Cluster Analysis to Explore Clinical Subphenotypes of Eosinophilic Granulomatosis With Polyangiitis.

OBJECTIVE: Previous studies suggested that distinct phenotypes of eosinophilic granulomatosis with polyangiitis (EGPA; formerly known as Churg-Strauss syndrome) could be determined by the presence or absence of antineutrophil cytoplasmic antibodies (ANCA), reflecting predominant vasculitic or eosinophilic processes, respectively. This study explored whether ANCA-based clusters or other clusters can be identified in EGPA. METHODS: This study used standardized data of 15 European centers for patients with EGPA fulfilling widely accepted classification criteria. We used multiple correspondence analysis, hierarchical cluster analysis, and a decision tree model. The main model included 10 clinical variables (musculoskeletal [MSK], mucocutaneous, ophthalmological, ENT, cardiovascular, pulmonary, gastrointestinal, renal, central, or peripheral neurological involvement); a second model also included ANCA results. RESULTS: The analyses included 489 patients diagnosed between 1984 and 2015. ANCA were detected in 37.2% of patients, mostly perinuclear ANCA (85.4%) and/or antimyeloperoxidase (87%). Compared with ANCA-negative patients, those with ANCA had more renal (P < 0.001) and peripheral neurological involvement (P = 0.04), fewer cardiovascular signs (P < 0.001), and fewer biopsies with eosinophilic tissue infiltrates (P = 0.001). The cluster analyses generated 4 (model without ANCA) and 5 clusters (model with ANCA). Both models identified 3 identical clusters of 34, 39, and 40 patients according to the presence or absence of ENT, central nervous system, and ophthalmological involvement. Peripheral neurological and cardiovascular involvement were not predictive characteristics. CONCLUSION: Although reinforcing the known association of ANCA status with clinical manifestations, cluster analysis does not support a complete separation of EGPA in ANCA-positive and -negative subsets. Collectively, these data indicate that EGPA should be regarded as a phenotypic spectrum rather than a dichotomous disease.

[Eosinophilia: hypereosinophilic syndrome vs. eosinophilic granulomatosis with polyangiitis]. / Eosinophilie: hypereosinophiles Syndrom versus eosinophile Granulomatose mit 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.

The safety and effectiveness of tocilizumab in elderly patients with rheumatoid arthritis and in patients with comorbidities associated with age.

OBJECTIVES: To examine the safety and effectiveness of long-term tocilizumab treatment in elderly patients with rheumatoid arthritis (RA) and patients with age-associated comorbidities. METHODS: ICHIBAN (NCT01194401) was a prospective, non-interventional study that observed adult patients with active moderate-to-severe RA in German rheumatology clinics and practices for up to two years. Patients were to be treated according to the tocilizumab label. Here, we present safety and effectiveness data analysed according to patient age. RESULTS: Of the 3,164 patients treated with at least one dose of tocilizumab, 924 patients were <50 years old, 1496 patients were 50-65 years old, and 744 patients were >65 years old at baseline. Patients >65 years had the highest baseline DAS28-ESR, CDAI, and HAQ-DI scores, along with the highest burden of comorbidities, such as diabetes, coronary heart disease, anaemia, and renal insufficiency. Under treatment with tocilizumab, patients >65 years had similar improvements in DAS28-ESR, CDAI and patient-reported outcomes (fatigue, pain, sleeplessness) with similar glucocorticoid savings compared to patient groups <65 years. Patients >65 years with late-onset RA achieved similar reductions in disease activity compared to early-onset patients. Despite numerically higher rates of adverse events (AEs), serious AEs and serious infections in patients >65 years, there were similar rates of AEs leading to withdrawal. CONCLUSIONS: Elderly patients in ICHIBAN experienced improvements similar to younger patients in most effectiveness endpoints with only slightly higher rates of AEs, indicating an overall net-positive risk-benefit ratio of tocilizumab treatment regardless of patient age.

[Update on treatment of ANCA-associated vasculitis: Granulomatosis with polyangiitis and Microscopic Polyangiitis]. / Therapie-Update der ANCA-assoziierten Vaskulitiden: Granulomatose mit Polyangiitis und Mikroskopische Polyangiitis.

