Abatacept inhibits inflammation and onset of rheumatoid arthritis in individuals at high risk (ARIAA): a randomised, international, multicentre, double-blind, placebo-controlled trial.

BACKGROUND: Individuals with anti-citrullinated protein antibodies (ACPAs) and subclinical inflammatory changes in joints are at high risk of developing rheumatoid arthritis. Treatment strategies to intercept this pre-stage clinical disease remain to be developed. We aimed to assess whether 6-month treatment with abatacept improves inflammation in preclinical rheumatoid arthritis. METHODS: The abatacept reversing subclinical inflammation as measured by MRI in ACPA positive arthralgia (ARIAA) study is a randomised, international, multicentre, double-blind, placebo-controlled trial done in 14 hospitals and community centres across Europe (11 in Germany, two in Spain, and one in the Czech Republic). Adults (aged ≥18 years) with ACPA positivity, joint pain (but no swelling), and signs of osteitis, synovitis, or tenosynovitis in hand MRI were randomly assigned (1:1) to weekly subcutaneous abatacept 125 mg or placebo for 6 months followed by a double-blind, drug-free, observation phase for 12 months. The primary outcome was the proportion of participants with any reduction in inflammatory MRI lesions at 6 months. The primary efficacy analysis was done in the modified intention-to-treat population, which included participants who were randomly assigned and received study medication. Safety analyses were conducted in participants who received the study medication and had at least one post-baseline observation. The study was registered with the EUDRA-CT (2014-000555-93). FINDINGS: Between Nov 6, 2014, and June 15, 2021, 139 participants were screened. Of 100 participants, 50 were randomly assigned to abatacept 125 mg and 50 to placebo. Two participants (one from each group) were excluded due to administration failure or refusing treatment; thus, 98 were included in the modified intention-to-treat population. 70 (71%) of 98 participants were female and 28 (29%) of 98 were male. At 6 months, 28 (57%) of 49 participants in the abatacept group and 15 (31%) of 49 participants in the placebo group showed improvement in MRI subclinical inflammation (absolute difference 26·5%, 95% CI 5·9-45·6; p=0·014). Four (8%) of 49 participants in the abatacept group and 17 (35%) of 49 participants in the placebo group developed rheumatoid arthritis (hazard ratio [HR] 0·14 [0·04-0·47]; p=0·0016). Improvement of MRI inflammation (25 [51%] of 49 participants in the abatacept group, 12 [24%] of 49 in the placebo group; p=0·012) and progression to rheumatoid arthritis (17 [35%] of 49, 28 [57%] of 49; HR 0·14 [0·04-0·47]; p=0·018) remained significantly different between the two groups after 18 months, 12 months after the end of the intervention. There were 12 serious adverse events in 11 participants (four [8%] of 48 in the abatacept group and 7 [14%] of 49 in the placebo group). No deaths occurred during the study. INTERPRETATION: 6-month treatment with abatacept decreases MRI inflammation, clinical symptoms, and risk of rheumatoid arthritis development in participants at high risk. The effects of the intervention persist through a 1-year drug-free observation phase. FUNDING: Innovative Medicine Initiative.

Defects in B-lymphopoiesis and B-cell maturation underlie prolonged B-cell depletion in ANCA-associated vasculitis.

OBJECTIVES: B-cell depletion time after rituximab (RTX) treatment is prolonged in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) compared with other autoimmune diseases. We investigated central and peripheral B-cell development to identify the causes for the defect in B-cell reconstitution after RTX therapy. METHODS: We recruited 91 patients with AAV and performed deep phenotyping of the peripheral and bone marrow B-cell compartment by spectral flow and mass cytometry. B-cell development was studied by in vitro modelling and the role of BAFF receptor by quantitative PCR, western blot analysis and in vitro assays. RESULTS: Treatment-naïve patients with AAV showed low transitional B-cell numbers, suggesting impaired B-lymphopoiesis. We analysed bone marrow of treatment-naïve and RTX-treated patients with AAV and found reduced B-lymphoid precursors. In vitro modelling of B-lymphopoiesis from AAV haematopoietic stem cells showed intact, but slower and reduced immature B-cell development. In a subgroup of patients, after RTX treatment, the presence of transitional B cells did not translate in replenishment of naïve B cells, suggesting an impairment in peripheral B-cell maturation. We found low BAFF-receptor expression on B cells of RTX-treated patients with AAV, resulting in reduced survival in response to BAFF in vitro. CONCLUSIONS: Prolonged depletion of B cells in patients with AAV after RTX therapy indicates a B-cell defect that is unmasked by RTX treatment. Our data indicate that impaired bone marrow B-lymphopoiesis results in a delayed recovery of peripheral B cells that may be further aggravated by a survival defect of B cells. Our findings contribute to the understanding of AAV pathogenesis and may have clinical implications regarding RTX retreatment schedules and immunomonitoring after RTX therapy.

