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Objective: Fixed and tailored rituximab retreatment strategies to maintain remission in antineutrophil cytoplasmic antibody (ANCA)–associated vasculitis (AAV) are associated with tradeoffs. The current study was undertaken to develop a simulation model (AAV‐Sim) to project clinical outcomes with these strategies. Methods: We developed the AAV‐Sim, a microsimulation model of clinical events among individuals with AAV initiating treatment to maintain remission. Individuals transition between health states of remission or relapse and are at risk for severe infection, end‐stage renal disease, or death. We estimated transition rates from published literature, stratified by individual‐level characteristics. We performed validation using the mean average percent error (MAPE) and the coefficient of variation of root mean square error (CV‐RMSE). In internal validation, we compared model‐projected outcomes over 28 months with outcomes observed in the Rituximab versus Azathioprine in ANCA‐Associated Vasculitis 2 (MAINRITSAN2) trial, which compared fixed versus tailored retreatment. In external validation, we compared outcomes with fixed rituximab retreatment from the AAV‐Sim to outcomes from the MAINRITSAN1 trial and an observational study. Results: The AAV‐Sim projected outcomes similar to those in the MAINRITSAN2 trial, including minor (AAV‐Sim 6.0% fixed versus 7.3% tailored; MAINRITSAN2 6.2% versus 8.6%; MAPE 3% and 15%) and major relapse (AAV‐Sim 3.5% versus 5.5%; MAINRITSAN2 3.7% versus 7.4%; MAPE 5% and 26%), severe infection (AAV‐Sim 19.4% versus 11.1%; MAINRITSAN2 19.8% versus 10.2%; MAPE 2% and 9%), and relapse‐free survival (AAV‐Sim 84.8% versus 82.3%; MAINRITSAN2 86% versus 84%; CV‐RMSE 2.3% and 2.5%). Similar performance was observed in external validation. Conclusion: The AAV‐Sim projected a range of clinical outcomes for different treatment approaches that were validated against published data. The AAV‐Sim has the potential to inform management guidelines and research priorities. [ABSTRACT FROM AUTHOR]

Objective: To compare rituximab‐ versus cyclophosphamide‐based remission induction strategies for the long‐term risks of kidney failure and death in antineutrophil cytoplasmic antibody (ANCA)–associated vasculitis (AAV) in a real‐world cohort. Methods: We performed a cohort study using the Mass General Brigham AAV Cohort, which includes proteinase 3–ANCA+ and myeloperoxidase (MPO)‐ANCA+ AAV patients diagnosed from January 1, 2002 to December 31, 2019. We included cases in which the initial remission induction strategy was based either on rituximab or cyclophosphamide. The primary outcome was the composite outcome of kidney failure or death. We used multivariable Cox proportional hazards models and propensity score–matched analyses to assess the association of rituximab‐ versus cyclophosphamide‐based treatment strategies with the composite outcome of kidney failure or death. Results: Of 595 included patients, 352 patients (~60%) received rituximab‐based and 243 patients (~40%) received cyclophosphamide‐based regimens. The mean age was 61 years, 58% of patients were female, 70% of patients were MPO‐ANCA+, and 69% of patients had renal involvement (median estimated glomerular filtration rate 37.3 ml/minute/1.73 m2). There were 133 events at 5 years, and the incidence rates in rituximab‐ and cyclophosphamide‐based regimens were 6.8 and 6.1 per 100 person‐years, respectively. The risk of kidney failure or death was similar in both groups in multivariable‐adjusted analyses (hazard ratio [HR] 1.03 [95% confidence interval (95% CI) 0.55–1.93]) and in propensity score–matched analyses (HR 1.05 [95% CI 0.55–1.99]) at 5 years. Our findings were similar when outcomes were assessed at 1 and 2 years as well as in subgroups stratified according to renal involvement and severity as well as major organ involvement. Conclusion: Rituximab‐ and cyclophosphamide‐based remission induction strategies for AAV are associated with similar risks of kidney failure and death. [ABSTRACT FROM AUTHOR]

