The 2019 American College of Rheumatology/European League Against Rheumatism Classification Criteria for IgG4‐Related Disease

CT Chest findings in IgG4-related disease

PURPOSE

To investigate the multi-slice spiral Computed Tomography(MSCT) findings of chest involvement in IgG4-related diseases and to improve doctors' understanding of this disease.

MATERIALS AND METHODS

We retrospectively analyzed the clinical and imaging data of 67 patients with clinically confirmed or suspected IgG4-related diseases.

RESULTS

Sixty patients (89.60%) had abnormal chest CT findings. Among them, 47 patients (70.10%) had enlarged mediastinal lymph nodes. Thickening of the tracheal and tracheobronchial perivascular walls was observed in 35 patients (52.20%). Nodules were observed in 29 patients (43.30%). Patches or ground-glass opacities were observed in 15 cases (22.40%); bilateral enlarged axillary lymph nodes, 9 (13.40%); bilateral enlarged hilar lymph nodes, 3 (4.50%); and, interstitial changes, 3 (11.90%). Pleural and pericardial effusion occurred in five cases (7.46%, two bilateral and three unilateral) and three cases (4.50%), respectively. Seven (10.45%) patients showed no obvious abnormalities. The abnormally elevated IgG4 level (>135 mg/dL) was positively correlated with thickening of the tracheal and tracheobronchial walls (r = 0.328, p = 0.007) and enlargement of mediastinal lymph nodes (r = -0.252, p = 0.039), and the logistic regression model 1 showed that the incidence of lung as the first symptom was higher in patients with bilateral enlarged hilar lymph nodes on chest images.

CONCLUSION

Chest CT is of great significance for the diagnosis and follow-up of IgG4-RLD. Chest CT scans should be suggested to be performed when ocular symptoms, bilateral enlarged hilar lymph nodes, pancreatitis, pituitary adenitis, Takayasu arteritis, or abnormally elevated IgG4 levels (>135 mg/dL) are present, and IgG4-RLD should be considered.

Burden of Glucocorticoid Use and Risk of Toxicities Among Patients with Immunoglobulin-G4-Related Disease: A Retrospective US-Based Claims Study

INTRODUCTION

Glucocorticoids are commonly used to treat immunoglobulin G4-related disease (IgG4-RD), but there is limited real-world evidence describing glucocorticoid-related toxicities in this population. This study assessed glucocorticoid use and toxicities during the first year after diagnosis among patients with IgG4-RD.

METHODS

The IQVIA PharMetrics® Plus database was used to identify adults with IgG4-RD using a validated algorithm. Patients were stratified according to glucocorticoid use during the 12-month study period following the first observed IgG4-RD-related diagnosis (index date): low glucocorticoid use (prednisone equivalent daily dose [PEDD] < 5 mg/day) or high glucocorticoid use (PEDD ≥ 5 mg/day). Incident glucocorticoid-related toxicities were assessed during the study period and incidence was compared between groups using Chi-square tests.

RESULTS

Among 295 patients with IgG4-RD, 150 (50.8%) had low glucocorticoid use, and 145 (49.2%) had high glucocorticoid use during the study period. In each glucocorticoid group, mean PEDD was highest in the 3 months post-index and subsequently decreased. At 12 months post-index, 24.7% of the low glucocorticoid use group and 60.7% of the high glucocorticoid use group were receiving glucocorticoids. The high glucocorticoid use group had a significantly higher mean (± standard deviation) number of incident glucocorticoid-related toxicities (1.8 ± 1.7 vs. 1.2 ± 1.3) and more frequently had ≥ 3 glucocorticoid-related toxicities (29.0% vs. 13.3%; both p < 0.01) compared to the low glucocorticoid use group. Specifically, cardiovascular- (29.0% vs. 18.7%), gastrointestinal- (29.7% vs. 16.0%), and infection-related (31.0% vs. 17.3%) toxicities were significantly more common in the high glucocorticoid use group than the low glucocorticoid use group (all p < 0.05).

CONCLUSIONS

In this retrospective, claims-based analysis, high glucocorticoid use was seen in half of patients with IgG4-RD during the first year following diagnosis. Patients with high glucocorticoid use experienced significantly more incident glucocorticoid-related toxicities than those with low use during this first year.

MPO-ANCA-Associated Hypertrophic Pachymeningitis Mimicking IgG4-Related Disease: A Case Report and Literature Review

Hypertrophic pachymeningitis (HP) is a rare and chronic clinical disease characterized by thickening of the dura mater, leading to persistent headache, cranial neuropathy, seizures, and other neurological symptoms. Immune-mediated causes, particularly antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis and IgG4-related disease (IgG4-RD), are among the most common etiologies. We report a case of a 54-year-old female with recurrent headache, blepharoptosis, hearing loss, and markedly elevated inflammatory markers. Blood tests, and serum levels of IgG4 were within normal ranges. Contrast enhanced cranial MRI revealed thickening and enhancement of bilateral cerebral hemispheres and tentorial dural maters. Additional findings included mild left lacrimal gland enlargement, bilateral middle ear mastoiditis, and tympanic tegmen destruction. Abdominal high-resolution computed tomography (CT) showed enlarged retroperitoneal lymph nodes. Histopathology demonstrated dense lymphoplasmacytic and neutrophilic infiltration with 80 IgG4-positive plasma cells per high-power field and an IgG4+/IgG+ cell ratio of 20%. An initial diagnosis of possible IgG4-RD was made. However, the patient's symptoms responded poorly to prednisolone (20 mg/day), and fever ensued. Pseudomonas aeruginosa, nocardia malleis, and leptocyclus virus were found in the cerebrospinal fluid measured by NGS. Subsequent laboratory testing showed positive p-ANCA and anti-myeloperoxidase antibodies (anti-MPO), with a negative anti-nuclear antibodies panel, leading to a revised diagnosis of MPO-ANCA-associated HP. Treatment was escalated to intravenous methylprednisolone (40 mg/day), cyclophosphamide, and anti-infectious agents, leading to improved symptoms and decreased inflammatory markers. However, there was a recurrence during the taper of prednisolone. The addition of rituximab achieved complete remission. MPO-ANCA-associated HP is a rare inflammatory disorder that brings diagnostic challenges and requires comprehensive differential diagnosis. In relapsed or refractory cases, rituximab may be a valuable therapeutical option.

Evaluation of serum IgG4 levels as a screening tool for IgG4-related disease: Data from a retrospective study

BACKGROUND AND OBJECTIVE

IgG4-related disease (IgG4-RD) is a systemic, immune-mediated, fibro-inflammatory condition with an uncertain etiology and pathophysiology that can affect multiple organs, presenting common clinical, radiological, and serological features. Although the disease is associated with IgG4, serum levels are not elevated in all patients and have also been described in other diseases. The aim of this study is to evaluate the clinical utility of elevated serum IgG4 as a screening marker in the suspicion of IgG4-related disease.

MATERIALS AND METHODS

A retrospective single-center study was conducted, analysing serological IgG4 test requests from electronic medical records of patients ordered by various hospital departments from January 2010 to June 2023. Only those with elevated IgG4 levels were included in the analysis. Additionally, demographic data and final diagnoses, including those with IgG4-RD, were collected.

RESULTS

A total of 2288 test requests were reviewed, of which 247 showed elevated IgG4 levels (181 after excluding duplicates). Among the patients with elevated IgG4, only 11 met the criteria for IgG4-RD based on the 2011 Umehara-Okazaki classification and its 2020 update. However, only 6 patients (3.31%) met the more recent 2019 ACR/EULAR classification criteria for IgG4-RD. In the remaining patients with elevated IgG4, the most common diagnoses were respiratory diseases, such as COPD and asthma, followed by systemic autoimmune diseases, primarily SLE, RA, and EGPA. Elevated IgG4 levels were also observed in malignant neoplasms, predominantly lung and hematologic cancers.