High-resolution Magnetic Resonance Imaging visualizes intracranial large artery involvement in Giant Cell Arteritis.

OBJECTIVE: Giant Cell arteritis (GCA) is a large vessel vasculitis, typically involving the aorta and its branches with predilection for the scalp arteries. Intracranial involvement is still part of ongoing research. We assess inflammation of the intracranial arteries on 3D-black-blood magnetic resonance imaging (3D-CS-BB-MRI) in patients with GCA and age-matched controls. METHODS: 105 patients with 3D-CS-BB-MRI of the brain were included in this retrospective dual-center case-control study; 55 with diagnosed GCA and 50 age-matched controls. High-resolution 3D-CS-BB-MRI was performed on a 3 Tesla MR scanner with a post-contrast 3D-compressed-sensing (CS) MR pulse sequence, specifically a T1-weighted sampling perfection, application-optimized contrasts using different flip angle evolution (SPACE) pulse sequence with whole-brain coverage and isotropic resolution of 0.55 mm3. Two neuroradiologists blinded to clinical data independently scored the cerebral arteries qualitatively for inflammation; circumferential vessel wall thickening and contrast enhancement were scored positive for vasculitis. RESULTS: 8 of 55 GCA patients (14.5%) showed inflammation of at least one intracranial artery. The internal carotid artery (ICA) was affected in 6/55 (10.9%), the vertebral artery in 4/55 (7.3%) and the basilar artery and posterior cerebral artery in 1/55 (1.8%). All patients with inflammatory changes reported headaches and none showed any focal neurological deficit. Besides headache and general weakness, there was no significant correlation between inflammation of the intracranial arteries and clinical symptoms. No age-matched control patient showed inflammatory changes of the intracranial arteries. CONCLUSION: High-resolution 3D-CS-BB-MRI revealed inflammatory changes of intracranial arteries in 14.5% of GCA patients with the intradural ICA as the most frequently affected vessel.

Association of rheumatological markers with neuronal antibodies, cerebrospinal fluid, electroencephalography, and magnetic resonance imaging findings in 224 patients with psychotic syndromes.

INTRODUCTION: Psychotic syndromes can have autoimmune-mediated causes in some patients. Thus, this retrospective work aims to investigate the role of rheumatological markers in the development of psychosis. PATIENTS AND METHODS: In total, 224 patients with psychotic syndromes receiving a "rheumatological laboratory screening" (including C-reactive protein [CRP], immunofixation, complement factors, rheumatoid factor [RF], antiphospholipid antibodies [APAs], antineutrophil cytoplasmic antibodies [ANCAs], and antinuclear antibodies [ANAs]) were analyzed. A further diagnostic work-up included investigations of neuronal antibodies and cerebrospinal fluid (CSF), as well as electroencephalography (EEG) and magnetic resonance imaging (MRI) of the brain. ANA testing was routinely performed in all patients using serum on human epithelioma-2 (Hep2) cells, and a subset of patients (N = 73) also underwent tissue-based assays from serum and CSF. The number of cases with autoimmune psychotic syndromes was descriptively collected, and ANA-positive and -negative patients were compared in detail. RESULTS: CRP was elevated in 9 % of patients, immunofixation identified alterations in 8 %, complement factor C3 was decreased in 14 %, RF was elevated in 1 %, APAs were elevated in 7 %, ANCAs were not clearly positive, and ANAs were positive in 19 % (extractable nuclear antigen [ENA] differentiation resulted in positive findings in 14 patients). From the 73 patient samples additionally investigated using tissue-based assays, there were 26 positive results for some kind of ANA (36 %), and overall using both methods, 54 patients (24 %) were considered positive for ANAs. A neuropsychiatric evaluation revealed a possible autoimmune psychotic syndrome in seven patients (3 %) and a probable autoimmune psychotic syndrome in two patients (1 %). ANA-positive patients were more frequently treated with antidepressants (p = 0.040) and had a higher number of somatic comorbidities (p < 0.001). In addition, (chronic) inflammatory MRI lesions (p = 0.008) and focal atrophies (p = 0.012) were found more frequently in ANA-positive than ANA-negative patients. DISCUSSION: Rheumatological screening led to suspicion of a possible or probable autoimmune psychotic syndrome in 4%. ANAs were associated with MRI pathologies. Therefore, rheumatological processes may contribute to the development of psychotic syndromes in rare cases.