Objective: Proteinase 3 (PR3) is the major antigen for antineutrophil cytoplasmic antibodies (ANCAs) in the systemic autoimmune vasculitis, granulomatosis with polyangiitis (GPA). PR3‐targeting ANCAs (PR3‐ANCAs) recognize different epitopes on PR3. This study was undertaken to study the effect of mutations on PR3 antigenicity. Methods: The recombinant PR3 variants, iPR3 (clinically used to detect PR3‐ANCAs) and iHm5 (containing 3 point mutations in epitopes 1 and 5 generated for epitope mapping studies) immunoassays and serum samples from patients enrolled in ANCA‐associated vasculitis (AAV) trials were used to screen for differential PR3‐ANCA binding. A patient‐derived monoclonal ANCA 518 (moANCA518) that selectively binds to iHm5 within the mutation‐free epitope 3 and is distant from the point mutations of iHm5 was used as a gauge for remote epitope activation. Selective binding was determined using inhibition experiments. Results: Rather than reduced binding of PR3‐ANCAs to iHm5, we found substantially increased binding of the majority of PR3‐ANCAs to iHm5 compared to iPR3. This differential binding of PR3‐ANCA to iHm5 is similar to the selective moANCA518 binding to iHm5. Binding of iPR3 to monoclonal antibody MCPR3‐2 also induced recognition by moANCA518. Conclusion: The preferential binding of PR3‐ANCAs from patients, such as the selective binding of moANCA518 to iHm5, is conferred by increased antigenicity of epitope 3 on iHm5. This can also be induced on iPR3 when captured by monoclonal antibody MCPR2. This previously unrecognized characteristic of PR3‐ANCA interactions with its target antigen has implications for studying antibody‐mediated autoimmune diseases, understanding variable performance characteristics of immunoassays, and design of potential novel treatment approaches. [ABSTRACT FROM AUTHOR]

Objective: Autoreactive B cells are responsible for antineutrophil cytoplasmic antibody (ANCA) production in ANCA‐associated vasculitis (AAV). Rituximab (RTX) depletes circulating B cells, including autoreactive B cells. We aimed to evaluate changes and associations with relapse of the circulating autoreactive B cell pool following therapeutic B cell depletion in AAV. Methods: Sequential flow cytometry was performed on 148 samples of peripheral blood mononuclear cells from 23 patients with proteinase 3 (PR3)–ANCA–positive AAV who were treated with RTX for remission induction and monitored after stopping therapy during long‐term follow‐up in a prospective clinical trial. PR3 was used as a ligand to target autoreactive PR3‐specific (PR3+) B cells. B cell recurrence was considered as the first blood sample with ≥10 B cells/μl after RTX treatment. Results: At B cell recurrence, PR3+ B cell frequency among B cells was higher than baseline (P < 0.01). Within both PR3+ and total B cells, frequencies of transitional and naive subsets were higher at B cell recurrence than at baseline, while memory subsets were lower (P < 0.001 for all comparisons). At B cell recurrence, frequencies of B cells and subsets did not differ between patients who experienced relapse and patients who remained in remission. In contrast, the plasmablast frequency within the PR3+ B cell pool was higher in patients who experienced relapse and associated with a shorter time to relapse. Frequencies of PR3+ plasmablasts higher than baseline were more likely to be found in patients who experienced relapse within the following 12 months compared to those in sustained remission (P < 0.05). Conclusion: The composition of the autoreactive B cell pool varies significantly following RTX treatment in AAV, and early plasmablast enrichment within the autoreactive pool is associated with future relapses. [ABSTRACT FROM AUTHOR]

The antineutrophil cytoplasmic antibody (ANCA)–associated vasculitides (AAV) comprise a major subset of diseases that cause destructive inflammation of small and medium‐sized blood vessels. Although these conditions have a predilection for pulmonary and renal involvement, they are in fact protean diseases that can involve essentially any organ system. AAV is among the most difficult rheumatic diseases to diagnose and treat. Therapy for AAV has evolved over the past two decades. Rituximab, an anti‐CD20 monoclonal antibody, is now the preferred agent for remission induction in conjunction with a reduced‐dose glucocorticoid taper. Rituximab is also often a key therapy for remission maintenance. Glucocorticoid toxicity reduction has become a major priority for treatment regimens. Avacopan, an important new adjunct to remission induction therapy, may reduce glucocorticoid use and its resulting toxicity. The role of avacopan as a remission maintenance agent requires further study. The duration of immunosuppression following remission is guided by a number of factors, including the patient's overall clinical state, the degree of damage from previous disease activity, the tolerability of remission maintenance medications, and SARS–CoV‐2 vaccination and immunity status. Certain features, including history of previous relapse, the presence of ANCA directed against proteinase 3, and a diagnosis of granulomatosis with polyangiitis, favor prolonged remission maintenance therapy. The interval between rituximab doses can usually be lengthened over time during the maintenance phase. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study was to validate the diagnosis of antineutrophil cytoplasmic antibody (ANCA)–associated vasculitis (AAV) as the primary cause of end‐stage renal disease (ESRD) in the US Renal Data System (USRDS). Methods: We identified patients with ESRD in the Mass General Brigham (MGB) health care system who were enrolled in the USRDS. The health records of those with AAV listed as the primary cause of ESRD in the USRDS were reviewed to confirm the diagnosis and estimate positive predictive value (PPV). Sensitivity was estimated by evaluating the primary cause of ESRD listed in the USRDS for patients with ESRD due to AAV in the MGB AAV cohort. Results: We identified 89 MGB patients with ESRD due to AAV in the USRDS. Of these, 85 cases were confirmed to be true cases of AAV (PPV = 94%). Among the patients classified as having AAV, 84 (99%) had an ANCA test, which was predominantly myeloperoxidase/P‐ANCA (47 [55%]); 36 (42%) had a renal biopsy, and all biopsies were supportive of the diagnosis. The majority (81 [90%]) was identified as AAV by International Classification of Diseases Ninth Revision or International Classification of Diseases 10th Revision codes for granulomatosis with polyangiitis (446.4 or M313.1). Of the 77 MGB AAV cohort patients with ESRD who were linked to the USRDS, 41 (53%) had AAV listed as the cause of ESRD; in the remainder, ESRD was attributed to nonspecific nephritis. Conclusion: The diagnosis of AAV as the cause of ESRD in the USRDS has a high PPV; sensitivity was moderate. These findings support the continued use of the USRDS to study ESRD due to AAV. [ABSTRACT FROM AUTHOR]