CONCLUSIONS

Our study highlights that elevated IgG4 levels are not exclusive to IgG4-RD and can also be observed in various respiratory diseases (e.g., COPD), autoimmune diseases (e.g., SLE and RA), and neoplasms (e.g., lung cancer).

Case Report: IgG4-RD-related ophthalmopathy combined with monoclonal gammopathy of undetermined significance

IgG4-related disease (IgG4-RD), an immune-mediated fibroinflammatory disorder, has few reports in combination with monoclonal gammopathy of undetermined significance (MGUS). Herein, we present a case of a 69-year-old woman with manifestations of left orbital occupation and visual acuity decline. Ancillary tests indicated persistent positivity of IgG4 antibody, and IgG4-RD-related ophthalmopathy was diagnosed based on the criteria. Concurrently, serum protein electrophoresis revealed an M protein level of 12.23 g/L. Immunofixation electrophoresis suggested a positive IgG λ-type M protein, and MGUS was diagnosed in conjunction with bone marrow smear and flow cytometry.

Multiple myeloma presenting with retroperitoneal fibrosis and elevated IgG4

The role of IgG4 in the pathogenesis of IgG4-related disease remains unclear, particularly regarding whether IgG4 actively induces histopathological changes or if its elevation is merely a byproduct of an immune response to specific antigens. We present a case of a 66-year-old man with asymptomatic myeloma and elevated IgG4 who subsequently developed retroperitoneal fibrosis as a manifestation of IgG4-related disease. This condition led to hydronephrosis secondary to ureteral obstruction caused by the retroperitoneal fibrosis. Remarkably, chemotherapy for multiple myeloma led to remission of both multiple myeloma and retroperitoneal fibrosis. While previous reports indicated that patients with IgG4 myeloma did not exhibit clinical evidence of IgG4-related disease, this case is distinctly different, as the patient showed characteristic symptoms of IgG4-related disease. This case provides a valuable new perspective on IgG4-related disease and its link to the development of multiple myeloma.

Clinical characterization of malignant lymphoma mimicking IgG4-related disease

OBJECTIVE

To analyze the clinical characteristics of malignant lymphoma that closely resembles IgG4-related disease (IgG4-RD).

METHODS

This study retrospectively analysis involving 31 patients who were lymphoma mimicking, IgG4-RD and 50 contemporaneous IgG4-RD patients serving as controls. Lymphoma mimicking IgG4-RD was defined as presenting with masses in the typical sites of IgG4-RD, with or without elevated serum IgG4 levels, and ultimately confirmed to be lymphoma. The clinical data, including the extent of lymph node involvement, maximum diameter of lymph nodes, systemic symptoms, and laboratory parameters were assessed. Student's t-test, the Mann-Whitney test, and the chi-squared test were used to compare the two groups.

RESULTS

Fever emerged as a distinctive feature in lymphoma patients. Compared to IgG4-RD, lymphoma patients exhibited a greater extent of lymph node involvement (p < 0.001), larger maximum diameters of lymph nodes (p = 0.007), and higher frequency of enlargement in supraclavicular (41.9% vs 10.0%; p = 0.001), armpit (45.2% vs 16.0%; p = 0.004), retroperitoneal (70.9% vs 10.0%; p < 0.001), and groin lymph nodes (41.9% vs 8.0%; p < 0.001). In contrast, IgG4-RD patients were more likely to show involvement of submandibular gland (58.0% vs 29.0%; p = 0.015) and pancreatic (44.0% vs 9.7%; p = 0.001). Additionally, lymphoma patients presented with higher levels of erythrocyte sedimentation rate (ESR) (p = 0.010), C-reactive protein (CRP) (p < 0.001), and lactate dehydrogenase (LDH) (p = 0.002), along with a higher prevalence of anemia (35.5% vs 4.0%; p < 0.001) and lower albumin levels (p = 0.039), while IgG4-RD patients had higher IgG4/IgG ratio (p < 0.001) and lower complement 3 (C3) (p = 0.009) levels than lymphoma patients.

CONCLUSION

Although patients with malignant lymphoma and IgG4-RD share some overlapping presentations, they differ significantly in some distinct features, including fever, pattern of lymph node and organ involvement distribution, and some laboratory parameters. Key Points • IgG4-related disease (IgG4-RD) is an immune-mediated disorder characterized by elevated serum IgG4 levels, presenting lymphadenopathy and tumor-like sclerosing lesions in extranodal sites. • Lymphoma, a malignancy that originates from lymphocytes, can present with a variety of clinical manifestations, including painless swelling of lymph nodes and enlargement of different organs. • While patients with malignant lymphoma and IgG4-RD share certain overlapping clinical presentations, they exhibit significant differences in distinct features, including fever, patterns of lymph node and organ involvement, and various laboratory parameters.

A clinicopathological study of IgG4-related autoimmune hepatitis and IgG4-hepatopathy

BACKGROUND AND AIM

Although IgG4-related autoimmune hepatitis (IgG4-AIH) and IgG4-hepatopathy have been proposed as hepatic phenotypes of IgG4-related disease (IgG4-RD), their definitions and concepts remain insufficiently established. This study aims to conduct a clinicopathological investigation of cases reported as potential IgG4-AIH or IgG4-hepatopathy.

METHODS

In previous nationwide epidemiological studies conducted in 2015 and 2018, we registered 1096 cases of IgG4-sclerosing cholangitis (IgG4-SC). Among these, 19 cases were identified as potential IgG4-AIH by the attending physicians, and other 20 cases as potential IgG4-hepatopathy with available liver histology were further evaluated using immunohistochemistry to assess the possibility of IgG4-AIH or IgG4-hepatopathy. For this purpose, we provisionally established diagnostic criteria for IgG4-AIH and IgG4-hepatopathy, primarily based on the comprehensive diagnostic criteria for IgG4-RD, which include IgG4 + cell count > 10/HPF and an IgG4 + /IgG ratio > 40%.

RESULTS

Of the 19 cases, 2 were diagnosed as IgG4-AIH, with IgG4 + cell counts/HPF of 25.3 and 18.7, and IgG4 + /IgG ratios of 310.2% and 53.4%, respectively. Neither storiform fibrosis nor obliterative phlebitis was observed in the liver of these cases, and both responded excellently to corticosteroid treatment. In addition, from other 20 cases, we diagnosed 8 cases as IgG4-hepatopathy, with IgG4-SC and autoimmune pancreatitis being present in 7 and 2 cases, respectively.

CONCLUSION

This study identified two cases of IgG4-AIH and eight cases of IgG4-hepatopathy. Further studies are necessary to explore the occurrence of IgG4-AIH using these diagnostic criteria in the AIH cohort. The presence of IgG4-hepatopathy may facilitate the diagnosis of IgG4-SC.

A protocol for targeted B-lymphocyte depletion for the treatment of IgG4-related disease

OBJECTIVES

To determine the clinical outcomes of patients with immunoglobulin 4-related disease (IgG4-RD) treated with a defined B-cell depletion protocol using rituximab.

METHODS

Patients were included if they had (i) an IgG4-RD diagnosis at Imperial College Healthcare NHS Trust between February 2017 and October 2022, and (ii) >9 months of follow-up data available following the first rituximab dose. The rituximab protocol targeted B-cell depletion to <10 cells/microliter for a maintenance period of two years. Electronic records were used to define patient demographics, serological and radiological variables and treatment responses according to the IgG4-RD responder index (RI).

RESULTS

Forty-five patients received induction treatment with rituximab. Two patients had insufficient follow-up data for outcome analysis. All patients responded to rituximab therapy according to the IgG4-RD RI. Most patients (25/43, 58%) were also treated with low-dose glucocorticoids at the time of rituximab induction (median prednisolone dose 5 mg daily) and 4/25 (16%) remained on prednisolone at two years (median prednisolone dose 5 mg daily). Disease flares occurred in 11/43 (26%) patients; 9/11 flares occurred in the presence of B-cell repopulation; 2/11 (18.1%) flares occurred in the absence of B-cell repopulation (>10 cells/uL). All flares re-treated with rituximab (7/7, 100%) responded positively.

