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

Xanthogranulomatous cholecystitis with histologic features suggestive of IgG4 related cholecystitis - A morphologic overlap with IgG4 related disease

AIMS

Both xanthogranulomatous cholecystitis (XGC) and IgG4-related cholecystitis (IgG4-CC) are rare chronic fibroinflammatory tumefactive diseases of the gallbladder, which cause a strong confusion with resectable malignancy in view of their mass forming tendency with extension into the liver. We aim to study the histopathologic features of xanthogranulomatous cholecystitis with regard to IgG4-related cholecystitis in extended cholecystectomy specimens.

METHODS AND RESULTS

Sixty cases of extended cholecystectomy with liver wedge resection, diagnosed as XGC on histopathology from January 2018 to December 2021 were retrieved from the archives. Representative sections were reviewed by two pathologists independently. Immunohistochemistry was performed for IgG4 and IgG4/IgG was derived. The cases were dichotomized in two groups on the basis of IgG4 positive plasma cells. Six cases with >50 IgG4 positive plasma cells had storiform fibrosis, IgG4/IgG ratio >0.40 and extra-cholecystic extension. Of these, 50 % had obliterative phlebitis and 66.7 % had perineural plasma cell wrapping.

CONCLUSIONS

A small subset of XGC cases (~10 %) had morphologic overlap with IgG4-CC, but should not be overcalled as the diagnosis of IgG4-RD requires an integrative approach based on clinical, serologic and imaging criteria and not solely on histopathology.

Update on respiratory lesions in patients with IgG4-related autoimmune pancreatitis

We previously reported respiratory involvement in 25 patients with autoimmune pancreatitis, a pancreatic manifestation of IgG4-related disease that responds well to glucocorticoid treatment. However, whether all respiratory lesions in patients with autoimmune pancreatitis have genuine respiratory involvement is unclear. This study aimed to update respiratory lesions' clinical and radiological characteristics in patients with autoimmune pancreatitis. We retrospectively reviewed the clinical and radiological data of 74 consecutive patients diagnosed with autoimmune pancreatitis at Shinshu University Hospital and treated with glucocorticoid. Clinical features and chest high-resolution computed tomography findings before and after therapy were reviewed. Fifty-one patients (68.9%) had respiratory lesions. In 65 of the 74 patients, chest high-resolution computed tomography results were evaluated before and after treatment. Patients with IgG4-related disease and respiratory lesions showed significantly higher serum IgG4 levels and hypocomplementemia than those without respiratory lesions; they also had more affected organs. While most abnormal thoracic findings improved, 4 cases of 7 with reticular opacities and all 11 cases with emphysema did not improve. Therefore, these lesions with poor response to glucocorticoid treatment should not be considered due to respiratory involvement of autoimmune pancreatitis based on the current classification criteria for IgG4-related disease. Patients with autoimmune pancreatitis and respiratory lesions exhibited higher disease activity than those without. Most chest high-resolution computed tomography lesions were responsive to glucocorticoid treatment, whereas reticular opacities and emphysema were poorly responsive.

MPO-ANCA-positive granulomatosis with polyangiitis and concurrent IgG4-related disease with periaortitis and tubulointerstitial nephritis: A case report of a new overlap syndrome?

Immunoglobulin G4-related disease (IgG4-RD) is a fibroinflammatory condition that was first recognized as a unique disease entity in the early 2000s. Its diagnosis is based on specific pathologic, serologic, and clinical features, and the exclusion of several differential diagnoses, such antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). However, emerging evidence suggests that these 2 conditions may overlap in some cases. Here, we report a new case of overlapping IgG4-RD and AAV. The patient was diagnosed with IgG4-RD owing to the presence of periaortitis and IgG4 positive tubulointerstitial nephritis. Myeloperoxidase (MPO)-ANCA positivity, chronic paranasal sinusitis, and glomerulonephritis with granuloma led to a concurrent diagnosis of MPO-ANCA-positive granulomatosis with polyangiitis. Our case supports the hypothesis that diagnoses of IgG4-RD and AAV are not mutually exclusive but can overlap. It can be assumed that an overlap with IgG4-RD typically affects the granulomatous form of AAV, suggesting a common pathophysiological pathway for these 2 conditions.

IgG4-related pachymeningitis-Long term follow up and outcome of six patients

OBJECTIVE

Our understanding of IgG4-RD and pachymeningitis has grown substantially, but the optimal approach for diagnosis, management, and long-term outcomes is still an area of uncertainty.

METHODS

HUVAC is a database for IgG4-RD patients, this database was retrospectively evaluated for pachymeningeal disease. Demographic, clinical, serological, imaging, histopathological data, and treatment details were re-interpreted in patients with pachymeningitis.

