Revealing the distinct clinical patterns and relapse risk factors in seronegative IgG4-RD patients: A retrospective cohort study over a decade

OBJECTIVES

Our study aimed to investigate the distinct clinical patterns of seronegative IgG4-related disease (IgG4-RD) patients.

METHODS

We retrospectively enrolled 698 treatment-naïve IgG4-RD patients in this study. Patients were divided into four different subgroups according to their baseline serum IgG4 levels. The distinct clinical patterns of seronegative IgG4-RD patients were revealed through the comparison of baseline clinical data and disease prognosis among the different subgroups. COX regression analyses were used to investigate the risk factors for disease relapse and to construct the nomogram model.

RESULTS

Seronegative IgG4-RD patients account for a minority of IgG4-RD patients (49/698, 7.02%). The proportions of seronegative IgG-RD patients in our study and several Asian cohorts were significantly lower than those of the European and American cohorts. Seronegative IgG4-RD patients got lower serum IgG levels (p < 0.0001), lower eosinophil count (p < 0.0001), lower serum IgE levels (p < 0.0001)), lower IgG4-RD responder index (RI) scores (p < 0.0001), and fewer affected organ numbers (p < 0.0001) compared with other subgroups, whereas they were more likely to manifest fibrotic type with some special organ involvement. Younger age at onset, GCs monotherapy, elevated C-reactive protein level, and elevated erythrocyte sedimentation rate level are the risk factors for the disease relapse of seronegative IgG4-RD patients. An effective nomogram model predicting disease relapse of seronegative IgG4-RD patients was constructed. Seronegative IgG4-RD patients with scores >84.65 at baseline were susceptible to suffering from disease relapse.

CONCLUSIONS

Distinct clinical features and multiple risk factors for disease relapse of seronegative IgG4-RD patients have been revealed in this study. A nomogram model was constructed to effectively predict disease relapse during the follow-up period.

Pulmonary manifestations, treatments and outcomes of IgG4-related disease-a systematic literature review

Immunoglobulin G4-related disease (IgG4-RD) is a multisystem fibroinflammatory condition. A consistent feature of many cases is pulmonary infiltrates, or respiratory failure. This systematic literature review aims to summarise the pulmonary manifestations of IgG4-RD, including clinical outcomes and treatment. This review was registered on PROSPERO (CRD42023416410). Medline, Embase and Cochrane databases were searched for articles discussing IgG4-RD syndrome. Information was extracted on demographics, type and prevalence of pulmonary manifestations, treatment and clinical outcomes. Initially, after deduplication, 3123 articles were retrieved with 18 ultimately included. A pooled total of 724 patients with IgG4-RD were included, 68.6% male, mean age 59.4 years (SD 5.8) at disease onset. The most frequently described pulmonary manifestation was mediastinal lymphadenopathy (n = 186, 48.8%), followed by pulmonary nodules (n = 151, 39.6%) and broncho-vascular thickening (n = 85, 22.3%). Where treatment was reported, the majority of patients received glucocorticoids (n = 211, 93.4%). Other immunosuppressive therapy included cyclophosphamide (n = 31), azathioprine (n = 18), with mycophenolate mofetil (n = 6), rituximab (n = 6), methotrexate (n = 5) and other unspecified immunomodulators (50). Clinical outcomes were reported in 263 patients, where 196 patients had remission of their disease, 20 had relapse, 35 had stable disease, four had progression and eight patients died from complications of IgG4-RD. This systematic review summarises pulmonary manifestations, treatments and outcomes in patients with IgG4-RD. Pulmonary involvement in IgG4-RD is relatively common, leading to high levels of morbidity and mortality. Glucocorticoids remain the mainstay of treatment, but further work is required to explore the management of patients with pulmonary manifestations in association with IgG4-RD.

New insights into chronic rhinosinusitis associated with IgG4-related disease

IgG4-related disease (IgG4-RD) is a chronic inflammatory disorder characterized by elevated IgG4 serum levels, abundant IgG4-positive plasmacyte infiltration, and fibrosis of various organs, including the head and neck. We aimed to provide an overall review of IgG4-RD in the sinonasal region and propose a novel entity and criteria of chronic rhinosinusitis (CRS) associated with IgG4-RD as "IgG4-CRS," a distinct manifestation of IgG4-RD in the sinonasal region. Sinonasal involvement has been increasingly recognized; however, this region is not included in the classic IgG4-RD-affected organs. The clinical features of IgG4-CRS, including its prevalence and relationship with allergies and olfactory disturbances, have also been explored. Serum IgG4 levels and IgG4-positive plasma cell infiltrations, crucial diagnostic factors, have been discussed in association with IgG4-CRS pathogenesis. Fibrosis, a hallmark of IgG4-RD, is observed in sinonasal tissues; however, typical fibrosis, such as storiform fibrosis, is not usually found. Mimics or complications in eosinophilic CRS (ECRS) and antineutrophil cytoplasmic antibody-associated vasculitis (AAV) are highlighted. Treatment often involves typically effective glucocorticoids. Organ-specific diagnostic criteria for the sinonasal region have not currently been established. Hence, this review aims to foster awareness and understanding of IgG4-CRS among ENT physicians and to provide a basis for future research and diagnostic refinement.

IgG4-related disease: an update on pathology and diagnostic criteria with a focus on salivary gland manifestations

Immunoglobulin G4-related disease (IgG4-RD) is a multi-organ disorder characterized by a highly variable clinical presentation depending on the affected organ/s, extent of tumefactive fibroinflammatory lesions, and associated functional impairment. The disease pursues a chronic, relapsing, often asymptomatic course and hence may pose a significant diagnostic challenge. Diagnostic delay can lead to progressive fibrosis and irreversible organ damage resulting into significant morbidity and even mortality. Given its broad clinical spectrum, physicians of all specialties may be the first clinicians facing this diagnostic challenge. Outside the pancreatobiliary system, the head and neck represents the major site of IgG4-RD with variable organ-specific diffuse or mass-forming lesions. In up to 75% of cases, elevated serum IgG4 levels are observed, but this figure possibly underestimates the fraction of seronegative cases, as the disease manifestations may present metachronously with significant intervals. Together with negative serology, this can lead to misdiagnosis of seronegative cases. A standardized nomenclature and diagnostic criteria for IgG4-RD were established in 2012 and revised in 2020 facilitating scientific research and expanding the range of diseases associated with IgG4 abnormalities. In addition to orbital pseudotumor, dacryoadenitis, Riedel thyroiditis, sinonasal manifestations, and rare miscellaneous conditions, IgG4-related sialadenitis is one of the most frequent presentations in the head and neck region. However, controversy still exists regarding the relationship between sialadenitis and IgG4-RD. This review focuses on the clinicopathological features of IgG4-related sialadenitis and its contemporary diagnostic criteria.

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.

Clinical features of adult patients with allergic parotitis

Background

Allergic parotitis (AP), due to its non-specific symptoms, frequently poses a diagnostic challenge, leading to cases being overlooked or misdiagnosed by clinicians.

Objective

This study aimed to elucidate detailed clinical characteristics and common diagnostic indicators of AP.

Methods

A comprehensive review and analysis of medical records was conducted from patients diagnosed with AP, encompassing demographic, clinical, and laboratory data, at the Affiliated Stomatological Hospital of Nanjing Medical University between January 2019 and March 2022.

Results

The study enrolled 17 patients, evidenced by an average age of 36.00 ± 12.95 years. Common presentations of AP among the patients included notable symptoms such as parotid gland swelling, associated pain, and xerostomia. Ten patients had other atopic diseases. Palpation revealed the affected parotid glands to be soft and nodular, with an elevated local skin temperature. The unstimulated whole saliva flow rate was decreased. Ultrasonography demonstrated increased volume, reduced echo heterogeneity, and lymph node enlargement in the affected parotid glands. All cases observed increased serum salivary amylase and total IgE levels. Investigation of food allergens and inhaled allergen-specific IgE showed that all patients had suspected food allergies. Food provocation tests (FPT) induced AP in 13 cases, confirming the role of food allergens.

Conclusion

Food allergens are involved in the etiology of AP, underscoring the importance of comprehensive clinical evaluation, including symptoms, signs, and confirmatory auxiliary tests, such as FPT, for accurate diagnosis and differentiation from other salivary gland pathologies.

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.

