Comprehensive diagnostic criteria for IgG4-related disease (IgG4-RD), 2011

Immunoglobulin G4-related disease presenting with hypertrophy and sclerosis of the inferior turbinate

Immunoglobulin G4-related disease (IgG4-RD) is a novel clinical disease entity characterized by elevated serum IgG4 concentration and tumefaction or tissue infiltration by IgG4+ plasma cells.1 We report the case of a 56-year-old man who presented with nasal obstruction for 5 years. Rhinoscopy revealed hypertrophy and sclerosis of the inferior turbinate, whereas computed tomography revealed inflammation of the anterior ethmoid sinus and frontal sinuses. An endoscopic inferior turbinectomy was performed, and IgG4-RD was definitively diagnosed based on the histopathological features of the turbinate tissue. Prednisolone was administered postoperatively. IgG4-RD presenting with hypertrophy and sclerosis of the inferior turbinate is rare. Awareness of IgG4-RD originating in the sinonasal cavity is essential to avoid delayed diagnosis.

Clinical and Imaging Pulmonary Manifestations in IgG4-Related Disease

OBJECTIVES

The aims of this study were to describe the frequency of pleuropulmonary computed tomography (CT) findings in patients with IgG4-related disease (IgG4-RD) and to compare clinical and laboratory characteristics between patients with and without pleuropulmonary involvement in chest CT.

METHODS

This is a study conducted within the IgG4-RD study group of the Argentine Society of Rheumatology (GESAR IgG4) cohort of patients with IgG4-RD. Member centers of the group were requested to submit pulmonary CT scans of the patients. Lung lesions were classified into 4 subtypes: (1) nodules, (2) ground-glass opacity, (3) interstitial-alveolar involvement, and (4) bronchovascular involvement. The presence of pleural involvement and mediastinal adenopathy was also assessed.

RESULTS

We examined data from 28 patients, with 17 (61%) showing pulmonary involvement. The subtypes of pulmonary involvement, in order of frequency, were as follows: type 4 (n = 17, 100%), type 3 (n = 10, 59%), type 2 (n = 6, 36%), and type 1 (n = 5, 29%). Pleural lesions were observed in 2 (12%) cases, and mediastinal adenopathies were found in 4 (23%) cases. No demographic, clinical, or laboratory differences were noted between patients with and without pulmonary involvement, except for serum levels of IgG4, which were higher among patients without pulmonary involvement (339.0 [293.1-1592.1 mg/dL] vs 2869 [1156.3-4037.4 mg/dL]; p = 0.022).

CONCLUSIONS

In this case series, the predominant subtype of pulmonary involvement was septal thickening and increased bronchovascular tissue. Patients with and without pleuropulmonary involvement exhibited similar clinical and laboratory manifestations, except for serum IgG4, which was higher in patients without pleuropulmonary involvement.

Symmetrical polyarthritis in IgG4-related sialadenitis: a diagnostic challenge with seronegative rheumatoid arthritis

BACKGROUND

IgG4-related disease (IgG4-RD) is a systemic fibro-inflammatory condition characterized by elevated IgG4 serum levels and tissue infiltration by IgG4-positive plasma cells. While often presenting with organ-specific involvement, such as sialadenitis or pancreatitis, its rheumatologic manifestations are rare and poorly understood. IgG4-RD often overlaps with autoimmune diseases such as rheumatoid arthritis (RA), posing a diagnostic challenge, particularly in seronegative presentations.

CASE PRESENTATION

We report a 48-year-old male presenting with progressive symmetrical polyarthritis mimicking rheumatoid arthritis. Laboratory findings showed elevated serum IgG4 levels and inflammatory markers, while autoantibodies (RF, ACPA, ANA, ANCA) were negative. A biopsy of a submandibular gland revealed dense lymphoplasmacytic infiltrates + fibrosis and IgG4-positive plasma cells, confirming the diagnosis of IgG4-RD. The patient responded well to a combination of glucocorticoids and methotrexate, with complete symptom resolution within one month and normalization of inflammatory markers.The therapeutic response observed in this case demonstrates the effectiveness of immunosuppression therapy in IgG4-RD management, while emphasizing the need for long-term follow-up.

DISCUSSION

This case underscores the diagnostic challenges in recognizing arthritis in a patient with biopsy-confirmed IgG4-related sialadenitis particularly when seronegative rheumatoid arthritis (RA) remains a plausible differential diagnosis.The overlapping clinical features and shared treatment responses make it challenging to attribute the arthritis to a single etiology.This report emphasizes the importance of considering IgG4-RD in the differential diagnosis of atypical arthritis presentations, particularly in patients with systemic manifestations. Histopathological confirmation, supported by clinical and serological evaluation, remains pivotal in guiding diagnosis and management. Long-term follow-up is essential to monitor for evolving features, including the potential development of overlapping conditions, and to ensure optimal treatment outcomes. Early recognition and tailored interventions are critical to preventing complications and improving patient quality of life.

CONCLUSION

IgG4-related disease (IgG4-RD) must be considered in the differential diagnosis of seronegative arthritis, especially when systemic symptoms or organ involvement are present. This case underscores the growing recognition of IgG4-RD in rheumatologic practice and the importance of a multidisciplinary approach to diagnosis and management. Clinicians should maintain heightened awareness of the overlap between IgG4-RD and rheumatoid arthritis (RA), advocating for the integration of histopathology, imaging, and serological testing to ensure accurate diagnosis. Additionally, long-term follow-up is essential to monitor disease progression, recurrence, development of new symptoms, and treatment response, ultimately enhancing patient care and outcomes.

Thalidomide can effectively prevent relapse in IgG4-related disease outweighing its side effects: a multicentre, randomised, double-blinded, placebo-controlled study

OBJECTIVES

To investigate the effects of thalidomide in preventing disease relapse with 'zero' glucocorticoids (GCs) usage in IgG4-related disease (IgG4-RD).

METHODS

This was a multicentre, randomised, double-blinded, placebo-controlled study, in which eligible patients in disease active status were randomised into 2 groups (group 1: GCs+Thalidomide; group 2: GCs+Placebo) at a 1:1 ratio. The primary outcome of this trial was the disease relapse rate at month 12, whereas the secondary outcomes were the disease remission rate at month 12 and the incidence of adverse events (AEs).

RESULTS

A total of 60 patients were randomised, and 57 patients (GCs+Thalidomide: 29; GCs+Placebo: 28) finished the study per protocol. The relapse rates of the GCs+Thalidomide and GCs+Placebo groups at month 12 were 13.8% and 67.8%, respectively. A 100% response rate was observed in both treatment group, while the remission rates of the GCs+Thalidomide and GCs+Placebo groups were 75.8% and 32.1%, respectively. In total. 49 AEs were recorded in 35 participants, in which 4 were graded as moderate, and 45 were graded as mild. The risk-benefit analysis based on the evaluation of rates of disease relapse and moderate AEs within the 12-month follow-up showed a NNT (number needed to treat) of 2 and a NNH (number needed to harm) of 8 for thalidomide treatment.

CONCLUSIONS

Thalidomide can effectively prevent relapse in IgG4-RD outweighing its side effects, which indicating that thalidomide can be a potential safe therapeutic option for disease relapse prevention in parallel with steroid sparing in IgG4-RD.

Pharmacological Management of IgG4-Related Disease: From Traditional to Mechanism-Based Targeted Therapies

IgG4-related disease (IgG4-RD) is an immune-mediated disorder characterized by organ enlargement and dysfunction. The formation of tertiary lymphoid tissues (TLTs) in affected organs is crucial for understanding IgG4-RD, as T follicular helper (Tfh) 2 cells within TLTs drive IgG4+B cell differentiation, contributing to mass formation. Key cytokines IL-4 and IL-10, produced by Tfh2 cells, are essential for this process. Additionally, cytotoxic T cells and M2 macrophages significantly contribute to inflammation and fibrosis in the lesions. These insights into IgG4-RD have led to the development of innovative targeted therapies. While glucocorticoids are effective in many cases, they often cause disease flares during tapering and rarely result in long-term, treatment-free remissions. Long-term glucocorticoid use poses significant challenges owing to potential side effects, particularly in older patients who may already have complications such as diabetes and atherosclerotic diseases. In contrast, targeted therapies offer a promising alternative, potentially providing more effective disease control with fewer side effects. Current research is exploring several exciting approaches, including B-cell depletion, targeted immunomodulation of B cells, Bruton's tyrosine kinase inhibition, disruption of co-stimulation pathways, targeting the SLAMF7 cytokine or its receptor blockade (BAFF, IL-4, or IL-6), and JAK-STAT signaling pathway inhibition. These emerging strategies hold the promise of improving patient outcomes and advancing the management of IgG4-RD.

Discriminative features of immunoglobulin G4-related disease (IgG4-RD) and associated autoimmune rheumatic diseases (ARDs) in a nationwide observational cohort: study from the Egyptian College of Rheumatology

OBJECTIVE

The objective of this study is to present the clinical characteristics of immunoglobulin G4-related diseases (IgG4-RD) patients and describe associated overlap with autoimmune rheumatic diseases (ARDs).

