Association of baseline soluble immune checkpoints with the risk of relapse in PR3-ANCA vasculitis following induction of remission.

OBJECTIVES: We investigated whether soluble immune checkpoints (sICPs) predict treatment resistance, relapse and infections in patients with antineutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV). METHODS: Plasma sICP concentrations from available samples obtained during conduct of the RAVE trial were measured by immunoabsorbent assays from patients with either proteinase 3 (PR3) or myeloperoxidase (MPO)-ANCA vasculitis and were correlated with clinical outcomes, a set of biomarkers and available flow cytometry analyses focusing on T cell subsets. Log-rank test was used to evaluate survival benefits, and optimal cut-off values of the marker molecules were calculated using Yeldons J. RESULTS: Analysis of 189 plasma samples at baseline revealed higher concentrations of sTim-3, sCD27, sLag-3, sPD-1 and sPD-L2 in patients with MPO-ANCA vasculitis (n=62) as compared with PR3-ANCA vasculitis (n=127). Among patients receiving rituximab induction therapy (n=95), the combination of lower soluble (s)Lag-3 (<90 pg/mL) and higher sCD27 (>3000 pg/mL) predicted therapy failure. Twenty-four out of 73 patients (32.9%) in the rituximab arm reaching remission at 6 months relapsed during follow-up. In this subgroup, high baseline values of sTim-3 (>1200 pg/mL), sCD27 (>1250 pg/mL) and sBTLA (>1000 pg/mL) were associated with both sustained remission and infectious complications. These findings could not be replicated in 94 patients randomised to receive cyclophosphamide/azathioprine. CONCLUSIONS: Patients with AAV treated with rituximab achieved remission less frequently when concentrations of sLag-3 were low and concentrations of sCD27 were high. Higher concentrations of sTim-3, sCD27 and sBTLA at baseline predicted relapse in patients treated with rituximab. These results require confirmation but may contribute to a personalised treatment approach of AAV.

The Impact of Global Collaboration on the Academic Focus of the West African College of Surgeons: Are Worldwide Efforts Aligning with Local Priorities?

BACKGROUND: Global collaboration has the potential to induce a shift in research focus away from the priorities of those in low- and low-middle-income countries (LICs and LMICs). This study quantified international collaboration among surgery publications by Fellows of the West African College of Surgeons (WACS) and investigated if collaboration with upper-middle-income and high-income countries (UMICs and HICs) decreases the homophily of research focus. METHODS: Publications by WACS surgery Fellows from 1960 to 2019 were characterized as local WACS publications, collaborative publications without UMIC/HIC participation, or collaborative publications with UMIC/HIC participation. Research topics were determined for each publication, and topic percentages were compared between collaboration groups. RESULTS: We analyzed 5065 publications. Most (3690 publications, 73%) were local WACS publications, while 742 (15%) were collaborative publications with UMIC/HIC participation and 633 (12%) were collaborative publications without UMIC/HIC participation. UMIC/HIC collaborations contributed to 49% of the increase (378 out of 766 publications) from 2000 to 2019. Topic homophily was significantly lower between local WACS publications and collaborations with UMIC/HIC participation (differed in nine research topics) than it was between local WACS publications and collaborations without UMIC/HIC participation (differed in two research topics). CONCLUSIONS: Publications without international collaboration comprise most WACS research, but the rate of UMIC/HIC collaborations is rapidly increasing. We found that UMIC/HIC collaborations decreased the homophily of topic focus in WACS publications, indicating that global collaborations need to have greater emphasis on the priorities of those in LICs and LMICs.

Derivation of an angiographically based classification system in Takayasu's arteritis: an observational study from India and North America.