CONCLUSION

Rituximab administration targeting B-cell depletion for a two-year period is an effective treatment strategy for IgG4-RD and can limit the cumulative glucocorticoid exposure. Flares are uncommon and typically occur in the setting of B-cell repopulation, with good clinical responses to further rituximab administration.

IgG4-related disease and other fibro-inflammatory conditions

IgG4-related disease (IgG4-RD) is a fibro-inflammatory disorder usually characterized by multi-organ involvement. Its pathogenesis is complex and involves genetic and environmental factors, while immune responses usually mediate organ damage and promote fibrosis, which is a key feature of the disease. IgG4 responses, however, are not exclusive to IgG4-RD and can be encountered in other diseases with phenotypes that partially overlap that of IgG4-RD. Although IgG4-RD has clinical and histological hallmarks, the lack of validated diagnostic criteria often makes the diagnosis challenging, requiring a multi-dimensional approach that integrates clinical, radiological and serological data. The present Review covers recent advances in the understanding of disease drivers and its clinical phenotypes, mainly focusing on the differential diagnosis with potential IgG4-RD mimickers, namely histiocytoses, lymphoproliferative disorders, systemic vasculitides and other immune-mediated conditions. The Review also provides a schematic approach to IgG4-RD treatment, including a brief overview of glucocorticoid-sparing agents and emerging therapies, from B cell-depleting monoclonal antibodies to cytokine-targeting drugs, the majority of which are currently under investigation in randomized clinical trials.

2024 Comprehensive Recommendations of the Qazaq College of Rheumatology for the Diagnosis and Management of Sjögren's Syndrome

BACKGROUND

Sjögren's syndrome (SjS) is a chronic autoimmune disease characterized by exocrine gland dysfunction and systemic involvement. Although international guidelines exist, regional adaptations are necessary to address specific healthcare settings. In 2024, the Qazaq College of Rheumatology (QCR) developed comprehensive national recommendations for the diagnosis and management of SjS in Kazakhstan.

METHODS

A panel of national experts reviewed and synthesized international guidelines (EULAR, ACR, and BSR) alongside local clinical data to create tailored diagnostic and therapeutic algorithms. Special emphasis was placed on the management of severe systemic manifestations and accessibility of therapies within Kazakhstan's healthcare system.

RESULTS

The QCR recommendations propose a structured diagnostic approach combining clinical features, serological markers, and minor salivary gland biopsy. Treatment strategies emphasize non-pharmacological measures, symptomatic therapies, and immunomodulatory agents for systemic disease. Rituximab is prioritized as the first-line biologic for refractory severe extraglandular manifestations. A national registry for SjS is proposed to monitor implementation and outcomes.

CONCLUSION

These guidelines aim to standardize the diagnosis and management of Sjögren's syndrome across Kazakhstan, improve patient outcomes, and support further research initiatives.

IgG4‑related disease with endobronchial nodules: A case report and literature review

The present case report describes the case of a rare presentation of IgG4-related lung disease (IgG4-RLD) with endobronchial nodules and systemic involvement. An 84-year-old male presented with unexplained weight loss and enlarged submandibular lymph nodes. Diagnostic examinations revealed elevated serum IgG4 levels, along with findings of endobronchial nodules during bronchoscopy. Biopsies of endobronchial nodules revealed benign bronchial mucosa with fibrosis and inflammatory infiltration; however, he was not diagnosed with IgG4-RLD. A histological examination of the left salivary gland and submandibular lymph nodes confirmed the diagnosis of IgG4-related disease, revealing storiform fibrosis and abundant IgG4-positive plasma cells. The patient was treated with prednisolone, resulting in a reduction in submandibular swelling and decreased serum IgG4 levels. This case emphasizes the importance of considering IgG4-RLD as a potential diagnosis in patients presenting with endobronchial nodules and systemic disease. Accurate sampling methods, such as surgical lung biopsy or transbronchial cryobiopsies, are crucial for definitive diagnosis. Increased awareness among physicians can lead to timely recognition and appropriate management of this rare condition.

Long-Term Clinical Landscapes of Spinal Hypertrophic Pachymeningitis With Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis

BACKGROUND AND OBJECTIVES

Spinal hypertrophic pachymeningitis (HP) is an extremely rare disorder characterized by the thickening of the spinal dura mater, which harbors distinct repertoires of immune cells due to the unique partitioning of the arachnoid blood-CSF barrier. The objectives were to identify the pathogenesis and therapeutic strategies for spinal HP.

METHODS

This retrospective cohort study analyzed the clinical and pathologic profiles of patients with idiopathic/immune-mediated HP including spinal HP.

RESULTS

Among 61 patients with idiopathic/immune-mediated HP, all 6 Japanese patients with spinal HP, with a median observation period of 88.8 months, were myeloperoxidase (MPO)-anti-neutrophil cytoplasmic antibody (ANCA)-seropositive. The MPO-ANCA+ spinal HP cohort had the following characteristics: (1) a predominance of older women; (2) all patients were classified as having microscopic polyangiitis based on the 2022 American College of Rheumatology/European League Against Rheumatism criteria; (3) 83% of patients developed subacute/chronic myelopathy due to extramedullary spinal cord compression; (4) 50% of patients had lesion extension to the epidural compartment and vertebral column; (5) 50% of patients presented with chronic sinusitis, otitis media, or mastoiditis; (6) 33% of patients had involvement of the lower airways or kidneys; (7) a higher disease activity of the nervous system was noted based on the Birmingham Vasculitis Activity Score (BVAS), in contrast to MPO-ANCA+ cranial HP; (8) granulomatous inflammation with myofibroblasts, immune cells including granulocytes, and B-cell follicle-like structures were observed in the thickened dura mater; (9) immunotherapies (with or without surgical decompression) were effective in reducing the modified Rankin Scale score and reduced BVAS during the first active insults; (10) combined immunotherapies with glucocorticoids and cyclophosphamide/rituximab helped in reducing relapses in the long term; and (11) surgical decompression, including laminectomy and duraplasty, was necessary for compressive myelopathy. These data suggest that MPO-ANCA+ spinal HP shares common features with MPO-ANCA+ cranial HP (1, 2, 6, 8, 9, and 10), but also has unique clinical features (3, 4, 5, 7, and 11).

DISCUSSION

Our findings highlight the significant pathogenic role of ANCA in spinal HP. MPO-ANCA+ spinal HP, as an organ-threatening disease, should be positioned as having unique characteristics, whether limited to the CNS or as part of a generalized form in ANCA-associated vasculitis.

Sinonasal Presentations of Immunoglobulin G4-Related Disease: A Scoping Review

OBJECTIVE

Immunoglobulin G4 related disease (IgG4RD) is a recently identified systematic immune disease that may manifest in various organ systems. The latest classification criteria from 2019 combine data from 11 "typical" organ systems for diagnosis, notably excluding the sinonasal region. As sinonasal involvement is not included in this criteria, we performed a scoping review to better clarify sinonasal presentations of IgG4RD.

DATA SOURCES

We conducted a literature search in three bibliographic resources: Pubmed, Scopus, and Web of science.

REVIEW METHODS

All the databases' results were reviewed by two authors utilizing Endnote and Rayyan platforms. Articles were included if they presented a case (or cases) with sinonasal IgG4RD. Critical appraisal of all included articles was performed according to JBI guidelines.