The Joint Vasculitis Registry in German-speaking countries (GeVas): subgroup analysis of 266 AAV patients.

OBJECTIVES: Prospective long-term observational data on the disease course of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) were missing in Germany to date. Therefore, the Joint Vasculitis Registry in German-speaking countries (GeVas) has been established to follow the course of patients with AAV. The aim of this study is to present baseline data of patients with newly diagnosed and relapsing AAV enrolled in the GeVas registry. METHODS: GeVas is a prospective, web-based, multicentre, clinician-driven registry for the documentation of organ manifestations, damage, long-term outcomes, and therapy regimens in various types of vasculitis. Recruitment started in June 2019. RESULTS: Between June 2019 and October 2022, 266 patients with AAV were included in the GeVas registry: 173 (65%) with new-onset and 93 (35%) with relapsing AAV. One hundred and sixty-two (61%) patients were classified as granulomatosis with polyangiitis (GPA), 66 (25%) as microscopic polyangiitis (MPA), 36 (13%) as eosinophilic granulomatosis with polyangiitis (EGPA), and 2 (1%) as renal limited AAV. The median age was 59 years (51-70 years, IQR), 130 (51%) patients were female. Most patients were ANCA positive (177; 67%) and affected by general symptoms, pulmonary, ear nose throat (ENT), renal and neurological involvement. For induction of remission, the majority of patients received glucocorticoids (247, 93%) in combination with either rituximab (118, 45%) or cyclophosphamide (112, 42%). CONCLUSIONS: Demographic characteristics are comparable to those in other European countries. Differences were found regarding ANCA status, frequencies of organ manifestations, and therapeutic regimens. The GeVas registry will allow longitudinal observations and prospective outcome measures in AAV.

The Joint Vasculitis Registry in German-speaking countries (GeVas): subgroup analysis of 195 GCA patients.

OBJECTIVES: Giant cell arteritis (GCA) is one of the most common forms of vasculitis. There is an abundance of studies which are conducted in a randomised controlled trial setting but limited with respect to cohort size and follow-up time. GeVas is the first large-scale registry for vasculitides in German-speaking countries that enables to evaluate this rare disease. Herein we focus on the subgroup of GCA patients including follow-up data up to one year. METHODS: GeVas is a prospective, web-based, multicentre registry for the documentation of organ manifestations, outcomes, and therapy regimens in vasculitides. Recruitment started in June 2019. By April 2023, 15 centres were initiated and have started to enrol patients. RESULTS: After 4 years, 195 GCA-patients were included in the registry, of which 64% were female and 36% were male. The average age was 76 years at the time of recruitment (IQR=69-82). Seventy-nine percent were included in the registry because of a newly diagnosed GCA and 21% because of a relapse. At the first assessment most of the patients (89%) described general symptoms. Thirty-one percent stated ocular symptoms. Cranial symptoms were documented in 78% of the cases. All patients were documented with immunosuppressive treatment at start, of whom 95% received prednisolone, 16% cyclophosphamide, 20% methotrexate, and 48% tocilizumab. After three months 62% and after one year 91% of the patients achieved remission. CONCLUSIONS: Regarding demographics, clinical manifestations and diagnostics, our study showed a similar composition compared to other studies. However, our data differed in terms of treatment regimens.

[News on the treatment of large vessel vasculitis]. / Neues zur Therapie von Großgefäßvaskulitiden.