Objective: To provide evidence-based recommendations and expert guidance for the management of antineutrophil cytoplasmic antibody-associated vasculitis (AAV), including granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA).Methods: Clinical questions regarding the treatment and management of AAV were developed in the population, intervention, comparator, and outcome (PICO) format (47 for GPA/MPA, 34 for EGPA). Systematic literature reviews were conducted for each PICO question. The Grading of Recommendations Assessment, Development and Evaluation methodology was used to assess the quality of evidence and formulate recommendations. Each recommendation required ≥70% consensus among the Voting Panel.Results: We present 26 recommendations and 5 ungraded position statements for GPA/MPA, and 15 recommendations and 5 ungraded position statements for EGPA. This guideline provides recommendations for remission induction and maintenance therapy as well as adjunctive treatment strategies in GPA, MPA, and EGPA. These recommendations include the use of rituximab for remission induction and maintenance in severe GPA and MPA and the use of mepolizumab in nonsevere EGPA. All recommendations are conditional due in part to the lack of multiple randomized controlled trials and/or low-quality evidence supporting the recommendations.Conclusion: This guideline presents the first recommendations endorsed by the American College of Rheumatology and the Vasculitis Foundation for the management of AAV and provides guidance to health care professionals on how to treat these diseases. [ABSTRACT FROM AUTHOR]

Objective: The management of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) has evolved substantially over the last 2 decades. We sought to characterize AAV treatment patterns in the United States.Methods: We identified patients with AAV in the Rheumatology Informatics System for Effectiveness (RISE) registry who had at least 2 rheumatology clinician visits between January 1, 2015, and December 31, 2017. Demographics, medications, laboratory test results, and billing codes were extracted from the medical record. Demographic and prescription trends were assessed overall and across US regions.Results: We identified 1462 patients with AAV, 259 (18%) with new or relapsing AAV. The majority were classified as having granulomatosis with polyangiitis (75%). The mean age was 59.8 years and 59% were female. The majority of patients were in the South (45%) followed by the Mid-West (32%), West (12%), and Northeast (8%). Patients had a median of 3 visits and follow-up of 579 days. The most commonly prescribed medications during the study period were glucocorticoids (86%) followed by rituximab (45%), methotrexate (33%), azathioprine (32%), and mycophenolate mofetil (18%); cyclophosphamide (CYC) was rarely used (7%). At the most recent visits in RISE, 47% of patients were on glucocorticoids. Prescription trends were similar across regions.Conclusion: To our knowledge, this is the first study to evaluate the demographics and management of AAV by rheumatologists outside of major referral centers. Management strategies vary widely, but CYC is rarely used. These observations can be used to inform future research priorities. Additional studies are needed to characterize AAV severity in RISE as well as patient and provider treatment preferences. [ABSTRACT FROM AUTHOR]