RESULTS

Among 97 patients with IgG4-RD, 6 (6.2%) had pachymeningitis. None of these patients had extracranial features, and also, in most of the patients, serum IgG4 levels were normal. Tentorium cerebelli and transverse sinus dura were the most commonly involved in the posterior fossa. During 18 months of median follow-up on steroid+-rituximab, none of them relapsed as pachymeningitis.

CONCLUSION

Our patients were mainly older males with sole neurological involvement. Non-specific headache was the most common manifestation, and serum IgG4 levels were not useful for diagnosis. Typical radiology and tentorial thickening should suggest IgG4-RD and prompt an early biopsy. Moreover, accompanying hypophysitis could also be a clue. With steroids+ rituximab treatment, no relapse related to meningeal involvement was seen in long-term follow-up.

Imaging manifestations of IgG4-related disease

IgG4-related disease is a multisystem immune-mediated disorder associated with lesions manifesting an IgG4-rich plasma cell infiltrate and often raised serum IgG4 concentrations. The disease can mimic neoplastic, infective, and inflammatory processes due to features such as development of masses or organ enlargement. Prompt consideration of this diagnosis is essential to avoid unnecessary investigations and offer appropriate treatments, which can include steroids and other immunosuppressive agents. Although histology is typically diagnostic, imaging is critical to assess disease burden, determine biopsy targets, and evaluate response to treatment. Characteristic imaging features can also point towards the diagnosis in the absence of biopsy. This review highlights these features, as well as more atypical findings, grouped by organ or system. Differential diagnoses are emphasised. The full spectrum of imaging methods is discussed. Whole-body imaging with integrated 2-[18F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography (PET)/computed tomography (CT) has an evolving role in the detection of multi-organ involvement and subsequent follow-up.

Clinical and Prognostic Factors in Patients with IgG4-Related Kidney Disease

BACKGROUND

IgG4-related kidney disease is a major manifestation of IgG4-related disease, a systemic fibroinflammatory disorder. However, the clinical and prognostic kidney-related factors in patients with IgG4-related kidney disease are insufficiently defined.

METHODS

We conducted an observational cohort study using data from 35 sites in two European countries. Clinical, biologic, imaging, and histopathologic data; treatment modalities; and outcomes were collected from medical records. Logistic regression was performed to identify the possible factors related to an eGFR ≤30 ml/min per 1.73 m 2 at the last follow-up. Cox proportional hazards model was performed to assess the factors associated with the risk of relapse.

RESULTS

We studied 101 adult patients with IgG4-related disease with a median follow-up of 24 (11-58) months. Of these, 87 (86%) patients were male, and the median age was 68 (57-76) years. Eighty-three (82%) patients had IgG4-related kidney disease confirmed by kidney biopsy, with all biopsies showing tubulointerstitial involvement and 16 showing glomerular lesions. Ninety (89%) patients were treated with corticosteroids, and 18 (18%) patients received rituximab as first-line therapy. At the last follow-up, the eGFR was below 30 ml/min per 1.73 m 2 in 32% of patients; 34 (34%) patients experienced a relapse, while 12 (13%) patients had died. By Cox survival analysis, the number of organs involved (hazard ratio [HR], 1.26; 95% confidence interval [CI], 1.01 to 1.55) and low C3 and C4 concentrations (HR, 2.31; 95% CI, 1.10 to 4.85) were independently associated with a higher risk of relapse, whereas first-line therapy with rituximab was protective (HR, 0.22; 95% CI, 0.06 to 0.78). At their last follow-up, 19 (19%) patients had an eGFR ≤30 ml/min per 1.73 m 2 . Age (odd ratio [OR], 1.11; 95% CI, 1.03 to 1.20), peak serum creatinine (OR, 2.74; 95% CI, 1.71 to 5.47), and serum IgG4 level ≥5 g/L (OR, 4.46; 95% CI, 1.23 to 19.40) were independently predictive for severe CKD.

CONCLUSIONS

IgG4-related kidney disease predominantly affected middle-aged men and manifested as tubulointerstitial nephritis with potential glomerular involvement. Complement consumption and the number of organs involved were associated with a higher relapse rate, whereas first-line therapy with rituximab was associated with lower relapse rate. Patients with high serum IgG4 concentrations (≥5 g/L) had more severe kidney disease.

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.

Immunoglobulin G4-related Disease of the Small Bowel: A Case of Long-term Remission Achieved by Surgical Resection without Maintenance Therapy

Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated fibroinflammatory disease. IgG4-RD can affect any organ system, including the pancreas, bile ducts, salivary glands, mesentery, and retroperitoneum. On the other hand, small intestine involvement is extremely rare. This paper describes a case of IgG4-RD involving the small bowel, particularly at the distal ileum. An 81-year-old female was admitted to the authors' hospital complaining of abdominal pain, dyspepsia, and hematochezia. The laboratory tests, including tumor markers and IgG4, were within normal limits. A colonoscopy did not show any abnormal findings. Abdominal computed tomography revealed segmental aneurysmal dilatation and wall thickening at the distal ileum, suggesting malignant conditions, such as small bowel lymphoma. The patient underwent an exploratory laparoscopy and ileocecectomy to differentiate a malignancy. A histopathology examination revealed dense lymphoplasmacytic infiltration, storiform fibrosis, and IgG4-positive plasma cells (>50 per high power field). The patient was finally diagnosed with IgG4-RD. The patient was followed up in the outpatient clinic for five years without recurrence. This paper suggests that a radical resection without maintenance therapy can be a treatment option, particularly when the IgG4-RD manifests as a localized gastrointestinal tract lesion.