Large vessel vasculitis, such as giant cell arteritis (GCA) and Takayasu arteritis (TAK) are primarily manifested on large and medium-sized arteries. While GCA mainly affects older people after the 6th decade of life onwards, TAK mainly affects young women under the age of 40 years. Glucocorticoids (GC) are still the standard treatment for both diseases. Refractory courses and relapses in particular often lead to long-term treatment with high cumulative doses of GC, which can lead to increased morbidity and mortality. To date, only the interleukin 6 (IL-6) receptor blocker tocilizumab has been approved for the treatment of GCA. The data on methotrexate and other conventional immunosuppressants are incomplete and in some cases contradictory. The early use of steroid-sparing immunosuppressants is recommended for TAK, although the number of randomized placebo-controlled trials is limited and no steroid-sparing treatment has yet been approved for TAK. For both diseases there is still a great need for modern and safe steroid-sparing treatment that effectively treats vasculitis, prevents damage and enables adequate disease monitoring. This article provides an overview of the current study situation and possible future treatment options for GCA and TAK.

[Macrocytic anemia and polychondritis: VEXAS syndrome]. / Makrozytäre Anämie und Polychondritis: VEXAS-Syndrom.

An adult-onset autoinflammatory syndrome caused by somatic mutations in the UBA1 gene on the X chromosome was first reported in 2020. This VEXAS syndrome (acronym for vacuoles, E1 enzyme, X­linked, autoinflammatory, somatic) is characterized by an overlap of rheumatic inflammatory diseases with separate hematologic abnormalities. A substantial number of affected patients suffer from treatment refractory relapsing polychondritis and nearly always show signs of macrocytic anemia. This case report illustrates the diagnostic key points to recognizing patients with VEXAS syndrome.

[Recommendations for defining giant cell arteritis fast-track clinics]. / Empfehlungen zur Definition von Riesenzellarteriitis-Fast-Track-Kliniken.

An expert committee recommends defining fast-track clinics (FTC) for the acute diagnostics of giant cell arteritis (GCA) as follows: low-threshold, easy and prompt reachability at least on weekdays, scheduling appointments ideally within 24 h, examination by a specialist with GCA expertise, ≥ 2 experts per FTC, ≥ 50 patients with suspected GCA per year, sonologists with ≥ 300 (≥ 50) temporal and axillary artery examinations, adherence to standard operating procedures, availability of an ≥ 18 (≥ 15) MHz and a lower frequency linear ultrasound probe and collaboration with partners for fast performance of neurological and ophthalmological examinations, magnetic resonance imaging (MRI), positron emission tomography-computed tomography (PET-CT, possibly CT) and for temporal artery biopsy.

Recommendations for defining giant cell arteritis fast-track clinics. English version.

A German expert committee recommends defining fast-track clinics (FTC) for the acute diagnosis of giant cell arteritis (GCA) as follows: easy and prompt reachability at least on weekdays, scheduling appointments ideally within 24 h, examination by a specialist with GCA expertise, ≥ 2 experts per FTC, ≥ 50 patients with suspected GCA per year, sonologists with ≥ 300 (≥ 50) temporal and axillary artery examinations, adherence to standard operating procedures, availability of an ≥ 18 (≥ 15) MHz and a lower frequency linear ultrasound probe, and collaboration with partners for neurology and ophthalmology consultations, magnetic resonance imaging (MRI), positron emission tomography-computed tomography (PET-CT, possibly CT), and for temporal artery biopsy.

[Eosinophilic granulomatosis with polyangiitis: a review article]. / Eosinophile Granulomatose mit Polyangiitis ­ ein Übersichtsartikel.

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare form of ANCA-associated vasculitis (AAV) within the group of small vessel vasculitides. It is defined by vasculitis of small and medium-sized vessels with granulomatous inflammation and blood and tissue eosinophilia. Almost all patients have allergic symptoms with bronchial asthma and rhinosinusitis symptoms. Further clinical manifestations vary depending on the localisation, severity, and type of disease manifestation. Eosinophilic infiltration and inflammation may result in rhinosinusitis, pneumonitis, gastrointestinal involvement, and cardiomyopathy. The latter, in particular, is associated with a poorer prognosis. As a necrotising pauci-immune small-vessel vasculitis, EGPA, similar to the other AAVs, can cause pulmonary infiltrates with alveolar haemorrhage, glomerulonephritis, cutaneous vasculitis with purpura as well as central and peripheral neurologic injuries. The presence of perinuclear ANCA (pANCA) with specificity against myeloperoxidase (MPO) is observed in approximately one-third of patients but is not specific to EGPA. MPO-ANCA-positive patients are more likely to have peripheral neurologic involvement and glomerulonephritis, whereas ANCA-negative patients are more likely to have cardiac and pulmonary involvement. What is frequently challenging in the clinical routine is to differentiate EGPA from the hypereosinophilic syndrome (HES). The therapeutic approach to EGPA depends on whether the severity of the disease is potentially organ or life-threatening. For severe forms of EGPA, acute therapy mainly includes glucocorticoids in combination with cyclophosphamide. Rituximab has come to be mentioned as an alternative treatment option in the guidelines. Various immunosuppressive therapies are available for remission maintenance. In EGPA without severe organ involvement, IL-5 blockade with mepolizumab is an approved treatment.