RESULTS

Eighty articles containing 145 patients with sinonasal manifestations of IgG4RD were included. Ages ranged from 13 to 83 years (mean 54.57 ± 15.85 years). The most common clinical symptoms were nasal (63.4%) and visual/orbital (37.9%) complaints. The most frequent sites of involvement were maxillary sinus (N = 75), ethmoid sinus (N = 65) and nasal cavity (N = 59). Seventy-three percent of patients had involvement of at least one other organ system outside the sinonasal region.

CONCLUSION

Sinonasal manifestations have been described despite not being considered a typical organ system eligible for the recent classification criteria of IgG4RD; however, simultaneous involvement of other organ systems outside the sinonasal region is common. Familiarity with common presentations of IgG4RD and related diagnostic elements is critical to the diagnosis and management of all involved sites.

LEVEL OF EVIDENCE

N/A.

Management of IgG4-related cholangitis: diagnosis, therapy, and long-term surveillance

IgG4-related cholangitis (IRC) is a chronic cholestatic liver disease that often occurs concomitantly with autoimmune pancreatitis type 1. Both conditions are manifestations of IgG4-related disease, a systemic autoimmune-mediated fibroinflammatory disorder. Patients often present with jaundice and weight loss, mimicking hepatobiliary malignancies, such as cholangiocarcinoma, primary sclerosing cholangitis, and pancreatic cancer. Accurate diagnosis is challenging due to the absence of pathognomonic findings but can be achieved using the HISORt criteria (histology, imaging, serology, other organ involvement, and response to immunosuppressive therapy). Early diagnosis is critical to avoid unnecessary surgery and prevent progression to liver fibrosis or cirrhosis. IRC responds well to corticosteroid therapy, though relapses are common, necessitating long-term immunosuppressive treatment in many cases. Steroid-sparing agents for remission induction and maintenance therapy comprise immunomodulators, such as azathioprine, as well as B-cell depletion therapies, such as rituximab. This review provides a structured clinical overview of the diagnosis, differential diagnosis, and therapy, including novel therapeutic options, such as inebilizumab, for this rare yet severe condition. A key focus is on long-term surveillance strategies, which include laboratory tests, imaging (contrast-enhanced magnetic resonance imaging/magnetic resonance cholangiopancreatography, ultrasound, endosonography), and, particularly in patients with fibrotic bile duct strictures, endoscopy (endoscopic retrograde cholangiopancreatography, cholangioscopy).

B cell depletion after treatment with rituximab predicts relapse of IgG4-related disease

OBJECTIVES

B cell depletion therapy with rituximab is effective in most patients with IgG4-related disease (IgG4-RD) but requires repeated cycles to prevent disease flares. We here aimed to assess B cells after rituximab to predict relapse of IgG4-RD and guide retreatment.

METHODS

Patients with active IgG4-RD included in this retrospective study fulfilled the ACR/EULAR Classification Criteria. Total CD19+ B cells, plasmablasts, naïve and memory B cells were measured on peripheral blood by flow-cytometry at baseline and 6 months after rituximab. All patients were treated with two 1 g infusions of rituximab 15 days apart and monitored for 48 months. Disease response was assessed using the IgG4-RD Responder Index.

RESULTS

Thirty-three patients were included. Six months after rituximab, disease response was observed in all patients. Complete depletion of CD19+ B cells, plasmablasts, naïve and memory B cell depletion was achieved in 30%, 55%, 39% and 42% of cases, respectively. Twenty-three relapses (70%) were observed at a median time of 24 months after rituximab. Relapse rate was significantly higher in patients who failed to achieve complete depletion of CD19+ cells (60% vs 17%, P = 0.02), naïve B cells (54% vs 15%, P = 0.01), or memory B cells (50% vs 16%, P = 0.03) 6 months after rituximab. The median relapse free survival time was shorter in patients who failed to achieve complete depletion of CD19+ cells (19 vs 38 months, P = 0.02), naïve B cells (16 vs 38 months, P = 0.01), or memory B cells (19 vs 38 months, P = 0.03) 6 months after rituximab.

CONCLUSION

The degree of B cell depletion 6 months after rituximab may predict disease flare and may instruct on the pacing of B cell depletion therapy in IgG4-RD.

Unusual Presentation of an Orphan Syndrome Masquerading as Castleman Disease in a Young Adult: Diagnostic Challenges and Clinical Implications: A Case Report

IgG4-related disease (IgG4-RD) is a rare and diagnostically challenging fibroinflammatory condition characterized by diverse clinical presentations. We present the case of a 33-year-old male with a progressively enlarging right groin swelling over 6 months. A similar episode occurred 4 years prior in Nepal, with an inconclusive biopsy. Initial investigations pointed to chronic subcutaneous infectious granulomatous disease with lymphadenopathy. Following multiple missed appointments, the patient underwent excision of a soft tissue mass and lymph nodes. Histopathology revealed features consistent with IgG4-RD, including follicular hyperplasia and a Castleman disease-like pattern, negative for malignancy. This case underscores the diagnostic challenges of IgG4-RD and the importance of considering it in the differential diagnosis of chronic lymphadenopathy. Timely follow-up, histological evaluation, and awareness of IgG4-RD diagnostic criteria are crucial for proper management and avoiding delayed treatment.

Eosinophilic Granulomatosis With Polyangiitis Presenting as Bilateral Orbital Inflammation

Eosinophilic granulomatosis with polyangiitis (EGPA) is a small vessel vasculitis that most commonly presents with peripheral eosinophilia, upper airway disease, and asthma, and can also cause cutaneous, cardiac, neurologic, musculoskeletal, gastrointestinal, and renal disease. This case describes a 57-year-old male with a history of chronic sinusitis and asthma who presented with bilateral orbital inflammation causing proptosis and diplopia. He was initially treated with antibiotics for orbital cellulitis without benefit, then high-dose prednisone with taper for idiopathic orbital inflammation, with resolution of ocular symptoms. He was diagnosed with EGPA after rheumatologic evaluation. Serum Immunoglobulin G4 (IgG4) level was significantly elevated, but his clinical presentation was more consistent with EGPA than IgG4-related disease (IgG4-RD). The patient significantly improved with the addition of mepolizumab and later methotrexate. This case details a rare manifestation of EGPA-bilateral orbital inflammation and highlights the potential overlapping features between EGPA and IgG4-RD.

A rare disease with many faces: a multicentre registry of IgG4-related disease in children

OBJECTIVES

We aimed to report the characteristics of paediatric IgG4-related disease (IgG4-RD) through a multicentre registry, to assess disease clusters, and to evaluate the performances of the 2019 American College of Rheumatology and European League Against Rheumatism (ACR/EULAR) classification criteria and the 2020 revised comprehensive diagnostic (RCD) criteria in this cohort.

METHODS

Data of IgG4-RD patients in 13 paediatric rheumatology centres were recorded to a web-based registration system. The diagnosis of IgG4-RD was made according to the 2011 comprehensive diagnostic criteria.

RESULTS

Thirty-five children (19 females and 16 males) with IgG4-RD were enrolled. The median age at diagnosis was 13.3 (25p-75p; 9.9-15.2) years. The most common organ involvement was the eye (n = 21, 60%), followed by lymph nodes (n = 12, 34.3%), musculoskeletal system (n = 12, 34.3%), and neurological system (n = 9, 25.7%). We identified three clusters in our study cohort: those with eye involvement (n = 11, 31.4%), those with eye involvement and neurological findings (n = 15, 42.9%), and those with pancreato-hepatobiliary disease and lymph node involvement (n = 9, 25.7%). Serum IgG4 levels were high in 19 out of 28 patients (67.8%). All patients except one received corticosteroid treatment, and azathioprine was the most preferred drug as a steroid-sparing agent. The sensitivities of the 2019 ACR/EULAR classification criteria and the 2020 RCD criteria were 5.7% and 88.5%, respectively.

CONCLUSION

IgG4-RD has a wide variety of clinical manifestations; however, in children, the most common presentation was orbital involvement. The 2020 RCD criteria had a better performance whereas the 2019 ACR/EULAR classification criteria performed poorly in paediatric patients.