Inflammatory and Infectious Disorders in Endocrine Pathology

A variety of inflammatory conditions may directly involve the endocrine glands, leading to endocrine dysfunction that can cause severe consequences on patients' health, if left untreated. Inflammation of the endocrine system may be caused by either infectious agents or other mechanisms, including autoimmune and other immune-mediated processes. Not infrequently, inflammatory and infectious diseases may appear as tumor-like lesions of endocrine organs and simulate neoplastic processes. These diseases may be clinically under-recognized and not infrequently the diagnosis is suggested on pathological samples. Thus, the pathologist should be aware of the basic principles of their pathogenesis, as well as of their morphological features, clinicopathological correlates, and differential diagnosis. Interestingly, several systemic inflammatory conditions show a peculiar tropism to the endocrine system as a whole. In turn, organ-specific inflammatory disorders are observed in endocrine glands. This review will focus on the morphological aspects and clinicopathological features of infectious diseases, autoimmune disorders, drug-induced inflammatory reactions, IgG4-related disease, and other inflammatory disorders involving the endocrine system. A mixed entity-based and organ-based approach will be used, with the aim to provide the practicing pathologist with a comprehensive and practical guide to the diagnosis of infectious and inflammatory disorders of the endocrine system.

Treatment outcomes and their determinants of IgG4-related ophthalmic disease: a territory-wide cohort study

BACKGROUND

Oral corticosteroid remains the first-line treatment of IgG4-related ophthalmic disease, but steroid-dependence is common and serious. Factors associated with steroid dependence and relapse have to be further explored.

STUDY POPULATION

A city-wide, biopsy-proven, Chinese cohort.

METHODS

Retrospective, masked review of medical records, orbital images and histopathology reports.

RESULTS

There were 101 patients with at least 24-month follow-up. Up to 82% (82/101) received oral corticosteroid as first-line treatments, and 7 of them received also concomitant steroid-sparing agents (SSA)/biological agents as primary treatment. There was 61% (50/82) of patients required long-term corticosteroid (alone=23, with SSA=27) after 1.9±0.7 (range 1-5) relapses. When compared with the 21% (17/82) of patients who tapered corticosteroid successfully for 24 months, steroid dependence was associated with elevated baseline serum IgG4 level (94% vs 65%, p<0.01) and Mikulicz syndrome (46% vs 18%, p<0.05). Up to 13% (11/82) of patients tolerated residual disease after tapering off corticosteroid. There was 17% (17/101) of patients did not require any medications after biopsies. They were more likely to have debulking surgeries (71% vs 40%, p<0.05), discrete orbital lesions (65% vs 26%, p<0.05), normal baseline serum IgG4 level (24% vs 6%, p<0.05) and no Mikulicz syndrome (94% vs 61%, p<0.05).

CONCLUSION

In this cohort, 60% of patients required long-term maintenance oral corticosteroid. Elevated pretreatment serum IgG4 level and Mikulicz syndrome were associated with steroid dependence. Debulking surgery is an alternative for a subgroup of patients with discrete orbital lesions, normal baseline IgG4 level and no Mikulicz syndrome.

Clinical features and relapse risks factors of IgG4 related disease: a single-center retrospective study

OBJECTIVE

The aim of this study was to observe the demographic and clinical characteristics of immunoglobulin (Ig) G4-related disease (IgG4-RD). We aimed to compare different treatment methods and to identify the risk factors for non-response and relapse after treatment.

METHODS

We performed a retrospective study of 201 IgG4-RD patients initially diagnosed and treated at the First Affiliated Hospital of China Medical University from January 2016 to December 2020. Patients' sex, age, clinical manifestations, baseline biochemical values, the number of organs involved, and the type of organ involvement were recorded. All patients received glucocorticoid (GC) monotherapy or GC + immunosuppressant combination therapy. The serum IgG4 concentration as well as the details of clinical response, relapse, and side effects were recorded at 1, 3, 6, and 12 months after treatment.

RESULTS

The incidence of IgG4-RD was primarily centered in the age group of 50-70 years old, and the proportion of affected male patients increased with age. The most common clinical symptom was swollen glands or eyes (42.79%). The rates of single- and double-organ involvement were 34.83% and 46.27%, respectively. The pancreas (45.77%) was the most frequently involved organ in cases of single-organ involvement, and the pancreas and biliary tract (45.12%) was the most common organ combination in cases of double-organ involvement. Correlation analysis showed that the number of organs involved was positively related to the serum IgG4 concentration (r = 0.161). The effective rate of GC monotherapy was 91.82%, the recurrence rate was 31.46%, and the incidence of adverse reactions was 36.77%. Meanwhile, the effective rate of GC + immunosuppressant combination therapy was 88.52%, the recurrence rate was 19.61%, and the adverse reaction rate was 41.00%. There were no statistically significant differences in response, recurrence, and adverse reactions. The overall response rate within 12 months was 90.64%. Age (< 50 years old) and aorta involvement were significantly associated with non-response. The overall recurrence rate within 12 months was 26.90%. Age (< 50 years old), low serum C4 concentration, a high number of involved organs, and lymph node involvement were significantly associated with recurrence.

CONCLUSION

The clinical features vary among different age groups and according to gender. The number of organs involved in IgG4-RD is related to the serum IgG4 concentration. Age (< 50 years old), low serum C4 concentration, a high number of involved organs, and lymph node involvement are risk factors for recurrence.

Clues to mortality trends and their related factors in IgG4-related disease: A Japanese single-centre retrospective study

OBJECTIVES

This study aimed to clarify mortality trends and their related factors in immunoglobulin G4-related disease (IgG4-RD) with various organ involvement.

METHODS

We retrospectively reviewed the medical records of patients with IgG4-RD at a single rheumatology centre in Japan. We calculated the standardized mortality ratio using Japanese national mortality statistics. Cox regression analyses were also performed to assess mortality-related factors.

RESULTS

A total of 179 patients with IgG4-RD were included with a median follow-up period of 47 months. The standardized mortality ratio in our cohort was 0.86 (95% confidence interval 0.41-1.59). Univariate Cox regression analyses indicated that the number of affected organs at diagnosis (hazard ratio 1.45, 95% confidence interval 1.02-2.05), estimated glomerular infiltration rate <45 ml/min/1.73 m2 at diagnosis (vs. ≥45, hazard ratio 8.48, 95% confidence interval 2.42-29.79), and the presence of malignancy during the clinical course (hazard ratio 5.85, 95% confidence interval 1.62-21.15) had a significant impact on the time to death.

CONCLUSIONS

Our findings suggest that in the rheumatology department, IgG4-RD does not significantly affect long-term patient survival. However, multi-organ involvement, renal dysfunction, and malignancy may be associated with higher mortality trends in IgG4-RD. Early detection and appropriate management of risk factors may improve the long-term prognosis of patients with IgG4-RD.

Efficacy and Safety of Glucocorticoid Monotherapy Versus the Combination of Glucocorticoid and Immunosuppressive Agents for Immunoglobulin G4-Related Disease: A Systematic Review and Meta-Analysis

We conducted the current systematic review and meta-analysis to evaluate the efficacy and safety of the combination of glucocorticoid and immunosuppressive agents (IM) compared to glucocorticoid (GC) monotherapy for the treatment of immunoglobulin G4-related disease (IgG4-RD). PubMed, Web of Science, Scopus, OVID, and the Cochrane Library were searched for related articles. Meta-analysis was conducted with outcomes including relapse rate, remission, and adverse events. We calculated the odds ratio (ORs) and 95% confidence interval (CI) with the meta-analysis model. Ten studies involving 906 patients were included in the systematic review; of them, seven studies were included in the meta-analysis. The effect size showed that the GC group was associated with a higher relapse rate (OR = 2.97, 95% CI [1.91, 4.62], p < 0.0001) and a less complete remission rate (OR = 0.27, 95% CI [0.16, 0.47], p < 0.0001) than the combination of GC and IM group. While there was no significant difference between the two compared groups in terms of adverse events (OR = 0.73, 95% CI [0.44, 1.21], p = 0.22). No significant heterogeneity was detected regarding all outcomes (p > 0.1, I2 < 50%). Treatment of IgG4-RD patients with a combination of GC and IM was associated with higher remission rates, lower relapse rates, and comparable safety profiles. Larger RCTs should be conducted and focused on exploring the genetic and geographic differences between different cohorts.

