-associated vasculitis. These data provide preliminary support for the concept that proteinase 3 ANCA-associated vasculitis and myeloperoxidase ANCA-associated vasculitis are distinct autoimmune syndromes. (Funded by the British Heart Foundation and others.).

Comparative analysis of different commercial ELISA systems for the detection of anti-neutrophil cytoplasm antibodies in ANCA-associated vasculitides

OBJECTIVES

To assess the diagnostic performance of 11 commercial PR3- and MPO-ANCA ELISA systems (direct, capture and high sensitive [hs] ELISA).

METHODS

Sera from 90 patients with AAV (GPA, MPA and CSS) and 20 disease controls (SLE; RA) and healthy individuals were tested for the presence of ANCA by IFT and by different ELISAs for the presence of PR3-and MPO-ANCA, respectively. Furthermore, the binding capacity of the IUIS-CDC reference sera for PR3-/MPO-ANCA in different commercial assays was analysed.

RESULTS

Commercial ELISA kits for PR3-ANCA differed moderately in their sensitivity (from 45% to 62.5%). The highest sensitivity for PR3-ANCA was obtained with hs ELISA (kit A) and capture ELISA (kit N). Testing for MPO-ANCA the highest sensitivity (85%) was obtained with direct ELISA (kit D and I). Specificity was high in all kits. Only three PR3-ANCA commercial kits and three MPO-ANCA kits produced binding at the expected value for the IUIS-CDC reference sera (100 U/ml). In all of the kits, serial dilutions of the reference sera did not yield linearity.

CONCLUSIONS

Second (capture) and third (high sensitivity) generation PR3-ANCA ELISA kits are superior to conventional ELISAs. Direct and capture MPO-ANCA ELISAs showed a good overall performance in all kits. Most of the kits have not been standardised to allow their results to be compared.

Rituximab for refractory granulomatosis with polyangiitis (Wegener's granulomatosis): comparison of efficacy in granulomatous versus vasculitic manifestations

OBJECTIVE

First, to investigate the overall efficacy and safety of rituximab (RTX) in refractory granulomatosis with polyangiitis (GPA) in a tertiary referral centre. Second, to compare the efficacy of RTX in granulomatous and vasculitic manifestations in GPA.

PATIENTS AND METHODS

This study comprised a retrospective, standardised data collection from all patients who received RTX for refractory Wegener's granulomatosis from 2002 to 2010. Patients were assessed by a standardised interdisciplinary diagnostic procedure (including ear, nose and throat and ophthalmology assessment, MRI, immunodiagnostics, B-cell levels and Birmingham Vasculitis Activity Score) and were treated by standardised therapeutic regimens according to available evidence.

RESULTS

59 patients received 75 cycles of RTX. 9.3% achieved complete remission. A response was documented in 61.3% (improvement in 52%, unchanged disease activity in 9.3%), 26.7% had refractory disease. Birmingham Vasculitis Activity Score, disease extent index, erythrocyte sedimentation rate, C-reactive protein and prednisolone demand decreased significantly. All patients achieved B-cell depletion. Granulomatous manifestations such as orbital granuloma and pachymeningitis were more frequently refractory to RTX than vasculitis or other granulomatous manifestations. Thus, for example, complete remission/improvement was found in 89.2% of patients with renal disease and in only 44.4% of those with orbital masses (p=0.003). The relapse rate was 44.4% after a median period of 13.5 months. Adverse events occurred in 29%, pneumonia in 15% and death in 3%.

CONCLUSION

The overall response rate of refractory GPA to RTX was high (61.3% complete remission or improvement). Response rates of vasculitic manifestations were excellent; failure of response/progress was mostly due to granulomatous manifestations, especially orbital masses. Relapse rates were high (40%) despite maintenance treatment.

ANCA-associated vasculitis is linked to carriage of the Z allele of α₁ antitrypsin and its polymers

BACKGROUND

Small studies have linked α1 antitrypsin (α1AT) deficiency to patients with antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV).

