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.

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.

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.

Antisynthetase Syndrome Causing Necrotizing Myositis Involving Extraocular Muscles.

The authors describe the clinical, histologic, and serologic findings of a patient with necrotizing myositis of the extraocular muscles in the setting of antisynthetase syndrome, as well as subsequent management. This is the first case in the literature of a systemic necrotizing myositis to have associated ophthalmic findings.

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.

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.

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.

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.

Activation of a Latent Epitope Causing Differential Binding of Antineutrophil Cytoplasmic Antibodies to Proteinase 3.

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.

Perspectives on current and emerging therapies for immunoglobulin G4-related disease.

Understanding of the pathophysiology of immunoglobulin G4-related disease (IgG4-RD) over the last dozen years has opened the door to a variety of targeted treatment approaches. Glucocorticoids are an effective treatment for IgG4-RD if used at a sufficiently high dose, but disease flares are common during or after glucocorticoid tapers and these medications seldom lead to long-term, treatment-free remissions. Moreover, their long-term use in a disease that frequently affects middle-aged to elderly individuals and often causes major pancreatic damage leads to a narrow therapeutic index. Biological therapies offer the possibility of effective disease control with fewer treatment-associated side effects. Promising avenues of investigation include B-cell depletion, immunomodulation of B-cell subsets, interference with co-stimulation, Bruton's tyrosine kinase inhibition, and Signaling lymphocytic activation molecule F7-directed treatment.

The Positive Predictive Value of a Very High Serum IgG4 Concentration for the Diagnosis of IgG4-Related Disease.

OBJECTIVE: Serum IgG4 concentrations are used to evaluate a diagnosis of IgG4-related disease (IgG4-RD), but the positive predictive value (PPV) of a very high IgG4 level is uncertain. This study evaluated the PPV of a very high IgG4 concentration for diagnosing IgG4-RD. METHODS: The data warehouses of 2 large academic healthcare systems were queried for IgG4 concentration test results. Cases with serum IgG4 concentrations > 5× the upper limit of normal (ULN) were included. Cases of IgG4-RD were determined using the American College of Rheumatology/European Alliance of Associations for Rheumatology (ACR/EULAR) classification criteria. The PPV for IgG4-RD of an IgG4 concentration > 5× ULN was estimated. Other conditions associated with very high IgG4 concentrations and specific features of IgG4-RD cases were characterized. RESULTS: IgG4 concentrations were available in 32,206 cases. Of these, 3039 (9.4%) had elevated IgG4 concentrations, and a final cohort of 191 (0.6%) cases had IgG4 concentrations > 5× ULN (median age 66 yrs, 72% male). The PPV of an IgG4 concentration > 5× ULN for a diagnosis of IgG4-RD was 75.4% (95% CI 68.7-81.3). In the remaining cases, elevated IgG4 concentrations were observed among patients with malignancies, autoimmune diseases, and infections. CONCLUSION: The majority of cases with serum IgG4 concentrations > 5× ULN in this study had IgG4-RD. These data support the high weight placed on very high serum IgG4 concentrations in the ACR/EULAR classification criteria. However, 25% of cases with very high IgG4 concentrations had an alternative diagnosis, underscoring the importance of considering the broad differential of etiologies associated with an elevated IgG4 concentration when evaluating a patient.

Evaluation of the safety, efficacy, and mechanism of action of obexelimab for the treatment of patients with IgG4-related disease: an open-label, single-arm, single centre, phase 2 pilot trial.