Single-Cell RNA-Sequencing Reveals Peripheral T Helper Cells Promoting the Development of IgG4-Related Disease by Enhancing B Cell Activation and Differentiation

Abnormal B cell differentiation plays a critical role in IgG4-related disease (IgG4-RD), but the underlying mechanism remains largely unknown. We investigated the cell landscape from three IgG4-RD retroperitoneal tissues and three control tissues using single-cell RNA-sequencing. Critical cell type or markers were further validated in the peripheral blood from the patients with IgG4-RD and healthy controls via flow cytometry as well as in the IgG4-RD and control tissue via immunofluorescence staining. The increases in B cells, plasma cells, and CD4+ T cells were found in IgG4-RD retroperitoneal tissue. Importantly, among CD4+ T cells, an increase in CD4+CXCR5-PD1hi peripheral T helper (Tph) cells with a high expression of IL-21 and TIGIT was discovered in IgG4-RD tissue, which was further validated in peripheral blood of the patients with IgG4-RD. The Tph cell and TIGIT+ Tph cell proportion were remarkably higher in active IgG4-RD patients and correlated with disease activity. Moreover, TIGIT+CD4+ cells were able to promote B cell differentiation via IL-21. Our study revealed that Tph cells are increased in IgG4-RD and probably play critical roles in B cell differentiation through TIGIT-IL-21 axis. Peripheral Tph cell and TIGIT+Tph cell are potential markers for IgG4-RD disease activity.

IgG4-related retroperitoneal fibrosis: A case report of a challenging disease

Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) is a multi-organ immune-mediated fibroinflammatory disorder that may imitate malignancy, infectious or any other inflammatory disorder. IgG4-related retroperitoneal fibrosis (IgG4-RPF) is a rare form of IgG4-RD, diagnosis of which is often relied on radiological technology. Herein, we describe a case of 60 year old male, presenting with low back pain and weight loss for a period of 2 months and 15 days. Imaging studies showed a retroperitoneal tumorous mass along with bilateral hydroureteronephrosis, which was later confirmed to be IgG4-related retroperitoneal fibrosis on the basis of extensive histopathological analysis. Immunosuppressive therapy resulted in a decrease in fibrosis and restoration of renal function.

'Spikeopathy': COVID-19 Spike Protein Is Pathogenic, from Both Virus and Vaccine mRNA

The COVID-19 pandemic caused much illness, many deaths, and profound disruption to society. The production of 'safe and effective' vaccines was a key public health target. Sadly, unprecedented high rates of adverse events have overshadowed the benefits. This two-part narrative review presents evidence for the widespread harms of novel product COVID-19 mRNA and adenovectorDNA vaccines and is novel in attempting to provide a thorough overview of harms arising from the new technology in vaccines that relied on human cells producing a foreign antigen that has evidence of pathogenicity. This first paper explores peer-reviewed data counter to the 'safe and effective' narrative attached to these new technologies. Spike protein pathogenicity, termed 'spikeopathy', whether from the SARS-CoV-2 virus or produced by vaccine gene codes, akin to a 'synthetic virus', is increasingly understood in terms of molecular biology and pathophysiology. Pharmacokinetic transfection through body tissues distant from the injection site by lipid-nanoparticles or viral-vector carriers means that 'spikeopathy' can affect many organs. The inflammatory properties of the nanoparticles used to ferry mRNA; N1-methylpseudouridine employed to prolong synthetic mRNA function; the widespread biodistribution of the mRNA and DNA codes and translated spike proteins, and autoimmunity via human production of foreign proteins, contribute to harmful effects. This paper reviews autoimmune, cardiovascular, neurological, potential oncological effects, and autopsy evidence for spikeopathy. With many gene-based therapeutic technologies planned, a re-evaluation is necessary and timely.

Gastroenterological Manifestations of Immunoglobulin G Subclass 4-Related Disease-Epidemiology, Clinical Manifestations, Diagnosis and Treatment

Despite causing high morbidity, IgG4-related disease (IgG4-RD) and its gastroenterological manifestations lack better and greater theoretical contributions. Therefore, the objective of this work was to evaluate the clinical-epidemiological, diagnostic and treatment aspects of the gastrointestinal manifestations of this disease. A systematic review was carried out using the PubMed, Scopus and Embase databases between January 2012 and March 2023 with the following descriptors: "Immunoglobulin G4-Related Disease" (MeSH) AND #2 "Gastrointestinal Tract" (MeSH). Our data collection grouped a total of 3607 patients from mostly epidemiological cohort studies and cross-sectional follow-ups. In the subgroup analysis, IgG4-RD was associated with male gender, with an estimated prevalence between 54% and 80%. In our findings, the prevalence by topography was presented in the following ranges: lacrimal glands (17-57%); salivary glands (28-72%); pancreas (19-60%); biliary tract (5-40%); retroperitoneal cavity (9-43%). Longitudinal studies are needed to better map the natural history of the gastrointestinal manifestations of IgG4-RD and enable the formulation of individualized treatments.

IgG4-Related Disease Manifested as Cutaneous Plasmacytosis: A Case Report

BACKGROUND

IgG4-related disease (IgG4-RD) is a rare fibroinflammatory disease that has a high tendency to misdiagnosis in clinics.

CASE PRESENTATION

A 48-year-old man developed a rash with progressive itching 3 years ago after hormone therapy for an ocular "inflammatory pseudotumor". The disease condition of this patient involved multiple organs which involved the skin. The patient was misdiagnosed with other diseases during the period of hospitalization, leading to poor therapeutic effects and repeated skin lesions. The dermatopathological report indicated plasma cell proliferative disorder, with IgG4/IgG exceeding 40% and abnormally elevated serum IgG4 levels. After the patient was diagnosed with IgG4-RD, a series of treatments improved skin lesions, relieved other symptoms, and decreased serum IgG4 levels.

CONCLUSION

IgG4-RD is a highly misdiagnosed disease that deserves the attention of physicians. The patient we reported could be considered a representative case of IgG4-RD that presents with skin lesions. For patients with suspected IgG4-RD, serum IgG4 testing should be performed, and further imaging, serological tests, and pathology examinations are needed to exclude malignancy, infection, and autoimmune diseases.

The external validation of the 2019 ACR/EULAR classification criteria for IgG4-related disease in a large cohort from China

OBJECTIVE

To externally validate the performance of the 2019 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) classification criteria for IgG4-related disease (IgG4-RD) within a cohort from China and to compare the criteria with the 2020 revised comprehensive diagnostic (RCD) criteria for IgG4-RD.

METHODS

This study included 875 IgG4-RD and 302 non-IgG4-RD cases (213 mimickers and 89 patients with other diseases). Using expert clinical judgment as the gold standard for diagnosis of IgG4-RD, the performance (sensitivity, specificity, area under the curve (AUC) of the 2019 ACR/EULAR criteria for IgG4-RD was evaluated. We also compared it with the 2020 RCD criteria.

RESULTS

The 2019 ACR/EULAR classification criteria had a sensitivity of 76.6% (95% CI: 73.8% to 79.4%) and a specificity of 98.0% (96.0%-99.4%), an AUC of 0.873 (0.857-0.889) in the overall cohort. Those false negative cases under the 2019 ACR/EULAR classification criteria had significantly lower levels of serum IgG4, and fewer had pathological information, with a higher frequency in the involvement of those uncommon organs compared with the true positive cases. The cases judged as negative by the 2019 ACR/EULAR classification criteria yet judged as "definite" by the 2020 RCD criteria had more involvement of uncommon organs.

CONCLUSIONS

The 2019 ACR/EULAR classification criteria for IgG4-RD show outstanding specificity and good sensitivity in real-world clinical practice. The 2020 RCD criteria are helpful for the diagnosis of IgG4-RD in clinical scenarios where IgG4-RD presents as involving an isolated organ, especially the unusual sites.

Hypertrophic pachymeningitis due to IgG4-related disease (RD-IgG4). A case report

INTRODUCTION

Hypertrophic pachymeningitis (HP) is a clinico-radiological entity characterized by a thickening of the dura mater that may be focal or diffuse and manifested by a variety of neurological syndromes. Aetiologically, it is classified as infectious, neoplastic, autoimmune, and idiopathic. Many of these formerly idiopathic cases have been shown to fall into the spectrum of IgG4-related disease.

OBJECTIVE

To describe the case of a patient attended for neurological involvement due to hypertrophic pachymeningitis with initial diagnosis of inflammatory myofibroblastic tumour and final diagnosis of IgG4-related disease.

CASE

A 25-year-old woman with neurological symptoms of 3 years' evolution characterized initially by right hypoacusis, evolving with headache and diplopia. Magnetic resonance imaging (MRI) of the encephalon showed pachymeningeal thickening with involvement of vasculo-nervous structures in the tip of the cerebellum, cavernous sinus, ragged foramen, and optic chiasm. The patient presented for consultation with the result of an incisional biopsy that reported a proliferative lesion combining fibrous elements of fascicular or swirling arrangement with collagenized streaks with dense, lymphoplasmacytic infiltrate and some macrophages, with negative staining for ALK 1, with a diagnosis of inflammatory myofibroblastic tumour. Due to suspicion of IgG4-related disease (IgG4-RD) the biopsy was sent for review and pertinent complementary studies were requested.

