Fibrotic phenotype of IgG4-related disease.

A prompt response to glucocorticoids is a clinical hallmark of IgG4-related disease. However, manifestations characterised by prominent tissue fibrosis on histological examination can be less responsive to glucocorticoid therapy than other types of IgG4-related disease. These manifestations include retroperitoneal fibrosis, fibrosing mediastinitis, Riedel thyroiditis, orbital pseudotumor, and hypertrophic pachymeningitis, among others. To explain this discrepancy, a preliminary distinction into proliferative and fibrotic phenotypes of IgG4-related disease has been proposed on the basis of clinical presentation, pathological features, and response to immunosuppressive therapy. Implications of this classification for patient management remain an important area of investigation. In this Series paper, we aim to dissect the pathophysiology of tissue fibrosis in IgG4-related disease and discuss how clinicians should approach the management of fibrotic manifestations of IgG4-related disease based on the most recent diagnostic and therapeutic developments.

The clinical outcomes and healthcare resource utilization in IgG4-related disease: a claims-based analysis of commercially insured adults in the United States.

OBJECTIVES: IgG4-related disease (IgG4-RD) can affect nearly any organ and is often treated with glucocorticoids, which contribute to organ damage and toxicity. Comorbidities and healthcare utilization in IgG4-RD are poorly understood. METHODS: We conducted a cohort study using claims data from a United States managed care organization. Incident IgG4-RD cases were identified using a validated algorithm; general population comparators were matched by age, sex, race/ethnicity, and index date. The frequency of 21 expert-defined clinical outcomes associated with IgG4-RD or its treatment and healthcare-associated visits and costs were assessed 12 months before and 36 months after the index date (date of earliest IgG4-RD-related claim). RESULTS: There were 524 cases and 5,240 comparators. Most cases received glucocorticoids prior to (64.0%) and after (85.1%) the index date. Nearly all outcomes, many being common glucocorticoid toxicities, occurred more frequently in cases vs comparators. During follow-up, the largest differences between cases and comparators were seen for gastroesophageal reflux disease (prevalence difference: +31.2%, p< 0.001); infections (+17.3%, p< 0.001); hypertension (+15.5%, p< 0.01); and diabetes mellitus (+15.0%, p< 0.001). The difference in malignancy increased during follow-up from +8.8% to + 12.5% (p< 0.001). 17.4% of cases used pancreatic enzyme replacement therapy during follow-up. Over follow-up, cases were more often hospitalized (57.3% vs 17.2%, p< 0.01) and/or had an ER visit (72.0% vs 36.7%, p< 0.01); all costs were greater in cases than comparators. CONCLUSIONS: Patients with IgG4-RD are disproportionately affected by adverse outcomes, some of which may be preventable or modifiable with vigilant clinician monitoring. Glucocorticoid-sparing treatments may improve these outcomes.

Multimodality Imaging Features of Immunoglobulin G4-related Vessel Involvement.

Immunoglobulin 4 (IgG4)-related disease is a chronic immune-mediated fibroinflammatory disorder. Involvement of the vascular system, including large- and medium-sized vessels, is increasingly recognized. The varied appearances of vascular involvement reflect the sequela of chronic inflammation and fibrosis and can include aortitis and periaortitis with resultant complications such as aneurysm formation and dissection. A diagnosis of IgG4-related large vessel involvement should be considered when there is known or suspected IgG4-related disease elsewhere. Other organs that are typically affected in IgG4-related disease include the lacrimal and salivary glands, thyroid, pancreas, biliary tree, lungs, kidneys, and meninges. Diagnosis typically requires careful correlation with clinical, imaging, serum, and pathologic findings. Patients may be managed with corticosteroid therapy or the anti-CD20 monoclonal antibody, rituximab, if needed. The varied clinical presentations and imaging features of large vessel involvement are discussed herein. Keywords: Vascular, Inflammation, Aorta, IgG4-related Vessel Involvement © RSNA, 2024.