PATIENTS AND METHODS

This cross-sectional study included 81 patients with IgG4-RD who were recruited from 13 specialized rheumatology departments and centers across the country in collaboration with the Egyptian College of Rheumatology (ECR). Patients underwent a thorough history-taking and clinical examination. We reviewed patients' medical records and recorded the medications they used. The presence of comorbidities or cumulative manifestations was determined. Laboratory investigations, imaging, and biopsy histopathology were assessed.

RESULTS

The mean (SD) age was 41.4 (14.6) years with 60 females and 21 males (F/M 2.9:1). The diagnosis was definite in 50 (61.7%), probable in 19 (23.5%), and possible in 12 (14.8%). The most common cumulative clinical features are IgG4-related respiratory disease in 19 (23.5%), autoimmune pancreatitis (AIP) in 18 (22.2%), and Riedel's thyroiditis in 17 (21.0%). Approximately 80% were administered corticosteroids, whereas 40% received azathioprine as adjunct therapy. Approximately 16% developed a relapse with this combination and transitioned to an alternative steroid-sparing treatment. Twelve individuals (14.7%) required rituximab. Fifty percent of patients receiving rituximab (six patients) exhibited complete improvement, while the remaining had partial improvement. Ten (12.3%) patients had associated ARDs: five (6.2%) with systemic lupus erythematosus (SLE), four (4.9%) with rheumatoid arthritis (RA), and one with vasculitis. Of the four patients with associated RA, three were rheumatoid factor (RF) negative. IgG4 was in all cases, RF was positive in 18.5%, and antinuclear antibody was in 14.7%.

CONCLUSION

IgG4-RDs exhibit a wide range of presentations, closely associated with ARDs. Awareness among clinicians about this condition will increase their consideration and rate of prompt diagnosis, which is essential to prevent damage to critical organs. Key Points • IgG4-RDs have a myriad spectrum of presentation with a close link to rheumatic diseases. • Awareness among clinicians about this condition will increase their consideration and rate of prompt diagnosis. • The lack of reliable biomarkers for this condition has been an important hurdle for diagnosis.

Unraveling the Microenvironment and the Pathogenic Axis of HIF-1α-Visfatin-Fibrosis in Autoimmune Pancreatitis Using a Single-Cell Atlas

Autoimmune pancreatitis (AIP) is identified as a severe chronic immune-related disorder in pancreas, including two subtypes. In this study, pancreatic lesions in patients diagnosed as either type 1 AIP or type 2 AIP are examined, and these patients' peripheral blood at single-cell level. Furthermore, flow cytometry, immunofluorescence, and functional assays are performed to verify the identified cell subtypes. In type 1 AIP, there is a notable increase in the amount of B cells and plasma cells, and IgG4+ plasma cells are key pathogenic cells of AIP. The differentiation path of naïve-stage B cells into IgG4+ produced plasma cells is observed, and an increased amount of T helper cells and T follicular helper (Tfh) cells. This study also reveals that HIF-1α, an activated transcriptional factor, can directly bind to promoter site of NAMPT, promoting higher levels of visfatin production in HIF1A+ classical monocytes. Pancreatic stellate cells can be activated by extracellular visfatin and promote the development of fibrotic response in pancreatic lesions across both AIP subtypes. The current findings shed light on the exploration of dynamic alterations in peripheral blood cells and cell subgroups in pancreatic lesions of AIP, while elucidating a pathogenic cell subset and potential fibrosis mechanism of AIP.

The Platelet-Specific Gene Signature in the Immunoglobulin G4-Related Disease Transcriptome

Background and Objectives: Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated, fibroinflammatory, multiorgan disease with an obscure pathogenesis. Findings indicating excessive platelet activation have been reported in systemic sclerosis, which is another autoimmune, multisystemic fibrotic disorder. The immune-mediated, inflammatory, and fibrosing intersections of IgG4-RD and systemic sclerosis raised a question about platelets' role in IgG4-RD. Materials and Methods: By borrowing transcriptomic data from Nakajima et al. (GEO repository, GSE66465) we sought a platelet contribution to the pathogenesis of IgG4-RD. GEO2R and BRB-ArrayTools were used for class comparisons, and WebGestalt for functional enrichment analysis. During the selection of differentially expressed genes (DEGs), the translationally active but significantly low amount of platelet mRNA was specifically considered. The platelet-specific gene signature derived was used for cluster analysis of patient and control groups. Results: When IgG4-RD patients were compared with controls, 268 DEGs (204 with increased and 64 with decreased expression) were detected. Among these, a molecular signature of 22 platelet-specific genes harbored genes important for leukocyte-platelet aggregate formation (i.e., CLEC1B, GP1BA, ITGA2B, ITGB3, SELP, and TREML1) and extracellular matrix synthesis (i.e., CLU, PF4, PPBP, SPARC, and THBS1). Functional enrichment analysis documented significantly enriched terms related to platelets, including but not limited to "platelet reactivity", "platelet degranulation", "platelet aggregation", and "platelet activation". During clustering, the 22 gene signatures successfully discriminated IgG4-RD and the control and the IgG4-RD before and after treatment groups. Conclusions: Patients with IgG4-RD apparently display an activated platelet phenotype with a potential contribution to disease immunopathogenesis. If the platelets' role is validated through further carefully designed research, the therapeutic potentials of selected conventional and/or novel antiplatelet agents remain to be evaluated in patients with IgG4-RD. Transcriptomics and/or proteomics research with platelets should take into account the relatively low amounts of platelet mRNA, miRNA, and protein. Secondary analysis of omics data sets has great potential to reveal new and valuable information.

Epigenetic age acceleration and methylation differences in IgG4-related cholangitis and primary sclerosing cholangitis

BACKGROUND

IgG4-related cholangitis (IgG4-SC) and primary sclerosing cholangitis (PSC) are chronic fibro-inflammatory hepatobiliary conditions, with genetic, environmental, and immunologic risk factors, in which epigenetic alterations may provide insights into pathophysiology and novel biomarkers. This study is the first to assess methylation signatures in IgG4-SC.

RESULTS

Whole blood DNA methylation profiling and genotyping was performed in 264 individuals; 47 with IgG4-SC, 65 with PSC, 64 with ulcerative colitis (UC), and 88 healthy controls. We identified 19 significant methylation differences between IgG4-SC and controls and 38 between PSC and controls. IgG4-SC and PSC shared 8 probes. Inflammatory genes (including CEP97, IFNAR1, TXK, HERC6, C5orf36, PYY, and MTRNR2L1) were predominantly involved in dysregulated methylation. Epigenetic age acceleration was observed in patients with IgG4-SC, but not in those with PSC or UC. meQTL analyses to identify genetic determinants of methylation revealed a strong human leucocyte antigen (HLA) signal in both PSC and IgG4-SC (HLA-DQB2, HLA-DPA1, HLA-F and HLA-DRA).

CONCLUSIONS

We identify novel epigenetic alterations in IgG4-SC and PSC, with biological age acceleration in IgG4-SC, providing insights into disease pathogenesis, and highlight the role of genetic variation especially within the HLA region in shaping the methylome.

Identification of red flags for IgG4-related disease: an international European Reference Network for Rare Connective Tissue Diseases framework

IgG4-related disease is a rare fibroinflammatory condition. Prompt recognition is fundamental to initiate treatment and to prevent organ damage. Diagnostic and classification criteria are primarily intended for use by clinicians with established expertise in IgG4-related disease. Absence of disease awareness among primary care physicians and specialists without expertise in IgG4-related disease remains the main cause of diagnostic delay. We aimed to identify red flags that might increase the suspicion of IgG4-related disease in primary and secondary care settings. A task force of experts in IgG4-related disease from the European Reference Network for Rare Connective Tissue Diseases (ERN-ReCONNET), patient representatives, and primary care physicians derived potential red flags for IgG4-related disease through a systematic literature search and a level of agreement exercise. Five red flags reached 100% agreement among experts: swelling in one or more organ system; pancreatic and biliary tree involvement; increased serum IgG4; IgG4+ plasma cell tissue infiltration; and obliterative phlebitis. Red flags for IgG4-related disease are intended for use in primary and secondary care to improve referral to centres of expertise and prompt early diagnosis.

The Differential Complement, Fc and Chemokine Receptor Expression of B Cells in IgG4-Related Pancreatobiliary Disease and Primary Sclerosing Cholangitis and Its Relevance for Targeting B Cell Pathways in Disease

Background: Immune-mediated liver and biliary conditions, such as IgG4-related pancreatobiliary disease (IgG4-PB) and a subset of primary sclerosing cholangitis (PSC- high(h)IgG4), exhibit increased IgG4 levels in the blood. The relative expression of IgG4+ and IgG1+ B cells in the blood and the expression of complement and Fc receptors on these IgG1+ and IgG4+ B cells in IgG4-PB and PSC have not been previously described. We hypothesised that the patterns of expression of these cells and their receptors would differ, are relevant to disease pathogenesis and may represent therapeutic targets. Methods: CD19+ B cells were sorted from blood collected from patients with IgG4-PB, PSC-high(h)IgG4 and healthy volunteers. Cells were stained with fluorescent labelled antibodies specific to IgG1, IgG4, complement receptors (CR1 and CR2), Fc receptors (FcεRII and FcγRIIb) and chemokine receptors (CXCR3, CXCR4, CXCR5) and were analysed by flow cytometry. Findings: IgG4-PB, compared to healthy volunteers, showed decreased CR2 expression on IgG1+ B cells (MFI 416 (275-552) vs. 865 (515-3631), p = 0.04) and IgG4+ B cells (MFI 337 (231-353) vs. 571 (398-2521), p = 0.03). IgG4-PB, compared to healthy volunteers, showed increased FcεRII expression on IgG4+ B cells (MFI 296 (225-617) vs. 100 (92-138), p = 0.0145) and decreased FcγRIIb expression on IgG1+ B cells (134 (72-161) vs. 234 (175-291), p = 0.0262). FcγRIIb expression was also decreased in IgG1+ B cells in patients with PSC-hIgG4 compared to healthy volunteers. Conclusions: This exploratory study indicates that in IgG4-PB, B cells have decreased CR2 and FcγRIIb expression and increased FcεRII expression, suggesting altered sensitivity to complement, IgG-mediated inhibition and sensitisation by IgE, which may promote the relative expansion of IgG4+ B cells in this disease.