OBJECTIVES: To develop and replicate, using data-driven methods, a novel classification system in Takayasu's arteritis based on distribution of arterial lesions. METHODS: Patients were included from four international cohorts at major academic centres: India (Christian Medical College Vellore); North America (National Institutes of Health, Vasculitis Clinical Research Consortium and Cleveland Clinic Foundation). All patients underwent whole-body angiography of the aorta and branch vessels, with categorization of arterial damage (stenosis, occlusion or aneurysm) in 13 territories. K-means cluster analysis was performed to identify subgroups of patients based on pattern of angiographic involvement. Cluster groups were identified in the Indian cohort and independently replicated in the North American cohorts. RESULTS: A total of 806 patients with Takayasu's arteritis from India (n = 581) and North America (n = 225) were included. Three distinct clusters defined by arterial damage were identified in the Indian cohort and replicated in each of the North American cohorts. Patients in cluster one had significantly more disease in the abdominal aorta, renal and mesenteric arteries (P < 0.01). Patients in cluster two had significantly more bilateral disease in the carotid and subclavian arteries (P < 0.01). Compared with clusters one and two, patients in cluster three had asymmetric disease with fewer involved territories (P < 0.01). Demographics, clinical symptoms and clinical outcomes differed by cluster. CONCLUSION: This large study in Takayasu's arteritis identified and replicated three novel subsets of patients based on patterns of arterial damage. Angiographic-based disease classification requires validation by demonstrating potential aetiological or prognostic implications.

Face Transplantation for Granulomatosis With Polyangiitis (Wegener Granulomatosis): Technical Considerations, Immunological Aspects, and 3-Year Posttransplant Outcome.

BACKGROUND: We report new data for a rare face transplant performed 3 years ago. Granulomatosis with polyangiitis (GPA) (Wegener) is a severe autoimmune necrotizing vasculitis and parenchymal inflammatory disease that can affect any organ including those of the craniofacial region. Skin involvement manifests as malignant pyoderma. This account (1) highlights the technical details of face transplantation for this unique indication, (2) reports the 3-year posttransplant outcome, and (3) describes relevant immunological aspects. METHODS: A Le Fort III near-total face and near-total scalp transplant was performed after extensive trauma and subsequent bone and soft tissue infection in a patient with GPA. Incisions were planned along facial aesthetic subunits. The vascular pedicle comprised the facial and superficial temporal arteries bilaterally. The functioning left eye was preserved and fitted into the donor tissues. RESULTS: The procedure took 21 hours, and transfusion was limited to 4 units of packed red cells. Early medical and surgical complications were successfully treated. At 3 years, acceptable aesthetic outcome was achieved with adequate color match and scalp hair growth. The patient has recovered light touch, temperature, and 2-point discrimination and has evidence of symmetric cheek elevation albeit with limited eyelid and frontalis function. GPA relapse did not occur. Four acute rejections were fully reversed. CONCLUSIONS: This case represents a new underlying disease (trauma + GPA) leading to face transplantation and a unique clinical scenario where allografting was indicated for potentially life-threatening and sight-preserving reasons and not for mere functional and aesthetic concerns. Despite complexity, 3-year clinical outcome is encouraging, and the patient is no longer at risk for dural exposure, meningitis, and related morbidity.

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.

Evaluation of damage in giant cell arteritis.

Objectives: To evaluate damage and variables associated with damage in GCA. Methods: Patients with GCA enrolled in a prospective, multicentre, longitudinal study were included. Per-protocol assessments were made with the Vasculitis Damage Index and the Large-Vessel Vasculitis Index of Damage. Results: The study included 204 patients: 156 women (76%), mean age at diagnosis 71.3 years (s.d. 8.3), mean follow-up of 3.5 years (s.d. 1.9). One or more damage item was present in 54% at baseline and 79% at the last follow-up on the Vasculitis Damage Index, and 60% at baseline and 82% at the last follow-up on the Large-Vessel Vasculitis Index of Damage. The most frequently observed damage items were large-artery complications (29% cohort) and ocular (22%). Among 117 patients with new damage, most new items were ocular (63 patients), cardiac/vascular (48) and musculoskeletal (34). Of these, treatment-associated items were frequently observed, including cataracts (46 patients), osteoporosis (22) and weight gain (22). Disease-associated new damage included ischaemic optic neuropathy (3 patients), limb claudication (13), arterial occlusions (10) and damage requiring vascular intervention (10). In univariate analysis, the risk of damage increased 22% for every additional year of disease duration [odds ratio (OR) 1.22 (95% CI 1.04, 1.45)]. In 94 patients enrolled within ⩽90 days of diagnosis of GCA, the risk of new damage at the last follow-up decreased 30% for each additional relapse [OR 0.70 (95% CI 0.51, 0.97)]. Conclusions: Large-artery complications and ocular manifestations are the most commonly occurring items of damage in GCA. Most new damage is associated with treatment. These findings emphasize the cumulative burden of disease in GCA.