BIOPSY REVIEW

Non storiform fibrosis, predominantly lymphoplasmacytic infiltrate, histiocytes, and polymorphonuclear infiltrate in sectors, without granulomas or atypia. Staining for germs negative. Immunohistochemistry with 50-60 IgG4+/HPF cells and range of 15%-20%, CD68⁺ in histiocytes, CD1a^-, S100^-. The patient presented deterioration of visual acuity due to ophthalmic nerve involvement, so glucocorticoid treatment was started in pulses and rituximab with regression of symptoms and imaging improvement of the lesions.

CONCLUSION

HP is a clinical imaging syndrome with variable symptoms and aetiologies that poses a diagnostic challenge. In this case the initial diagnosis was inflammatory myofibroblastic tumour, which is a neoplasm of variable behaviour, locally aggressive, and can metastasize; it is one of the main differential diagnoses of IgG4-related disease because they share anatomopathological features, including storiform fibrosis. IgG4-RD is an immune-mediated condition that can have single or multiple involvement. Its diagnosis is complex when it presents with single organ involvement or in non-typical organs (CNS, meninges) in which data are scarce, as in the case of our patient with single organ involvement of the CNS. Although there are classification criteria to guide non-specialists in the diagnosis, the sum of the clinical picture, imaging, laboratory, pathological anatomy, and immunohistochemistry will always be evaluated together for a definitive diagnosis.

Systematic Review of Treatment Options and Therapeutic Responses for Lesions of the Sella and Orbit: Evidence-Based Recommendations

OBJECTIVE

Inflammatory pathologies of the sella and orbit are rare but require prompt diagnosis to initiate effective treatment. Because uniform recommendations for treatment are currently lacking, we performed an evidence-based review to identify recommendations.

METHODS

We performed a literature search of the PubMed, Embase, and Web of Science databases to identify papers evaluating treatment of inflammatory pathologies of the sella and orbit. We used PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to define recommendations, specifically examining aggregated sample sizes, disease-specific patient follow-up, and clinical trials focused on inflammatory diseases of the sella and orbit.

RESULTS

A total of 169 studies were included and organized by disease pathology. Treatments for various pathologies were recorded. Treatment options included surgery, radiation, steroids, targeted treatments, immunomodulators, intravenous immune globulin, and plasmapheresis. Steroids were the most often employed treatment, second-line management options and timing varied. Pathological diagnosis was highly associated with treatment used. Most evidence were level 3 without available control groups, except for 13 trials in neuromyelitis optica with level 1 or 2 evidence.

CONCLUSIONS

This is the first evidence-based review to provide recommendations on specific treatments for pathologies of the orbit and sella. The reported data may be useful to help guide randomized clinical trials and provide resource for clinical management decisions based on the available evidence.

Implication of allergy and atopy in IgG4-related disease

Immunoglobulin G4-related disease (IgG4-RD) is a chronic multi-organic immune fibrosing disease. It affects preferentially men around middle age and almost any organs can be involved; however, lymph nodes, submandibular and lacrimal glands, pancreas, and retroperitoneum are the most affected. The mainstay treatment is corticosteroids, sometimes adjuncts with DMARDs or rituximab as steroid sparing agents. Th2 inflammation is implicated in the pathophysiology of the disease. Several reports indicate that allergy and/or atopy often affect patients with IgG4-RD. The frequency varies greatly between studies with allergies/allergic diseases reported in 18-76% while atopy is reported in 14-46%. In studies including both, they affect 42 and 62% of patients. Rhinitis and asthma are the most frequent allergic diseases. IgE and blood eosinophiles are often elevated and few studies report that basophils and mast cells could participate in the disease pathogenesis; however, the implication of allergy and atopy remain unclear. No common allergen has been identified and IgG4 production seems to be polyclonal. Although a direct causal effect is unlikely, they could potentially shape the clinical phenotype. Allergies/allergic diseases and/or atopy are reported to be more frequent in IgG4-RD patients presenting head, neck, and thoracic involvement, with higher IgE and eosinophils and less frequent in retroperitoneal fibrosis; however, studies regarding allergy and atopy in IgG4-RD are highly heterogenous. The aim of this article is to review what is currently known about the allergy and atopy in the context of Ig4-RD.

Recent advances in IgG4-related kidney disease

Recent advances in the management and understanding of immunoglobulin (Ig)G4-related kidney disease (RKD) have emphasized the importance of urgent treatment in IgG4-related tubulointerstitial nephritis. On the other hand, to avoid long-term glucocorticoid toxicity, strategies for early withdrawal of steroids or combination of immunosuppressants, such as rituximab, and the minimum dose of steroids have been pursued. However, disease recurrence after reducing or stopping steroid therapy hampers early withdrawal of glucocorticoid maintenance therapy. In addition, knowledge has accumulated in diagnostic approaches including differential diagnosis of anti-neutrophil cytoplasmic antibodies-associated vasculitis, idiopathic multicentric Castleman's disease, and Rosai-Dorfman disease with kidney lesion, which leads to earlier and precise diagnosis of IgG4-RKD. This review summarizes recent progress in the differential diagnosis of IgG4-RKD and related treatment strategies and recent topics of hypocomplementaemia, membranous glomerulonephritis, and IgG4-related pyelitis and periureteral lesion.

Immunoglobulin G4-Related Disease, Lymphadenopathy, and Lymphoma

Lymphadenopathy occurring in patients with immunoglobulin G4 (IgG4)-related disease, termed IgG4-related lymphadenopathy, shows morphologic heterogeneity and overlap with other nonspecific causes of lymphadenopathy including infections, immune-related disorders, and neoplasms. This review describes the characteristic histopathologic features and diagnostic approach to IgG4-related disease and IgG4-related lymphadenopathy, with comparison to nonspecific causes of increased IgG4-positive plasma cells in lymph nodes, and with emphasis on distinction from IgG4-expressing lymphoproliferative disorders.

Effects of Fibulin-5 Gene Silencing on Proliferation and Apoptosis of IgG4-ROD Lacrimal Gland Fibroblasts

Objective

This study is aimed at discussing the value of RNA interference technology on inhibiting lacrimal gland fibrosis in IgG4-related ocular disease (IgG4-ROD).

Methods

Six patients with IgG4-ROD who came to the hospital for surgical treatment from October 2018 to August 2019 were selected, and their diseased lacrimal glands were taken for primary cell culture and fibroblast identification. High efficiency and specificity small interference RNA (siRNA) plasmid vector was constructed, its inhibitory effect on fibroblast proliferation was determined by CCK-8 assay, and the appropriate concentration was selected as the siRNA concentration for subsequent experiments. RT-PCR and Western blot detected the relative expression levels of Fibulin-5 mRNA and protein in the cells 48 hours after transfection. The apoptosis rate of each group of cells at 24 hours, 48 hours, and 72 hours after transfection was detected by flow cytometry, and the proliferation and apoptosis of cells after silencing Fibulin-5 were analyzed and compared.

Results

24 hours after transfection, there was no significant difference in the proliferation rate among the four groups (P > 0.05); 48 hours and 72 hours after Fibulin-5 siRNA transfection, the proliferation activity of the transfected cells was significantly decreased compared with the 0 nM group, and the inhibitory effect of 75 nM siRNA was the strongest. The expression of Fibulin-5 mRNA and protein in the siRNA-transfected cells was significantly decreased compared with the blank and empty vector negative siRNA groups, and the difference was statistically significant (P < 0.05). The apoptosis rate of cells in the Fibulin-5 siRNA transfection group was significantly higher than that of cells in the blank and empty vector negative siRNA groups, and the difference was statistically significant (P < 0.05).

Conclusion

Fibulin-5 siRNA recombinant plasmid can significantly downregulate the mRNA and protein expressions of target gene Fibulin-5 and promote apoptosis after transfection into IgG4-ROD lacrimal gland fibroblasts. It is speculated that Fibulin-5 can be used as a target to effectively inhibit the fibrosis of lacrimal gland tissues by RNAi technique.