Outcomes of retroperitoneal fibrosis-related hydronephrosis and its risk factors for poor prognosis: a multi-center retrospective cohort study in Chinese patients

Objective

Retroperitoneal fibrosis (RPF) is a rare disease characterized by the presence of fibroinflammatory tissue that surrounds the abdominal aorta and the iliac arteries and often entraps the ureters. Hydronephrosis is a common complication of RPF, however, its clinical features and outcomes have not been well elucidated.

Methods

A total of 115 RPF-related hydronephrosis patients have been recruited from 9 clinical centers in China since March 2010. They were followed up until death or September 2021, whichever came first.

Results

The mean age at diagnosis was 58.83 ± 12.13 years, and 80 patients (69.57%) were men. The median disease duration was 3.00 (1.00, 9.00) months. Renal impairment was observed in 88.35% of the patients, and 49.57% showed bilateral ureteral involvement. Elevated ESR and CRP were presented in 80.28 and 62.02% of the patients, respectively. Overall, 28.21% (11/39) of the patients had increased IgG4 levels, and 41.38% (12/29) showed positive pathological IgG4 staining (IgG4+/IgG+ ≥ 40% or IgG4+ ≥ 10/HPF). Among them, three patients were diagnosed as IgG4RD. After 60.43 ± 34.53 months of follow-up, 36 patients had poor prognosis, which was associated with severe kidney impairment, bilateral hydronephrosis and inflammation status (elevated ESR and IgG) at diagnosis by case-control study. eGFR and creatinine were independent risk factors after adjusting for all other significant associations (p = 0.002 and p = 0.067, respectively). Glucocorticoid-based therapy could reduce the time of stenting, decrease the need for long-term ureteral stenting/percutaneous nephrostomy (PNS)/ureterolysis, increase the rate of mass shrinkage, and reduce the new requirement of hemodialysis compared to surgery-only strategy for RPF-related hydronephrosis patients in need of renal drainage, but did not reduce new-onset renal atrophy.

Conclusion

Severity of kidney dysfunction and inflammation status were related to the poor prognosis of hydronephrosis induced by RPF. More efficient interventions and strategies are needed to further improve outcomes.

Systemic diseases affecting the GI tract: A review of clinical and histopathologic manifestations

A variety of systemic diseases may affect the gastrointestinal (GI) tract. Since the GI tract responds to injury in limited ways, identifying these processes may be challenging, especially on small endoscopic biopsies. This article reviews the clinicopathologic features of commonly encountered systemic diseases affecting the tubular GI tract: sarcoidosis, graft vs. host disease, mast cell disorders, systemic sclerosis, and IgG-4 related disease. In addition, we offer guidance in differentiating them from their mimics.

Comparative Analysis of Classification Criteria in IgG4-Related Disease and Evaluating Diagnostic Accuracy from a Retrospective Cohort in Clinical Practice

INTRODUCTION

We conducted a comprehensive comparative analysis of the Okazaki, Umehara, and American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) classification criteria for diagnosing immunoglobulin G4-related disease (IgG4-RD).

MATERIALS AND METHODS

A retrospective study was conducted in a single tertiary hospital, using expert clinical judgment as the gold standard. We compared the diagnostic accuracy of the Okazaki, Umehara, and ACR/EULAR criteria in a cohort of 41 patients with suspected IgG4-RD. We assessed sensitivity, specificity, and positive and negative predictive values for each criterion, and conducted a separate analysis based on four IgG4-RD subtypes.

RESULTS

A total of 30 patients were confirmed to have IgG4-RD and 11 were identified as mimickers. The Umehara criteria demonstrated the highest sensitivity (83.33%), followed by the ACR/EULAR 2019 (66.67%) and Okazaki (60.0%) criteria. All three criteria exhibited 100% specificity, with overall diagnostic accuracy ranging from 70% to 88%. The areas under the curve (AUC) were 0.917 (Umehara), 0.800 (Okazaki), and 0.833 (ACR/EULAR 2019), indicating significant diagnostic effectiveness (p < 0.000). Subtype analysis revealed that the Umehara and ACR/EULAR 2019 criteria were more effective in diagnosing pancreato-hepato-biliary involvement (subtype 1), while the Okazaki and ACR/EULAR 2019 criteria were more effective in diagnosing retroperitoneal fibrosis and/or aortitis (subtype 2).

CONCLUSIONS

Our study provides valuable insights into the diagnostic performance of the Okazaki, Umehara, and ACR/EULAR criteria for a cohort of patients with suspected IgG4-RD. The Umehara criterion demonstrated the highest sensitivity, suggesting its potential utility for screening purposes, while all three criteria showed consistent specificity.

Validation of a diagnostic flowchart for tuberculous pleurisy in pleural fluid with high levels of adenosine deaminase

INTRODUCTION

Adenosine deaminase (ADA) in pleural fluid is a useful marker for diagnosing tuberculous pleurisy. However, recent studies have reported a lower specificity of pleural fluid ADA levels. We previously developed a diagnostic flowchart for patients with pleural fluid ADA ≥40 U/L, incorporating variables such as pleural fluid lactate dehydrogenase <825 U/L, predominant pleural fluid neutrophils or cell degeneration, and a pleural fluid ADA/total protein ratio <14. This flowchart was effective in distinguishing between tuberculous pleurisy and other diseases. Here, we conducted a validation analysis of this flowchart.

MATERIALS AND METHODS

We retrospectively collected data from 458 patients with pleural fluid ADA concentrations ≥40 U/L across eight institutions from January 2019 to December 2023. The diagnostic accuracy rate, sensitivity, and specificity of the diagnostic flowchart were analysed and compared to those in the original study.

RESULTS

Eighty-seven patients were diagnosed with tuberculous pleurisy, and 371 patients were diagnosed with other diseases. The diagnostic accuracy, sensitivity, and specificity for diagnosing tuberculous pleurisy were 77.7%, 86.2%, and 75.7%, respectively. Compared with that in the original study, the rate of tuberculous pleurisy was lower (19.0% vs. 44.5%, p < 0.001), but the diagnostic accuracy rates were not significantly different (p = 0.253). On the basis of the findings from this validation study, we have revised the flowchart to enhance its utility.

CONCLUSION

The diagnostic flowchart exhibited high diagnostic accuracy in this validation study, comparable to that in the original study. This validation confirms the effectiveness of the flowchart, even in settings with a low incidence of tuberculosis.

Evaluation of the specificity of trigeminal nerve enlargement in the diagnosis of IgG4-related ophthalmic disease

PURPOSE

Enlargement of the trigeminal nerve is observed in 20-53% of patients with IgG4-related ophthalmic disease (IgG4-ROD) and is known to be a useful finding for the diagnosis of IgG4-ROD. On the other hand, enlargement of the trigeminal nerve has also been found at a certain frequency in orbital lymphoproliferative diseases other than IgG4-ROD. Therefore, we here re-evaluated the specificity of trigeminal nerve enlargement in the diagnosis of IgG4-ROD.

STUDY DESIGN

Retrospective, comparative study.

METHODS

A total of 149 consecutive cases of IgG4-ROD diagnosed at the Department of Ophthalmology, Tokyo Medical University Hospital were studied. As controls, 218 cases of orbital lymphoma, 13 cases of reactive lymphoid hyperplasia (RLH), and 117 cases of benign orbital tumors other than lymphoproliferative diseases were included. Enlargement of the trigeminal nerve (infraorbital or supraorbital nerve) in IgG4-ROD and all the control cases was evaluated on MRI or CT coronal images.

RESULTS

Enlargement of the trigeminal nerve was observed in 35 of the 149 cases (23.5%) of IgG4-ROD and in 7 of the 218 cases (3.2%) of lymphoma, with a significantly highly frequency in IgG4-ROD (P < .0001). No cases of trigeminal nerve enlargement were observed in the cases of RLH or benign orbital tumors. The sensitivity and the specificity of trigeminal nerve enlargement in the diagnosis of IgG4-ROD were 23.5% and 96.8%, respectively. Additionally, enlargement of the trigeminal nerve was significantly more common in men than in women (P < .028).

CONCLUSIONS

The present study indicates that trigeminal nerve enlargement is a characteristic imaging finding and has diagnostic value for IgG4-ROD.