In the past 2 years several important studies on the treatment of granulomatosis with polyangiitis (PGA) and microscopic polyangiitis (MPA) have been published, which led to a change in the therapeutic procedure of these diseases. Rituximab is now established as the standard treatment for remission induction and maintenance in cases of organ-threatening disease. Adjunctive glucocorticoid treatment can be tapered according to a new reduced dose scheme and avacopan, a C5a receptor inhibitor, offers even more potential in the future for additional economization of glucocorticoids. Uncertainties remain regarding the duration of treatment for maintaining remission. New studies suggest that treatment for maintaining remission for longer than 24 months is meaningful.

[Eosinophilic granulomatosis with polyangiitis : Update on classification and management]. / Eosinophile Granulomatose mit Polyangiitis : Update zu Klassifikation und Management.

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare chronic inflammatory systemic disease that occurs in patients with bronchial asthma and is associated with significant blood and tissue eosinophilia. Another characteristic is vasculitis of small and/or medium-sized vessels, which may be absent in prodromal stages of the disease and is therefore no longer an obligatory part of the disease definition. Antineutrophil cytoplasmic antibodies (ANCA) can be detected in approximately one third of patients. The ANCA-positive and ANCA-negative EGPA are genetically distinct diseases with common clinical manifestations, which, however, occur with different frequencies. Cardiac involvement is associated with a poor prognosis. Permanent organ damage often occurs as a result of the underlying disease or treatment, especially with glucocorticoids (GC). The standard treatment of EGPA consists of GC in combination with cyclophosphamide for severe organ involvement or medium potency immunosuppressants for more prognostically favorable manifestations. Biologics are increasingly being used in the treatment of EGPA. The interleukin (IL) 5 antagonist mepolizumab reduces the risk of relapses and decreases the demand for GC in patients with relapsing EGPA without severe organ involvement. In analogy to the approach to other ANCA-associated vasculitides, the use of rituximab in ANCA-positive EGPA patients with severe vasculitis recurrence is a possible option, even though formal evidence for such an approach is currently low and formal approval is lacking.

ICHIBAN, a non-interventional study evaluating tocilizumab long-term effectiveness and safety in patients with active rheumatoid arthritis.

OBJECTIVES: We aimed to measure long-term effectiveness and safety of tocilizumab in patients with rheumatoid arthritis in daily German practice. METHODS: ICHIBAN was a prospective, multi-centre, non-interventional study (ML22928) that enrolled adult patients with active moderate to severe rheumatoid arthritis. Patients were to be treated according to tocilizumab label and observed for up to two years. Effectiveness outcomes included DAS28-ESR remission, EULAR response, CDAI and HAQ. RESULTS: Overall, 3164 patients received at least one dose of tocilizumab. Patient mean age was 55.5±13.1 years (74.8% female). At baseline, 72.1% of patients had at least one comorbidity. Approximately 50.9% of patients received concomitant csDMARDs, mostly methotrexate, and 80.7% received concomitant glucocorticoids (GCs). In patients receiving GCs at baseline, the mean dose decreased from 9.32±16.36 mg/d to 4.60±4.48 mg/d at week 104. In the effectiveness population with no prior TCZ (n=2902), 61.4% of patients achieved the primary outcome, DAS28-ESR remission. Improvements were seen as early as week 4. At week 104, 77.9% of patients had DAS28-ESR low disease activity, 89.6% achieved good or moderate EULAR response, and 29.5% achieved a CDAI-based remission. Effectiveness outcomes were similar in all previous therapy subgroups. The incidence of serious infections was similar to the rates in former studies involving tocilizumab. Patients receiving GC at baseline experienced slightly higher rates of treatment-related serious adverse events, mainly infections. No new safety signals were observed. CONCLUSIONS: Long-term effectiveness and safety in ICHIBAN were in line with previously reported tocilizumab efficacy and safety studies.

International Consensus on ANCA Testing in Eosinophilic Granulomatosis with Polyangiitis.