Pharmacokinetics of rituximab and clinical outcomes in patients with anti-neutrophil cytoplasmic antibody associated vasculitis.

Objectives: To study the determinants of the pharmacokinetics (PK) of rituximab (RTX) in patients with ANCA-associated vasculitis (AAV) and its association with clinical outcomes. Methods: This study included data from 89 patients from the RTX in AAV trial who received the full dose of RTX (four weekly infusions of 375 mg/m2). RTX was quantified at weeks 2, 4, 8, 16 and 24, and summarized by computing the trapezoidal area under the curve. We explored potential determinants of the PK-RTX, and analysed its association with clinical outcomes: achievement of remission at 6 months, duration of B-cell depletion and time to relapse in patients who achieved complete remission. Results: RTX serum levels were significantly lower in males and in newly diagnosed patients, and negatively correlated with body surface area, baseline B-cell count and degree of disease activity. In multivariate analyses, the main determinants of PK-RTX were sex and new diagnosis. Patients reaching complete remission at month 6 had similar RTX levels compared with patients who did not reach complete remission. Patients with higher RTX levels generally experienced longer B-cell depletion than patients with lower levels, but RTX levels at the different time points and area under the curve were not associated with time to relapse. Conclusion: Despite the body-surface-area-based dosing protocol, PK-RTX is highly variable among patients with AAV, its main determinants being sex and newly diagnosed disease. We did not observe any relevant association between PK-RTX and clinical outcomes. The monitoring of serum RTX levels does not seem clinically useful in AAV.

Interstitial Immunostaining and Renal Outcomes in Antineutrophil Cytoplasmic Antibody-Associated Glomerulonephritis.

BACKGROUND: Immunopathologic features predict renal function at baseline and follow-up in antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis (GN). The interstitial infiltrate consists predominantly of T lymphocytes, but their pathophysiologic significance is unclear, especially in light of the success of B-cell-directed therapy. METHODS: Renal biopsies from 33 patients treated with cyclophosphamide (CYC; n = 17) or rituximab (RTX; n = 16) in the RTX in ANCA-associated vasculitis (RAVE) trial were classified according to the new ANCA GN classification. T- and B-cell infiltration in the interstitium was assessed by immunostaining for CD3 and CD20. Correlations of clinical and histologic parameters with renal function at set time points were examined. RESULTS: The mean (SD) baseline estimated glomerular filtration rate was 36 (20) mL/min/1.73 m2. ANCA GN class distribution was 46% focal, 33% mixed, 12% sclerotic and 9% crescentic. The interstitial infiltrate consisted of >50% CD3 positive cells in 69% of biopsies, but >50% CD20 positive cells only in 8% of biopsies. In a multiple linear regression model, only baseline glomerular filtration rate (GFR) correlated with GFR at 6, 12, and 18 months. Interstitial B- and T-cell infiltrates had no significant impact on long-term prognosis, independent of the treatment limb. A differential effect was noted only at 6 months, where a dense CD3 positive infiltrate predicted lower GFR in the RTX group and a CD20 positive infiltrate predicted higher GFR in the CYC group. CONCLUSIONS: In ANCA-associated GN, the interstitial infiltrate contains mainly T lymphocytes. However, it is neither reflecting baseline renal function nor predictive of response to treatment, regardless of the immunosuppression regimen employed.

IgA antibodies to myeloperoxidase in patients with eosinophilic granulomatosis with polyangiitis (Churg-Strauss).