BACKGROUND: Obexelimab is a bifunctional, non-cytolytic, humanised monoclonal antibody that binds CD19 and Fc gamma receptor IIb to inhibit B cells, plasmablasts, and CD19-expressing plasma cells. We aimed to evaluate the safety, clinical efficacy, and pharmacodynamic effects of obexelimab in patients with active IgG4-related disease. METHODS: We conducted an open-label, single-arm, single centre, phase 2 pilot trial at the Massachusetts General Hospital in Boston, MA, USA. Eligible patients were aged 18-80 years and had active IgG4-related disease confirmed by an IgG4-related disease responder index score of 3 or more. Patients received 5 mg/kg of obexelimab intravenously every 2 weeks for 24 weeks. Patients on glucocorticoids at baseline were expected to discontinue usage within 2 months following enrolment. The primary endpoint was the proportion of patients with a decrease of 2 or more from baseline in the IgG4-related disease responder index at day 169 (ie, primary responders). Patients who achieved a decrease of 2 or more at any visit were designated as responders. Adverse events were graded on a scale of 1-5 (ie, mild, moderate, severe, life-threatening, or death) according to the Common Terminology Criteria for Adverse Events grading scale (version 4.3). Exploratory analyses were quantification of B-cell CD19 receptor occupancy, plasmablast, total B-cell and CD4+ cytotoxic T-cell count by flow cytometry, and immunoglobulin concentrations by nephelometry. This study is registered with ClinicalTrials.gov, NCT02725476. FINDINGS: Between Feb 24, 2016, and Dec 21, 2016, we enrolled 15 patients. The median age was 63 years (IQR 52-65). Ten (67%) of 15 patients were male, five (33%) were female, and 12 (80%) were White. At baseline, 12 (80%) of 15 patients had an elevated median serum IgG4 concentration of 220 mg/dL (IQR 124-441), and the median IgG4-related disease responder index score was 12 (IQR 7-13). 12 (80%) of 15 patients achieved the primary endpoint (ie, primary responders), 14 (93%) were defined as responders. Reductions from baseline in serum B cells and plasmablasts were observed following treatment with obexelimab. However, in most patients with follow-up data, serum B cells recovered to 75% of baseline concentrations within 42 days of the final obexelimab dose. 13 (87%) of 15 patients reported adverse events, one of which (an infusion reaction) resulted in treatment discontinuation. INTERPRETATION: All patients except for one had clinical responses to obexelimab treatment. Both reductions in circulating B cells without evidence of apoptosis during obexelimab treatment and their rapid rebound after treatment discontinuation suggest that obexelimab might lead to B-cell sequestration in lymphoid organs or the bone marrow. These results support the continued development of obexelimab for the treatment of IgG4-related disease. FUNDING: Xencor, Zenas BioPharma, National Institute of Arthritis and Musculoskeletal and Skin Diseases, and National Institute of Allergy and Infectious Diseases.

Treatment for giant cell arteritis with 8 weeks of prednisone in combination with tocilizumab: a single-arm, open-label, proof-of-concept study.

BACKGROUND: Even after the approval of tocilizumab, substantial glucocorticoid exposure (usually ≥6 months) and toxicity continue to be important problems for patients with giant cell arteritis. We aimed to assess the outcomes of a group of patients with giant cell arteritis treated with tocilizumab in combination with 8 weeks of prednisone. METHODS: This prospective, single arm, proof-of-concept study was conducted at Massachusetts General Hospital (Boston, MA, USA). Individuals aged 50 years or older who had new-onset or relapsing giant cell arteritis with active disease were eligible for inclusion. Participants received 12 months of tocilizumab 162 mg weekly subcutaneously in combination with 8 weeks of prednisone. The primary endpoint was sustained prednisone-free remission at week 52. Adverse events were also evaluated. This trial is registered with ClinicalTrials.gov (NCT03726749), and is complete. FINDINGS: Between Nov 28, 2018, and Nov 2, 2020, we enrolled 30 patients (mean age 73·7 years [SD 8·1], 18 [60%] women and 12 [40%] men, 30 [100%] White race, 15 [50%] new-onset disease, 23 [77%] temporal artery biopsy-proven, 14 [47%] imaging-proven). The initial prednisone doses were 60 mg (n=7), 50 mg (n=1), 40 mg (n=7), 30 mg (n=6), and 20 mg (n=9). All patients entered remission within 4 weeks from baseline. 23 (77%) of 30 patients were in sustained prednisone-free remission at week 52 and seven (23%) patients relapsed, with a mean time to relapse of 15·8 weeks (SD 14·7). Overall, four (13%) participants developed a serious adverse event, including one related or probably related to prednisone exclusively, two related or probably related to tocilizumab exclusively, and one related or probably related to prednisone, tocilizumab, or both. Two of the non-responder patients stopped tocilizumab and withdrew from the study prematurely after having a second disease relapse. No cases of giant cell arteritis-related permanent vision loss occurred during the study. INTERPRETATION: These results suggest that 12 months of tocilizumab in combination with 8 weeks of prednisone could induce and maintain remission in patients with giant cell arteritis. Confirmation of these findings in a randomised controlled trial is required. FUNDING: Genentech.

The pediatric glucocorticoid toxicity index.