An international consensus on anti-neutrophil cytoplasm antibodies (ANCA) testing in eosinophilic granulomatosis with polyangiitis (EGPA) is presented. ANCA, specific for myeloperoxidase (MPO), can be detected in 30-35% of EGPA patients. MPO-ANCA should be tested with antigen-specific immunoassays in any patient with eosinophilic asthma and clinical features suggesting EGPA, including constitutional symptoms, purpura, polyneuropathy, unexplained heart, gastrointestinal or kidney disease, and/or pulmonary infiltrates or hemorrhage. A positive MPO-ANCA result contributes to the diagnostic work­up for EGPA. Patients with MPO-ANCA associated EGPA have more frequently vasculitis features, such as glomerulonephritis, neuropathy, and skin manifestations than patients with ANCA negative EGPA. However, the presence of MPO-ANCA is neither sensitive nor specific enough to identify whether a patient should be subclassified as having "vasculitic" or "eosinophilic" EGPA. At present, ANCA status cannot guide treatment decisions, that is, whether cyclophosphamide, rituximab or mepolizumab should be added to conventional glucocorticoid treatment. In EGPA, monitoring of ANCA is only useful when MPO-ANCA was tested positive at disease onset.

[Cortisone-free rheumatology-Vasculitides]. / Kortisonfreie Rheumatologie ­ Vaskulitiden.

Glucocorticoids (GC) still represent an essential pillar of treatment in the phase of remission induction of vasculitides, which are often organ or life-threatening; however, they entail a significant potential for side effects. In the phase of remission maintenance prednisolone should be reduced to 7.5 mg/day or less. Whether a discontinuation can alway be achieved for any form of vasculitis without increasing relapse rates, is unclear. By the use of biologics, e.g. tocilizumab in giant cell arteritis (GCA), a fast tapering and discontinuation of GC seems to be more easily achievable compared to using a GC monotherapy regimen. Avacopan could in the future be an efficient agent to spare GC in the phase of remission induction in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), e.g. granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA). Mepolizumab is a promising option to reduce the use of GC in eosinophilic granulomatosis with polyangiitis (EGPA).

Mepolizumab or Placebo for Eosinophilic Granulomatosis with Polyangiitis.

BACKGROUND: Eosinophilic granulomatosis with polyangiitis is an eosinophilic vasculitis. Mepolizumab, an anti-interleukin-5 monoclonal antibody, reduces blood eosinophil counts and may have value in the treatment of eosinophilic granulomatosis with polyangiitis. METHODS: In this multicenter, double-blind, parallel-group, phase 3 trial, we randomly assigned participants with relapsing or refractory eosinophilic granulomatosis with polyangiitis who had received treatment for at least 4 weeks and were taking a stable prednisolone or prednisone dose to receive 300 mg of mepolizumab or placebo, administered subcutaneously every 4 weeks, plus standard care, for 52 weeks. The two primary end points were the accrued weeks of remission over a 52-week period, according to categorical quantification, and the proportion of participants in remission at both week 36 and week 48. Secondary end points included the time to first relapse and the average daily glucocorticoid dose (during weeks 48 through 52). The annualized relapse rate and safety were assessed. RESULTS: A total of 136 participants underwent randomization, with 68 participants assigned to receive mepolizumab and 68 to receive placebo. Mepolizumab treatment led to significantly more accrued weeks of remission than placebo (28% vs. 3% of the participants had ≥24 weeks of accrued remission; odds ratio, 5.91; 95% confidence interval [CI], 2.68 to 13.03; P<0.001) and a higher percentage of participants in remission at both week 36 and week 48 (32% vs. 3%; odds ratio, 16.74; 95% CI, 3.61 to 77.56; P<0.001). Remission did not occur in 47% of the participants in the mepolizumab group versus 81% of those in the placebo group. The annualized relapse rate was 1.14 in the mepolizumab group, as compared with 2.27 in the placebo group (rate ratio, 0.50; 95% CI, 0.36 to 0.70; P<0.001). A total of 44% of the participants in the mepolizumab group, as compared with 7% of those in the placebo group, had an average daily dose of prednisolone or prednisone of 4.0 mg or less per day during weeks 48 through 52 (odds ratio, 0.20; 95% CI, 0.09 to 0.41; P<0.001). The safety profile of mepolizumab was similar to that observed in previous studies. CONCLUSIONS: In participants with eosinophilic granulomatosis with polyangiitis, mepolizumab resulted in significantly more weeks in remission and a higher proportion of participants in remission than did placebo, thus allowing for reduced glucocorticoid use. Even so, only approximately half the participants treated with mepolizumab had protocol-defined remission. (Funded by GlaxoSmithKline and the National Institute of Allergy and Infectious Diseases; ClinicalTrials.gov number, NCT02020889 .).