Mitochondrial DNA: a novel indicator of active inflammation in ANCA-associated vasculitides.

OBJECTIVES: ANCA-associated vasculitis (AAV) includes granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA). ANCA triggers neutrophil extracellular trap formation, which releases either mitochondrial (mt) DNA or nuclear DNA (n) DNA, contributing to inflammation. Our aim was to prospectively examine the extent and nature of circulating DNA in AAV and the clinical utility of DNA quantification. METHODS: DNA was isolated from platelet-free plasma of consecutive GPA and MPA patients and healthy controls (HCs). mtDNA and nDNA copy numbers were quantified by PCR. Clinical data, including the BVAS, were collected. RESULTS: Ninety-two HCs (median age 51 years, 58.7% female) and 101 AAV patients (80 GPA, 21 MPA, median age 64 years, 50.5% female, BVAS range: 0-30) were included. Median mtDNA copies were 13-fold higher in patients with AAV than in HCs; nDNA concentrations did not differ. Patients with active AAV (BVAS > 0) had 4-fold higher median mtDNA copies than patients in remission (P = 0.03). mtDNA, unlike nDNA, correlated with BVAS (r = 0.30, P = 0.002) and was associated with AAV activity at multivariable analysis. Receiver operating characteristic curve analysis indicated that mtDNA quantification differentiates patients with active AAV (BVAS > 0) from HCs with 96.1% sensitivity and 98.9% specificity (area under the curve 0.99). In 27 AAV patients with follow-up, mtDNA changes but not CRP or ANCA-titres correlated with BVAS changes (r = 0.56, P = 0.002). CONCLUSIONS: mtDNA, unlike nDNA, is elevated in the plasma of AAV patients and may contribute to systemic inflammation. mtDNA could be superior to established biomarkers in the laboratory monitoring of AAV activity.

Intraorbital findings in giant cell arteritis on black blood MRI.

OBJECTIVE: Blindness is a feared complication of giant cell arteritis (GCA). However, the spectrum of pathologic orbital imaging findings on magnetic resonance imaging (MRI) in GCA is not well understood. In this study, we assess inflammatory changes of intraorbital structures on black blood MRI (BB-MRI) in patients with GCA compared to age-matched controls. METHODS: In this multicenter case-control study, 106 subjects underwent BB-MRI. Fifty-six patients with clinically or histologically diagnosed GCA and 50 age-matched controls without clinical or laboratory evidence of vasculitis were included. All individuals were imaged on a 3-T MR scanner with a post-contrast compressed-sensing (CS) T1-weighted sampling perfection with application-optimized contrasts using different flip angle evolution (SPACE) BB-MRI sequence. Imaging results were correlated with available clinical symptoms. RESULTS: Eighteen of 56 GCA patients (32%) showed inflammatory changes of at least one of the intraorbital structures. The most common finding was enhancement of at least one of the optic nerve sheaths (N = 13, 72%). Vessel wall enhancement of the ophthalmic artery was unilateral in 8 and bilateral in 3 patients. Enhancement of the optic nerve was observed in one patient. There was no significant correlation between imaging features of inflammation and clinically reported orbital symptoms (p = 0.10). None of the age-matched control patients showed any inflammatory changes of intraorbital structures. CONCLUSIONS: BB-MRI revealed inflammatory findings in the orbits in up to 32% of patients with GCA. Optic nerve sheath enhancement was the most common intraorbital inflammatory change on BB-MRI. MRI findings were independent of clinically reported orbital symptoms. KEY POINTS: • Up to 32% of GCA patients shows signs of inflammation of intraorbital structures on BB-MRI. • Enhancement of the optic nerve sheath is the most common intraorbital finding in GCA patients on BB-MRI. • Features of inflammation of intraorbital structures are independent of clinically reported symptoms.