Qualitative interviews to support development of a patient-reported companion measure to the Glucocorticoid Toxicity Index.

INTRODUCTION: Glucocorticoids (GCs) are associated with multiple toxicities that have substantial impact on patients. We conducted qualitative interviews with patients to identify the toxicities that are most relevant from their perspective, with the goal of creating a patient-reported companion measure to the Glucocorticoid Toxicity Index (GTI), a clinician-facing instrument. METHODS: Thirty-one patients with recent or current GC use participated in concept elicitation interviews. Participants received GC treatment for myasthenia gravis, chronic inflammatory demyelinating polyradiculoneuropathy, vasculitis, or systemic lupus erythematosus. Transcripts were coded following a thematic analysis approach. RESULTS: Participants reported more than 100 toxicities they believed to be associated with their GC medications. Common toxicities included weight gain (87%), increased appetite (84%), insomnia/sleep problems (77%), cognitive impairment/brain fog (71%), easy bruising (68%), anxiety (65%), irritability/short temper (65%), and osteoporosis (39%). These toxicities often centered on self-esteem, neuropsychiatric effects, skin toxicities, and musculoskeletal function. They can be categorized into domains such emphasizing neuropsychiatric, metabolic/endocrine, musculoskeletal, and dermatological effects, highlighting aspects of GC toxicity that patients are uniquely positioned to appreciate and report. CONCLUSION: Our results confirm that the toxicities associated with GCs are pervasive and diverse, with substantial impact on patients' lives. These data will be used to inform the development of a patient-reported outcome measure assessing GC toxicity. This patient-reported instrument will be designed to complement the clinician-reported GTI, facilitating a more detailed understanding of the nuances of change in GC toxicity.

Diagnosis and management of ANCA-associated vasculitis.

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.

Granzyme K- and amphiregulin-expressing cytotoxic T cells and activated extrafollicular B cells are potential drivers of IgG4-related disease.

BACKGROUND: IgG4-related disease (IgG4-RD), an example of a type I immune disease, is an immune-mediated fibrotic disorder characterized by dysregulated resolution of severe inflammation and wound healing. However, truly dominant or pathognomonic autoantibodies related to IgG4-RD are not identified. OBJECTIVE: We sought to perform single-cell RNA sequencing and T-cell receptor and B-cell receptor sequencing to obtain a comprehensive, unbiased view of tissue-infiltrating T and B cells. METHODS: We performed unbiased single-cell RNA-sequencing analysis for the transcriptome and T-cell receptor sequencing and B-cell receptor sequencing on sorted CD3+ T or CD19+ B cells from affected tissues of patients with IgG4-RD. We also conducted quantitative analyses of CD3+ T-cell and CD19+ B-cell subsets in 68 patients with IgG4-RD and 30 patients with Sjögren syndrome. RESULTS: Almost all clonally expanded T cells in these lesions were either Granzyme K (GZMK)-expressing CD4+ cytotoxic T cells or GZMK+CD8+ T cells. These GZMK-expressing cytotoxic T cells also expressed amphiregulin and TGF-ß but did not express immune checkpoints, and the tissue-infiltrating CD8+ T cells were phenotypically heterogeneous. MKI67+ B cells and IgD-CD27-CD11c-CXCR5- double-negative 3 B cells were clonally expanded and infiltrated affected tissue lesions. GZMK+CD4+ cytotoxic T cells colocalized with MKI67+ B cells in the extrafollicular area from affected tissue sites. CONCLUSIONS: The above-mentioned cells likely participate in T-B collaborative events, suggesting possible avenues for targeted therapies. Our findings were validated using orthogonal approaches, including multicolor immunofluorescence and the use of comparator disease groups, to support the central role of cytotoxic CD4+ and CD8+ T cells expressing GZMK, amphiregulin, and TGF-ß in the pathogenesis of inflammatory fibrotic disorders.

Efficacy and Safety of Inebilizumab in IgG4-Related Disease: Protocol for a Randomized Controlled Trial.