Omics in IgG4-related disease

ABSTRACT

Research on IgG4-related disease (IgG4-RD), an autoimmune condition recognized to be a unique disease entity only two decades ago, has processed from describing patients' symptoms and signs to summarizing its critical pathological features, and further to investigating key pathogenic mechanisms. Challenges in gaining a better understanding of the disease, however, stem from its relative rarity-potentially attributed to underrecognition - and the absence of ideal experimental animal models. Recently, with the development of various high-throughput techniques, "omics" studies at different levels (particularly the single-cell omics) have shown promise in providing detailed molecular features of IgG4-RD. While, the application of omics approaches in IgG4-RD is still at an early stage. In this paper, we review the current progress of omics research in IgG4-RD and discuss the value of machine learning methods in analyzing the data with high dimensionality.

An Evidence-Based Approach to Diagnosing Patients Presenting With Orbital Inflammatory Syndromes (An American Ophthalmological Society Thesis)

PURPOSE

The initial management of patients presenting with orbital inflammatory syndromes varies-with some pursuing a diagnostic workup while others treat without any testing. The evidence behind this rationale is limited. A review of patients with orbital inflammation is performed with an analysis of diagnostic testing to develop a workflow for such patients.

DESIGN

A retrospective review of patients presenting with acute orbital inflammation at a single institution from 2011 to 2020 was conducted.

METHODS

Orbital imaging was required for inclusion. Patients with high suspicion of neoplasm, bacterial infection, vascular malformation, or thyroid eye disease were excluded. A review of presenting clinical findings, laboratory workup, orbital imaging, and biopsy were performed. Statistical analysis was performed identifying statistically significant diagnostic and treatment maneuvers.

RESULTS

In total, 172 patients met inclusion criteria (66% female, mean age 46 years). The primary clinical presentation was myositis, dacryoadenitis, and infiltrative in 67, 73, and 32 patients (39.0%, 43.0%, 18.6%, respectively). Laboratory studies were conducted in 145 (84%) while biopsy was performed in 55 (32%). Specific orbital inflammation (SOI) was diagnosed in 29 (16.9%) with the most frequent diagnoses being sarcoidosis, IgG4-related disease, inflammatory bowel disease, and systemic lupus erythematosus. The majority (147, 85.5%) was initially treated with steroids, but steroid-sparing agent use was statistically higher in patients with SOI.

CONCLUSIONS

In patients presenting with orbital inflammatory syndromes, distinguishing myositis, dacryoadenitis, and infiltrative disease has workup and differential diagnosis impacts. Because SOI is relatively common, sequelae of SOI, and potential steroid-sparing therapy needs, diagnosis via an evidence-based systemic approach is critical. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Systemic Involvement in Immunoglobulin G4-Related Ophthalmic Disease

BACKGROUND

Immunoglobulin G4-related ophthalmic disease (IgG4-ROD) poses clinical challenges due to its heterogeneous ocular and systemic manifestations. We aim to report the systemic involvement and the clinical, serological and radiological associations of a cohort of Chinese patients.

METHODS

A territory-wide, biopsy-proven, Chinese cohort. A retrospective, masked chart review of medical records, orbital images, and histopathology reports.

RESULTS

A total of 122 (65 male) patients with a follow-up of 81 ± 49 (24 to 84) months were reviewed. Ninety (74%) patients presented bilaterally. Subacute upper eyelid swelling was the commonest presentation (82/122, 67%). During follow-up, 91/122 patients (75%) underwent extra-orbital imaging including computer tomography (692 films), ultrasonography (182 films), magnetic resonance imaging (76 films) and whole body FDG-PET scan (33 films). Eighty-six (95%) of these 91 patients had extra-orbital involvement radiologically (2.7 ± 1.6 regions, range: 0 to 9). Lymph node was the most prevalent (N = 60,66%), followed by salivary gland (N = 51,56%), lung (N = 49,54%), kidney (N = 22, 24%), hepatobiliary tree (N = 18, 20%) and pancreas (N = 17, 19%). Other organs include thyroid, aorta, meninges/brain and skin. Twenty-eight (23%) patients had allergic diseases (19 asthma, 16 allergic rhinitis, and 6 eczemas). Fifty-seven (48%) patients had paranasal sinusitis. Serum eosinophilia was associated with a higher number (3.24 versus 2.52, P = 0.0304) of organ involvement. Patients with deep organ involvement was associated with a higher age of IgG4-ROD onset (70 ± 12 versus 56 ± 13, P < 0.0001).

CONCLUSIONS

95% of the patients who underwent systemic imaging in our cohort had systemic organ involvement. An early physicians' assessment and radiological imaging are recommended after the diagnosis of IgG4-ROD.

IgG4-related disease: Effectiveness evaluation through Umehara-Okazaki 2011 and ACR/EULAR 2019 diagnostic criteria

BACKGROUND

IgG4-related disease (IgG4-RD) is a rare, systemic immune-mediated fibro-inflammatory condition with an unclear etiology and pathophysiology, potentially affecting multiple organs. It presents with common clinical, radiological, and serological characteristics. This study aims to compare the latest two IgG4-RD classification and diagnostic criteria: Umehara-Okazaki 2011 and ACR/EULAR 2019.

MATERIAL AND METHODS

In a retrospective cross-sectional study conducted across two centers from January 2010 to July 2023, we included patients suspected of having IgG4-RD from various hospital departments. Patients finally diagnosed with other pathologies were excluded. The remaining suspected IgG4-RD cases were evaluated using both Umehara-Okazaki 2011 and ACR/EULAR 2019 criteria.

RESULTS

Out of 34 patients with a clinical diagnosis of IgG4-RD, the Umehara-Okazaki 2011 classified 20 patients: 5 as definitive, 7 as probable, and 8 as possible cases. Applying the ACR/EULAR 2019 criteria to the same cohort resulted in the diagnosis of 9 patients. Notably, retroperitoneal fibrosis and aortitis were the most prevalent form of presentation, accounting for 25% and 22.2% of cases classified under the 2011 and 2019 criteria, respectively.

DISCUSSION

The more recent and stringent ACR/EULAR 2019 criteria focus on histopathology, various forms of presentation, and analytical data, allow for a more accurate classification of patients.

Immunoglobulin G4-Related Disease in the Diaphragm: A Case Report

Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated condition characterized by mass-forming inflammation with a sclerosing pattern that can affect nearly any organ. However, involvement of the diaphragm in IgG4-RD is exceptionally rare. We present the case of a 62-year-old male patient with chest radiographic abnormalities. Further investigation with CT revealed an infiltrative mass in the right hemidiaphragm. This mass, composed of engorged feeding vessels, an atypical manifestation of IgG4-RD, was also associated with lymphadenopathy. Surgical excision confirmed the presence of IgG4-positive cell infiltration, solidifying the diagnosis of IgG4-RD. Notably, the patient remained asymptomatic and did not require any treatment postoperatively. This case highlights the uncommon presentation of IgG4-RD as an infiltrative diaphragmatic mass.

Non-IgG4-Related Fibrosing Mediastinitis Diagnosed on Core Needle Biopsy and Treated with Steroids: A Case Study and Review of the Differential Diagnoses

OBJECTIVES

This study aimed to investigate the histological characteristics and treatment efficacy of non-immunoglobulin G4-related fibrosing mediastinitis and discuss differential diagnoses for this rare entity.

METHODS

We present a case study of non-immunoglobulin G4-related fibrosing mediastinitis diagnosed on core biopsy and treated with steroids. A total of four 18-gauge core needle biopsy specimens were obtained for surgical pathology. Analysis of the patient's medical history, radiological characteristics of fibrosing mediastinitis, histological features, immunohistochemistry results, the differential diagnosis and treatment efficacy of different types of fibrosing mediastinitis was performed.

RESULTS

This report describes a unique presentation of fibrosing mediastinitis (syncope and weight loss) that was concerning for malignancy. Histological, laboratory and radiographical studies confirmed the diagnosis of non-immunoglobulin G4-related fibrosing mediastinitis. The patient received corticosteroid treatment which showed marked improvement after 1 month of treatment.

CONCLUSIONS

Fibrosing mediastinitis is an extremely uncommon entity with unknown pathogenesis, and it is more important to rule out malignancy and infection than to delineate between fibrosing mediastinitis and IgG4-related disease. In doing this, we may reasonably initiate a trial of corticosteroids which may prove beneficial, as in this patient. More studies on the pathogenesis of fibrosing mediastinitis are necessary to guide better directed treatments.

Efficacy and safety of rituximab induction therapy and effect of rituximab maintenance for IgG4-related disease: a systematic review and meta-analysis

BACKGROUND

Previous studies have reported that rituximab (RTX) therapy might be beneficial in reducing relapse rates in patients with IgG4-related disease (IgG4-RD). Therefore, we aimed to systematically assess the efficacy and safety of RTX induction treatment and the effect of RTX maintenance in patients with IgG4-RD.

METHODS

The protocol was registered in the PROSPERO (CRD42023427352). PubMed, Embase, the Cochrane database, Scopus, and the Web of Science were interrogated to identify studies that evaluated the impact of RTX on prognosis in IgG4-RD. We explored the impact of various subgroups of factors on relapse outcomes and focused on the possible role of maintenance therapy in reducing relapse rates. The pooled incidence of adverse events of RTX therapy and the influencing factors have also been evaluated.