OBJECTIVES: To determine the prevalence of anti-myeloperoxidase (MPO) antibodies of IgA (IgA anti-MPO) isotype in patients with eosinophilic granulomatosis with polyangiitis (EGPA), and the association of the IgA antibodies with IgG anti-MPO and with disease activity. METHODS: Serum samples from patients with EGPA followed in a multicenter longitudinal cohort were tested by ELISA for the presence of IgA anti-MPO and IgG anti-MPO antibodies. Sera from 87 healthy controls were used to define a positive test. Sera from 168 patients with EGPA (298 samples) were tested. Frequencies of positive testing for IgA anti-MPO were compared between patients with active EGPA, patients in remission, and controls. RESULTS: IgA anti-MPO was detected in 10 of 168 (6%) patients with EGPA (11 of 298 serum samples) compared to 1 of 87 (1%) healthy controls (p=0.10). All 11 samples testing positive for IgA anti-MPO also tested positive for IgG anti-MPO. Ninety samples tested positive for IgG anti-MPO but negative for IgA. Samples taken during active EGPA were positive for IgA anti-MPO in 6/72 cases (8%), compared to 5/226 (2%) during remission (p=0.03). Among samples taken during moderate or high disease activity, 5/41 were positive (12%, p=0.01 compared to remission). CONCLUSIONS: Although IgA anti-MPO antibodies are detectable in some patients with EGPA and may be detectable more frequently during active disease, their presence seems unlikely to provide information beyond what is obtained from conventional IgG anti-MPO.

Giant Cell Arteritis.

This issue provides a clinical overview of giant cell arteritis, focusing on diagnosis, treatment, and practice improvement. The content of In the Clinic is drawn from the clinical information and education resources of the American College of Physicians (ACP), including MKSAP (Medical Knowledge and Self-Assessment Program). Annals of Internal Medicine editors develop In the Clinic in collaboration with the ACP's Medical Education and Publishing divisions and with the assistance of additional science writers and physician writers.

Identification of multiple genetic susceptibility loci in Takayasu arteritis.

Takayasu arteritis is a rare inflammatory disease of large arteries. The etiology of Takayasu arteritis remains poorly understood, but genetic contribution to the disease pathogenesis is supported by the genetic association with HLA-B*52. We genotyped ~200,000 genetic variants in two ethnically divergent Takayasu arteritis cohorts from Turkey and North America by using a custom-designed genotyping platform (Immunochip). Additional genetic variants and the classical HLA alleles were imputed and analyzed. We identified and confirmed two independent susceptibility loci within the HLA region (r(2) < 0.2): HLA-B/MICA (rs12524487, OR = 3.29, p = 5.57 × 10(-16)) and HLA-DQB1/HLA-DRB1 (rs113452171, OR = 2.34, p = 3.74 × 10(-9); and rs189754752, OR = 2.47, p = 4.22 × 10(-9)). In addition, we identified and confirmed a genetic association between Takayasu arteritis and the FCGR2A/FCGR3A locus on chromosome 1 (rs10919543, OR = 1.81, p = 5.89 × 10(-12)). The risk allele in this locus results in increased mRNA expression of FCGR2A. We also established the genetic association between IL12B and Takayasu arteritis (rs56167332, OR = 1.54, p = 2.18 × 10(-8)).

Efficacy of remission-induction regimens for ANCA-associated vasculitis.