INTRODUCTION: Immunoglobulin G4-related disease (IgG4-RD) is a debilitating multiorgan disease characterized by recurring flares leading to organ dysfunction, decreased quality of life, and mortality. Glucocorticoids, the standard of care for IgG4-RD, are associated with substantial treatment-related toxicity. Inebilizumab, an antibody directed against CD19, mediates the rapid and durable depletion of CD19+ B cells thought to be involved in IgG4-RD pathogenesis. We describe the first international, prospective, double-blind, placebo-controlled trial to evaluate the safety and efficacy of B-cell depletion for flare prevention in IgG4-RD (MITIGATE). METHODS: The study was designed by an international panel of physicians with expertise in IgG4-RD. Critical trial design decisions included the selection of participants, definition of clinically meaningful primary and secondary endpoints, accommodation of standard of care, and development of flare diagnostic criteria. The study is approved for conduct in 22 countries. PLANNED OUTCOMES: The primary efficacy endpoint is time from randomization to the occurrence of the first centrally adjudicated and investigator-treated disease flare during the 1-year randomized controlled period. A set of novel, organ-specific flare diagnostic criteria were developed specifically for this trial, incorporating symptoms and signs, laboratory findings, imaging study results, and pathology data. MITIGATE aims to accrue 39 flares for the primary endpoint, which provides sufficient power to detect a relative risk reduction of 65% in the inebilizumab group. It is anticipated that enrollment of 160 participants will achieve this goal. Additional endpoints include safety, annualized flare rate, flare-free complete remission, quality-of-life measures, and cumulative glucocorticoid use. MITIGATE represents the first randomized, double-blind, placebo-controlled trial of any treatment strategy conducted in IgG4-RD. Data from this study will provide insights into the natural history and pathophysiology of IgG4-RD and the efficacy and safety of B-cell depletion as a therapeutic avenue. TRIAL REGISTRATION: NCT04540497.

A phase 3 randomized, double-blind, placebo-controlled study to evaluate the efficacy and safety of sarilumab in patients with giant cell arteritis.

BACKGROUND: Giant cell arteritis (GCA) is primarily treated with glucocorticoids (GCs), which have substantial toxicity. Tocilizumab, an interleukin-6-receptor inhibitor (IL-6Ri), showed beneficial effects in GCA, leading to its approval. This study investigated the efficacy and safety of sarilumab (another IL-6Ri) in GCA. METHODS: This Phase 3, double-blind study comprised a 52-week treatment period and a 24-week follow-up phase. Eligible GCA patients were randomized to receive sarilumab 200 mg (SAR200 + 26W) or 150 mg (SAR150 + 26W) with a 26-week GC taper, or placebo with a 52-week (PBO + 52W) or 26-week (PBO + 26W) GC taper. The primary efficacy endpoint was sustained remission (SR) at week 52. Additional endpoints were SR at week 24, cumulative GC dose, and safety. The study was discontinued prematurely due to protracted recruitment timelines, because of the impact of COVID-19. Therefore, only descriptive statistics were summarized. RESULTS: Of the planned 360 subjects, only 83 were randomized and 36 were included in the week 52 analysis. At week 52, 46% (n = 6/13) of patients in SAR200 + 26W, 43% (n = 3/7) in SAR150 + 26W, 30% (n = 3/10) in PBO + 52W, and 0 (n = 0/6) in PBO + 26W taper groups achieved SR. Sensitivity analyses, excluding acute-phase reactants from the SR definition, showed similar results for SAR groups, but 60% (n = 6/10) in PBO + 52W and 17% (n = 1/6) in PBO + 26W taper groups achieved SR at week 52. Similar findings were noted at week 24. The proportions of patients who adhered to GC taper from week 12 through week 52 in each group were as follows: 46% (n = 6/13, SAR200 + 26W), 43% (n = 3/7, SAR150 + 26W), 60% (n = 6/10, PBO + 52W), and 33% (n = 2/6, PBO + 26W). The median actual cumulative GC dose received in the SAR200 + 26W group was lower than other groups. Most patients (80-100%) experienced treatment-emergent adverse events, with similar incidences reported across groups. CONCLUSIONS: Owing to the small sample size due to the early termination, it is difficult to draw clear conclusions from this study. There were no unexpected safety findings. TRIAL REGISTRATION: ClinicalTrials.gov NCT03600805. Registered on July 26, 2018.