Evaluation of clinical benefit from treatment with mepolizumab for patients with eosinophilic granulomatosis with polyangiitis.

BACKGROUND: In a recent phase III trial (NCT02020889) 53% of mepolizumab-treated versus 19% of placebo-treated patients with eosinophilic granulomatosis with polyangiitis (EGPA) achieved protocol-defined remission. OBJECTIVE: We sought to investigate post hoc the clinical benefit of mepolizumab in patients with EGPA using a comprehensive definition of benefit encompassing remission, oral glucocorticoid (OGC) dose reduction, and EGPA relapses. METHODS: The randomized, placebo-controlled, double-blind, parallel-group trial recruited patients with relapsing/refractory EGPA receiving stable OGCs (prednisolone/prednisone, ≥7.5-50 mg/d) for 4 or more weeks. Patients received 300 mg of subcutaneous mepolizumab or placebo every 4 weeks for 52 weeks. Clinical benefit was defined post hoc as follows: remission at any time (2 definitions used), 50% or greater OGC dose reduction during weeks 48 to 52, or no EGPA relapses. The 2 remission definitions were Birmingham Vasculitis Activity Score of 0 plus OGC dose of 4 mg/d or less (remission 1/clinical benefit 1) or 7.5 mg/d or less (remission 2/clinical benefit 2). Clinical benefit was assessed in all patients and among subgroups with a baseline blood eosinophil count of less than 150 cells/µL, baseline OGC dosage of greater than 20 mg/d, or weight of greater than 85 kg. RESULTS: With mepolizumab versus placebo, 78% versus 32% of patients experienced clinical benefit 1, and 87% versus 53% of patients experienced clinical benefit 2 (both P < .001). Significantly more patients experienced clinical benefit 1 with mepolizumab versus placebo in the blood eosinophil count less than 150 cells/µL subgroup (72% vs 43%, P = .033) and weight greater than 85 kg subgroup (68% vs 23%, P = .005); in the OGC greater than 20 mg/d subgroup, results were not significant but favored mepolizumab (60% vs 36%, P = .395). CONCLUSION: When a comprehensive definition of clinical benefit was applied to data from a randomized controlled trial, 78% to 87% of patients with EGPA experienced benefit with mepolizumab.

[Recommendations of the German Society for Rheumatology for management of patients with inflammatory rheumatic diseases in the context of the SARS-CoV-2/COVID-19 pandemic - Update July 2020]. / Handlungsempfehlungen der Deutschen Gesellschaft für Rheumatologie e. V. für die Betreuung von Patienten mit entzündlich rheumatischen Erkrankungen im Rahmen der SARS-CoV-2/COVID-19-Pandemie ­ Update Juli 2020.

A few days after the SARS-CoV-2 infection was declared a pandemic, the German Society for Rheumatology (DGRh) compiled first recommendations for the care of patients with inflammatory rheumatic diseases (IRD). These first recommendations were based on an expert consensus and were largely non-evidence-based. Now that the first scientific data from registers, cross-sectional studies, case reports and case series are available, the present update is intended to update the previous recommendations and to add new findings. The current recommendations are based on a literature search of publications available up to 15 June 2020 and address preventive measures (such as hygiene measures or vaccinations) and the use of immunomodulatory/immunosuppressive drugs. An important goal of the current recommendations is also to prevent harm to patients with IRD through unjustified restriction of care. The DGRh will continue to update its recommendations in the case of new aspects and will publish them as well as further information on the COVID-19 pandemic on its homepage ( www.dgrh.de ) in an ongoing process.