Background: The utility of ANCA testing as an indicator of disease activity in ANCA-associated vasculitis (AAV) remains controversial. This study aimed to determine the association of ANCA testing by various methods and subsequent remission and examine the utility of a widely used automated addressable laser-bead immunoassay (ALBIA) to predict disease relapses. Methods: Data from the Rituximab vs. Cyclophosphamide for ANCA-Associated Vasculitis (RAVE) trial were used. ANCA testing was performed by direct ELISA, capture ELISA, and ALBIA. Cox proportional hazards regression models were used to evaluate the association of PR3-ANCA level and subsequent remission or relapse. The ALBIA results are routinely reported as >8 when the value is high. For this study, samples were further titrated. A decrease and increase in PR3-ANCA were defined as a halving or doubling in value, respectively. Results: A decrease in ANCA by ALBIA at 2 months was associated with shorter time to sustained remission (HR 4.52, p = 0.035). A decrease in ANCA by direct ELISA at 4 months was associated with decreased time to sustained remission (HR 1.77, p = 0.050). There were no other associations between ANCA decreases or negativity and time to remission. An increase in PR3-ANCA by ALBIA was found in 78 of 93 subjects (84%). Eleven (14%) had a PR3-ANCA value which required titration for detection of an increase. An increase of ANCA by ALBIA was associated with severe relapse across various subgroups. Conclusions: A decrease in ANCA by ALBIA at 2 months and by direct ELISA at 4 months may be predictive of subsequent remission. These results should be confirmed in a separate cohort with similarly protocolized sample and clinical data collection. A routinely used automated ALBIA for PR3-ANCA measurement is comparable to direct ELISA in predicting relapse in PR3-AAV. Without titration, 14% of the increases detected by ALBIA would have been missed. Titration is recommended when this assay is used for disease monitoring. The association of an increase in PR3-ANCA with the risk of subsequent relapse remains complex and is affected by disease phenotype and remission induction agent. [ABSTRACT FROM AUTHOR]

Objective The objective of this study was to evaluate causes of death in a contemporary inception cohort of ANCA-associated vasculitis patients, stratifying the analysis according to ANCA type. Methods We identified a consecutive inception cohort of patients newly diagnosed with ANCA-associated vasculitis from 2002 to 2017 in the Partners HealthCare System and determined vital status through the National Death Index. We determined cumulative mortality incidence and standardized mortality ratios (SMRs) compared with the general population. We compared MPO- and PR3-ANCA+ cases using Cox regression models. Results The cohort included 484 patients with a mean diagnosis age of 58 years; 40% were male, 65% were MPO-ANCA+, and 65% had renal involvement. During 3385 person-years (PY) of follow-up, 130 patients died, yielding a mortality rate of 38.4/1000 PY and a SMR of 2.3 (95% CI: 1.9, 2.8). The most common causes of death were cardiovascular disease (CVD; cumulative incidence 7.1%), malignancy (5.9%) and infection (4.1%). The SMR for infection was greatest for both MPO- and PR3-ANCA+ patients (16.4 and 6.5). MPO-ANCA+ patients had an elevated SMR for CVD (3.0), respiratory disease (2.4) and renal disease (4.5). PR3- and MPO-ANCA+ patients had an elevated SMR for malignancy (3.7 and 2.7). Compared with PR3-ANCA+ patients, MPO-ANCA+ patients had a higher risk of CVD death [hazard ratio 5.0 (95% CI: 1.2, 21.2]; P = 0.03]. Conclusion Premature ANCA-associated vasculitis mortality is explained by CVD, infection, malignancy, and renal death. CVD is the most common cause of death, but the largest excess mortality risk in PR3- and MPO-ANCA+ patients is associated with infection. MPO-ANCA+ patients are at higher risk of CVD death than PR3-ANCA+ patients. [ABSTRACT FROM AUTHOR]

Objective: To assess the frequency of venous thromboembolism (VTE) events in the Rituximab in Antineutrophil Cytoplasmic Antibody (ANCA)–Associated Vasculitis (RAVE) trial and identify novel potential risk factors. Methods: VTE events in 197 patients enrolled in the RAVE trial were analyzed. Baseline demographic and clinical characteristics were recorded, and univariate and multivariate analyses were performed to identify factors associated with VTE in ANCA‐associated vasculitis (AAV). Results: VTE occurred in 16 patients (8.1%) with an overall average time to event of 1.5 months (range 1.0–2.75). In univariate analyses with calculation of hazard ratios (HRs) and 95% confidence intervals (95% CIs), heart involvement (HR 17.408 [95% CI 2.247–134.842]; P = 0.006), positive proteinase 3 (PR3)–ANCA (HR 7.731 [95% CI 1.021–58.545]; P = 0.048), pulmonary hemorrhage (HR 3.889 [95% CI 1.448–10.448]; P = 0.008), and the presence of red blood cell casts (HR 15.617 [95% CI 3.491–69.854]; P < 0.001) were associated with the onset of VTE. In multivariate models adjusted for age and sex, the significant associations between VTE events and heart involvement (HR 21.836 [95% CI 2.566–185.805]; P = 0.005), PR3‐ANCA (HR 9.12 [95% CI 1.158–71.839]; P = 0.036), pulmonary hemorrhage (HR 3.91 [95% CI 1.453–10.522]; P = 0.007), and urinary red blood cell casts (HR 16.455 [95% CI 3.607–75.075]; P < 0.001) remained. Conclusion: Patients diagnosed as having AAV with pulmonary hemorrhage, positive PR3‐ANCA, heart involvement, and the presence of red blood cell casts are at an increased risk to develop VTE. Further studies are needed to confirm and expand these findings and to explore the mechanisms of hypercoagulability in these patients with the aim of informing potential targets for therapeutic intervention. [ABSTRACT FROM AUTHOR]