OBJECTIVES: To develop a Pediatric glucocorticoid toxicity index (pGTI), a standardized, weighted clinical outcome assessment that measures change in glucocorticoid (GC) toxicity over time. METHODS: Fourteen physician experts from 7 subspecialties participated. The physician experts represented multiple subspecialties in which GCs play a major role in the treatment of inflammatory disease: nephrology, rheumatology, oncology, endocrinology, genetics, psychiatry, and maternal-fetal medicine. Nine investigators were from Canada, Europe, or New Zealand, and 5 were from the United States. Group consensus methods and multi-criteria decision analysis were used. The pGTI is an aggregate assessment of GC toxicities that are common, important, and dynamic. These toxicities are organized into health domains graded as minor, moderate, or major and are weighted according to severity. The relative weights were derived by group consensus and multi-criteria decision analysis using the 1000MindsTM software platform. Two quantitative scores comprise the overall toxicity profile derived from pGTI data: (1) the Cumulative Worsening Score; and (2) the Aggregate Improvement Score. The pGTI also includes a qualitative, unweighted record of GC side-effects known as the Damage Checklist, which documents less common toxicities that, although potentially severe, are unlikely to change with varying GC dosing. RESULTS: One hundred and seven (107) toxicity items were included in the pGTI and thirty-two (32) in the Damage Checklist. To assess the degree to which the pGTI corresponds to expert clinical judgement, the investigators ranked 15 cases by clinical judgement from highest to lowest GC toxicity. Expert rankings were then compared to case ranking by the pGTI, yielding excellent agreement (weighted kappa 0.86). The pGTI was migrated to a digital environment following its development and initial validation. The digital platform is designed to ensure ease-of-use in the clinic, rigor in application, and accuracy of scoring. Clinic staff enter vital signs, laboratory results, and medication changes relevant to pGTI scoring. Clinicians record findings for GC myopathy, skin toxicity, mood dysfunction, and infection. The pGTI algorithms then apply the weights to these raw data and calculate scores. Embedded logic accounts for the impact of age- and sex-related reference ranges on several health domains: blood pressure, lipid metabolism, and bone mineral density. Other algorithms account for anticipated changes in the height Z-scores used in the growth domain, thereby addressing a concern unique to GC toxicity in children. The Damage Checklist ensures comprehensive measurement of GC toxicity but does not contribute to pGTI scoring, because the scored domains emphasize manifestations of GC toxicity that are likely to change over the course of a trial. CONCLUSIONS: We describe the development and initial evaluation of a weighted, composite toxicity index for the assessment of morbidity related to GC use in children and adolescents. Developing the pGTI digital platform was essential for performing the nuanced calculations necessary to ensure rigor, accuracy, and ease-of-use in both clinic and research settings.

The effect of achieving serological remission on subsequent risk of relapse, end-stage renal disease and mortality in ANCA-associated vasculitis: a target trial emulation study.

OBJECTIVE: To evaluate the effect of achieving a negative postinduction antineutrophil cytoplasmic antibody ANCA) assay on the risk of relapse, end-stage renal disease (ESRD) and death in ANCA-associated vasculitis (AAV). METHODS: We emulated a target trial using observational data from the Mass General Brigham AAV cohort comparing patients who achieved versus did not achieve serological remission (negative ANCA assay) within 180 days of induction. Outcomes were relapse, ESRD or death within 5 years, obtained from medical records, the US Renal Data System and the National Death Index. We placed a 'clone' of each patient in both trial arms, censored those deviating from their assigned protocol and weighted each by the inverse probability of censoring. Outcomes were assessed by pooled logistic regression. RESULTS: The study included 506 patients with AAV. The mean age was 61 years (SD 18) and the majority were women (58%), white (87%), myeloperoxidase-ANCA+ (72%) and had renal involvement (68%). Rituximab (59%) or cyclophosphamide (33%) was most often used for induction treatment. Within 5 years, 81 (16%) died, 51 (10%) had ESRD and 64 (13%) had relapse. Patients treated to a negative ANCA assay within 180 days had HR 0.55 (95% CI 0.38 to 0.81) for relapse and HR 0.87 (95% CI 0.61 to 1.25) for the composite of ESRD or death within 5 years. CONCLUSIONS: In this emulated target trial from a large AAV cohort, achieving serological remission within 180 days of induction was associated with lower risk of relapse, but no statistically significant difference in ESRD or mortality outcomes.

Distinct disease-specific Tfh cell populations in 2 different fibrotic diseases: IgG4-related disease and Kimura disease.