[Three years of the appointment service office: high rate of false referrals and no show patients-A retrospective anaysis of the Rheumatism Center Schleswig-Holstein Mitte]. / Drei Jahre Terminservicestelle: hohe Rate an Fehlzuweisungen und No-show-Patienten ­ Eine retrospektive Auswertung des Rheumazentrum Schleswig-Holstein Mitte.

This article presents a retrospective analysis of patients who attended a rheumatology specialist practice (with two specialist rheumatologists) between 2016 and 2018 via an appointment arranged by the appointment service office (Terminservicestelle, TSS). Patients were analyzed in a pseudonymized manner and categorized according to the following criteria: 1. patient did not keep the appointment, 2. patient had no inflammatory rheumatic disease, 3. patient suffered from an inflammatory rheumatic disease but had no urgent indications to be seen and 4. patient suffered from an inflammatory rheumatic disease with urgent indications to be seen. Since the start of the TSS at the beginning of 2016 until the end of 2018 a total of 103 patients were allocated to this specialist practice via the TSS. An appointment was offered to 102 patients who underwent further analysis: 4.9% of the patients (n = 5) suffered from an acute inflammatory rheumatic disease and had urgent indications to be seen, 18.63% of patients (n = 19) suffered from an inflammatory rheumatic disease with no urgent indications to attend, 28.43% of patients (n = 29) did not keep the appointment and 48.04% of patients (n = 49) did not have an inflammatory rheumatic disease but other diseases, such as osteoarthritis, fibromyalgia and other forms of chronic pain syndromes. The positive predictive value (PPV) for patients with inflammatory rheumatic disease and urgent indications was 0.05 when all patients were included in the analysis and 0.07 when only patients who showed up were included. This retrospective analysis demonstrates that the TSS does not fulfill its purpose, namely to promptly arrange appointments at a specalist rheumatologist practice for patients with an acute inflammatory rheumatic disease.

A large-scale genetic analysis reveals a strong contribution of the HLA class II region to giant cell arteritis susceptibility.

We conducted a large-scale genetic analysis on giant cell arteritis (GCA), a polygenic immune-mediated vasculitis. A case-control cohort, comprising 1,651 case subjects with GCA and 15,306 unrelated control subjects from six different countries of European ancestry, was genotyped by the Immunochip array. We also imputed HLA data with a previously validated imputation method to perform a more comprehensive analysis of this genomic region. The strongest association signals were observed in the HLA region, with rs477515 representing the highest peak (p = 4.05 × 10(-40), OR = 1.73). A multivariate model including class II amino acids of HLA-DRß1 and HLA-DQα1 and one class I amino acid of HLA-B explained most of the HLA association with GCA, consistent with previously reported associations of classical HLA alleles like HLA-DRB1(∗)04. An omnibus test on polymorphic amino acid positions highlighted DRß1 13 (p = 4.08 × 10(-43)) and HLA-DQα1 47 (p = 4.02 × 10(-46)), 56, and 76 (both p = 1.84 × 10(-45)) as relevant positions for disease susceptibility. Outside the HLA region, the most significant loci included PTPN22 (rs2476601, p = 1.73 × 10(-6), OR = 1.38), LRRC32 (rs10160518, p = 4.39 × 10(-6), OR = 1.20), and REL (rs115674477, p = 1.10 × 10(-5), OR = 1.63). Our study provides evidence of a strong contribution of HLA class I and II molecules to susceptibility to GCA. In the non-HLA region, we confirmed a key role for the functional PTPN22 rs2476601 variant and proposed other putative risk loci for GCA involved in Th1, Th17, and Treg cell function.

[Update: polyarteritis nodosa]. / Update: Polyarteriitis nodosa.

Polyarteritis nodosa (PAN) is a necrotizing arteritis of medium-sized vessels, which is often fatal if untreated. It frequently affects the skin (nodules and ulcers), the peripheral nervous system (mononeuritis multiplex) and the visceral vessels (stenoses and microaneurysms). The complex diagnostic work-up requires discriminating PAN from infectious, malignant, drug-induced and other inflammatory conditions. It can be subclassified into further variants (idiopathic, associated with hepatitis B, associated with hereditary inflammatory diseases or isolated cutaneous disease). While idiopathic and hereditary inflammatory variants require immunosuppressive treatment, the hepatitis B-associated variant is treated with virustatic agents and plasmapheresis. The isolated cutaneous variant has a good prognosis and rarely requires highly potent immunosuppressives.