Assessment of patient-reported symptoms and distress in IgG4-related disease (IgG4-RD): Development, clinical validation, and content validation of the IgG4-RD Symptom Severity Index.

OBJECTIVE: IgG4-related disease (IgG4-RD), a multi-organ autoimmune disease, causes diverse manifestations that can lead to symptoms and distress. We developed and validated the Symptom Severity Index (SSI) to assess symptom burden. METHODS: A pilot SSI was tested in n = 5; several gaps were identified. Twenty semi-structured qualitative interviews were performed to expand the item set and identify missing symptoms. Subsequent changes resulted in the current SSI; it was administered with quality of life (QOL) measures to n = 136. We assessed symptom burden and the construct validity of the SSI. A distress score for each symptom is calculated by multiplying symptom frequency ("Never" [0 points] to "Every Day" [3 points]) by associated distress ("None" [0 points] to "Very Much" [4 points]). Each distress score is summed to calculate a total SSI score. RESULTS: The SSI assesses the frequency and distress of 24 symptoms. Among n = 136 with ≥ 1 SSI, 90% experienced ≥ 1 symptom and 88% had distress. The median SSI score was 6.5 (IQR 3.0, 18.0). Fear of more severe disease was observed in 49%. The SSI inversely correlated with the SF-36 (r= - 0.51, p<0.001), the feeling thermometer (r= - 0.28, p<0.001), and the EQ-5D (r= - 0.28, p<0.001). The median SSI score was higher during active vs non-active disease among n = 52 who completed >1 SSI (15 [6, 26] vs. 3 [2, 14], p = 0.008). CONCLUSIONS: Symptoms and distress are common in IgG4-RD and associated with worse health-related QOL. The SSI has face, content, and construct validity; it corresponds with QOL measures.

Eosinophilic Angiocentric Fibrosis of the Orbit: A Clinicopathologic Review of 6 Novel Cases With Review of the Literature.

PURPOSE: To describe 6 cases and review the current state of knowledge of eosinophilic angiocentric fibrosis (EAF) involving the orbit. DESIGN: Retrospective clinicopathologic case series and review of the current literature METHODS: Clinical records and histopathologic data of orbit-involving EAF were gathered between 2004 and 2022 from a single academic institution. The patients' presenting clinical symptoms and signs, laboratory data, radiographic studies, and management documentation were collected. RESULTS: Retrospective review identified 6 novel cases, totaling 31 cases of EAF involving the orbit described as of this writing. Fourteen patients were male, and the average age of presentation was 49.8 years (range 25-78 years). Eighteen patients had concurrent sinonasal involvement, whereas 13 had primary orbital involvement. The median duration of symptoms prior to evaluation was 24 months, with nasal symptoms, proptosis, periorbital swelling, and pain being the most common presenting symptoms. The majority of patients underwent surgical debulking, as well as treatment with glucocorticoids and steroid-sparing agents, such as rituximab, with varied results. CONCLUSION: EAF involving the orbit is uncommon. The histopathologic findings include a perivascular, eosinophil-rich infiltrate and a pauci-inflammatory storiform type of fibrosis concentrated around small vessels. Orbital involvement usually results from local extension from adjacent sinuses, but primary orbital involvement has been described. Surgical debulking and immunosuppressive agents such as rituximab have been shown to stabilize disease.

Extrafollicular IgD-CD27-CXCR5-CD11c- DN3 B cells infiltrate inflamed tissues in autoimmune fibrosis and in severe COVID-19.