RESULTS

Eighteen studies comprising 374 patients (mean age 56.0 ± 8.7 years; male 73.7 %) with a mean follow-up duration of 23.4 ± 16.3 months were included. The pooled estimate of the response rate, complete remission rate, overall relapse rate, adverse event rate, and serious adverse event rate of RTX induction therapy were 97.3 % (95 % CI, 94.7 %-99.1 %), 55.8 % (95 % CI, 39.6 %-71.3 %), 16.9 % (95 % CI, 8.7 %-27.1 %), 31.6 % (95 % CI, 16.7 %-48.9 %) and 3.9 % (95 % CI, 0.8 %-8.9 %), respectively. In subgroup analysis, the pooled relapse rate was significantly lower in studies with maintenance than without maintenance (2.8% vs 21.5 %, p < 0.01). Pooled Kaplan-Meier relapse curves also demonstrated that RTX maintenance therapy provided a better prognosis.

CONCLUSIONS

RTX induction therapy appears to have satisfactory efficacy in the induction of remission in IgG4-RD. In addition, prophylactic RTX maintenance therapy after induction may be beneficial in preventing relapse of IgG4-RD.

Open repair of an abdominal aortic and right common iliac artery aneurysm with idiopathic retroperitoneal fibrosis in a 19-month-old infant

An abdominal aortic aneurysm (AAA) in children is a rare clinical condition, with idiopathic AAAs even more atypical. We report a case of a 19-month-old girl with incidental findings of an infrarenal AAA and right common iliac artery aneurysm during workup for heart failure. Extensive genetic testing was unremarkable for connective tissue disorders. An aortic bi-iliac artery bypass with a Dacron graft from the infrarenal aorta to the right external iliac artery and left common iliac artery was performed. The patient achieved complete recovery and only required one oral hypertensive medication at 30 days of follow-up. Wide patency of the graft was observed on the 3-month follow-up computed tomography angiogram.

IgG4-related disease with subcutaneous involvement and the associated diagnostic challenges with MRI

IgG4-related disease is a rare fibroinflammatory disorder characterized by the infiltration of IgG4-rich plasma cells. Herein, we report a case of IgG4-related disease of the subcutaneous tissue with atypical MRI findings and difficulties in the histopathological examination using needle biopsy. Based on the clinical presentation and MRI findings, the patient was diagnosed with a benign myxoid or cystic tumor. Additionally, histopathological findings from a needle biopsy suggested a myxoma. Therefore, the correct diagnosis of IgG4-related disease was not made preoperatively. The resected specimens confirmed IgG4-related disease with an IgG4/IgG ratio > 80%. Previous reports have shown that the MRI findings of IgG4-related disease mimic both malignancy and inflammation; surprisingly, the features of subcutaneous IgG-related disease, including tail sign, unclear border, and heterogeneous enhancement, were similar to those found in sarcoma. Therefore, histopathological findings are needed for a correct diagnosis. Furthermore, careful examination is essential because the neoplasm and inflammation may overlap with IgG4-related disease, and needle biopsy is not fully reflective of the tumor. As is highlighted in the present case, IgG4-related disease is often misdiagnosed; therefore, clinicians should adequately recognize that even if the histopathological findings in biopsy were consistent with those observed in the MRI, misdiagnosis may occur.

Coronary periarteritis and pericarditis are rare but distinct manifestations of heart involvement in IgG4-related disease: a retrospective cohort study

BACKGROUND

The heart can be involved in immunoglobulin (Ig)-G4-related disease (IgG4-RD). This study aimed to summarize the clinical features and efficacy of treatment for IgG4-RD patients with heart involvement.

METHODS

We conducted a retrospective study enrolling 42 IgG4-RD patients with heart involvement from the IgG4-RD cohorts of the Peking Union Medical College Hospital and Beijing An Zhen Hospital, from 2010 to 2022. Clinical, laboratory, radiological data were collected, and treatment responses to glucocorticoids and immunosuppressants were analyzed.

RESULTS

IgG4-related cardiac involvement is a rare part of the IgG4-RD spectrum. The incidences of coronary periarteritis and pericarditis were 1.2%(13/1075) and 3.1%(33/1075), respectively in our cohort. Valvular disease possibly related to IgG4-RD was detected in two patients. None of the patients with myocardial involvement were identified. The average age was 58.2 ± 12.8 years, with a male predominance (76.7%). Coronary artery CT revealed that mass-like and diffuse wall-thickening lesions were the most frequently observed type of coronary periarteritis. Pericarditis presented as pericardial effusion, localized thickening, calcification and mass. After treatment with glucocorticoid and immunosuppressants, all patients achieved a reduced IgG4-RD responder index score and achieved radiological remission. Two patients with coronary peri-arteritis experienced clinical relapses during the maintenance period.

CONCLUSIONS

Cardiac involvement in IgG4-RD is rare and easily overlooked since many patients are asymptomatic, and the diagnosis relies on imaging. Patients showed a satisfactory response to glucocorticoid based treatment.

The 2023 revised diagnostic criteria for IgG4-related ophthalmic disease

Immunoglobulin G4 (IgG4)-related disease is a clinical entity characterized by elevated serum IgG4 concentrations and infiltration of IgG4-immunopositive plasmacytes in various organs, including ophthalmic lesions. Diagnostic criteria for IgG4-related ophthalmic disease (IgG4-ROD) were established in 2014 and describe the most affected ocular adnexal tissues such as lacrimal glands, trigeminal nerves and extraocular muscles, but do not mention optic neuropathy, the most severe indication of ophthalmic lesions. We reviewed published case reports of optic neuropathy in IgG4-related disease (n = 44), and in many cases, decreased visual acuities recovered well following treatment such as systemic corticosteroids, rituximab, and orbital surgery. However, some patients did not recover, especially when pretreatment visual acuities were as low as light perception or less. Herein, we propose a 2023 revised diagnostic criteria for IgG4-ROD, which include a reminder not to overlook optic neuropathy. The 2014 diagnostic criteria specify mucosa-associated lymphoid tissue (MALT) lymphoma as an important differential diagnosis for the relationship between IgG4-ROD and orbital lymphoma. The 2023 revision directs physicians' attention toward lymphomas other than MALT lymphoma, considering that the 2014 criteria might have placed too much emphasis on MALT lymphoma.

Duodenal stricture secondary to IgG4-related chronic sclerosing duodenitis-A case report with review of the literature

Key Clinical Message

This case highlights the importance of a definite diagnosis of an IgG4-related chronic sclerosing duodenitis based on histological and radiological findings to rule out any malignancy in the mass. While dealing with patients having concentric duodenal thickening resulting in stricture formation, one should think of inflammatory etiology as well. IgG4-related disease is one of these inflammatory disorders where we see soft tissue thickening without a large mass or any associated lymphadenopathy as in our case.

Abstract

Immunoglobulin G4-related disease (IgG4-RD) is distinguished as an infiltration of IgG-4-positive plasmacytes involving inflammatory lesions across multiple organs which is accompanied by raised IgG4 levels in the serum. Several inflammatory disorders are recognized as part of the IgG4-RD family based on shared histopathological features, which include Mikulicz's disease, chronic sclerosing sialadenitis, or Riedel's thyroiditis. Our case highlights a distinctive presentation of IgG4-related diseases; a 58-year-old man presenting with duodenal stricture highly suspicious of a duodenal mass/ampullary mass later found to be due to IgG4-related sclerosing duodenitis with negative malignancy on biopsy. We present the diagnostic challenges faced and relevant findings noted.

Probable IGG4 related ophthalmic disease presenting with uveitis

We present a case of an uncommon presentation of IgG4-related ophthalmic disease (ROD). A 58-year-old female presented with unilateral acute anterior uveitis of the right eye, which progressed to scleritis with the development of an associated orbital mass despite treatment with oral glucocorticoid. Initial histopathology of an orbital biopsy was non-diagnostic and continued progression of the disease lead to complete loss of vision in the right eye. The development of uveitis in the previously unaffected left eye led to the decision for enucleation of the right globe and further orbital biopsy. Histopathology revealed features supporting IgG4-related ophthalmic disease. Oral glucocorticoid therapy failed to induce remission, and rituximab therapy was initiated, leading to a rapid resolution in her symptoms. Other cases with a similar presentation report a poor visual prognosis, highlighting the need for prompt diagnosis and treatment of uveitis associated with signs of orbital or scleral involvement.

IgG4-related disease-rare but you should not forget it

Immunoglobulin G4-related disease is a systemic immune-mediated disease with insidious evolution characterized by fibroinflammatory lesions over virtually any organ system. Despite the remarkable progression of knowledge, its etiology remains undefined. Due to its relapse-remitting pattern, it could accumulate irreversible damage, increasing comorbidities and mortality. This paper emphasizes key concepts for diagnosing and treating patients with this condition.

Deciphering three predominant biopsy-proven phenotypes of IgG4-associated kidney disease: a retrospective study

Background

IgG4-associated kidney disease (IgG4-RKD) encompasses a spectrum of disorders, predominantly featuring tubulointerstitial nephritis (TIN) and membranous glomerulonephropathy (MGN). The limited understanding of the co-occurrence of IgG4-RD-TIN with anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) poses a diagnostic and therapeutic challenge.

Methods

We examined 49 cases, comprising 21 cases of IgG4-RD-TIN (group A), 10 cases of IgG4-RD-TIN accompanied with MGN (group B), and 18 cases of IgG4-RD-TIN concurrent with AAV (group C), at the First Affiliated Hospital of Zhejiang University, China, from June 2015 to December 2022.