OBJECTIVE

To test the validity and the mechanism of this association between α1AT and AAV.

METHODS

The distribution of α1AT deficiency alleles Z and S was compared between 856 White Europeans with AAV and 1505 geographic and ethnically matched healthy controls. Genotyping was performed by allelic discrimination assay.

RESULTS

were compared between cases and controls using χ(2) tests. The serum and renal biopsies for α1AT polymers were compared using the polymer-specific 2C1 antibody. The role of α1AT polymers in promoting inflammation was investigated by examining their ability to prime neutrophils for ANCA activation as assessed by CD62L shedding, superoxide production and myeloperoxidase degranulation. Results The Z but not the S allele was over-represented in the patients compared with controls (HR=2.25, 95% CI 1.60 to 3.19). Higher concentrations of polymers of α1AT were detected in serum from patients carrying the Z allele than in those not carrying the Z allele (median (IQR) 1.40 (0.91-3.32) mg/dl vs 0.17 (0.06-0.28) mg/dl, p<0.001); polymers of α1AT were also seen in the renal biopsy of a patient with vasculitic glomerulonephritis. Polymers of α1AT primed neutrophils with CD62L shedding and increased superoxide production following ANCA activation. Carriage of the Z allele was not associated with disease severity, survival or relapse.

CONCLUSIONS

The Z but not the S deficiency allele is associated with AAV. Polymers of α1AT are present in the serum and glomeruli of at least some patients with the Z allele, which may promote inflammation through priming of neutrophils.

Conditions in subjects with rheumatic diseases: pulmonary manifestations of vasculitides

Pulmonary involvement is a common complication of vasculitides, especially small vessel vasculitides. This review provides an overview of vasculitic manifestations of the lung as well as of other organs involved in vasculitides. Furthermore, it provides the diagnostic procedures required to asses a patient with vasculitic lung involvement and gives an overview of current treatment strategies.

[The genetics of vasculitides]

Genetic association studies have been of great value in the past by contributing to the understanding of pathophysiological mechanisms of chronic inflammatory and autoimmune diseases. Many genetic risk factors have been identified which confer susceptibility for one or several (autoimmune) disease(s). Using a candidate-gene approach, the first genetic risk factors and polymorphisms of vasculitides have been identified. Due to the rarity of autoimmune vasculitides often only small sample numbers have been generated and analysed, leading to inconsistent results. Furthermore, differences in ethnic background may complicate analysis. Only few of the detected risk factors have been reliably replicated in larger cohorts, such as the association of the PTPN22*620W allele with WG and MPA, the deficiency allele Pi*Z of the alpha1 antitrypsin gene and the HLA-DPB*04041 allele with WG and the HLA-DRB3/DRB4 with CSS. Genome-wide association studies (GWAS) offer the advantage of screening the whole genome for risk factors rather than relying on disease models postulated by the investigator; however, they require even larger sample sizes. Initial results from GWA studies are available for Behçet's disease and Kawasaki syndrome, which identified new genetic associations but require replication, especially since some of the identified risk factors could not be linked to pathophysiological pathways to date.

[Classification and therapy of vasculitis according to recommendations of the European League Against Rheumatism (EULAR)]

Vasculitis is still being classified according the criteria of the American College of Rheumatology and the Chapel Hill Consensus Conference Definitions. Diagnostic criteria are currently being established. The classification criteria are based on the size of the inflamed blood vessel (e.g. large vessel vasculitis with inflammation of the aorta and its branches), clinical symptoms and findings (such as cephalalgia in giant cell arteritis) and histological findings. In recent years a definition of disease stages and activity has been established and a number of controlled trials have been carried out in order to provide evidence-based stage and activity adapted therapy regimens. Recommendations for the management of vasculitis have been published in 2009 by EULAR (European League Against Rheumatism). This article gives a review of the classification of vasculitis and summarizes the current European guidelines on management.