Urogenital Schistosomiasis Mimicking IgG4-RD in a Patient With HIV

This article reports a case of urogenital schistosomiasis mimicking IgG4-related disease (IgG4-RD) in a 47-year-old immunocompromised man with HIV. Initially diagnosed with IgG4-RD, further biopsies revealed schistosoma eggs. Elevated IgG4 levels indicated a Th2 immune response, highlighting its complex role in antischistosomal immunity and the need for careful differential diagnosis.

Hypereosinophilia and Hypereosinophilic Syndromes: First Findings From a Nationwide Multicenter Cohort

BACKGROUND

Hypereosinophilic syndromes (HES) are a heterogenous group of eosinophilic disorders. To date, only retrospective studies of limited sample-size and/or follow-up duration are available.

METHODS

The COHESion study is a national prospective multicenter multidisciplinary cohort recruiting both adults or children with the spectrum of eosinophilic disorders (including reactive HE/HES [HE/HES-R], idiopathic HES [HES-I], lymphocytic HES [HES-L], neoplastic HE/HES [HE/HES-N], HE of unknown significance [HE-US], as well as IgG4-related disease [IgG4RD] or ANCA-negative eosinophilic granulomatosis with polyangiitis [EGPA] overlaps). Patients are followed-up yearly. All data about final diagnosis, organ involvement assessments, and outcome profiles in HES-I were captured and analyzed centrally by HES expert centers.

RESULTS

From May 2019 to November 2023, 779 patients were included. For this preliminary analysis, 550 cases were available for centralized review (mean ± SD age: 56 ± 18 years, 42% of female patients). The final diagnoses were HES-I (47%), HE/HES-R (16%), HE-US (15%), HE/HES-N (7%), HE/HES-L (6%), IgG4RD (2%), and ANCA-negative EGPA (7%). In the 258 HES-I patients, outcome profiles were classified as follows: 16.3% had a "single-flare" without further relapse, 28.3% had a "relapsing-remitting" disease when there was at least a 6-month period free of symptoms between two flares, 46.1% had a "persistent disease" requiring continuous treatment to avoid relapses (9.3% remained unclassified because of insufficient follow-up).

CONCLUSIONS

The COHESion cohort is the first nationwide prospective multicenter study collecting data on the full spectrum of HE/HES disorders. This preliminary analysis confirms that idiopathic HES patients have various outcome profiles, suggesting different underlying pathophysiological mechanisms and the need of patient-specific management.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT04018118.

A Rare Presentation of a Spinal Lesion: Immunoglobulin G4-Related Hypertrophic Spinal Pachymeningitis

Immunoglobulin G4-related disease is a rare systemic condition that can affect multiple organs, though involvement of the central nervous system is uncommon. This report discusses an unusual case of a 64-year-old man who experienced neurological symptoms due to a spinal lesion. Imaging revealed a compressive mass at the cervical spine level, which was surgically removed and later confirmed to be IgG4-related hypertrophic spinal pachymeningitis. This case highlights the importance of considering rare inflammatory conditions in the differential diagnosis of spinal lesions and emphasizes the role of histopathological confirmation for accurate diagnosis and treatment planning.

Inebilizumab for Treatment of IgG4-Related Disease

BACKGROUND

IgG4-related disease is a multiorgan, relapsing, fibroinflammatory, immune-mediated disorder with no approved therapy. Inebilizumab targets and depletes CD19+ B cells and may be effective for treating patients with IgG4-related disease.

METHODS

In this phase 3, multicenter, double-blind, randomized, placebo-controlled trial, adults with active IgG4-related disease underwent randomization in a 1:1 ratio to receive inebilizumab (300-mg intravenous infusions on days 1 and 15 and week 26) or placebo for a 52-week treatment period. Participants in both groups received identical glucocorticoid tapers. Glucocorticoids were allowed to treat disease flares, but background immunosuppressants were not permitted. The primary end point was the first treated, adjudicated disease flare during the treatment period, assessed in a time-to-event analysis. Key secondary end points were the annualized flare rate and treatment-free and glucocorticoid-free complete remission.

RESULTS

A total of 135 participants with IgG4-related disease underwent randomization: 68 participants were assigned to receive inebilizumab and 67 were assigned to receive placebo. Treatment with inebilizumab reduced flare risk; 7 participants (10%) in the inebilizumab group had at least one flare, as compared with 40 participants (60%) in the placebo group (hazard ratio, 0.13; 95% confidence interval [CI], 0.06 to 0.28; P<0.001). The annualized flare rate was lower with inebilizumab than with placebo (rate ratio, 0.14; 95% CI, 0.06 to 0.31; P<0.001). More participants in the inebilizumab group than in the placebo group had flare-free, treatment-free complete remission (odds ratio, 4.68; 95% CI, 2.21 to 9.91; P<0.001) and flare-free, glucocorticoid-free complete remission (odds ratio, 4.96; 95% CI, 2.34 to 10.52; P<0.001). Serious adverse events occurred during the treatment period in 12 of the participants (18%) who received inebilizumab and 6 of the participants (9%) who received placebo.

CONCLUSIONS

Inebilizumab reduced the risk of flares of IgG4-related disease and increased the likelihood of flare-free complete remission at 1 year, confirming the role of CD19-targeted B-cell depletion as a potential treatment for IgG4-related disease. (Funded by Amgen; MITIGATE ClinicalTrials.gov number, NCT04540497.).

Altered IgG4 serum levels in VEXAS syndrome - a retrospective monocentric cohort study

VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome is an autoinflammatory disorder characterized by somatic mutations in the UBA1 gene in hematopoietic stem cells and associated with diffuse inflammation and myelodysplastic changes amongst others. Due to unspecific symptoms the diagnosis is challenging, and there is an unmet need for clinical markers to select patients for genetic examination. Sera of 9 patients with confirmed VEXAS syndrome were analyzed for immunoglobulin (Ig)G4 levels. Disease parameters and clinical response to therapy were correlated with IgG4 levels. A histopathological examination was performed on the available samples to exclude IgG4-related autoimmune diseases. In this cohort, 44% of our patients showed markedly elevated serum IgG4 levels. We observed a general trend toward a positive correlation between IgG4 levels and inflammatory markers as well as a correlation with clinical response in one patient. Histopathological analysis showed no evidence of IgG4 related disease. IgG4 levels seem to be elevated in a relevant fraction of patients with VEXAS syndrome. In some cases, this might be misinterpreted as IgG4-related disease, a pitfall clinicians should be aware of. Furthermore, our results warrant the further evaluation of a potential correlation of IgG4 levels with disease activity and severity of inflammation. IgG4 serum levels might be useful in the evaluation of the disease course.

Diagnostic accuracy of IgG 4/IgG and IgG 4 in patients with IgG 4-related disease: a meta-analysis

OBJECTIVE

This study aimed to evaluate and compare the diagnostic performance of immunoglobulin G4/Immunoglobulin G (IgG 4/IgG) and immunoglobulin G4 (IgG 4) alone in identifying immunoglobulin G4-related disease (IgG 4-RD).

METHODS

A systematic review and meta-analysis were conducted using data from Medline, Embase, and the Cochrane Library from inception to November 2024. Two meta-analyses were performed to assess the diagnostic accuracies of IgG 4/IgG and IgG 4 in IgG 4-RD patients.