Results

The mean age and gender of the three IgG4-RKD subtypes were not statistically significant. IgG4-RD-TIN exhibited higher serum creatinine and a higher incidence of hypocomplementemia (group A 47.6%, group B 30%, group C 16.7%). IgG4-RD-TIN-MGN was characterized by proteinuria (group A 0.3 g/d, group B 4.0 g/d, group C 0.8 g/d, P < 0.001) and hypoalbuminemia. IgG4-RD-TIN-AAV exhibited hypohemoglobinemia (group A 103.45 g/l, group B 119.60 g/l, group C 87.94 g/l, P < 0.001) and a high level of urine erythrocytes. The primary treatment for IgG4-RD-TIN was steroids alone, whereas IgG4-RD-TIN-MGN and IgG4-RD-TIN-AAV necessitated combination therapy. Group A experienced two relapses, whereas groups B and C had no relapses. There was no significant difference in patient survival among the three groups, and only two cases in group C suffered sudden death.

Conclusions

This study provides valuable insights into clinical manifestations, auxiliary examination features, pathological characteristics, and prognosis of IgG4-RD-TIN, IgG4-RD-TIN-MGN, and IgG4-RD-TIN concurrent AAV. Large-scale studies are required to validate these findings.

Association of autoimmune pancreatitis and intraductal papillary mucinous neoplasm. A retrospective analysis from a tertiary care referral center

BACKGROUND

Autoimmune Pancreatitis (AIP) is a rare chronic inflammatory disease affecting the pancreas. Chronic pancreatic inflammation represents a risk factor for pre-neoplastic conditions such as Intraductal Papillary Mucinous Neoplasia (IPMN). Due to the rarity of AIP, the incidence, and clinical features of IPMN occurring in AIP patients remains unknown.

AIMS

In the present study we aimed to explore the relationship between AIP and IPMN and to characterize the clinical features and outcomes of IPMN occurring in the context of AIP.

METHODS

We retrospectively (2008-2020) analyzed the clinical and radiological records of a large single center cohort of patients with AIP and investigated the prevalence of IPMN. We then compared the clinical, laboratory and radiological characteristics of patients with IPMN and AIP with a cohort of patients with isolated IPMN.

RESULTS

Five hundred and nineteen patients were included in this retrospective study. Sixteen patients had concomitant IPMN and AIP(3%); 61 patients had isolated AIP (12%); 442 patients had isolated IPMN (85%). The prevalence of IPMN in patients with AIP was higher than that observed in the general population (21%vs8-10%). Worrisome Features and High-Risk Stigmata were more frequently observed in IPMN occurring together with AIP compared to isolated IPMN(p < 0.05). Based on radiological features IPMN in the context of AIP was more frequently of main-duct type compared to isolated IPMN(p < 0.05).

CONCLUSION

Our data suggest that AIP represents a chronic inflammatory condition that might favor IPMN development with high-risk features. Prolonged surveillance of these patients and longitudinal studies are required to further test the association with AIP and malignant and pre-malignant conditions.

IgG4-related autoimmune pancreatitis and sclerosing cholangitis: A case report and literature review

RATIONALE

Immunoglobulin G4-related disease (IgG4-RD) can involve various organs throughout the body, primarily manifesting as endocrine dysfunction, visual impairment, jaundice, and limited sexual function. IgG4-related autoimmune pancreatitis is triggered by autoimmune reactions and characterized by structural changes in the pancreas and pancreatic ducts. The disease mainly affects middle-aged and elderly males, typically presenting as progressive painless jaundice and misdiagnosed as cholangiocarcinoma or pancreatic cancer.

PATIENT CONCERNS

This study reports a 54-year-old male who consulted with different institutions multiple times due to diabetes, pancreatitis, elevated liver enzymes, and jaundice.

DIAGNOSES

Magnetic resonance imaging revealed swollen head of the pancreas and atrophic tail. Liver and pancreatic tissue pathology showed IgG4 plasma cell infiltration, while liver biopsy indicated interface hepatitis, liver fibrosis, and pseudolobule formation, with no evidence of bile duct damage.

INTERVENTIONS

Following hormone therapy, the patient's serum IgG4 levels and liver enzyme levels returned to normal.

OUTCOMES

The disease relapsed 2 years after maintaining hormone therapy, and the patient underwent additional hormone-induced remission therapy combined with azathioprine.

LESSONS

The purpose of this research report is to enhance the awareness and understanding of IgG4-RD, emphasizing the necessity for personalized treatment strategies that take into account its recurrence, associations, and imaging features. This report provides valuable insights and guidance for clinicians in managing and diagnosing patients with IgG4-RD.

IgG4-Related disease with diffuse myopericardial involvement- value of CMR: a case report and literature review of cardiac involvement

BACKGROUND

IgG4-related disease is a fibro-inflammatory disorder with an unknown etiology, which can affect multiple organ systems, including the cardiovascular system. While most reported cases of cardiovascular involvement are primarily associated with the aorta, there have been sporadic reports of isolated cardiac involvement.

CASE PRESENTATION

This paper presents a documented case of IgG4-related systemic disease with symptoms indicative of restrictive cardiomyopathy. Subsequent Cardiac Magnetic Resonance imaging revealed diffuse myopericardial involvement, characterized by pericardial thickening and enhancement, accompanied by subepicardial and myocardial infiltration. Considering the rarity of cardiac involvement in our case, we conducted a thorough review of the existing literature pertaining to various patterns of cardiac involvement in IgG4-related disease, as well as the diagnostic modalities that can be employed for accurate identification and assessment.

CONCLUSIONS

This case report sheds light on the importance of recognizing and evaluating cardiac manifestations in IgG4-related systemic disease to facilitate timely diagnosis and appropriate management.

A single-centre retrospective study of factors affecting steroid-free remission of immunoglobulin G4-related disease conducted in South Korea: A notable outcome after complete resection

OBJECTIVES

Few studies have examined factors affecting steroid-free remission (SFR) in patients with immunoglobulin G4-related disease (IgG4-RD). The aim of this study was to investigate clinical factors affecting SFR in IgG4-RD.

METHODS

The medical records of 68 patients who met the 2020 revised comprehensive diagnostic criteria for IgG4-RD were reviewed retrospectively. SFR was defined as remission maintained for at least 6 months without corticosteroids. Cox regression analysis was performed to examine the associations between SFR and various clinical factors. The relapse rate after SFR was examined using the log-rank test.

RESULTS

After a median follow-up of 36 months, 30.9% (21/68) of patients with IgG4-RD achieved SFR. Multivariate Cox regression analysis revealed that IgG4-RD diagnosed by complete resection rather than by common diagnostic procedures was the only factor positively associated with SFR (hazard ratio, 7.41; 95% confidence interval, 2.23-24.60; P = .001). Furthermore, relapse after attainment of SFR was significantly less common in the group that underwent complete resection than in the group that did not undergo complete resection (log-rank P = .006).

CONCLUSIONS

Patients with IgG4-RD diagnosed by complete resection had a higher likelihood of achieving SFR and a lower rate of relapse after attaining SFR.

Radiology domain in the diagnosis of IgG4-RD according to the 2019 American College of Rheumatology and European League Against Rheumatism classification

OBJECTIVES

To evaluate the performance of radiology-related inclusion criteria of the 2019 ACR-EULAR classification system in the diagnosis of IgG4-related disease (IgG4-RD).

METHODS

This retrospective single-institution study included patients who received a diagnosis of IgG4-RD between January 2010 and December 2020. Two abdominal radiologists independently reviewed baseline imaging studies and scored radiology findings according to the 2019 ACR-EULAR classification criteria. Additional scores were assigned based on serological, histopathological, and immunostaining features.

RESULTS

Seventy-four patients (58 males and 16 females) with a mean age of 59.3 ± 13.9 years diagnosed with IgG4-RD were included. 51/74 (68.9%) were classified as having IgG4-RD according to the 2019 ACR-EULAR classification criteria. To reach a score ≥ 20 in these 51 patients, the radiology domain was sufficient in 20/51 (39.2%) and adding the serology domain was required for another 20/51 (39.2%). The remaining 11/51 patients (21.6%) required the histopathology and immunostaining domains. Radiological involvement of two or more organs at presentation was significantly associated with a score of ≥ 20 and seen in 43/51 (84.3%) compared to 5/23 (21.7%) of the non-classified group (p < 0.001). The group classified as having IgG4-RD showed a significantly higher proportion of elevated IgG4 levels (39/51, 76.5%) than the non-classified group (8/23, 34.8%) (< 0.001).

CONCLUSION

The study findings support the effectiveness of the radiology-related inclusion criteria of the 2019 ACR-EULAR classification system in diagnosing IgG4-RD. Combining radiology and serology domains achieved the cut-off in 80% of IgG-RD patients, enabling non-invasive diagnosis. The classification of IgG4-RD was significantly associated with multi-organ involvement, particularly affecting the pancreas and biliary system.

CRITICAL RELEVANCE STATEMENT

This study is the first to evaluate the diagnostic performance of the radiology domain in the 2019 ACR-EULAR classification criteria. The study results confirm its utility and potential to enable non-invasive diagnosis when combined with serological testing in a significant proportion of patients.