BACKGROUND: The 18-month efficacy of a single course of rituximab as compared with conventional immunosuppression with cyclophosphamide followed by azathioprine in patients with severe (organ-threatening) antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis is unknown. METHODS: In a multicenter, randomized, double-blind, double-dummy, noninferiority trial, we compared rituximab (375 mg per square meter of body-surface area administered once a week for 4 weeks) followed by placebo with cyclophosphamide administered for 3 to 6 months followed by azathioprine for 12 to 15 months. The primary outcome measure was complete remission of disease by 6 months, with the remission maintained through 18 months. RESULTS: A total of 197 patients were enrolled. As reported previously, 64% of the patients in the rituximab group, as compared with 53% of the patients in the cyclophosphamide-azathioprine group, had a complete remission by 6 months. At 12 and 18 months, 48% and 39%, respectively, of the patients in the rituximab group had maintained the complete remissions, as compared with 39% and 33%, respectively, in the comparison group. Rituximab met the prespecified criteria for noninferiority (P<0.001, with a noninferiority margin of 20%). There was no significant difference between the groups in any efficacy measure, including the duration of complete remission and the frequency or severity of relapses. Among the 101 patients who had relapsing disease at baseline, rituximab was superior to conventional immunosuppression at 6 months (P=0.01) and at 12 months (P=0.009) but not at 18 months (P=0.06), at which time most patients in the rituximab group had reconstituted B cells. There was no significant between-group difference in adverse events. CONCLUSIONS: In patients with severe ANCA-associated vasculitis, a single course of rituximab was as effective as continuous conventional immunosuppressive therapy for the induction and maintenance of remissions over the course of 18 months. (Funded by the National Institute of Allergy and Infectious Diseases and others; RAVE ClinicalTrials.gov number, NCT00104299.)

Using Mass Spectrometry to Quantify Rituximab and Perform Individualized Immunoglobulin Phenotyping in ANCA-Associated Vasculitis.

Therapeutic monoclonal immunoglobulins (mAbs) are used to treat patients with a wide range of disorders including autoimmune diseases. As pharmaceutical companies bring more fully humanized therapeutic mAb drugs to the healthcare market analytical platforms that perform therapeutic drug monitoring (TDM) without relying on mAb specific reagents will be needed. In this study we demonstrate that liquid-chromatography-mass spectrometry (LC-MS) can be used to perform TDM of mAbs in the same manner as smaller nonbiologic drugs. The assay uses commercially available reagents combined with heavy and light chain disulfide bond reduction followed by light chain analysis by microflow-LC-electrospray ionization-quadrupole-time-of-flight mass spectrometry (ESI-Q-TOF MS). Quantification is performed using the peak areas from multiply charged mAb light chain ions using an in-house developed software package developed for TDM of mAbs. The data presented here demonstrate the ability of an LC-MS assay to quantify a therapeutic mAb in a large cohort of patients in a clinical trial. The ability to quantify any mAb in serum via the reduced light chain without the need for reagents specific for each mAb demonstrates the unique capabilities of LC-MS. This fact, coupled with the ability to phenotype a patient's polyclonal repertoire in the same analysis further shows the potential of this approach to mAb analysis.

Clinical outcomes of treatment of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis based on ANCA type.

OBJECTIVE: To evaluate whether the classification of patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) according to ANCA type (anti-proteinase 3 (PR3) or anti-myeloperoxidase (MPO) antibodies) predicts treatment response. METHODS: Treatment responses were assessed among patients enrolled in the Rituximab in ANCA-associated Vasculitis trial according to both AAV diagnosis (granulomatosis with polyangiitis (GPA)/microscopic polyangiitis (MPA)) and ANCA type (PR3-AAV/MPO-AAV). Complete remission (CR) was defined as disease activity score of 0 and successful completion of the prednisone taper. RESULTS: PR3-AAV patients treated with rituximab (RTX) achieved CR at 6 months more frequently than did those randomised to cyclophosphamide (CYC)/azathioprine (AZA) (65% vs 48%; p=0.04). The OR for CR at 6 months among PR3-AAV patients treated with RTX as opposed to CYC/AZA was 2.11 (95% CI 1.04 to 4.30) in analyses adjusted for age, sex and new-onset versus relapsing disease at baseline. PR3-AAV patients with relapsing disease achieved CR more often following RTX treatment at 6 months (OR 3.57; 95% CI 1.43 to 8.93), 12 months (OR 4.32; 95% CI 1.53 to 12.15) and 18 months (OR 3.06; 95% CI 1.05 to 8.97). No association between treatment and CR was observed in the MPO-AAV patient subset or in groups divided according to AAV diagnosis. CONCLUSIONS: Patients with PR3-AAV respond better to RTX than to CYC/AZA. An ANCA type-based classification may guide immunosuppression in AAV. TRIAL REGISTRATION NUMBER: NCT00104299; post-results.