Diagnostic and therapeutic management of Churg-Strauss syndrome

Churg-Strauss syndrome is a rare small-vessel vasculitis that is associated with asthma, granulomatous inflammation, peripheral/tissue eosinophilia and a positive antineutrophil cytoplasmic antibody status (in approximately 40% of patients). The disease can be organ- and life-threatening, either due to tissue eosinophil infiltration such as myocarditis or due to vasculitis manifestations, for example glomerulonephritis. Furthermore, life-threatening disease can also occur due to the side effects of immunosuppression, for example, infection. A thorough diagnostic work-up should be performed in order to identify all organs involved and to rule out other disorders with similar features, such as hypereosinophilic syndrome. Therapeutic management is conducted according to disease stage and activity. Glucocorticoids remain the mainstay of therapy; however, further immunosuppressants (e.g., cyclophosphamide for life-threatening disease) are usually required. Future promising therapy options target cytokines involved in the disease process, such as IL-5.

Prospective long-term follow-up of patients with localised Wegener's granulomatosis: does it occur as persistent disease stage?

Objective

To identify patients with localised Wegener's granulomatosis (locWG) to assess whether it occurs as a long-term disease stage or phenotype and to characterise its outcome.

Methods

Patients in a ‘localised stage’ with histological criteria compatible with WG and a follow-up period of ≥1 year were included. They were prospectively followed at the Vasculitis Center Schleswig-Holstein from 1989 to 2009 and the clinical manifestations, antineutrophil cytoplasmic autoantibodies (ANCA) status and damage were evaluated. Immunosuppression was adapted to disease activity and severity in a step-up regimen.

Results

Of 1024 patients with suspected WG, 99 were clinically diagnosed with locWG and 50 fulfilled the inclusion criteria (72% women, median age 43 years, 46% ANCA-positive). The median follow-up was 48 months. All achieved a response to treatment, 34% achieved complete remission, 1–4 relapses occurred in 46%, 5 (10%) had generalised disease (median 6 years after onset). ANCA status was not associated with relapse (p=0.98), transition to generalised disease (p=0.51) or refractory manifestations (p=0.60). 47% required cyclophosphamide for localised manifestations, 36% of them for pulmonary masses and 24% for orbital masses. 66% developed organ damage, mostly due to bony destruction or space obturation (28% saddle nose, 24% septal perforation, 10% orbital wall destruction). There were two deaths that were not related to WG.

Conclusion

There is evidence that locWG is a long-term disease stage or phenotype (5% of all patients with WG), 46% of whom are ANCA-positive. LocWG is characterised by destructive and/or space-consuming lesions associated with high relapse rates (46%) and local damage.

A functionally relevant IRF5 haplotype is associated with reduced risk to Wegener's granulomatosis

Wegener's granulomatosis (WG), characterized by systemic vasculitis and granulomatous inflammation, is a rare chronic rheumatic condition potentially sharing some etiopathological principles with other autoimmune disorders, e.g., rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). Several large association studies have identified genetic risk factors for RA and SLE. Thereof, we have evaluated the relevance of the most promising ones in WG. 22 single nucleotide polymorphisms (SNPs) within or in the vicinity of CCL21, CD40, CDK6, IL21, IL2RB, IRF5, KIF5A, KLF12, MMEL1, PRKCQ, STAT4, TNFAIP3, and TRAF1/C5 have been genotyped in >600 German WG cases and >800 matched controls. While most polymorphisms did not show suspicious effects on WG susceptibility, SNPs representing TNFAIP3 (rs6922466, p = 0.032, odds ratio (OR) 0.83, 95% confidence interval (CI) 0.7--0.98) and CDK6 (rs42041, p = 0.0201, OR 1.21, 95% CI 1.03-1.43) revealed nominally significant differences in allele distribution. The strongest association was detected for a functionally relevant four SNP haplotype of IRF5, which comprised a protective effect (p = 0.0000897, p (corrected) = 0.0012, OR 0.73, 95% CI 0.62-0.85) similar to those previously seen in RA and SLE. Thus, we suggest that WG, SLE, and RA share some, but not many, genetic risk factors, which supports models of partly overlapping etiopathological mechanisms in these disorders.