Objective: Patients with antineutrophil cytoplasmic antibody (ANCA)–associated vasculitis (AAV) have an elevated risk of cardiovascular disease (CVD). This study was undertaken to develop a clearer understanding of the association between changes in disease activity and lipid levels in AAV, which may inform CVD risk stratification in this population. Methods: Lipid levels were assessed in stored serum samples (obtained at baseline and month 6) from the Rituximab for ANCA‐Associated Vasculitis (RAVE) trial, which randomized patients to receive either rituximab or cyclophosphamide followed by azathioprine. Paired t‐tests and multivariable linear regression were used to assess changes in lipid levels. Results: Of the 142 patients with serum samples available, the mean ± SD age was 52.3 ± 14.7 years, 72 (51%) were male, 95 (67%) were proteinase 3 (PR3)–ANCA positive, 72 (51%) had received a new diagnosis of AAV, and 75 (53%) were treated with rituximab. Several lipid levels increased between baseline and month 6, including total cholesterol (+12.4 mg/dl [95% confidence interval (95% CI) +7.1, +21.0]), low‐density lipoprotein (+10.3 mg/dl [95% CI +6.1, +17.1]), and apolipoprotein B (+3.5 mg/dl [95% CI +1.0, +8.3]). These changes were observed among newly diagnosed and PR3‐ANCA–positive patients but not among those with relapsing disease or myeloperoxidase‐ANCA–positive patients. There was no difference in change in lipid levels between rituximab‐treated patients and cyclophosphamide‐treated patients. Changes in lipid levels correlated with changes in erythrocyte sedimentation rate but not with other inflammatory markers or glucocorticoid exposure. Conclusion: Lipid levels increased during remission induction among patients with newly diagnosed AAV and those who were PR3‐ANCA positive. Disease activity and ANCA type should be considered when assessing lipid profiles to stratify CVD risk in patients with AAV. [ABSTRACT FROM AUTHOR]