Detection of antineutrophil cytoplasmic antibodies (ANCAs): a multicentre European Vasculitis Study Group (EUVAS) evaluation of the value of indirect immunofluorescence (IIF) versus antigen-specific immunoassays.

OBJECTIVE: This multicentre study was performed to evaluate the diagnostic accuracy of a wide spectrum of novel technologies nowadays available for detection of myeloperoxidase (MPO) and proteinase 3 (PR3)-antineutrophil cytoplasmic antibodies (ANCAs). METHODS: Sera (obtained at the time of diagnosis) from 251 patients with ANCA-associated vasculitis (AAV), including granulomatosis with polyangiitis and microscopic polyangiitis, and from 924 disease controls were tested for the presence of cytoplasmic pattern/perinuclear pattern and atypical ANCA (A-ANCA) by indirect immunofluorescence (IIF) (at two sites) and for the presence of PR3-ANCA and MPO-ANCA by eight different immunoassays. RESULTS: The area under the curve (AUC) of the receiver operating characteristic curve to discriminate AAV from controls was 0.923 (95% CI 0.902 to 0.944) and 0.843 (95% CI 0.814 to 0.871) for the two IIF methods. For the antigen-specific immunoassays, the AUC varied between 0.936 (95% CI 0.912 to 0.960) and 0.959 (95% CI 0.941 to 0.976), except for one immunoassay for which the AUC was 0.919 (95% CI 0.892 to 0.945). CONCLUSIONS: Our comparison of various ANCA detection methods showed (i) large variability between the two IIF methods tested and (ii) a high diagnostic performance of PR3-ANCA and MPO-ANCA by immunoassay to discriminate AAV from disease controls. Consequently, dual IIF/antigen-specific immunoassay testing of each sample is not necessary for maximal diagnostic accuracy. These results indicate that the current international consensus on ANCA testing for AAV needs revision.

Environmental factor and inflammation-driven alteration of the total peripheral T-cell compartment in granulomatosis with polyangiitis.

Autoimmune diseases are initiated by a combination of predisposing genetic and environmental factors resulting in self-perpetuating chronic inflammation and tissue damage. Autoantibody production and an imbalance of effector and regulatory T-cells are hallmarks of autoimmune dysregulation. While expansion of circulating effector memory T-cells is linked to disease pathogenesis and progression, the causes driving alterations of the peripheral T-cell compartment have remained poorly understood so far. In granulomatosis with polyangiitis (GPA), a prototypical autoimmune disorder of unknown aetiology, we performed for the first time a combined approach using phenotyping, transcriptome and functional analyses of T-cell populations to evaluate triggers of memory T-cell expansion. In more detail, we found increased percentages of circulating CD4+CD28-, CD8+CD28- and CD4+CD161+ single-positive and CD4+CD8+ double-positive T-cells in GPA. Transcriptomic profiling of sorted T-cell populations showed major differences between GPA and healthy controls reflecting antigen- (bacteria, viruses, fungi) and cytokine-driven impact on T-cell populations in GPA. Concomitant cytomegalovirus (CMV) and Epstein-Barr virus (EBV) - positivity was associated with a significant increase in the percentage of CD28- T-cells in GPA-patients compared to sole CMV- or EBV-positivity or CMV- and EBV-negativity. T-cells specific for other viruses (influenza A virus, metapneumovirus, respiratory syncytial virus) and the autoantigen proteinase 3 (PR3) were infrequently detected in GPA. Antigen-specific T-cells were not specifically enriched in any of the T-cell subsets. Altogether, on a genetic and cellular basis, here we show that alterations of the peripheral T-cell compartment are driven by inflammation and various environmental factors including concomitant CMV and EBV infection. Our study provides novel insights into mechanisms driving autoimmune disease and on potential therapeutic targets.

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.