Although therapeutic B cell depletion dramatically resolves inflammation in many diseases in which antibodies appear not to play a central role, distinct extrafollicular pathogenic B cell subsets that accumulate in disease lesions have hitherto not been identified. The circulating immunoglobulin D (IgD)-CD27-CXCR5-CD11c+ DN2 B cell subset has been previously studied in some autoimmune diseases. A distinct IgD-CD27-CXCR5-CD11c- DN3 B cell subset accumulates in the blood both in IgG4-related disease, an autoimmune disease in which inflammation and fibrosis can be reversed by B cell depletion, and in severe COVID-19. These DN3 B cells prominently accumulate in the end organs of IgG4-related disease and in lung lesions in COVID-19, and double-negative B cells prominently cluster with CD4+ T cells in these lesions. Extrafollicular DN3 B cells may participate in tissue inflammation and fibrosis in autoimmune fibrotic diseases, as well as in COVID-19.

Treatment of IgG4-related disease-associated hypertrophic pachymeningitis with intrathecal rituximab: a case report.

IgG4-related disease-associated hypertrophic pachymeningitis (IgG4RD-HP) is a fibroinflammatory autoimmune disorder in which diagnosis is difficult without biopsy. Guidance on management of disease refractory to glucocorticoids and intravenous rituximab is limited. We present the case of a 68-year-old woman with IgG4RD-HP who developed sensorineural hearing loss with associated bulky basilar pachymeningeal enhancement. Her cerebrospinal fluid was inflammatory and had an elevated IgG4 concentration, strongly suggestive of IgG4RD-HP. Biopsy of involved meninges was not possible due to surgical risk. Over years she developed bilateral optic neuropathies and hydrocephalus, requiring intravenous rituximab and ventriculoperitoneal shunt. Her disease was refractory to glucocorticoids. Despite maintenance intravenous rituximab, she developed slowly progressive symptoms of intracranial hypertension and hydrocephalus with persistently inflammatory spinal fluid. Switching to intrathecal rituximab therapy led to dramatic improvement in gait and headache and reduced pachymeningeal bulk and metabolic activity. In patients with IgG4RD-HP refractory to glucocorticoids and intravenous rituximab, intrathecal rituximab may be an efficacious therapy.

Incidence, prevalence and mortality of IgG4-related disease in the USA: a claims-based analysis of commercially insured adults.

BACKGROUND: IgG4-related disease (IgG4-RD) is an immune-mediated condition that can affect nearly any organ or anatomic site. We sought to describe the epidemiology of IgG4-RD in the USA. METHODS: We used Optum's deidentified Clinformatics Data Mart Database from 1 January 2009 to 31 December 2021 to identify IgG4-RD cases using a validated algorithm. We estimated the incidence rate and prevalence between 2015 and 2019 (when rates stabilised), standardised to the US population by age and sex. We compared mortality rates among patients with IgG4-RD to the non-IgG4-RD population matched in a 1:10 ratio on age, sex, race/ethnicity and encounter date. We used Cox proportional hazards models to estimate HRs and 95% CIs. RESULTS: We identified 524 IgG4-RD cases. The mean age was 56.5 years with 57.6% female and 66% White. The incidence of IgG4-RD increased during the study period from 0.78 to 1.39 per 100 000 person-years in 2015 and 2019, respectively. The point prevalence on 1 Janury 2019 was 5.3/100 000 persons. During follow-up, there were 39 and 164 deaths among 515 IgG4-RD cases and 5160 comparators, resulting in a mortality rate of 3.42 and 1.46/100 person-years, respectively, and adjusted HR of 2.51 (95% CI 1.76 to 3.56). CONCLUSIONS: The incidence of IgG4-RD is similar to that of systemic rheumatic diseases such as ANCA-associated vasculitis and systemic sclerosis but may be increasing as familiarity with this diagnosis grows. Clinicians should be aware of this condition, especially given the excess risk of death. Identification of effective therapies is an important research agenda.