Objective: To evaluate circulating cytokine profiles in patients with antineutrophil cytoplasmic antibody–associated vasculitis (AAV), classified by antineutrophil cytoplasmic antibody (ANCA) specificity (proteinase 3 ANCA [PR3‐ANCA] versus myeloperoxidase ANCA [MPO‐ANCA]) or by clinical diagnosis (granulomatosis with polyangiitis [GPA] versus microscopic polyangiitis [MPA]). Methods: A panel of 29 cytokines was tested in 186 patients with active AAV at inclusion into the Rituximab in AAV trial. Cytokine concentrations were compared between groups within each classification system. Multivariable analyses adjusted for age, sex, and renal insufficiency were performed, with each biomarker as a dependent variable and ANCA specificity and clinical diagnosis as explanatory variables of interest. Results: Levels of 9 circulating cytokines (interleukin‐6 [IL‐6], granulocyte–macrophage colony‐stimulating factor [GM‐CSF], IL‐15, IL‐18, CXCL8/IL‐8, CCL‐17/thymus and activation–regulated chemokine [TARC], IL‐18 binding protein [IL‐18 BP], soluble IL‐2 receptor α [sIL‐2Rα], and nerve growth factor β [NGFβ]) were significantly higher in PR3‐AAV than MPO‐AAV, 4 cytokines (sIL6R, soluble tumor necrosis factor receptor type II [sTNFRII], neutrophil gelatinase–associated lipocalin [NGAL], and soluble intercellular adhesion molecule 1 [sICAM‐1]) were higher in MPO‐AAV than in PR3‐AAV, 6 cytokines (IL‐6, GM‐CSF, IL‐15, IL‐18, sIL‐2Rα, and NGFβ) were higher in GPA than in MPA, and 3 cytokines (osteopontin, sTNFRII, and NGAL) were higher in MPA than in GPA (all P < 0.05). For nearly all cytokines, the difference between PR3‐AAV and MPO‐AAV was larger than that between GPA and MPA. The multivariate analysis showed that 8 cytokines (IL‐15, IL‐8, IL‐18 BP, NGF‐β, sICAM‐1, TARC, osteopontin, and kidney injury molecule 1 (P < 0.05) distinguished patients with AAV better (lower P values and larger effect sizes) when grouped by ANCA specificity than by clinical diagnosis. Conclusion: Distinct cytokine profiles were identified for PR3‐AAV versus MPO‐AAV and for GPA versus MPA. Differences in these circulating immune mediators are more strongly associated with ANCA specificity than with clinical diagnosis, suggesting that heterogeneity in the AAV subtypes extends beyond clinical phenotypes. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Objective The Rituximab in ANCA-Associated Vasculitis (RAVE) trial compared rituximab to cyclophosphamide as induction therapy for the treatment of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. We undertook the current study to determine whether known single-nucleotide polymorphisms (SNPs) for Fcγ receptors (FcγR) or cytochrome P450 (CYP) enzymes were associated with the response to treatment with rituximab and cyclophosphamide, respectively. Methods Functional SNPs for FcγR (FcγRIIa 519G>A, FcγRIIb 695T>C, FcγRIIIa 559T>G) and CYP enzymes (CYP2B6 1459C>T, CYP2C19 681G>A) were analyzed by direct sequencing of polymerase chain reaction-amplified genomic DNA. Each SNP was tested as a predictor of complete remission at 6 months or remission with continued prednisone administration using logistic regression and including the covariates of baseline Birmingham Vasculitis Activity Score for Wegener's Granulomatosis, ANCA type, and new versus relapsing disease. The associations of these SNPs with the secondary outcomes of time to complete remission, time to relapse, or time to B cell reconstitution were analyzed by Cox proportional hazard tests. Results No significant associations were identified between complete remission and any FcγR genotype in the rituximab group or any CYP genotype in the cyclophosphamide group. However, when the treatment groups were combined, an association was found between the 519AA genotype of FcγRIIa and complete remission ( P = 0.01). The 519AA genotype predicted complete remission ( P = 0.006) and a shorter time to complete remission ( P < 0.001). Conclusion The finding that the homozygous FcγRIIa 519AA variant was associated with complete response and a shorter time to complete response in the RAVE trial, independent of treatment type, implies that FcγRIIa may be broadly involved in disease pathogenesis and response to therapy. [ABSTRACT FROM AUTHOR]

Objective To examine the relationship of antineutrophil cytoplasmic antibody (ANCA) type and ANCA-associated vasculitis (AAV) diagnosis with demographic features, disease manifestations, and clinical outcomes. We focused on patients who account for the differences between ANCA type and disease type classifications: anti-myeloperoxidase (MPO)-ANCA-positive and ANCA-negative patients with granulomatosis with polyangiitis (Wegener's) (GPA). Methods We performed a pooled analysis of the Wegener's Granulomatosis Etanercept Trial and the Rituximab in ANCA-Associated Vasculitis trial comparing patients with MPO-ANCA-positive GPA and patients with ANCA-negative GPA to patients with proteinase 3 (PR3)-ANCA-positive GPA and patients with MPO-ANCA-positive microscopic polyangiitis (MPA). Results Of the 365 patients analyzed, 273 (75%) had PR3-ANCA-positive GPA, 33 (9%) had MPO-ANCA-positive GPA, 15 (4%) had ANCA-negative GPA, and 44 (12%) had MPO-ANCA-positive MPA. MPO-ANCA-positive GPA patients were younger at diagnosis compared to MPO-ANCA-positive MPA patients (53 versus 61 years; P = 0.02). Their disease manifestations and rates of relapse were similar to those of PR3-ANCA-positive GPA patients. Relapse was more frequent in MPO-ANCA-positive GPA patients than in patients with MPO-ANCA-positive MPA at trial entry as well as at 12 and 18 months. ANCA-negative patients with GPA had lower Birmingham Vasculitis Activity Score for Wegener's Granulomatosis scores at trial entry than PR3-ANCA-positive patients with GPA (4.5 versus 7.7; P < 0.01), primarily because of a lower prevalence of renal involvement. Conclusion We were unable to demonstrate important clinical differences between MPO-ANCA-positive and PR3-ANCA-positive patients with GPA. The risk of relapse was associated more closely with disease type than with ANCA type in this patient cohort. These findings deserve consideration in the assessment of relapse risk in patients with AAV. [ABSTRACT FROM AUTHOR]