Spectrum of ANCA-specificities in eosinophilic granulomatosis with polyangiitis. A retrospective multicentre study.

OBJECTIVES: To determine the spectrum of anti-neutrophil cytoplasmic antibody (ANCA) antigen-specificities in eosinophilic granulomatosis with polyangiitis (EGPA), an ANCA-associated vasculitis (AAV) entity. METHODS: We conducted a retrospective analysis of 73 EGPA patients from three German tertiary referral centres for vasculitis. In addition to in-house ANCA testing, pentraxin 3 (PTX3)- and olfactomedin 4 (OLM4)-ANCA were determined using a prototype cell-based assay for research (EUROIMMUN, Lübeck, Germany). Patient characteristics and clinical manifestations were evaluated and compared based on ANCA status. RESULTS: Myeloperoxidase (MPO)-ANCA positive patients (n=8; 11%) significantly more frequently displayed peripheral nervous system (PNS) and pulmonary involvement and less frequently heart involvement compared to MPO-ANCA negative patients. PTX3-ANCA positive patients (n=5; 6.8%) had a significantly higher prevalence of ear, nose and throat, pulmonary, gastrointestinal and PNS involvement, and a lower prevalence of renal and central nervous system involvement compared to PTX3-ANCA negative patients. Proteinase 3 (PR3)-ANCA and OLM4-ANCA were detected in 2 patients (2.7%) each with multiorgan involvement. One PR3-ANCA positive patient was also positive for bactericidal permeability increasing protein (BPI)-ANCA. CONCLUSIONS: In addition to MPO, the spectrum of ANCA antigen specificities includes various other target antigens such as PR3, BPI, PTX3, and OLM4, potentially segregating further EGPA subgroups. A lower prevalence of MPO-ANCA was detected in this study compared with other studies. OLM4 is reported as novel ANCA antigen-specificity in EGPA, and thus AAV.

Nonpermissive bone marrow environment impairs early B-cell development in common variable immunodeficiency.

Common variable immunodeficiency (CVID) is a disease characterized by increased susceptibility to infections, hypogammaglobulinemia, and immune dysregulation. Although CVID is thought to be a disorder of the peripheral B-cell compartment, in 25% of patients, early B-cell development in the bone marrow is impaired. Because poor B-cell reconstitution after hematopoietic stem cell transplantation has been observed, we hypothesized that in some patients the bone marrow environment is not permissive to B-cell development. Studying the differentiation dynamics of bone marrow-derived CD34+ cells into immature B cells in vitro allowed us to distinguish patients with B-cell intrinsic defects and patients with a nonpermissive bone marrow environment. In the former, immature B cells did not develop and in the latter CD34+ cells differentiated into immature cells in vitro, but less efficiently in vivo. In a further group of patients, the uncommitted precursors were unable to support the constant development of B cells in vitro, indicating a possible low frequency or exhaustion of the precursor population. Hematopoietic stem cell transplantation would result in normal B-cell repopulation in case of intrinsic B-cell defect, but in defective B-cell repopulation in a nonpermissive environment. Our study points to the importance of the bone marrow niche in the pathogenesis of CVID.

[Renal manifestations in vasculitides of small and medium-sized vessels]. / Nierenmanifestationen bei Vaskulitiden kleiner und mittelgroßer Gefäße.