RESULTS

Eight studies encompassing 754 IgG 4-RD patients and 9496 non-IgG 4-RD controls were included in the analysis. IgG 4/IgG demonstrated a sensitivity of 89% and a specificity of 91.6%, accurately detecting IgG 4-RD in 89% of cases and correctly identifying non-IgG 4-RD in 91.6% of cases. IgG 4 alone exhibited a higher sensitivity (94.9%) and a similar specificity (91%), indicating a slightly improved ability to identify IgG 4-RD cases. The positive likelihood ratio (PLR) and the negative likelihood ratio (NLR) for IgG 4/IgG were 7580 and 0.132, respectively, while IgG 4 alone had a PLR of 6403 and a lower NLR of 0.066, confirming the high diagnostic reliability. The diagnostic odds ratio (DOR) was 62.97 for IgG 4/IgG compared to 105.6 for IgG 4 alone, reflecting enhanced accuracy. The area under the curve (AUC) was 0.949 for IgG 4/IgG and 0.986 for IgG 4. The Q* index was 0.889 for IgG 4/IgG and 0.949 for IgG 4, further underscoring the diagnostic effectiveness of IgG 4 alone.

CONCLUSION

Both IgG 4/IgG and IgG 4 are highly accurate markers for diagnosing IgG 4-RD, with IgG 4 alone showing marginally higher sensitivity, DOR, and AUC. This suggests that IgG 4 alone may offer a slight advantage as a diagnostic marker for IgG 4-RD.

Imaging findings in cardiovascular involvements of IgG4-related disease: a systematic review study

BACKGROUND

Immunoglobulin G4-related disease (IgG4-RD) is a fibroinflammatory condition characterized by IgG4-positive plasma cell infiltration that can affect multiple organs, including the cardiovascular system. The diagnosis of IgG4-RD relies on a combination of clinical, serological, radiological and pathological findings. However, due to the varied and insidious clinical presentations, normal IgG4 levels in a significant percentage of patients and frequent multi-organ involvement, imaging plays a crucial role in the diagnosis of IgG4-RD. The aim of this study is to comprehensively examine the imaging findings in IgG4-related cardiovascular disease for accurate diagnosis and appropriate treatment.

METHODS

A systematic search was conducted across the electronic databases PubMed, Scopus, Embase and Web of Science, to 1 September 2023, following PRISMA guidelines, searching for studies reporting detailed cardiovascular imaging findings in IgG4-RD.

RESULTS

The search yielded 68 studies (60 case reports, 5 case series, 2 cross-sectional, 1 case-control) with 120 cases of cardiovascular IgG4-RD. Most of the cases were male, averaging 62.8 years. The common initial symptoms were dyspnoea and chest pain. The most common imaging finding was vasculopathy, including vessel wall thickening, periarteritits, periaortitis, aortitis, stenosis, ectasia, aneurysm formation, intramural haemorrhage, fistula formation and dissection, followed by pericardial involvement and mediastinal masses. Case series and cross-sectional studies also showed vasculopathy to be the most common finding on various imaging modalities, including angiography and PET/CT, highlighting the complex pathology of IgG4-RD.

CONCLUSION

This study evaluated current IgG4-RD articles, revealing a higher prevalence in men and vasculopathy as the most common cardiovascular complication.

Highlights from the breakout session: other forms of vasculitis

The session on other forms of vasculitis included a masterful review on IgG4-related disease (IgG4-RD) following which two research studies evaluating therapeutic agents and one study on histopathologic findings of IgG4-RD were presented. Peyronel F., et al. discussed the results of a prospective multicentre randomized clinical trial evaluating methotrexate for patients with retroperitoneal fibrosis. Methotrexate, in combination with a tapering regimen of glucocorticoids, was effective in inducing remission and allows use of lower cumulative prednisone doses. Hobbelink J., et al. evaluated the histopathologic scoring system from the ACR/EULAR Classification criteria for IgG4-RD. Their study found that these criteria were able to distinguish patients with confirmed and suspected IgG4-RD. Trivioli G et al. retrospectively evaluated rituximab in adult-onset IgA Vasculitis (IgAV) and crescentic IgA Nephropathy (cIgAN). Rituximab resulted in high rate of renal response in IgAV but remission rates in cIgAN remained lower with poorer renal outcomes compared with IgAV.

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.

Dapagliflozin for rheumatic musculoskeletal disease in patients with chronic kidney disease

OBJECTIVES

To elucidate the effectiveness of dapagliflozin, a sodium-glucose cotransporter 2 inhibitor, on renal function in patients with rheumatic musculoskeletal diseases complicated by chronic kidney disease (CKD).

METHODS

We conducted a retrospective analysis of patients with rheumatic musculoskeletal disease and chronic kidney disease who were treated with dapagliflozin for more than a year. The good response was defined as an improvement in the estimated glomerular filtration rate slope per year after dapagliflozin treatment compared to that before treatment. Additionally, we investigated the response rate and its predictive factors.

RESULTS

In this analysis, 43 patients were included. The average estimated glomerular filtration rate slope demonstrated a significant improvement after dapagliflozin treatment compared to that before the treatment (0.04 vs -0.55 ml/min/1.73 m2/year, P = .001). A good response rate was 69.8% and was associated with low average levels of C-reactive protein, a high frequency of angiotensin II receptor blocker (ARB) use, and a low frequency of tacrolimus use compared to nonresponse (0.08 ± 0.18 vs 0.25 ± 0.29 mg/dl, P = .03; 80.0 vs 38.4%, P = .01; 10.0 vs 76.9%, P < .01).

CONCLUSIONS

Dapagliflozin is effective for rheumatic musculoskeletal disease patients with CKD for preventing deterioration of renal function. Antihypertensive treatment with ARB and inflammation control without tacrolimus was associated with a high likelihood of favourable response to dapagliflozin.

Acute hypophysitis with pachymeningitis

Often the workup to find the causes of common symptoms can lead to unexpected findings, thereby emphasising the need to keep a broad suspicion and continued search for emerging evidence. In this report, we describe the case of an elderly woman in her late 60s without any comorbidities, who presented with new-onset neck stiffness, progressive headache and continuous fever with no other clue that could lead us to a telltale diagnosis, and in whom the diagnostic staircase ultimately led to the diagnosis of IgG4 hypophysitis and pachymeningitis. Only a prompt clinical suspicion and appropriately timed workup can help in revealing such intricate and uncommon diagnosis among the maze of more common differentials having similar manifestations. Especially in such uncommon scenarios, common aetiologies such as tuberculosis should always be kept in the horizon.

IgG4-related disease causing dacryoadenitis, bronchial stenosis and lobar collapse

Immunoglobulin G4-related disease (IgG4-RD) is a rare systemic fibroinflammatory disease that can affect almost any organ in the body. The most common sites of IgG4-RD include the salivary glands, orbits and lacrimal glands, pancreas, biliary tree, retroperitoneum and thyroid. Immunoglobulin G4-related lung disease (IgG4-RLD) can occur in isolation or as a component of multisystem disease. Its manifestations are heterogeneous and include lung cavitation, interstitial changes, pleural effusions and lung lesions.We describe a patient with Ig4-RLD manifesting as bronchial stenosis and left upper lobe collapse.

The Management of IgG4-Related Disease in Children: A Systematic Review

Background/Objectives: IgG4-related disease (IgG4-RD) is a multi-organ disease with greatly varying therapeutic approaches and a lack of specific treatment algorithms. This systematic review aimed to determine the therapeutic approaches for pediatric IgG4-RD in real-word practice. Methods: We searched PubMed and Google Scholar for articles on pediatric IgG4-RD cases published in English from 2012 to August 2024, focusing on treatments and outcomes. Study type, treatment(s), dose/regimen, age and sex, organ(s) involved, and treatment outcomes were manually extracted from each study. Results: Of the 219 studies identified, we analyzed 81 studies, including 114 pediatric IgG4-RD cases. Fifty-seven percent of patients suffered from multi-organ disease and required several treatment schemes. Around 75% received steroids, alone or in combination, regardless of the organ affected. The treatment outcomes were positive in most cases, although relapses occurred in approximately 30% of patients, usually upon steroid tapering. Other common therapeutic approaches included immunosuppressants, often used as steroid-sparing agents, with azathioprine and mycophenolate mofetil being the most common; surgery for localized disease; and biologics, mainly rituximab, used in more severe/refractory cases. Uncommon but effective therapies included adalimumab and ruxolitinib. Drug combinations seemed to be more efficacious than monotherapies across studies. Patients > 10 years old more frequently received aggressive approaches (surgery and rituximab) and more often experienced relapses. Relapse rates were higher among females. Conclusions: This review highlights the use of systemic steroids as an effective first-line treatment for pediatric IgG4-RD, but also underscores the use of non-steroid-based alternatives in combination with steroids or other immunosuppressants for the effective management of IgG4-RD.