Objective Relapse following remission is common in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), particularly with ANCAs directed at proteinase 3 (PR3). This study was undertaken to evaluate the association of an increase in PR3-ANCA level with subsequent relapse. Methods Data from the Rituximab versus Cyclophosphamide for ANCA-Associated Vasculitis (RAVE) trial were used. Starting from the time of achieving complete remission, serial measurements by direct and capture enzyme-linked immunosorbent assays (ELISAs) were analyzed in 93 patients with PR3-ANCA, using Cox proportional hazards regression. Results An increase in PR3-ANCA level was identified in 58 of 93 subjects (62.4%) by direct ELISA and in 59 of 93 (63.4%) by capture ELISA. Relapses occurred in 55 of 93 subjects (59.1%), with 25 and 21 occurring within 1 year after an increase by direct ELISA and capture ELISA, respectively. An increase by direct ELISA was associated with subsequent severe relapses (hazard ratio [HR] 4.57; P < 0.001), particularly in patients presenting with renal involvement (HR 7.94; P < 0.001) and alveolar hemorrhage (HR 24.19; P < 0.001). Both assays identified increased risk for severe relapse in the rituximab group (HR 5.80; P = 0.002 for direct ELISA and HR 4.54; P = 0.007 for capture ELISA) but not the cyclophosphamide/azathioprine group ( P = 0.103 and P = 0.197, respectively). Conclusion The association of an increase in PR3-ANCA level with the risk of subsequent relapse is partially affected by the PR3-ANCA detection methodology, disease phenotype, and remission induction treatment. An increase in PR3-ANCA level during complete remission conveys an increased risk of relapse, particularly severe relapse, among patients with renal involvement or alveolar hemorrhage and those treated with rituximab. Serial measurements of PR3-ANCA may be informative in this subset of patients, but the risk of relapse must be weighed carefully against the risks associated with therapy. [ABSTRACT FROM AUTHOR]

Background: IgG4-related disease (IgG4-RD) is a fibroinflammatory condition characterized by serum IgG4 elevation and tissue infiltration of IgG4-positive plasma cells. Substantial overlap between IgG4-RD and antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitides (AAV) exists in terms of organ involvement and histopathological features. A positive ANCA assay is regarded as a highly specific finding in favor of an AAV, and generally influences away from a diagnosis of IgG4-RD. Recent reports, however, have raised the possibility that some patients with IgG4-RD are ANCA positive, thus suggesting reconsideration of the role of ANCA in the diagnostic workup. In the present work, we describe the first case of concomitant biopsy-proven IgG4-RD and granulomatosis with polyangiitis (GPA), demonstrating antiproteinase 3 (PR3) ANCA of the IgG4 subclass in the patient's serum. We also review the literature in order to provide clinicians with tools for interpreting ANCA positivity in IgG4-RD patients. Case summary: A 51-year-old woman was referred for left exopthalmos due to lacrimal gland enlargement and increased serum IgG4 concentration. IgG4-RD was suspected and further imaging studies disclosed multiple pulmonary masses in the right lung. Histological analysis of the left lacrimal gland was diagnostic for IgG4-RD, but lung biopsy showed typical features of GPA. ANCA assay was positive for anti-PR3 antibodies. Further immunofluorescence studies demonstrated anti-PR3 antibodies of IgG1 and IgG4 subclass. Treatment with rituximab induced swift remission of both IgG4-RD and GPA manifestations. We identified 9 other reports of patients with IgG4-RD and positive ANCA in the English literature, 5 cases with biopsy-proven IgG4-RD and 4 cases in whom IgG4-RD was diagnosed presumptively. Four patients had also histological evidence of concomitant AAV. Conclusion: The present work demonstrates that ANCA positivity in patients with biopsy-proven IgG4-RD should prompt the exclusion of a concomitant vasculitic process; a positive ANCA does not exclude the diagnosis of IgG4-RD; confirmation through immunoenzymatic assays of the ANCA specificity, clinical-pathological correlation, and histopathological evaluation remain crucial steps for the differential diagnosis between AAV and IgG4-RD.