KEY POINTS

• A significant proportion of patients can be diagnosed with IgG4-RD using the radiology and serology domains exclusively. • Multi-organ involvement is significantly associated with classifying patients as IgG4-RD, with the pancreas and biliary system most frequently affected. • A high level of inter-reader agreement in the scoring of the radiology domain supports its reliability.

Expression of USP25 associates with fibrosis, inflammation and metabolism changes in IgG4-related disease

IgG4-related disease (IgG4-RD) has complex clinical manifestations ranging from fibrosis and inflammation to deregulated metabolism. The molecular mechanisms underpinning these phenotypes are unclear. In this study, by using IgG4-RD patient peripheral blood mononuclear cells (PBMCs), IgG4-RD cell lines and Usp25 knockout mice, we show that ubiquitin-specific protease 25 (USP25) engages in multiple pathways to regulate fibrotic and inflammatory pathways that are characteristic to IgG4-RD. Reduced USP25 expression in IgG4-RD leads to increased SMAD3 activation, which contributes to fibrosis and induces inflammation through the IL-1β inflammatory axis. Mechanistically, USP25 prevents ubiquitination of RAC1, thus, downregulation of USP25 leads to ubiquitination and degradation of RAC1. Decreased RAC1 levels result in reduced aldolase A release from the actin cytoskeleton, which then lowers glycolysis. The expression of LYN, a component of the B cell receptor signalosome is also reduced in USP25-deficient B cells, which might result in B cell activation deficiency. Altogether, our results indicate a potential anti-inflammatory and anti-fibrotic role for USP25 and make USP25 a promising diagnostic marker and potential therapeutic target in IgG4-RD.

Cytotoxic Tph subset with low B-cell helper functions and its involvement in systemic lupus erythematosus

T peripheral helper (Tph) cells are thought to contribute to extra-follicular B cell activation and play a pathogenic role in autoimmune diseases. However, the role of Tph subsets is not fully elucidated. Here, we investigate the immunological functions of Tph subsets and their involvement in systemic lupus erythematosus (SLE). We have defined four Tph subsets (Tph1: CXCR3+CCR6-, Tph2: CXCR3-CCR6-, Tph17: CXCR3-CCR6+, and Tph1-17: CXCR3+CCR6+) and performed RNA sequencing after cell sorting. Tph1 and Tph17 subsets express substantial levels of IL21, indicating B cell helper functions. However, Tph2 and Tph1-17 subsets express low IL21. Interestingly, we have found Tph2 subset express high levels of CX3CR1, GZMB, PRF1, GLNY, S1PR5, TBX21, EOMES, ZNF863, and RUNX3, indicating a feature of CD4+ cytotoxic T lymphocytes. In SLE patients, the frequency of Tph1 and Tph2 subsets are significantly increased and positively correlated with SLE disease activity indexes. Tph1 cells expansion has been observed in patients with cutaneous and musculoskeletal manifestations. On the other hand, Tph2 cell expansion has been found in patients with lupus nephritis in addition to the above manifestations. Our findings imply that Tph1 and Tph2 subsets exert distinct immunological functions and are contributed to the complexity of clinical manifestations in SLE.

Performance of the 2019 American College of Rheumatology/European League Against Rheumatism Classification Criteria for IgG4-Related Disease in a Latin American Cohort

BACKGROUND/OBJECTIVE

The 2019 American College of Rheumatology/European League Against Rheumatism Classification Criteria (2019 AECC) for IgG4-related disease (IgG4-RD) is considered a significant advancement in the study of this condition. Most studies evaluating their performance have focused on White and Asian patients, leaving a knowledge gap regarding Latin American populations. Therefore, this study aimed to assess the performance of the 2019 AECC for IgG4-RD in a cohort of Latin American patients.

METHODS

A multicenter medical records review study was conducted, involving centers from Argentina, Chile, Mexico, Peru, and Uruguay. Data on IgG4-RD patients and mimicker conditions were collected through a standardized online form. The criterion standard for diagnosing IgG4-RD was based on the fulfillment of the Comprehensive Diagnostic Criteria for IgG4-RD and/or the Consensus Statement on Pathology. The 2019 AECC was retrospectively applied.

RESULTS

We included 300 patients, with 180 (60%) having IgG4-RD and 120 (40%) having mimicker conditions. The 2019 AECC had a sensitivity of 66.7% and a specificity of 100%. Sensitivity increased to 73.3% when disease-specific autoantibody items were removed, without affecting specificity. The true-positive cases had more involved organs, a higher availability of biopsy results, and were more likely to belong to the Mikulicz/systemic and proliferative phenotypes.

CONCLUSIONS

The use of the 2019 AECC for IgG4-RD in a Latin American population confirms its high specificity in excluding those without the disease. The presence of concomitant autoimmune diseases and clinically nonsignificant disease-specific autoantibodies excludes a significant number of patients from fulfilling the criteria.

IgG4-related pancreatobiliary diseases could be associated with onset of pancreatobiliary cancer: A multicenter cohort study

BACKGROUND

The risk and prognosis of pancreatobiliary cancer and in patients with autoimmune pancreatitis (AIP) and IgG4-related sclerosing cholangitis (IgG4-SC) remain unclear. Therefore, we retrospectively investigated the risk of pancreatobiliary cancer and prognosis in patients with AIP and IgG4-SC.

METHODS

Patients with AIP and IgG4-SC at seven centers between 1998 and 2022 were investigated. The following data were evaluated: (1) the number of cancers diagnosed and standardized incidence ratio (SIR) for pancreatobiliary and other cancers during the observational period and (2) prognosis after diagnosis of AIP and IgG4-SC using standardized mortality ratio (SMR).

RESULTS

This study included 201 patients with AIP and IgG4-SC. The mean follow-up period was 5.7 years. Seven cases of pancreatic cancer were diagnosed, and the SIR was 8.11 (95% confidence interval [CI]: 7.29-9.13). Three cases of bile duct cancer were diagnosed, and the SIR was 6.89 (95% CI: 6.20-7.75). The SMR after the diagnosis of AIP and IgG4-SC in cases that developed pancreatobiliary cancer were 4.03 (95% CI: 2.83-6.99).

CONCLUSIONS

Patients with autoimmune pancreatitis and IgG4-SC were associated with a high risk of pancreatic and bile duct cancer. Patients with AIP and IgG4-SC have a worse prognosis when they develop pancreatobiliary cancer.

IgG4-related kidney disease: Clinicopathologic features, differential diagnosis, and mimics

IgG4-related kidney disease (IgG4-RKD) encompasses all forms of kidney disease that are part of IgG4-related disease (IgG4-RD). First recognized as IgG4-related tubulointerstitial nephritis (IgG4-TIN), and then IgG4-related membranous glomerulonephritis (IgG4-MGN), we now recognize additional patterns of interstitial nephritis, glomerular disease, and vascular disease that can be seen as part of IgG4-RKD. The clinical presentation is variable and can include acute or chronic kidney injury, proteinuria or nephrotic syndrome, mass lesion(s), and obstruction. While usually associated with other organ involvement by IgG4-RD, kidney-alone involvement is present in approximately 20 % of IgG4-RKD. Compared to IgG4-RD overall, patients with IgG4-RKD are more likely to show increased serum IgG4 or IgG, and more likely to have hypocomplementemia. In this review, we extensively cover other types of autoimmune and plasma cell-rich interstitial nephritis, mass forming inflammatory diseases of the kidney, and other mimics of IgG4-TIN, in particular ANCA-associated disease.

Performance of the 2019 ACR/EULAR Classification Criteria for IgG4-Related Disease in a Large Chinese Cohort

OBJECTIVE

The purpose of this research was to ascertain the effectiveness of the newly established criteria for classifying IgG4-related disease (IgG4-RD), as applied to a large Chinese cohort in real-world clinical settings.

METHODS

Patient data were procured from the digital health records of 4 prominent academic hospitals. The criterion standard for identifying IgG4-RD patients was from a seasoned rheumatologist. The control group consisted of individuals with other ailments such as cancer, other forms of pancreatitis, infectious diseases, and illnesses that mimic IgG4-RD.

RESULTS

A total of 605 IgG4-RD patients and 760 mimickers were available for analysis. The 2019 EULAR/ACR criteria have a sensitivity of 69.1% and a specificity of 90.9% in this large Chinese cohort. IgG4-RD had a greater proportion of males (55.89% vs 36.25%, p < 0.001), an older average age at diagnosis (54.91 ± 13.44 vs 48.91 ± 15.71, p < 0.001), more pancreatic (29.59% vs 6.12%, p < 0.001) and salivary gland (63.30% vs 27.50%, p < 0.001) involvement, and a larger number of organ involvement (3.431 ± 2.054 vs 2.062 ± 1.748, p < 0.001) compared with mimickers.

CONCLUSIONS

The 2019 EULAR/ACR criteria are effective in classifying IgG4-RD in Chinese patients, demonstrating high specificity and moderate sensitivity.

Myofibroblast and pro-fibrotic cytokines in fibrosis of IgG4-related disease (IgG4-RD) patients from South Asia: preliminary data

INTRODUCTION

Fibrosis is a typical pathological characteristic in IgG4-RD patients and often irreversible. There exists a lack of suitable markers for detection of earlier onset of fibrosis in various organs in IgG4-RD patients. Hence, this study aims at analysing ambispectively the myofibroblasts and the pro-fibrotic cytokines, IFN gamma and IL-33 involved in IgG4-RD associated fibrosis in South Asian patients.