Recurrent chylothorax in a patient with serositis as the only manifestation of IgG4-related disease: the diagnostic challenge and consideration

IgG4-related disease (IgG4-RD) is a systemic fibroinflammatory disorder characterised by IgG4-positive plasma cell infiltration into different tissues and organs. Among the heterogeneous clinical features of IgG4-RD, serositis, including pleural and pericardial effusions, is a rare and poorly understood presentation. We described a woman in her late 70s who developed recurrent chylothorax and failed to respond to corticosteroids, immunosuppressives and intrapleural octreotide injection while being treated for newly diagnosed IgG4-RD with serositis as the only manifestation. Her chylothorax was thought to be due to fibroinflammatory damage of the lymphatic duct system from her IgG4-RD, as other differential diagnoses have been largely excluded. We demonstrate the difficulty in establishing the diagnosis of IgG4-RD when only serositis is present, the importance of meticulous workup ruling out other causes and clinical judgement in identifying disease complications versus evaluating alternative diagnoses.

Diagnostic value of a novel salivary gland ultrasound scoring system in IgG4-related sialadenitis

OBJECTIVES

To develop a novel ultrasound scoring system for the major salivary glands in patients with immunoglobulin G4-related sialadenitis (IgG4-RS) and assess its diagnostic value in a multicentre cohort of Chinese patients.

METHODS

Twenty clinicians (rheumatologists, stomatologists and radiologists) participated. The study was conducted in four steps: (i) defining the ultrasonography (US) elements, (ii) developing a novel ultrasound scoring system for US of the salivary glands, (iii) evaluation of inter- and intra-reader reliabilities using the new ultrasound scoring system, and (iv) assessing the diagnostic value of this novel ultrasound scoring system in IgG4-RS patients in a Chinese multicentre cohort.

RESULTS

A novel ultrasound scoring system for the salivary glands was developed, with total scores ranging from 0 to 34. The inter- and intra-reader reliabilities of the ultrasound scoring system were excellent (0.972 and 0.940, respectively). A total of 470 people were recruited in this study; 187 patients were diagnosed with IgG4-RS, and the remaining 283 people were diagnosed with non-IgG4-RS. Patients with IgG4-RS group had significantly higher US scores than the non-IgG4-RS group (mean US score = 16 vs 4, P < 0.001). The calculated area under the curve for the total US score was 0.852 (95% CI: 0.814, 0.891). The total US scores ≥9 showed a sensitivity of 75.4% and a specificity of 91.9%. Association analysis showed a positive correlation between total US scores and serum IgG4 levels and hypocomplementaemia (r = 0.221 and r = 0.349, respectively; P = 0.002 and P < 0.001, respectively) and a negative correlation between total US scores and serum C3 and C4 levels (r = -0.210 and r = -0.303, respectively; P = 0.005 and P < 0.001, respectively).

CONCLUSION

A novel semiquantitative ultrasound scoring system for patients with IgG4-RS was developed, with good diagnostic performance. The inter- and intra-reader reliabilities were excellent. US scores were correlated with IgG4, C3 and C4 levels and hypocomplementaemia.

Marginal zone lymphoma of extranodal sites: A review with an emphasis on diagnostic pitfalls and differential diagnosis with reactive conditions

Marginal zone lymphoma of the mucosa-associated lymphoid tissue (MALT lymphoma) represents 8% of all B-cell lymphomas and it is the most common small B-cell lymphoma arising at extranodal sites. The gold-standard test to establish a diagnosis of MALT lymphoma remains histopathologic analysis with the aid of immunohistochemistry (IHC) and/or flow cytometry immunophenotypic analysis. MALT lymphoma represents a progression from a persistent chronic inflammatory process, and therefore distinguishing MALT lymphoma from chronic inflammation by histopathology may be challenging in some cases. Despite recent trends to consider IGH rearrangement/clonality as a confirmatory diagnostic test of MALT lymphoma, this method is far from ideal for this purpose since a positive or a negative result does not necessarily confirm or exclude that a process is lymphoma or reactive. This test must be correlated with the morphologic findings. Moreover, MALT lymphoma may arise in association with underlying autoimmune conditions where clonal lymphoid populations are not uncommonly detected. Therefore, we believe that an integrated approach including detailed morphologic review in combination with IHC and/or flow cytometry is best to establish a diagnosis of MALT lymphoma in most cases. We present helpful morphologic tips to avoid potential diagnostic pitfalls at some of the most common extranodal sites, including the stomach, ocular adnexa/conjunctiva, salivary gland, lung, thymus, breast, thyroid, small and large intestine and the dura. The differential diagnosis of MALT lymphoma with IgG4-related disease is also discussed.

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.

Diffuse orbital inflammation: an atypical manifestation of Behcet's disease

Behcet's disease is a chronic, relapsing systemic vasculitis characterised by multisystem involvement from small, medium and large vessel inflammation. Common manifestations include oral and genital ulcers, rash, uveitis and neurological symptoms, while orbital inflammation is rare. An Asian man in his 40s with Behcet's disease on immunosuppression presented with 10 days of unilateral periorbital swelling and painful eye movements, unresponsive to oral antibiotics. Imaging revealed diffuse orbital inflammation and optic neuritis. Investigations excluded an infectious cause. Despite broad-spectrum intravenous antibiotics, his condition worsened until typical Behcet's disease mucocutaneous symptoms emerged, indicating a Behcet's flare. Treatment with high-dose corticosteroids, followed by cyclophosphamide and azathioprine resolved the diffuse orbital inflammation. Unfortunately, the visual outcome was poor as he remained blind in the affected eye from optic neuritis and corneal ulceration. This case highlights the importance of early diagnosis and treatment of diffuse orbital inflammation in Behcet's disease to prevent severe ocular complications.

Castleman disease misdiagnosed as immunoglobulin G4-related disease: a case report

Castleman disease (CD) and immunoglobulin G4-related disease (IgG4-RD) are rare systemic immune-mediated disorders that share overlapping clinical features, posing significant challenges in differential diagnosis. Here, we present a case of generalized lymphadenopathy initially misdiagnosed as IgG4-RD, which demonstrated a poor response to hormonal therapy. Subsequent pathological biopsy and immunohistochemical analysis ultimately confirmed the diagnosis of CD. This case underscores the limitations of relying solely on serum IgG4 levels as a diagnostic marker to distinguish CD from IgG4-RD. Comprehensive evaluation, including clinical presentation, organ involvement, serological and pathological findings, as well as therapeutic response, is essential to ensure accurate diagnosis and timely management.

Immunoglobulin G4-related Autoimmune Pancreatitis and Hypopituitarism Following Immune Checkpoint Inhibitor Therapy

A 70-year-old man underwent nephrectomy for renal cell carcinoma followed by 3 cycles of pembrolizumab as adjuvant chemotherapy. Three months later, he complained of appetite loss. He was diagnosed with secondary adrenal insufficiency and pancreatic tumor. Amylase and immunoglobulin G (IgG) 4 levels were normal. The differential diagnosis poses challenges in distinguishing pancreatic cancer, renal cell carcinoma metastasis, and autoimmune pancreatitis, necessitating tumor resection surgery. A histological examination revealed IgG4-related sclerosing pancreatitis. Postoperatively, there was no recurrence of pancreatitis. It is essential to consider the potential development of IgG4-related diseases after the administration of immune checkpoint inhibitors.