Utility of navigation system-guided submandibular gland core needle biopsy in the diagnosis of immunoglobulin G4-related sialadenitis

Pathological diagnosis is important for the definite diagnosis of immunoglobulin G4-related sialadenitis (IgG4-RS). Core needle biopsy (CNB) is a scarless technique; however the pathological heterogeneity of IgG4-RS (a particular feature of this disease) could be the potential cause of the inferior diagnostic capability of submandibular gland CNB (SMG-CNB) for IgG4-RS. The aim of this study was to explore technical improvements in SMG-CNB and improve its diagnostic power in IgG4-RS diagnosis. Eighteen patients clinically suspected for IgG4-RS were enrolled and underwent both SMG-CNB and SMG surgical biopsy. A navigation system (Brainlab) was employed during SMG-CNB to obtain representative samples and avoid blood vessel injury. Histopathological and immunopathological findings for the SMG-CNB samples were in good concordance with SMG surgical biopsy. There was no statistically significant difference between SMG-CNB and SMG surgical biopsy in IgG-positive cell count (132.4 ± 59.3 vs 132.2 ± 47.5, P = 0.99), IgG4-positive cell count (102.2 ± 39.7 vs 97.2 ± 27.6, P = 0.67), or IgG4-positive/IgG-positive cell count ratio (78.6% ± 0.1% vs 75.2% ± 0.1%, P = 0.29). A moderate or strong significant correlation was found between SMG-CNB and SMG surgical biopsy for these cell counts and ratio (all P < 0.01). The diagnostic consistency of SMG-CNB and SMG surgical biopsy was 100%. The Brainlab navigation system may assist in collecting representative SMG-CNB samples from typical pathological lesions. Tissues obtained from SMG-CNB are sufficient for the pathological diagnosis of IgG4-RS. Standardized SMG-CNB is expected to replace SMG surgical biopsy for IgG4-RS diagnosis.

Clinical Characteristics and Classification Criteria Performance in a Single-Center Cohort of 114 Patients With Immunoglobulin G4-Related Disease

INTRODUCTION/OBJECTIVES

Immunoglobulin G4-related disease (IgG4-RD) is a heterogeneous fibroinflammatory condition. The 2019 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) Classification Criteria for IgG4-RD were published to provide unified classification criteria in clinical research. The purpose of this study was to characterize demographics, disease manifestations, and treatments of patients with IgG4-RD and assess performance of the Classification Criteria in a heterogeneous cohort with a large population of Black patients.

METHODS

This was a medical records review of all patients referred to a specialized IgG4-RD clinic. Demographics, serology, histopathology, disease manifestations, and treatment information were collected and analyzed. An ACR/EULAR Classification Criteria score for IgG4-RD was calculated to compare performance in definite diagnosis, probable diagnosis, and mimicker groups.

RESULTS

A total of 198 patients were evaluated. Eighty-five (43%) were mimickers. Of the remaining 114, 58 (51%) were classified as definite, and 56 (49%) as probable cases by treating clinicians. Pancreatitis was the most common presentation (37%) among 28 different organ manifestations of IgG4-RD. In patients with definite clinical diagnosis of IgG4-RD, 84% met the IgG4-RD Classification Criteria (i.e., score ≥20) with mean score of 29. Only 9% of the probable cases met this threshold with an average score of 8. None of the mimickers met the Classification Criteria.

CONCLUSIONS

This study highlights the broad spectrum of IgG4-RD and validates the use of the ACR/EULAR Classification Criteria for IgG4-RD, including a large proportion of Black patients. As shown in this study, IgG4-RD is a heterogeneous disease and continues to represent a diagnostic challenge to clinicians.

Malignancies in Immunoglobulin G4-related ophthalmic disease

PURPOSE

Clinical phenotypes in Immunoglobulin G4-related disease (IgG4-RD) according to the patterns of affecting organs have different risks of malignancies. We attempt to determine the association of malignancies with IgG4-related ophthalmic disease (IgG4-ROD).

DESIGN

Retrospective cohort study.

METHODS

Review of medical records, orbital images and histopathology reports in a territory-wide cohort of biopsy proven IgG4-ROD patients from 2005-2019.

FINDINGS

Among 122 patients who had biopsies taken from adnexal lesions including lacrimal glands (n = 108), orbital mass (n = 30), infiltrated orbital fat (n = 10), conjunctiva (n = 2) or extraocular muscles (n = 3), 13% (16/122) developed malignancies over 73 ± 48months' follow-up. There were 9 cases of ocular adnexal lymphoma (OAL) and 7 extra-orbital malignancies. Compared with the general population, the incidence of OAL was significantly higher (standardized incidence ratios, SIRs = 10.0, 95%CI = 4.5-17.6) while that of extra-orbital malignancies was similar. The SIRs was highest within the first year (SIR = 46.7, 95%CI = 18.5-87.6) when 7 OAL were concomitantly diagnosed. Patients who developed OAL or extra-orbital malignancies were older than other patients at IgG4-ROD diagnosis (64.9 ± 7.1, 68.3 ± 8.5 versus 55.2 ± 15.0 years, P < 0.05). Asymmetric lacrimal gland enlargement (78% versus 13%), lack of frontal (0% versus 12%) or infraorbital nerve enlargement (0% versus 36%) were associated with OAL (all P < 0.05). Pre-treatment serum IgG4 level or extra-orbital IgG4-RD involvement was similar among patients with or without malignancies.

CONCLUSION

In this biopsy-proven IgG4-ROD cohort, 7% developed OAL which was 10 times higher than the general population. Patients with asymmetric lacrimal gland enlargement or without trigeminal nerves involvement radiologically were associated with OAL.

Multidisciplinary diagnosis and management of inflammatory aortic aneurysms

BACKGROUND

Inflammatory abdominal aortic aneurysms (IAAAs) are a variant involving a distinct immunoinflammatory process, with nearly one half believed to be associated with IgG4-related disease (IgG4-RD).

METHODS

MEDLINE and Google Scholar searches were conducted for English-language publications relevant to inflammatory aortic aneurysms from January 1970 onward. The search terms included inflammatory aortic aneurysms, aortitis, periaortitis, IgG4-related disease, and retroperitoneal fibrosis. Relevant studies were selected for review based on their relevance.

RESULTS

Morphologically, IAAAs are characterized by a thickened aneurysm wall often displaying contrast enhancement and elevated metabolic activity on fluorine-18 fluorodeoxyglucose-positron emission tomography imaging. A strong association exists with perianeurysmal and retroperitoneal fibrosis. Although the rupture risk appears lower with IAAAs than with noninflammatory abdominal aortic aneurysms (AAAs), the currently recommended diameter threshold for operative management is the same. Open repair has been associated with increased morbidity compared with noninflammatory AAAs, and a retroperitoneal approach or minimal dissection transperitoneal approach has been recommended to avoid duodenal and retroperitoneal structural injuries. Endovascular aneurysm repair has been increasingly used, especially for patients unfit for open surgery. It is important to exclude an infectious etiology before the initiation of immunosuppressive therapy or operative repair. Multimodality imaging follow-up is critical to monitor disease activity and secondary involvement of retroperitoneal structures by the associated fibrotic process. Maintenance of immunosuppressive therapy will be needed postoperatively for most patients with active systemic disease, especially those with IgG4-RD and those with persistent symptoms. Additional interventions aimed at ureteral decompression could also be required, and lifelong follow-up is mandatory.

CONCLUSIONS

Preoperative multimodality imaging is a diagnostic cornerstone for assessment of the disease extent and activity. IgG4-RD is an increasingly recognized category of IAAAs, with implications for tailoring adjunctive medical therapy. Open surgical repair remains the procedure of choice, although endovascular aneurysm repair is increasingly being offered. Maintenance immunosuppressive therapy can be offered according to the disease activity as assessed by follow-up imaging studies.

Serum ANCA as Disease Biomarkers: Clinical Implications Beyond Vasculitis

Usually associated with autoimmune diseases, anti-neutrophil cytoplasmic antibodies are also detected in other conditions, such as infections, malignancies, and after intake of certain drugs. Even if the mechanisms of production and their pathogenic role have not been fully elucidated yet, ANCA are widely recognized as a clinically alarming finding due to their association with various disorders. While ANCA target several autoantigens, proteinase-3, and myeloperoxidase are the ones proved to be most frequently related to chronic inflammation and tissue damage in murine models. Albeit these autoantibodies could be present as an isolated observation without any implications, ANCA are frequently used in clinical practice to guide the diagnosis in a suspect of small vessel vasculitis. Conditions that should prompt the clinician to test ANCA status range from various forms of lung disease to renal or peripheral nervous system impairment. ANCA positivity in the presence of an autoimmune disease, especially rheumatoid arthritis, or connective tissue diseases, is frequently correlated with more clinical complications and treatment inefficacy, even in the absence of signs of vasculitis. For this reason, it has been postulated that ANCA could represent the final expression of an immune dysregulation rather than a pathogenic event responsible for organs damage. Recently, it has also been proposed that ANCA specificity (PR3 or MPO) could possibly define ANCA-associated vasculitides better than clinical phenotype. This review aims at summarizing the latest advancements in the field of ANCA study and clinical interpretation.