Outcomes during and after long-term tocilizumab treatment in patients with giant cell arteritis.

OBJECTIVE: To assess outcomes in giant cell arteritis (GCA) patients during and after long-term tocilizumab (TCZ) treatment. METHODS: Retrospective analysis of GCA patients treated with TCZ at a single centre (2010-2022). Time to relapse and annualised relapse rate during and after TCZ treatment, prednisone use, and safety were assessed. Relapse was defined as reappearance of any GCA clinical manifestation that required treatment intensification, regardless of C reactive protein levels and erythrocyte sedimentation rate. RESULTS: Sixty-five GCA patients were followed for a mean (SD) of 3.1 (1.6) years. The mean duration of the initial TCZ course was 1.9 (1.1) years. The Kaplan-Meier (KM)-estimated relapse rate at 18 months on TCZ was 15.5%. The first TCZ course was discontinued due to satisfactory remission achievement in 45 (69.2%) patients and adverse events in 6 (9.2%) patients. KM-estimated relapse rate at 18 months after TCZ discontinuation was 47.3%. Compared with patients stopping TCZ at or before 12 months of treatment, the multivariable adjusted HR (95% CI) for relapse in patients on TCZ beyond 12 months was 0.01 (0.00 to 0.28; p=0.005). Thirteen patients received >1 TCZ course. Multivariable adjusted annualised relapse rates (95% CI) in all periods on and off TCZ aggregated were 0.1 (0.1 to 0.2) and 0.4 (0.3 to 0.7), respectively (p=0.0004). Prednisone was discontinued in 76.9% of patients. During the study, 13 serious adverse events occurred in 11 (16.9%) patients. CONCLUSION: Long-term TCZ treatment was associated with remission maintenance in most patients with GCA. The estimated relapse rate by 18 months after TCZ discontinuation was 47.3%.

Comparative Effectiveness of Rituximab- Versus Cyclophosphamide-Based Remission Induction Strategies in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis for the Risk of Kidney Failure and Mortality.

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.

Risk of relapse of ANCA-associated vasculitis among patients homozygous for the proteinase 3 gene Val119Ile polymorphism.

BACKGROUND: The frequency of proteinase 3 gene (PRTN3) polymorphisms in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is not fully characterised. We hypothesise that the presence of a PRTN3 gene polymorphism (single nucleotide polymorphism (SNP) rs351111) is relevant for clinical outcomes. METHODS: DNA variant calling for SNP rs351111 (chr.19:844020, c.355G>A) in PRTN3 gene assessed the allelic frequency in patients with PR3-AAV included in the Rituximab in ANCA-Associated Vasculitis trial. This was followed by RNA-seq variant calling to characterise the mRNA expression. We compared clinical outcomes between patients homozygous for PRTN3-Ile119 or PRTN3-Val119. RESULTS: Whole blood samples for DNA calling were available in 188 patients. 75 patients with PR3-AAV had the allelic variant: 62 heterozygous PRTN3-Val119Ile and 13 homozygous for PRTN3-Ile119. RNA-seq was available for 89 patients and mRNA corresponding to the allelic variant was found in 32 patients with PR3-AAV: 25 heterozygous PRTN3-Val119Ile and 7 homozygous for PRTN3-Ile119. The agreement between the DNA calling results and mRNA expression of the 86 patients analysed by both methods was 100%. We compared the clinical outcomes of 64 patients with PR3-AAV: 51 homozygous for PRTN3-Val119 and 13 homozygous for PRTN3-Ile119. The frequency of severe flares at 18 months in homozygous PRTN3-Ile119 was significantly higher when compared with homozygous PRTN3-Val119 (46.2% vs 19.6%, p=0.048). Multivariate analysis identified homozygous PR3-Ile119 as main predictor of severe relapse (HR 4.67, 95% CI 1.16 to 18.86, p=0.030). CONCLUSION: In patients with PR3-AAV, homozygosity for PRTN3-Val119Ile polymorphism appears associated with higher frequency of severe relapse. Further studies are necessary to better understand the association of this observation with the risk of severe relapse.