Exploring cardiovascular involvement in IgG4-related disease: a case series approach with cardiovascular magnetic resonance

BACKGROUND

IgG4-related disease (IgG4-RD) is a relapsing-remitting, fibroinflammatory, multisystem disorder. Cardiovascular involvement from IgG4-RD has not been systematically characterised. In this study, we sought to evaluate consecutive patients with IgG4-RD using a detailed multiparametric cardiovascular magnetic resonance (CMR) imaging protocol.

METHODS

We prospectively enrolled 11 patients with histology-confirmed IgG4-RD; with active disease at time of scan. We undertook a detailed multiparametric CMR imaging protocol at 1.5T including cine imaging, native T1 and T2 mapping, stress perfusion imaging with inline quantitation of myocardial blood flow and late gadolinium enhancement (LGE) imaging.

RESULTS

All patients exhibited at least one abnormality on CMR imaging. Abnormal elevation of global or segmental left ventricular myocardial T1 and T2 values was present in four patients, suggesting myocardial oedema or inflammation. Abnormal LGE, suggesting myocardial scar fibrosis, was present in nine patients, with eight displaying a non-ischaemic pattern, and one showing an ischaemic pattern. Four patients fulfilled both Lake Louise Criteria for active myocardial inflammation, while a further six fulfilled one criterion. Myocardial perfusion reserve was normal in all evaluable patients. Ten patients had normal ventricular volumes, mass and systolic function. In addition, thoracic aortitis was identified in three patients who underwent 18F-flourodeoxyglucose PET/CT imaging, with resolution following anti-B-cell treatment.

CONCLUSIONS

In this cohort of patients with histology-confirmed IgG4-RD, multiparametric CMR revealed no changes in gross cardiac structure and function, but frequent myocardial tissue abnormalities. These data suggest a plausible pathophysiological link between IgG4-RD and cardiovascular involvement.

Are there atypical sites of IgG4 related disease in head and neck region? Personal experience and literature review

PURPOSE

Immunoglobulin G4-related disease (IgG4-RD) is a complex systemic fibroinflammatory condition with different clinical manifestations affecting multiple organ systems. Despite its rarity, the disease presents diagnostic and therapeutic challenges due to its mimicry of malignancies and other immune-mediated disorders. The 2019 American College of Rheumatology/European League Against Rheumatism Classification Criteria for IgG4-Related Disease is the current state of art to confirm the diagnosis of IgG4-RD even in the absence of histological analysis. However, this classification excludes atypical sites, focusing on the more typical ones, even in case of histological confirmation. In the ENT field, several localizations of this disease have been described.

METHODS

We report two clinical cases at the Otolaryngology Unit of IRCCS San Martino Hospital, Genoa affected by IgG4-RD arising in atypical sides of the head and neck region. Additionally, we perform a clinical review of the current literature.

DISCUSSION

The review provides an extensive overview of IgG4-RD, encompassing epidemiology, clinical manifestations, diagnostic approaches, and therapeutic strategies. We discuss the evolution of diagnostic criteria, emphasizing the necessity of interdisciplinary collaboration among clinicians, radiologists, and pathologists for accurate diagnosis. Diagnostic imaging plays a crucial role, with characteristic radiological patterns aiding in the identification of affected organs. However, definitive diagnosis often requires histopathological confirmation, highlighting the importance of biopsy in challenging cases. We also focus on the treatment of IgG4-RD which poses significant challenges, with glucocorticoids remaining the cornerstone of therapy. Emerging steroid-sparing agents such as rituximab and Dupilumab, show promising results in refractory or recurrent disease.

CONCLUSIONS

IgG4-RD is a multisystemic fibroinflammatory disease that can potentially affect any part of the body. The 2019 ACR/EULAR 3-stage classification criteria for IgG4-RD considers only a few head and neck sites. Therefore, it is of paramount importance that neurosurgeons, head and neck surgeons, and oral and maxillofacial pathologists are familiar with the clinicopathological manifestations of IgG4-RD in these sites to avoid misdiagnosis and inappropriate treatment, which can lead to a decrease in patients' quality of life. To our knowledge, there are no risk factors or genetic predispositions. Further studies are needed to elucidate the pathophysiology of IgG4-RD with the aim of providing a targeted therapy that could spare steroid-related effects and reduce relapses.

Efficacy and safety of anti-CD19 CAR-T in a mouse model of IgG4-related disease

Dysregulated B-cell activation plays pivotal roles in IgG4-related disease (IgG4-RD), which makes B-cell depletion a potential strategy for IgG4-RD treatment. In this study, we aimed to investigate the feasibility of applying anti-CD19 chimeric antigen receptor T(CAR-T) cell therapy to IgG4-RD treatment in a mouse disease model based on LatY136F knock-in (Lat) mice. We constructed murine anti-CD19 CARs with either CD28 or 4-1BB as the intracellular costimulatory motif and evaluated the therapeutic function of the corresponding CAR-T cells by infusing them into Lat mice. Next, we assessed the safety of CAR-T infusion by evaluating the risk of cytokine release syndrome (CRS) and the antiviral capabilities in a mouse influenza infection model. Finally, we performed human anti-CD19 CAR-T manufacturing from IgG4-RD patients and evaluated its activation level and functional effects in vitro. Compared with 1D3 antibody treatment, the adoptive transfer of anti-CD19 CAR-T cells with CD28 costimulatory motif showed comparable B-cell-depletion effect in Lat mice. Furthermore, the transfer of syngeneic anti-CD19 CAR-T cells also decreased the percentage of plasma cells as well as IL-4 secreting Th cells, therefore attenuating the inflammation and fibrosis condition. CAR-T cells with CD28 costimulatory motif showed better therapeutic efficiency without the incidence of serious CRS events or increasing the risk of infection. In addition, we validated the feasibility of human CAR-T preparation in vitro from IgG4-RD patients. Taken together, these results show that anti-CD19 CAR-T therapy was effective in the treatment of a murine model of IgG4-RD, indicating its potential for clinical use in patients.

Laparoscopic Resection for Colonic Obstruction Due to Immunoglobulin G4-Related Disease: A Case Report

An 89-year-old woman was referred to our hospital with complaints of body weight loss and anemia. Lower gastrointestinal imaging revealed a 3.5-cm stenosis in the descending colon near the splenic flexure. Endoscopy did not pass through the stricture. A biopsy showed no evidence of malignancy or lymphoma. Enhanced abdominopelvic computed tomography showed a thickened descending colon wall with swollen lymph nodes around the colon. Because descending colon cancer was suspected, laparoscopic-assisted left hemicolectomy with D2 lymph node dissection was performed. Hematoxylin and eosin staining showed severe fibrosis and chronic inflammatory cell infiltration. Immunohistochemistry staining showed the number of immunoglobulin G4 (IgG4)-positive cells at 100/high-power field (400×), and the IgG4/IgG ratio was >40%. The serum IgG4 level was measured postoperatively and was within the normal range at 54 mg/dL. The patient was diagnosed as a probable group of IgG4-related disease based on the comprehensive clinical diagnostic criteria for IgG4-related disease.

Predominantly multiple focal non-cystic renal lesions: an imaging approach

Multiple non-cystic renal lesions are occasionally discovered during imaging for various reasons and poses a diagnostic challenge to the practicing radiologist. These lesions may appear as a primary or dominant imaging finding or may be an additional abnormality in the setting of multiorgan involvement. Awareness of the imaging appearance of the various entities presenting as renal lesions integrated with associated extrarenal imaging findings along with clinical information is crucial for a proper diagnostic approach and patient work-up. This review summarizes the most relevant causes of infectious, inflammatory, vascular, and neoplastic disorders presenting as predominantly multiple focal non-cystic lesions.