Idiopathic retroperitoneal fibrosis with endometrial cancer: a case report and literature review

Background

Retroperitoneal fibrosis is a rare disease characterized by chronic nonspecific inflammation, which leads to clinical compression manifestations of retroperitoneal organs especially ureter. Approximately 70 percent of retroperitoneal fibrosis cases are idiopathic which has no clear etiology. This study reported a rare case of a 48-year-old woman presented with idiopathic retroperitoneal fibrosis and endometrial cancer.

Case presentation

A 48-year-old woman presented with irregular vaginal bleeding without abdominal pain, bloating or discomfort. The patient was diagnosed iRPF after splenectomy 13 years ago. Then she took prednisone for 2 years and took tamoxifen for about 11 years. She stopped taking the medication from October 2019 to May 2020 and then started taking tamoxifen again until November 2020. Two weeks after she stopped taking tamoxifen, she presented with irregular vaginal bleeding. Gynecological ultrasound revealed a thick endometrium with uneven echo enhancement and blood flow signals. Then diagnostic curettage was performed with pathological examination showed endometroid carcinoma. Later, the patient was admitted to Peking University Third Hospital for surgery. Preoperative imaging examinations, including CT, MRI, and PET/CT, all showed pelvic enlarged lymph nodes and they were highly suspected to have lymph node metastasis. The patient underwent laparoscopic surgical staging and enlarged lymph nodes in the pelvic and aortic regions were removed. Finally, the pathology confirmed that endometrioid adenocarcinoma and fibrosis, but there was no tumor infiltration in these enlarged lymph nodes. The patient is now in good condition.

Conclusion

This case report stressed the difficulty to distinguish between lymph node metastasis and inflammatory hyperplasia by common imaging methods. Due to increased surgical difficulty among retroperitoneal patients, lymphadenectomy should be carefully evaluated to avoid additional surgical complications and over-treatment.

IgG4 ‐related disease associated with the primary manifestation of recurrent cerebral venous thrombosis: A rare case report

Nervous system involvement in IgG4‐related systemic disease (IgG4‐RD) is rarely reported and manifests as hypertrophic pachymeningitis and hypophysitis. In this report, a 33‐year‐old woman with neurological manifestations was diagnosed with IgG4‐RD by biopsy. The patient showed improvement in symptoms after treatment.

Human epididymis protein 4 (HE4) is a novel biomarker for fibrosis in IgG4-related disease and can predict poor prognosis

Objectives

IgG4-related disease (IgG4-RD) is an immune-mediated fibroinflammatory disorder with heterogeneous manifestations. This study aimed to investigate the utility of human epididymis protein 4 (HE4) as a potential clinical biomarker of fibrosis in IgG4-RD.

Methods

Plasma HE4 levels were estimated in 136 patients with IgG4-RD and 73 healthy individuals (controls) by electrochemical luminescence. HE4 expression levels and the degree of fibrosis in pancreatic tissues from 15 patients with IgG4-RD and 10 controls were compared using immunohistochemistry and Masson trichrome staining. Correlation between HE4 levels and laboratory parameters was determined, and the efficacy of HE4 as a biomarker of fibrosis and prognosis in IgG4-RD was also evaluated.

Results

Plasma HE4 levels were significantly higher in patients with IgG4-RD compared with controls. Optimal HE4 cut-off value for identifying patients with IgG4-RD was determined to be 50.8 pmol/L with an AUC (area under curve) of 0.791. HE4 levels were positively correlated with diverse laboratory parameters, and indicators of organ function impairment. Additionally, HE4 was highly expressed in the affected organs in patients with IgG4-RD and its plasma levels were closely correlated with degree of fibrosis, indicating the utility of HE4 in assessing internal organ damage and fibrosis. Further analysis showed that patients in the HE4 high expression group had poor prognosis.

Conclusions

Our results demonstrate that HE4 can be used as a biomarker for IgG4-RD as it is correlated with diverse baseline clinical features, internal organ damage and degree of fibrosis in affected organs, and can predict poor prognosis.

Clinical characteristics and therapeutic response of immunoglobulin G4-related disease: a retrospective study of 127 Chinese patients

Background and aims

Immunoglobulin G4-related disease (IgG4-RD) is a multisystem fibroinflammatory condition. The aim of the present study was to characterize the clinical features and therapeutic response of patients with IgG4-RD and identify risk factors for disease relapse.

Methods

We collected baseline data of eligible patients with IgG4-RD and analyzed clinical features by interview and review of medical records. The patients who received glucocorticoids (GC) therapy with at least 3 months follow-up were used to characterize the therapeutic response and identify risk factors for relapse.

Result

Totally 127 IgG4-RD patients, including 92 males and 35 females, were enrolled in the present study. The median age of onset was 63.0 years, ranging from 23 to 86. The pancreas, bile duct and lymph nodes were the most frequently involved organs. The serum IgG4 level was elevated in 94.5% of the patients and was correlated with the number of organs involved. Patients classified as head and neck limited group were more likely to be female. Compared to Mikulicz syndrome and systemic involvement group, pancreato-hepatobiliary group had higher aminotransferase, alkaline phosphatase, gamma-glutamyl transpeptidase, bilirubin and lower IgG4 level. Mikulicz syndrome and systemic involvement group had the highest IgG4-RD RI score, IgG level. Among 92 patients who received medical therapy with at least 3 months follow-up, 76 received GC alone or in combination with immunomodulator (IM) and 16 patients did not take GC. 74 out of the 76 patients (97.3%) achieved remission, with 59 of them remained in remission and 15 of them relapsed. Whereas 16 patients did not take GC, among them, 6 patients achieved remission with one relapsed. On multivariate analysis, higher initial score of ACR/EULAR IgG4-RD Classification Criteria and GC withdrawal were independent predictors for relapse.

Conclusion

Four phenotypes of IgG4-RD showed different demographic and serological features. GC + IM therapy was safe and effective and might protect patients from relapse. The independent risk factors of relapse were GC withdrawal and higher score of ACR/EULAR IgG4-RD Classification Criteria.

Tissue IgG2/IgG4 Ratio as an Additional Tool to Distinguish IgG4-Related Disease From Other Fibroinflammatory Disorders

Interpretation of biopsies taken on suspicion of immunoglobulin (Ig)G4-related disease (IgG4-RD) may be hampered by uninterpretable immunohistochemical stains for IgG because of strong background signals. This study aims to determine the significance of tissue IgG2 positive plasma cell counts in IgG4-RD in comparison with non-IgG4-related inflammatory disorders. Descriptive, retrospective case-control study of 16 patients with IgG4-related orbital disease (IgG4-ROD) and 24 with extraorbital IgG4-RD. Histopathology and serology of this group was compared with 16 patients with orbital non-IgG4-related disorders and 22 patients with extraorbital non-IgG4-related disorders. The mean tissue IgG2/IgG4 ratio was 0.16 in IgG4-ROD and 0.27 in extraorbital IgG4-RD and far below 1 in 98% of patients. This was significantly lower compared with the non-IgG4-related disorders that showed a mean tissue IgG2/IgG4 ratio of 1.98 in the orbital and 2.20 in the extraorbital group (range: 0.20 to 10, P <0.05). In 74% of tissue samples an IgG2/IgG4 ratio >1 was seen. The tissue IgG2/IgG ratio was significantly lower in IgG4-RD compared with non-IgG4-related inflammatory disorders. Serum IgG2 concentration was not abnormal in patients with IgG4-RD. A significantly lower tissue IgG2/IgG4 and IgG2/IgG ratio was observed in IgG4-RD, compared with non-IgG4-related inflammatory disorders. Additional immunohistochemical staining for IgG2 positive plasma cells can be helpful in the diagnosis of IgG4-RD. Especially in cases with uninterpretable IgG staining, a well-recognized problem that may give rise to a failed interpretation of the biopsy.

The role of imaging in immunoglobulin G4-related disease of the upper urinary tract

Background

Immunoglobulin G4-related disease remains a modern, relatively unknown field in the urological world. An increasing number of cases require urological input, often with invasive diagnostics and aggressive medical treatment first-line. Given this, we sought to evaluate modern radiological options of disease affecting the upper urinary tract, to provide clarity and reduce diagnostic burden and delay in this poorly understood yet potentially debilitating disease process.

Summary

We conducted a systematic literature search including PubMed and Medline, focusing on immunoglobulin G4-related disease affecting the upper urinary tract, before reviewing articles assessing different radiological modalities in diagnosis. Consistent computed tomography findings have been demonstrated in the literature and contributed to recent breakthroughs in classification criteria, however invasive biopsy remains a mainstay in work-up, given the difficulties in comparing against malignancy. Early work in positron-emission tomography and magnetic resonance imaging has shown promise in radiologically distinguishing from other differentials, especially diffusion-weighted imaging showing high sensitivity levels, but not yet enough to formulate protocols and cause histological investigation to be redundant.