BACKGROUND: How T follicular (Tfh) cells contribute to many different B-cell class-switching events during T-cell-dependent immune responses has been unclear. Diseases with polarized isotype switching offer a unique opportunity for the exploration of Tfh subsets. Secondary and tertiary lymphoid organs in patients with elevated tissue expression levels of IgE (Kimura disease, KD) and those of IgG4 (IgG4-related disease, IgG4-RD) can provide important insights regarding cytokine expression by Tfh cells. OBJECTIVE: We sought to identify disease-specific Tfh cell subsets in secondary and tertiary lymphoid organs expressing IL-10 or IL-13 and thus identify different cellular drivers of class switching in 2 distinct types of fibrotic disorders: allergic fibrosis (driven by type 2 immune cells) and inflammatory fibrosis (driven by cytotoxic T lymphocytes). METHODS: Single-cell RNA sequencing, in situ sequencing, and multicolor immunofluorescence analysis were used to investigate B cells, Tfh cells, and infiltrating type 2 cells in lesion tissues from patients with KD or IgG4-RD. RESULTS: Infiltrating Tfh cells in tertiary lymphoid organs from IgG4-RD were divided into 6 main clusters. We encountered abundant infiltrating IL-10-expressing LAG3+ Tfh cells in patients with IgG4-RD. Furthermore, we found that infiltrating AICDA+CD19+ B cells expressing IL-4, IL-10, and IL-21 receptors correlated with IgG4 expression. In contrast, we found that infiltrating IL-13-expressing Tfh cells were abundant in affected tissues from patients with KD. Moreover, we observed few infiltrating IL-13-expressing Tfh cells in tissues from patients with IgG4-RD, despite high serum levels of IgE (but low IgE in the disease lesions). Cytotoxic T cells were abundant in IgG4-RD; in contrast, type 2 immune cells were abundant in KD. CONCLUSIONS: Our analysis revealed a novel subset of IL-10+LAG3+ Tfh cells infiltrating the affected organs of IgG4-RD patients. In contrast, IL-13+ Tfh cells and type 2 immune cells infiltrated those of KD patients.

Interleukin-6 inhibitors reduce mortality in coronavirus disease-2019: An individual patient data meta-analysis from randomized controlled trials.

OBJECTIVE: To assess the efficacy of IL-6 inhibitors compared to standard of care (SOC) in COVID-19 patients. DATA SOURCES: A systematic review of the MEDLINE and Scopus databases (last search: October 8th, 2021) was performed according to the PRISMA statement. STUDY SELECTION: Randomized control trials (RCTs) comparing IL-6 inhibitors to SOC in hospitalized COVID-19 patients were deemed eligible. DATA EXTRACTION AND SYNTHESIS: Individual patient data were extracted from the Kaplan-Meier curves or were obtained from authors of included studies. Additionally, the reviewers independently abstracted data and assessed study quality of each eligible report. RESULTS: Eleven studies were identified, incorporating 7467 patients (IL-6 inhibitors: 4103, SOC: 3364). IL-6 inhibitors were associated with decreased risk for death compared to SOC at the one-stage meta-analysis (Hazard Ratio [HR]: 0.75, 95% Confidence interval [CI]: 0.69-0.82, p<0.0001) and the two-stage meta-analysis (HR: 0.85, 95%CI: 0.77-0.93, p<0.001, I2 = 0.0%). Meta-regression analysis revealed that the difference in OS between the two groups was not influenced by the mean age of patients. At secondary meta-analyses, IL-6 inhibitors were associated with decreased odds for intubation OR:0.74, 95%CI:0.65-0.85, p<0.001, I2=0.0%). IL-6 inhibitors were associated with increased odds for discharge compared to SOC (OR:1.28, 95% CI:1.15-1.42, p<0.001, I2=0.0%). CONCLUSIONS AND RELEVANCE: This meta-analysis of individual patient data from randomized trials shows that IL-6 inhibitors significantly reduce the risk of death compared to SOC. IL-6 inhibitors are also associated with better outcomes in terms of intubation and discharge rates compared to SOC.

Expert Perspective: Management of Antineutrophil Cytoplasmic Antibody-Associated Vasculitis.

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.

Validation of Antineutrophil Cytoplasmic Antibody-Associated Vasculitis as the Cause of End-Stage Renal Disease in the US Renal Data System.

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.

IgG4-related diseases of the digestive tract.

IgG4-related conditions affecting the digestive tract are part of a multi-organ fibro-inflammatory disorder termed IgG4-related disease (IgG4-RD), with autoimmune pancreatitis and IgG4-related cholangitis being the most prominent manifestations. Gastrointestinal symptoms include jaundice, weight loss, abdominal pain, biliary strictures, and pancreatic and hepatic masses that mimic malignant diseases. IgG4-RD manifestations occur less frequently elsewhere in the digestive tract, namely in the oesophagus, retroperitoneum or intestine. Evidence-based European guidelines frame the current state-of-the-art in the diagnosis and management of IgG4-related digestive tract disease. Diagnosis is based on histology (if available), imaging, serology, other organ involvement and response to therapy (HISORt criteria). Few biomarkers beyond serum IgG4 concentrations are reliable. The first-line therapy (glucocorticoids) is swiftly effective but disease flares are common at low doses or after tapering. Second-line therapy might consist of other immunosuppressive drugs such as thiopurines or rituximab. Further trials, for example, of anti-CD19 drugs, are ongoing. Although an association between IgG4-RD and the development of malignancies has been postulated, the true nature of this relationship remains uncertain at this time.