IgG4-related disease as a variable-vessel vasculitis: A case series of 13 patients with medium-sized coronary artery involvement.

INTRODUCTION: IgG4-related disease (IgG4-RD) is a systemic autoimmune fibroinflammatory disease that can affect multiple organ systems. Although large-vessel vasculitis is a well-recognized manifestation of IgG4-RD, this condition is generally not regarded as a vasculitis. We aimed to describe coronary artery involvement (CAI), a vascular distribution about which little is known in IgG4-RD. MATERIAL AND METHODS: Patients with IgG4-related CAI were identified from a large, prospective IgG4-RD cohort. CAI was confirmed by imaging evidence of arterial or periarterial inflammation in any coronary artery. We extracted details regarding demographics, features of IgG4-RD, and manifestations of CAI. RESULTS: Of 361 cases in the cohort, 13 (4%) patients had IgG4-related CAI. All were male and all had highly-elevated serum IgG4 concentrations, with a median value of 955 mg/dL (interquartile range [IQR]: 510-1568 mg/dL; reference: 4-86 mg/dL). Median disease duration at the time of CAI diagnosis was 11 years (IQR: 8.23-15.5 years). Extensive disease in the coronary arteries was the rule: all three major coronary arteries were involved in 11 patients (85%). The coronary artery manifestations included wall thickening or periarterial soft tissue encasement (85%), stenosis (69%), calcification (69%), and aneurysms or ectasia (62%). Five patients (38%) had myocardial infarctions, 2 (15%) required coronary artery bypass grafting, and 2 (15%) developed ischemic cardiomyopathy. DISCUSSION: Coronary arteritis and periarteritis are important manifestations of IgG4-RD, which should be regarded as a variable-vessel vasculitis that is among the most diverse forms of vasculitis known. Potential complications of CAI include coronary artery aneurysms, myocardial infarction, and ischemic cardiomyopathy.

Baseline Glucocorticoid-Related Toxicity Scores in Giant Cell Arteritis: A Post Hoc Analysis of the GiACTA Trial.

OBJECTIVE: Giant cell arteritis (GCA) requires treatment with high-dose, long-term glucocorticoids (GCs). A score assessing and quantifying patients' baseline GC-related toxicity may be important to risk stratification and therapeutic decision-making in patients initiating immunosuppression. METHODS: We analyzed patients with GCA enrolled in the Tocilizumab in Giant Cell Arteritis (GiACTA) trial. Baseline GC-related toxicity scores for 12 domains were derived from the Glucocorticoid Toxicity Index using baseline medications, medical history, vital signs, and laboratory values. The 12 domains examined were body mass index, glucose tolerance, blood pressure, lipid metabolism, bone and/or tendon, GC myopathy, skin toxicity, neuropsychiatric effects, infection, ocular toxicity, gastrointestinal injury, and adrenal function. Potential scores ranged from 0 to 538. We compared differences between those with newly diagnosed versus relapsing disease at baseline. RESULTS: A total of 250 patients were included (75% female, mean age 69 years). The mean ± SD baseline GC-related toxicity score among all patients was 111.3 ± 53.2. The domains that contributed most to the overall scores were blood pressure (24.0% of the overall score), followed by glucose tolerance (22.6%) and neuropsychiatric effects (15.9%). Baseline GC-related toxicity scores were higher in patients with relapsing disease compared with those with newly diagnosed disease (mean of 122.5 vs. 98.9; P < 0.001). The body mass index and neuropsychiatric domain scores were significantly higher in patients with relapsing disease. CONCLUSION: This approach to the assessment of baseline GC-related toxicity distinguished patients with relapsing GCA from those with newly diagnosed disease. Baseline GC-related toxicity scores may be useful in therapeutic decision-making for patients beginning immunosuppressive treatment.

Development and Validation of a Simulation Model for Treatment to Maintain Remission in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis.

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.