Key messages

Our article has highlighted repeated findings in the literature of computed tomography appearances of IgG4-RD in the upper urinary tract, however invasive work-up remains a mainstay given the overlap with malignancy. Prospective, comparative studies into magnetic resonance imaging and positron-emission tomography are now required, given their early results, to improve consistency in reporting and reduce patient burden when investigating this benign, yet debilitating disease process.

Clinical and pathological predictors of relapse in IgG4-related disease

Objectives

In IgG4-related disease, the relationship between pathological findings and relapse has not been well established. This study aimed to identify the clinical and pathological predictors of disease relapse in IgG4-RD.

Methods

Patients with newly diagnosed IgG4-RD (n = 71) were enrolled between January 2011 and April 2020; all cases were pathologically confirmed. The clinical and pathological features were recorded in a database at baseline and each follow-up visit. Patients were followed up at least once a month via outpatient clinic examinations and telephone calls. Univariate and multivariate Cox regression analyses and receiver operating curve (ROC) analysis were used to identify the predictors of disease relapse and to assess their predictive value.

Results

Over a median follow-up of 26 (range, 6–123) months, 3/71 (4.2%) patients died. Of the remaining 68 patients, 47 (69.1%) patients had achieved clinical remission and 21 (30.9%) had suffered relapse at the last follow-up. The independent predictors of relapse were IgG4 ≥ 6.5 g/L (HR = 2.84, 95% CI: 1.11–7.23), IgG ≥ 20.8 g/L (HR = 4.11, 95% CI: 1.53–11.06), IgG4-RD responder index (RI) ≥ 9 (HR = 3.82, 95% CI: 1.28–11.37), and severe IgG4⁺ plasma cell infiltration (HR = 6.32, 95% CI: 1.79–22.41). A prognostic score developed using three of the identified predictors (IgG ≥ 20.8 g/L, IgG4-RD RI ≥ 9, and severe IgG4⁺ plasma cell infiltration) showed good value for predicting impending relapse (AUC, 0.806).

Conclusions

In patients with IgG4-RD, IgG4 ≥ 6.5 g/L, IgG ≥ 20.8 g/L, IgG4-RD responder index (RI) ≥ 9, and severe IgG4⁺ plasma cell infiltration are predictors of relapse.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-022-02792-z.

IgG4 ‐associated fibrosing mediastinitis requiring differentiation from posterior mediastinal tumour: A case report

A 71‐year‐old man, who was found to have a posterior mediastinal tumour, was referred to our hospital. Contrast‐enhanced computed tomography (CT) showed a 15‐cm soft tissue shadow in the posterior mediastinum, with many affected areas and a gradually increasing pattern. We also detected oligemic areas with poor contrast‐filling. There was no invasion into the adjacent vertebral body and the blood vessels penetrating the interior were intact. Positron emission tomography–CT revealed a high maximum standardized uptake level of 4.53 in the mediastinal masses. We performed thoracoscopic surgery for the biopsy. Histological findings showed lymphoplasmacytic infiltration in the fibrous stroma as well as storiform fibrosis. Immunohistochemical examination revealed abundant infiltration of immunoglobulin G4 (IgG4)‐positive plasma cells and 40% IgG4/IgG‐positive plasma cells. Postoperative serum examinations showed a high serum IgG4 level (570 mg/dl). Accordingly, we diagnosed the patient with IgG4‐related fibrosing mediastinitis, a rare manifestation of IgG4‐related disease.

Clinical Characteristics and CD4+ T Cell Subsets in IgG4-Related Disease

Objectives

To characterize the clinical features of IgG4-related disease (IgG4-RD) and analyze the peripheral T lymphocyte subsets and cytokine levels.

Methods

A total of 52 patients with newly diagnosed IgG4-RD were enrolled in the retrospective study. Baseline clinical characteristics and examinational findings were systematically reviewed.

Results

IgG4-RD patients had a male predominance, with an average age of 57.4 ± 10.3 years (range 27-81). The mean number of involved organs was 2.7 (range 1-8). Submandibular gland (57.7%) and lacrimal gland/orbit (40.4%) were the most commonly involved organs. Serum IgG4 increased in 97.9% of the patients, the median level was 1300 (585.25, 1975) mg/dl. Decreased C3 and C4 accounted for 77.8% and 55.6% of this patient cohort, respectively. Receiver operating characteristic (ROC) test indicated the possibility of lung/pleura involvement when C3 was less than 0.570 g/l (AUC = 0.788, P = 0.014), and kidney involvement when C3 was less than 0.545 g/l (AUC = 0.796, P = 0.014). Compared with healthy controls (HC), the absolute Th1 counts were higher in IgG4-RD patients (157.58 cells/μl vs. 130.54 cells/μl, P = 0.038), while the absolute counts of Th2, Th17 and T regulatory (Treg) cells, as well as Th17/Treg ratio were not statistically different. The levels of serum IL-4, IL-6, IL-10, IL-17, TNF-α, and IFN-γ were higher in patients with IgG4-RD as compared with HC (P < 0.001). Serum IL-10 was positively correlated with IL-4, TNF-α and IFN-γ, but uncorrelated with Treg cells. Serum IgG4 level was positively associated with the number of affected organs, eosinophil counts, and ESR, whereas inversely associated with C3, C4, IgM, and IgA.

Conclusion

Submandibular and lacrimal glands are the most commonly involved organs in IgG4-RD. Serum C3 level could be a predictor of lung/pleura and kidney involvement in the disease process. Elevated Th1 cells are probably related to chronic inflammation and fibrosis. Treg cells are unlikely to play an important role in the pathogenesis of IgG4-RD.

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.

Typing of inflammatory lesions of the pituitary

Inflammatory pituitary lesions account for 1.8% of all specimens from the German Pituitary Tumor Registry. They occure in 0.5% of the autoptical specimens and in 2.2% of the surgical cases. Women are significantly more often affected than men and are often younger when first diagnosed. In general, primary and secondary inflammation can be distinguished, with secondary types occurring more frequently (75.1%) than idiopathic inflammatory lesions (15.4%). In primary inflammation, the lymphocytic type is more common (88.5%) than the granulomatous type of hypophysitis (11.5%). The most common causes of secondary inflammation are Rathke's cleft cysts (48.6%), followed by tumors (17.4%) such as the craniopharyngioma (9.1%), adenoma (5.5%) or germinoma (2.0%). More causes are tumor-like lesions (7.1%) such as xanthogranuloma (3.5%) or Langerhans histiocytosis (3.5%), abscesses (5.5%), generalized infections (5.1%), spreaded inflammations (4.7%) and previous surgeries (4.0%). In 1.6% of all specimens the reason for the inflammation remains unclear. The described classification of hypophysitis is important for specific treatment planning after surgery.

Hypophysitis, the Growing Spectrum of a Rare Pituitary Disease

Hypophysitis is defined as inflammation of the pituitary gland that is primary or secondary to a local or systemic process. Differential diagnosis is broad (including primary tumors, metastases, and lympho-proliferative diseases) and multifaceted. Patients with hypophysitis typically present with headaches, some degree of anterior and/or posterior pituitary dysfunction, and enlargement of pituitary gland and/or stalk, as determined by imaging. Most hypophysitis causes are autoimmune, but other etiologies include inflammation secondary to sellar tumors or cysts, systemic diseases, and infection or drug-induced causes. Novel pathologies such as immunoglobulin G4-related hypophysitis, immunotherapy-induced hypophysitis, and paraneoplastic pituitary-directed autoimmunity are also included in a growing spectrum of this rare pituitary disease. Typical magnetic resonance imaging reveals stalk thickening and homogenous enlargement of the pituitary gland; however, imaging is not always specific. Diagnosis can be challenging, and ultimately, only a pituitary biopsy can confirm hypophysitis type and rule out other etiologies. A presumptive diagnosis can be made often without biopsy. Detailed history and clinical examination are essential, notably for signs of underlying etiology with systemic manifestations. Hormone replacement and, in selected cases, careful observation is advised with imaging follow-up. High-dose glucocorticoids are initiated mainly to help reduce mass effect. A response may be observed in all auto-immune etiologies, as well as in lymphoproliferative diseases, and, as such, should not be used for differential diagnosis. Surgery may be necessary in some cases to relieve mass effect and allow a definite diagnosis. Immunosuppressive therapy and radiation are sometimes also necessary in resistant cases.