METHOD

Archived biopsy samples of definite/probable/possible cases of IgG4-RD, classified according to diagnostic criteria, taken from patients who attended the OPD and IPD of our tertiary care centre during January 2015-January 2020 were chosen for this study. The paraffin sections were examined qualitatively for fibrosis and the excessive collagen deposition by Hematoxylin & Eosin and Masson's Trichrome staining. Also, the presence of alpha-Smooth muscle actin (α-SMA) expressing myofibroblasts and the involvement of pro-fibrotic cytokines (IFN-gamma, IL-33) were assessed by Immunohistochemistry and scored semi-quantitatively (+mild, ++moderate, +++ severe). Serum IL-33 levels were analysed by indirect Elisa (R & D Systems).

RESULTS

Myofibroblasts were present in 10/12 biopsy samples, in moderate levels in 4 (33%) and very high levels (+++) in 3 (25%) of the patients. IFN-gamma was expressed at low levels in 6 (50%) and absent in 6 (50%). All patients showed IL-33 expression with very high levels in tissue (6, 50%), as well as in serum samples.

CONCLUSION

The findings of this study reinforce the role of myofibroblasts and profibrotic cytokines like IL-33 in fibrosis of Ig4-RD patients, pointing to their potential as earlier predictive markers of onset and extent of fibrosis.

Comparison of clinical features and outcomes of proliferative, fibrotic, and mixed subtypes of IgG4-related disease: A retrospective cohort study

BACKGROUND

Immunoglobulin G4-related disease (IgG4-RD) is a recently recognized immune-mediated disorder that can affect almost any organ in the human body. IgG4-RD can be categorized into proliferative and fibrotic subtypes based on patients' clinicopathological characteristics. This study aimed to compare the clinical manifestations, laboratory findings, and treatment outcomes of IgG4-RD among different subtypes.

METHODS

We prospectively enrolled 622 patients with newly diagnosed IgG4-RD at Peking Union Medical College Hospital from March 2011 to August 2021. The patients were divided into three groups according to their clinicopathological characteristics: proliferative, fibrotic, and mixed subtypes. We compared demographic features, clinical manifestations, organ involvement, laboratory tests, and treatment agents across three subtypes. We then assessed the differences in treatment outcomes among 448 patients receiving glucocorticoids alone or in combination with immunosuppressants. Moreover, risk factors of relapse were revealed by applying the univariate and multivariate Cox regression analysis.

RESULTS

We classified the 622 patients into three groups consisting of 470 proliferative patients, 55 fibrotic patients, and 97 mixed patients, respectively. We found that gender distribution, age, disease duration, and frequency of allergy history were significantly different among subgroups. In terms of organ involvement, submandibular and lacrimal glands were frequently involved in the proliferative subtype, while retroperitoneum was the most commonly involved site in both fibrotic subtype and mixed subtype. The comparison of laboratory tests revealed that eosinophils ( P = 0.010), total IgE ( P = 0.006), high-sensitivity C-reactive protein ( P <0.001), erythrocyte sedimentation rate ( P <0.001), complement C4 ( P <0.001), IgG ( P = 0.001), IgG1 (P <0.001), IgG4 (P <0.001), and IgA ( P <0.001), at baseline were significantly different among three subtypes. Compared with proliferative and mixed subtypes, the fibrotic subtype showed the lowest rate of relapse (log-rank P = 0.014).

CONCLUSIONS

Our study revealed the differences in demographic characteristics, clinical manifestations, organ involvement, laboratory tests, treatment agents, and outcomes across proliferative, fibrotic, and mixed subtypes in the retrospective cohort study. Given significant differences in relapse-free survival among the three subtypes, treatment regimens, and follow-up frequency should be considered separately according to different subtypes.

South African flag sign to a giant coronary artery aneurysm

Background

Coronary arteritis leading to aneurysm is one of the unusual presentations of IgG4-related disease. Acute myocardial infarction as a complication of IgG4-related giant coronary artery aneurysm is even rarer.

Case summary

We describe the case of a 56-year-old gentleman who presented to our institute with Canadian Cardiovascular Society (CCS) class III angina. His symptoms were persistent even with high-dose antianginal medications. He had an acute coronary syndrome two weeks back for which he was treated conservatively in a peripheral health centre. His 12-lead electrocardiogram at the time of the event was suggestive of high lateral ST-segment elevation myocardial infarction (South African flag sign). His transthoracic echocardiography showed mild left ventricular dysfunction and a large echogenic mass lateral to the left ventricle. Coronary angiography followed by cardiac computed tomography revealed a giant pseudoaneurysm of the proximal and mid-left anterior descending coronary artery. FDG-PET scan showed significant metabolic activity in the aneurysm wall and mediastinal lymph nodes suggesting active inflammation. IgG4-related coronary arteritis was suspected, and the patient underwent aneurysmectomy and coronary artery bypass (CABG) surgery. The histopathology of the resected segment showed diffuse IgG4-secreting plasma cells confirming the diagnosis.

Discussion

Atherosclerosis is the most common cause of coronary aneurysms in adults. However, cardiologists should be aware of atypical causes like IgG4-related disease that can even present with acute coronary syndrome. Although multimodality imaging is beneficial during early evaluation, histopathological analysis is the cornerstone for the diagnosis of IgG4-related disease. The management involves both immunosuppressive medication and endovascular or surgical repair.

IgG4-related inflammatory pancreatic head pseudotumor mirrors pancreatic head tumor: A novel case series with a review of the literature

Key Clinical Message

In this noteworthy case series regarding pancreatic pseudo tumors, we intend to spread knowledge among physicians for the diagnostic and therapeutic approach and eventual disease prognosis.

Abstract

Inflammatory pseudotumor of pancreatic head greatly mimics pancreatic head tumor. One of them is IgG4-related pancreatic disease, which is commonly mistaken as neoplastic disease on imaging. In our novel case series, we report three cases of IgG4-related pancreatic head pseudotumor with patients ranging from 35 to 72 years of age. Patients presented with jaundice and abdominal pain. Alongside initial laboratory workup, abdominal CTs and serum IgG4 levels were also obtained. Imaging features in conjunction with IgG4 levels confirmed the diagnosis of IgG4-related autoimmune pancreatitis. Pancreatic pseudotumors are notorious for being often reported as real tumors. Through our noteworthy case series, we intend to highlight the imaging features and laboratory markers that are crucial in such cases to avoid invasive procedures.

Clinical patterns and risk factors for multiorgan involvement in IgG4-Related disease patients

Background

IgG4-related disease with multiorgan involvement predicts higher disease activity, thus, it is necessary to identify whether IgG4-related disease involves multiple organs at the early stage. To further clarify the clinical characteristics and risk factors for IgG4-related disease with multiorgan involvement, we conducted an observational study.

Methods

We retrospectively analysed the clinical data of 160 patients who were primarily diagnosed with IgG4-related disease at the First Affiliated Hospital of Zhengzhou University from January 2015 to January 2021. According to the number of involved organs, patients were divided into two groups: multiorgan involvement and nonmultiorgan involvement. Patients were divided into a multiorgan group and a nonmultiorgan group according to multiple organ involvement.

Results

There were 82 cases identified with multiorgan involvement and 78 cases diagnosed with no multiorgan involvement in this series. Most cases were elderly and male (p > 0.05). The most frequently affected organs in IgG4-RD were the lymph nodes (50.6 %), pancreas (38.7 %) and salivary glands (35.6 %). Multivariate analysis showed that eosinophilia, IgG4>2*ULN, lymph node involvement, salivary gland involvement and lung involvement were independent risk factors for multiorgan involvement (p < 0.05).

Conclusions

The main issues in clinical practice are how to accurately diagnose the disease and screen the more vulnerable organs.

A nomogram based on ultrasound scoring system for differentiating between immunoglobulin G4-related sialadenitis and primary Sjögren syndrome

OBJECTIVES

Accurate distinguishing between immunoglobulin G4-related sialadenitis (IgG4-RS) and primary Sjögren syndrome (pSS) is crucial due to their different treatment approaches. This study aimed to construct and validate a nomogram based on the ultrasound (US) scoring system for the differentiation of IgG4-RS and pSS.

METHODS

A total of 193 patients with a clinical diagnosis of IgG4-RS or pSS treated at our institution were enrolled in the training cohort (n = 135; IgG4-RS = 28, pSS = 107) and the validation cohort (n = 58; IgG4-RS = 15, pSS = 43). The least absolute shrinkage and selection operator regression algorithm was utilized to screen the most optimal clinical features and US scoring parameters. A model for the differential diagnosis of IgG4-RS or pSS was built using logistic regression and visualized as a nomogram. The performance levels of the nomogram model were evaluated and validated in both the training and validation cohorts.

RESULTS

The nomogram incorporating clinical features and US scoring parameters showed better predictive value in differentiating IgG4-RS from pSS, with the area under the curves of 0.947 and 0.958 for the training cohort and the validation cohort, respectively. Decision curve analysis demonstrated that the nomogram was clinically useful.

CONCLUSIONS

A nomogram based on the US scoring system showed favourable predictive efficacy in differentiating IgG4-RS from pSS. It has the potential to aid in clinical decision-making.