Rituximab versus cyclophosphamide for ANCA-associated vasculitis with renal involvement.

Rituximab (RTX) is non-inferior to cyclophosphamide (CYC) followed by azathioprine (AZA) for remission-induction in severe ANCA-associated vasculitis (AAV), but renal outcomes are unknown. This is a post hoc analysis of patients enrolled in the Rituximab for ANCA-Associated Vasculitis (RAVE) Trial who had renal involvement (biopsy proven pauci-immune GN, red blood cell casts in the urine, and/or a rise in serum creatinine concentration attributed to vasculitis). Remission-induction regimens were RTX at 375 mg/m(2) × 4 or CYC at 2 mg/kg/d. CYC was replaced by AZA (2 mg/kg/d) after 3-6 months. Both groups received glucocorticoids. Complete remission (CR) was defined as Birmingham Vasculitis Activity Score/Wegener's Granulomatosis (BVAS/WG)=0 off prednisone. Fifty-two percent (102 of 197) of the patients had renal involvement at entry. Of these patients, 51 were randomized to RTX, and 51 to CYC/AZA. Mean eGFR was lower in the RTX group (41 versus 50 ml/min per 1.73 m(2); P=0.05); 61% and 75% of patients treated with RTX and 63% and 76% of patients treated with CYC/AZA achieved CR by 6 and 18 months, respectively. No differences in remission rates or increases in eGFR at 18 months were evident when analysis was stratified by ANCA type, AAV diagnosis (granulomatosis with polyangiitis versus microscopic polyangiitis), or new diagnosis (versus relapsing disease) at entry. There were no differences between treatment groups in relapses at 6, 12, or 18 months. No differences in adverse events were observed. In conclusion, patients with AAV and renal involvement respond similarly to remission induction with RTX plus glucocorticoids or CYC plus glucocorticoids.

Evidence for a vascular microbiome and its role in vessel health and disease.

PURPOSE OF REVIEW: We have summarized available evidence for and against the presence of a vascular microbiome. Studies that have attempted to detect bacteria and viruses in blood vessels in both health and disease are critiqued in an attempt to explain contrary results that may be due to variations in methodology. RECENT FINDINGS: Many studies have demonstrated the presence of both bacteria and viruses within diseased blood vessels. Evidence is most compelling in atherosclerosis; however, recent reports have raised questions about the potential role of microbes in nonatherosclerotic aortic aneurysms and vasculitis. Preliminary evidence also suggests that apparently normal vessels may harbor microbes. With the exception of certain viral infections (e.g. hepatitis C virus, HIV, Epstein-Barr virus, and cytomegalovirus) and infectious endocarditis, systemic vasculitides have not been convincingly associated with infectious agents. However, emerging data suggest that different communities of microbes may be present in noninflammatory and inflammatory large-vessel diseases. Whether variations in vascular microbial communities are the cause or a secondary result (epiphenomena) of vessel injury remains to be determined. SUMMARY: Blood vessels may not be sterile. Future studies of microbes in vessel health and disease may provide important insights into disease pathogenesis and suggest new therapies for diseases now considered to be idiopathic and refractory.

Allosteric modulation of proteinase 3 activity by anti-neutrophil cytoplasmic antibodies in granulomatosis with polyangiitis.