Small-vessel vasculitides, in particular, are frequently manifested in the kidneys. A distinction is made between antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) and immune complex vasculitides. Even within the AAVs there are differences with respect to renal involvement, which manifest as necrotizing glomerulonephritis (GN) but renal involvement is much rarer in eosinophilic granulomatosis with polyangiitis than in microscopic polyangiitis and granulomatosis with polyangiitis. Disease progression, organ manifestation and prognosis vary according to the ANCA status. In immune complex vasculitides (cryoglobulinemic vasculitis, IgA vasculitis, hypocomplementemic urticarial vasculitis and antiglomerular basement membrane, GBM, disease), endothelial-adjacent activation of neutrophilic granulocytes leads to local vessel wall damage with subsequent ischemic tissue damage, similar to AAV. The sparse evidence of immune complexes is different in pauci-immune AAV. Polyarteritis nodosa is a disease with variable clinical presentations with necrotizing vasculitis of small and medium-sized arteries. Intrarenal aneurysms and hemorrhages but not GN lead to renal damage. Diagnostically, the detection of specific autoantibodies (e.g. anti-GBM), cryoglobulins or increased complement turnover can be decisive. Renal biopsy with qualified immunohistopathology is particularly important in cases of initial manifestation and unclear constellation of findings. The treatment of renal vasculitis is adapted to the severity, stage of disease, extrarenal organ manifestation and pathogenesis. It ranges from glucocorticoid monotherapy to moderate immunosuppression, up to targeted biologic therapy, chemotherapy and plasmapheresis.

Blood CD3-(CD56 or 16)+ natural killer cell distributions are heterogeneous in healthy adults and suppressed by azathioprine in patients with ANCA-associated vasculitides.

BACKGROUND: Cytotoxic Natural Killer (NK) cells are increasingly recognized as a powerful tool to induce targeted cell death in cancer and autoimmune diseases. Still, basic blood NK cell parameters are poorly defined. The aims of this study were 1) to establish reference values of NK cell counts and percentages in healthy adults; 2) to describe these parameters in the prototype autoimmune disease group ANCA-associated vasculitis (AAV); and 3) to investigate whether NK cell counts and percentages may be used as activity biomarkers in the care of AAV patients, as suggested by a preceding study. METHODS: CD3-(CD56 or 16)+ NK cell counts and percentages were determined in 120 healthy adults. Lymphocyte subset and clinical data from two German vasculitis centers were analyzed retrospectively (in total 407 measurements, including 201/49/157 measurements from 64/16/39 patients with granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA) and eosinophilic granulomatosis with polyangiitis (EGPA), respectively). RESULTS: CD3-(CD56 or 16)+ NK cell counts and percentages in healthy adults were highly variable, not Gaussian distributed and independent of age and sex. NK cell percentages ranged from 1.9 to 37.9% of lymphocytes, and were significantly more dispersed in AAV (0.3 to 57.6%), while the median percentage was not different between AAV and healthy donors. In contrast, median NK cell counts were significantly lower in AAV compared to healthy donors. Sub-group analyses revealed that NK cell counts were low independent of AAV entity and disease activity. Azathioprine therapy was associated with significantly lower NK cell counts and percentages compared to non-azathioprine therapies. In 13.6% of azathioprine-treated patients, percentages were

Significance of PR3-ANCA positivity in eosinophilic granulomatosis with polyangiitis (Churg-Strauss).

OBJECTIVES: Only a third of patients with eosinophilic granulomatosis with polyangiitis (EGPA) are ANCA-positive, mainly directed against MPO. ANCA directed against PR3 are rarely found in EGPA. We aimed to examine the significance of PR3-ANCA in EGPA. METHODS: We set up a retrospective European multicentre cohort including 845 patients. Baseline characteristics and outcomes were analysed and compared according to ANCA status. RESULTS: ANCA status was available for 734 patients: 508 (69.2%) ANCA-negative, 210 (28.6%) MPO-ANCA and 16 (2.2%) PR3-ANCA. At baseline, PR3-ANCA patients, compared with those with MPO-ANCA and ANCA-negative, less frequently had active asthma (69% vs 91% and 93%, P = 0.003, respectively) and peripheral neuropathy (31% vs 71% and 47%, P < 0.0001), more frequently had cutaneous manifestations (63% vs 38% and 34%, P = 0.03) and pulmonary nodules (25% vs 10% and 8%, P = 0.046), and lower median eosinophil count (1450 vs 5400 and 3224/mm3, P < 0.0001). Vasculitis relapse-free survival was shorter for PR3-ANCA (hazard ratio 6.05, P = 0.005) and MPO-ANCA patients (hazard ratio 1.88, P = 0.0002) compared with ANCA-negative patients. CONCLUSION: PR3-ANCA EGPA patients differ from those with MPO-ANCA and negative ANCA, and share clinical features with granulomatosis with polyangiitis. This suggests that PR3-ANCA EGPA could be a particular form of PR3-ANCA-associated vasculitis.