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis consists of two main diseases, granulomatosis with polyangiitis and microscopic polyangiitis, and remains among the most devastating and potentially lethal forms of autoimmune inflammatory disease. Granulomatosis with polyangiitis and microscopic polyangiitis are characterised by a necrotising vasculitis that can involve almost any organ, and have generally been studied together. The diseases commonly affect the kidneys, lungs, upper respiratory tract, skin, eyes, and peripheral nerves. Granulomatous inflammation and multinucleated giant cells are key pathological hallmarks of granulomatosis with polyangiitis, but are absent in microscopic polyangiitis. Many immune system events are essential to disease aetiopathogenesis, such as activation of the alternative complement pathway, neutrophil activation via complement receptors, and the influx of inflammatory cells, including monocytes and macrophages. These cells perpetuate inflammation and lead to organ damage. During the 21st century, the management of ANCA-associated vasculitis has moved away from reliance on cytotoxic medications and towards targeted biological medications for both the induction and maintenance of disease remission. Earlier diagnosis, partly the result of more reliable ANCA testing, has led to improved patient outcomes and better survival. Reductions in acute disease-related mortality have now shifted focus to long-term morbidities related to ANCA-associated vasculitis and their treatments, such as chronic kidney disease and cardiovascular disease. Therapeutic approaches in both clinical trials and clinical practice still remain too reliant on glucocorticoids, and continued efforts to reduce toxicity from glucocorticoids remain a priority in the development of new treatment strategies. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

To investigate serum IL-6 (sIL-6) levels during active disease, complete remission (CR), and relapse in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), and to explore the association of changes in sIL-6 with clinical outcomes. sIL-6 levels were measured at baseline and longitudinally over 18 months, in 78 patients with AAV enrolled in a randomized controlled trial comparing treatment with either rituximab (RTX) or cyclophosphamide (CYC)/azathioprine (AZA). Outcome variables included baseline clinical features, ANCA specificity, disease activity (active disease versus CR), time to relapse events, B cell repopulation, and ANCA titer increases. At baseline, sIL6 levels were detectable in 81% of patients; 73% (n = 57) of subjects were proteinase 3 (PR3)-ANCA positive, sIL-6 levels were higher in subjects with PR3-ANCAs and positively correlated with their levels (r s = 0.36, p < 0.01), but not with levels of myeloperoxidase (MPO)-ANCA (r s = −0.17, p = 0.47). Higher baseline sIL-6 levels were associated with PR3-ANCA positivity, fever, pulmonary nodules/cavities, conductive deafness, and absence of urinary red blood cell casts (p < 0.05). Baseline sIL6 levels did not predict CR at month 6 (p = 0.71), and the median sIL-6 level declined from baseline with induction therapy, regardless of CR achievement. An increase in sIL-6 during CR was a predictor for subsequent severe relapse in RTX-treated patients (hazard ratio (HR):7.24, p = 0.01), but not in CYC/AZA-treated patients (HR:0.62, p = 0.50). In contrast, a sIL-6 increase did not predict B cell repopulation or ANCA titer increase in either treatment arm (p > 0.05). At baseline, sIL-6 concentrations correlate with PR3-ANCA titers and are associated with specific clinical manifestations of AAV. Baseline sIL6 concentrations do not predict CR at 6 months, but the increase in sIL-6 concentrations during CR is associated with subsequent severe relapse among RTX-treated patients. Further investigation into the mechanistic role of IL6 in AAV might lead to identifying this pathway as a potential therapeutic target in this disease. Image 1 • IL-6 levels are increased at onset and decline with therapy in ANCA-associated vasculitis. • High IL-6 levels are associated with granulomatous manifestations and correlate with PR3-ANCA titers. • Increases in IL6 levels during complete remission are portend severe relapses in rituximab-treated patients. [ABSTRACT FROM AUTHOR]

Abstract: Background: The pathogenic significance of antineutrophilic cytoplasmic antibodies (ANCA) in Wegener’s granulomatosis is controversial. Their presence is influenced by the extent, severity, and activity of the disease at the time of sampling. The objective of this study was to determine the frequency of ANCA in patients with active Wegener’s granulomatosis and to assess the influence of disease severity on test results. Methods: Baseline serum samples from the 180 participants in a multicentric prospective trial were tested for ANCA by indirect immunofluorescence, direct enzyme-linked immunosorbent assay (ELISA), and capture ELISA. Disease activity was measured using the Birmingham Vasculitis Activity Score for Wegener’s granulomatosis. All patients had active disease at enrollment. Patients were categorized as having severe (n=128) or limited (n=52) Wegener’s granulomatosis. Results: When all ANCA detection methods were combined, 166 patients (92%) were ANCA positive, including 96% with severe disease and 83% with limited disease. Conclusion: ANCA are detectable in nearly all patients with active severe Wegener’s granulomatosis, but approximately 1 of 5 patients with active limited disease are ANCA negative. Immunofluorescence and both direct and capture ELISAs are required for optimal detection, suggesting that ANCA are not recognized equally well by all testing methods. [Copyright &y& Elsevier]