Anti-neutrophil cytoplasmic antibodies (ANCA) with proteinase 3 (PR3) specificity are a useful laboratory biomarker for the diagnosis of Granulomatosis with Polyangiitis (GPA) and are believed to be implicated in the pathogenesis. It has been repeatedly suggested that disease activity of GPA is more closely related to the appearance and rise of PR3-inhibiting ANCA than to an increase of total ANCA. Previous studies on a limited number of patient samples, however, have yielded inconclusive results. To overcome the previous methodological limitations, we established a new ultrasensitive method to quantify the inhibitory capacity of PR3-ANCA using small volumes of plasma from patients with GPA. A large collection of longitudinally-collected samples from the Wegener Granulomatosis Etanercept Trial (WGET) became available to us to determine the functional effects of ANCA on PR3 in comparison to clinical disease manifestations. In these patient samples we not only detected PR3-ANCA with inhibitory capacity, but also PR3-ANCA with enhancing effects on PR3 activity. However no correlation of these activity-modulating PR3-ANCA with disease activity at either the time of enrollment or over the course of disease was found. Only patients with pulmonary involvement, especially patients with nodule formation in the respiratory tract, showed a slight, but not significant, decrease of inhibitory capacity. Epitope mapping of the activity-modulating PR3-ANCA revealed a binding on the active site surface of PR3. Yet these ANCA were able to bind to PR3 with an occupied active site cleft, indicating an allosteric mechanism of inhibition. The recently described signal ratio between the MCPR3-3 and MCPR3-2 capture ELISA was consistent with the binding of activity-modulating ANCA to the active site surface. Evidence for a shared epitope between activity-modulating PR3-ANCA and MCPR3-7, however, was very limited, suggesting that a majority of PR3-ANCA species do not inhibit PR3 by the same mechanism as previously reported for MCPR3-7.

Value of commonly measured laboratory tests as biomarkers of disease activity and predictors of relapse in eosinophilic granulomatosis with polyangiitis.

OBJECTIVE: The aim of this study was to assess the clinical value of absolute eosinophil count, serum IgE, ESR and CRP as longitudinal biomarkers of disease activity and predictors of relapse in eosinophilic granulomatosis with polyangiitis (Churg-Strauss, EGPA). METHODS: Patients were selected from an observational EGPA cohort. Absolute eosinophil count, IgE, ESR and CRP were measured quarterly. Disease activity was defined by validated assessment tools. The association of tests with disease activity was assessed via regression models, adjusting for repeated measures and treatment status. Survival analysis was used to determine if laboratory tests were predictive of the 3 month future flare risk. RESULTS: Seventy-four per cent of 892 study visits in 141 patients occurred while patients were on treatment, mostly during remission or mild disease activity, defined as a BVAS for Wegener's granulomatosis (BVAS/WG) of 1 or 2. Correlations between absolute eosinophil count, IgE, ESR and CRP were mostly low or non-significant (r = -0.08 to 0.44). There were few weak associations with disease activity [absolute eosinophil count: OR) 1.01/100 U (95% CI 1.01, 1.02); ESR: OR 1.15/10 mg/l increase (95% CI 1.04, 1.27)]. When BVAS/WG ≥1 defined active disease, the absolute eosinophil count [hazard ratio (HR) 1.01/100 U (95% CI 1.01, 1.02)] was weakly predictive of flare. When BVAS/WG ≥3 defined active disease, ESR was weakly predictive of flare [HR 1.52/10 mm/h increase (95% CI 1.17, 1.67)]. CONCLUSION: The absolute eosinophil count, IgE, ESR and CRP have limitations as longitudinal biomarkers of disease activity or predictors of flare in EGPA. These findings suggest that novel biomarkers of disease activity for EGPA are needed.

Recent advances in the medical management of Takayasu arteritis: an update on use of biologic therapies.

PURPOSE OF REVIEW: To critically review recent advances in medical management of Takayasu arteritis, with a special focus on the rationale and evidence to support the use of biologic agents in this disease. RECENT FINDINGS: Multiple case series and observational studies support the use of anti-tumor necrosis factor (TNF) medications, in particular infliximab, in patients who relapse upon tapering steroids and/or adding nonbiologic immunosuppressive agents. However, these medications must be continued to maintain effect, and often patients require increased doses over time. Tocilizumab and rituximab have been shown to lead to improved disease activity in small numbers of Takayasu's patients, including those refractory to anti-TNF treatment. SUMMARY: Anti-TNF agents are recommended for the treatment of Takayasu's patients who are unable to taper prednisone despite treatment with a nonbiologic immunosuppressive medication. Whether these biologic agents should be considered earlier in the treatment algorithm of these complicated patients remains an area of interest. Tocilizumab and rituximab may also be of benefit in refractory patients. Prospective randomized controlled trials are needed to confirm these findings.