A rare case of IgG4-related disease masquerading as periurethral malignancy and review of the literature

Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated fibroinflammatory disease that typically manifests as mass lesions affecting almost any organ including the pancreas, lacrimal and salivary glands, liver, lung and kidney. However, IgG4-RD with urethra involvement is scarce. We describe a rare case of IgG4-RD involving the urethra mimicking urethral carcinoma and review the published literature. A 64-years-old female presented with progressive dysuria for more than 2 months. Pelvic gadolinium-enhanced magnetic resonance imaging revealed a huge mass encasing the urethra which showed obvious enhancement in the arterial phase. And contrast-enhanced ultrasound showed that the entire mass was heterogeneously enhanced and displayed a fast-forward and fast-out pattern, which was highly suggestive of malignant tumor. The diagnosis of IgG4-RD was finally established by ultrasound-guided transvaginal mass needle biopsy. The patient was treated with methylprednisolone and cyclophosphamide and dysuria disappeared in the first week of therapy. She has been followed up in our clinic for 1 year without recurrence. The diagnosis of IgG4-RD should be considered in the differential diagnosis of a periurethral mass. Ultrasound-guided transvaginal mass needle biopsy is a safe and well-established tissue sampling method and should be performed in order to avoid unnecessary surgery.

IgG4-Related Sclerosing Cholangitis: Rarely Diagnosed, but not a Rare Disease

IgG4-related sclerosing cholangitis, a biliary manifestation of an IgG4-related disease, belongs to the spectrum of sclerosing cholangiopathies which result in biliary stenosis. It presents with signs of cholestasis and during differential diagnosis it should be distinguished from cholangiocarcinoma or from other forms of sclerosing cholangitis (primary and secondary sclerosing cholangitis). Despite increasing information and recently established diagnostic criteria, IgG4-related sclerosing cholangitis remains underdiagnosed in routine clinical practice. The diagnosis is based on a combination of the clinical picture, laboratory parameters, histological findings, and a cholangiogram. Increased serum IgG4 levels are nonspecific but are indeed a part of the diagnostic criteria proposed by the Japan Biliary Association and the HISORt criteria for IgG4-SC. High serum IgG4 retains clinical utility depending on the magnitude of elevation. Approximately 90% of patients have concomitant autoimmune pancreatitis, while 10% present with isolated biliary involvement only. About 26% of patients have other organ involvement, such as IgG4-related dacryoadenitis/sialadenitis, IgG4-related retroperitoneal fibrosis, or IgG4-related renal lesions. A full-blown histological finding characterized by IgG4-enriched lymphoplasmacytic infiltrates, obliterative phlebitis, and storiform fibrosis is difficult to capture in practice because of its subepithelial localization. However, the histological yield is increased by immunohistochemistry, with evidence of IgG4-positive plasma cells. Based on a cholangiogram, IgG-4 related sclerosing cholangitis is classified into four subtypes according to the localization of stenoses. The first-line treatment is corticosteroids. The aim of the initial treatment is to induce clinical and laboratory remission and cholangiogram normalization. Even though 30% of patients have a recurrent course, in the literature data, there is no consensus on chronic immunosuppressive maintenance therapy. The disease has a good prognosis when diagnosed early.

An Interesting Case of Immunoglobulin G4-Related Retroperitoneal Fibrosis Treated With Rituximab

Immunoglobulin G4-related disease (IgG4-RD) is a fibroinflammatory condition. Its common manifestations include type I autoimmune pancreatitis and retroperitoneal fibrosis (RPF). We present a rare case involving a 43-year-old female who presented with left lower quadrant (LLQ) pain. Imaging of the abdomen and pelvis revealed left hydroureteronephrosis to the level of an inflammatory process in the left adnexal region, possibly reflecting a tubo-ovarian abscess (TOA). The gynecologic evaluation concluded that the mass was unlikely of gynecologic sources. Transgluteal biopsy of the mass was highly suggestive of IgG4-RD. The patient received prednisone and rituximab (RTX), resulting in complete resolution of the mass, which was confirmed on repeat imaging. This case report provides a valuable addition to the literature to highlight that the diagnosis of IgG4-RD is based on the combination of characteristic clinical, serologic, radiologic, and histopathologic findings. Also, it underlines that the management of the disease is through glucocorticoids (GCs) as the first-line agent for remission induction in all patients with active, untreated IgG4-RD. RTX therapy is an effective treatment for IgG4-RD that is refractory to GCs. Recent studies have suggested that RTX monotherapy can be used to induce and maintain remission in patients with IgG4-RD.

Mass-forming immunoglobulin G4-related disease shows indolent clinical course after surgical resection, clinicopathological analysis of a series of 15 cases

The purpose of this study is to characterize the clinicopathological features of mass-forming immunoglobulin G4-related disease (IgG4-RD). A retrospective search for cases of mass-forming IgG4-RD diagnosed at Singapore General Hospital between 2008 and 2019 was performed. A total of 15 cases of mass-forming IgG4-RD were identified. The male-to-female ratio was 2.5:1, and the median age was 61 years old. The majority of cases showed a solitary lesion (12/15) with a mean size of 35 mm. IgG4-RD was considered as a clinical differential diagnosis only in one case (1/15) prior to the surgical resection. Diagnostic histopathological features, such as dense lymphoplasmacytic infiltrate positive for IgG4 plasma cells (15/15), storiform fibrosis (15/15), and obliterative phlebitis (9/15), were observed in most cases. These findings were distributed heterogeneously within the lesions. Cases with single organ involvement showed a low relapse rate (2/10) and normal serum IgG4 level after surgical resection. Mass-forming IgG4-RD has a male predilection and involves various organ systems. It may be initially misdiagnosed as malignancy and undergo surgical resection. The diagnostic histological features of IgG4-RD are readily identified in different organs. However, they may be distributed heterogeneously within a single lesion. Cases of single organ involvement show an indolent clinical course and normal serum IgG4 level after surgical resection.

Association of retroperitoneal fibrosis with malignancy and its outcomes

INTRODUCTION

Retroperitoneal fibrosis (RPF) is characterized by a highly fibrotic retroperitoneal mass and encompasses the idiopathic form and secondary to malignancies. Because we have limited knowledge whether RPF is associated with malignancy, we aimed to investigate the relationship between RPF and malignancy and to compare the characteristics and prognosis of cancers among patients with RPF.

METHODS

Medical records of 111 patients diagnosed as having RPF were reviewed and 38 cases of cancer, confirmed by biopsy, were identified. Standardized incidence ratios (SIRs) were calculated for cancers and stratified according to cancer type and RPF-cancer diagnosis interval. Cancer characteristics and outcomes were compared between RPF-cancer diagnosis intervals.

RESULTS

The average age at RPF diagnosis was 59.2 ± 15.0 years, and 69.4% of the patients were male. The cancer SIRs in patients with RPF relative to age- and sex-matched individuals in the general population was 2.2 (1.6-3.1). SIRs of renal pelvis cancer and multiple myeloma were significantly higher than in the general population. When stratified by RPF-cancer intervals, the SIR for cancer was 9.9 within 1 year of RPF diagnosis, while no significant increase in the SIR was found after 1 year from RPF diagnosis. Cancer stage was more advanced at the time of diagnosis in patients within a 1-year interval for RPF than those with cancer within a >5-year interval, with a correspondingly increased mortality in the former patients.

CONCLUSIONS

RPF was significantly associated with malignancy, particularly those diagnosed within 1 year of RPF diagnosis. Cancer stages at diagnosis were more advanced and the mortality rate was higher in patients within a 1-year interval between RPF and cancer diagnosis than in those with a >5-year interval between diagnoses.

IgG4-related Disease: a diagnostic challenge

Immunoglobulin IgG4-related disease (IgG4-RD) is an immune-mediated fibroinflammatory condition with a characteristic histopathological appearance that can affect almost any organ. The clinical features result from a focal or diffuse appearance of a tumor-like swelling of the affected organs, identified by physical and/or imaging examination. Herein, we report the case of a 38-year-old male complaining of a worsening chronic right lumbar pain associated with legs and scrotum edema. He also had itchy and erythematous cutaneous lesions on the abdominal wall over the last 8 months, and complained of a diffuse and mild to moderate abdominal discomfort. On examination, the liver was firmly enlarged and tender. His legs had 2+ symmetrical pitting edema extending from his feet to just above the knees. An abdominal computed tomography scan showed a large mass (10 x 8 x 4cm) involving the abdominal infrarenal aorta and the iliac arteries, and compressing the inferior vena cava, with dilated iliac veins, raising the possibility of lymphoproliferative disease. During the initial investigation, the laboratory workup revealed anemia, without other marked changes. A laparoscopic-guided biopsy of the peri-aortic mass was undertaken. The histological report associated with IgG4 immunoglobulin measurement rendered the diagnosis of IgG4-RD. The patient had a favorable outcome after the use of glucocorticoids with the abdominal mass remission.