[AL amyloidosis mimicking IgG4-related disease: case report]

The article describes a unique clinical case of AL amyloidosis mimicking IgG4-related disease. Plasma cell dyscrasias can mimic clinical and laboratory manifestations of rheumatic diseases, which can lead to a delay in diagnosis and inappropriate therapy.

Can IgG4-related disease present as isolated myositis?

IgG4-Related Disease (IgG4-RD)is a chronic fibroinflammatory disease typically characterized by inflammation or tumefaction of the organs involved. Skeletal muscle is not one of the typical organs involved in IgG4-RD. Isolated myositis related to IgG4-RD without common organ involvement such as lacrimal or salivary glands or retroperitoneal fibrosis is a controversial and debatable entity. Here we report a case of inflammatory myopathy in an elderly woman with several atypical clinical, lab, and histopathological findings suggestive of IgG4-related myositis. Two such case reports of IgG4-related myositis were reported in the literature review. This is a third case report of elevated IgG4 positive plasma cell infiltration in muscle with severe endomysial fibrosis and unusual myositis features (Figs. 1 and 2). This case-based review opens a possibility of a novel presentation of IgG4-RD and new pathogenesis in myositis.

A Case of Immunoglobulin G4-Related Disease Presenting as a Parapharyngeal Mass

Immunoglobulin G4-related disease (IgG4-RD) is a fibroinflammatory condition characterized by tissue infiltration with lymphocytes and IgG4-secreting plasma cells. The presentation of IgG4-RD is heterogenous, making it difficult to diagnose. IgG4-RD presenting as a parapharyngeal mass is extremely rare. This report discusses the case of a 69-year-old African American female presenting with intermittent bilateral frontal headaches. Initial imaging revealed an ill-defined parapharyngeal mass encasing the left internal carotid artery and left internal jugular vein. Subsequent biopsy and immunohistochemistry showed a high concentration of IgG4-positive plasma cells with storiform fibrosis, despite normal serum IgG4 levels. The patient opted for conservative management. The localized parapharyngeal mass has remained stable over two years on annual imaging. This case report highlights that IgG4-RD can have varied and nonspecific presentations requiring high clinical suspicion to diagnose. Histopathology and IgG4 staining are vital to confirm the diagnosis of IgG4-RD, particularly in atypical cases not meeting the standard inclusion criteria.

The Incidence of IgG4-Related and Inflammatory Abdominal Aortic Aneurysm Is Rare in a 101 Patient Cohort

Abdominal aortic aneurysms (AAA) are the most frequent aortic dilation, with considerable morbidity and mortality. Inflammatory (infl) and IgG4-positive AAAs represent specific subtypes of unclear incidence and clinical significance. Here, histologic and serologic analyses with retrospective clinical data acquisition are investigated via detailed histology, including morphologic (HE, EvG: inflammatory subtype, angiogenesis, and fibrosis) and immunhistochemic analyses (IgG and IgG4). In addition, complement factors C3/C4 and immunoglobulins IgG, IgG2, IgG4 and IgE were measured in serum samples and clinical data uses patients' metrics, as well as through semi-automated morphometric analysis (diameter, volume, angulation and vessel tortuosity). A total of 101 eligible patients showed five (5%) IgG4 positive (all scored 1) and seven (7%) inflammatory AAAs. An increased degree of inflammation was seen in IgG4 positive and inflAAA, respectively. However, serologic analysis revealed no increased levels of IgG or IgG4. The operative procedure time was not different for those cases and the short-term clinical outcomes were equal for the entire AAA cohort. Overall, the incidence of inflammatory and IgG4-positive AAA samples seems very low based on histologic and serum analyses. Both entities must be considered distinct disease phenotypes. Short-term operative outcomes were not different for both sub-cohorts.

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.

How I Diagnose Rosai-Dorfman Disease

OBJECTIVES

Rosai-Dorfman disease (RDD) is one of 3 major types of histiocytosis, along with Erdheim-Chester disease and Langerhans cell histiocytosis. While historically, RDD was considered a benign self-limited condition, current data show MAPK/ERK pathway mutations in 30% to 50% of cases, indicative of a clonal process. Rosai-Dorfman disease was incorporated as a histiocytic neoplasm in the fifth edition of the World Health Organization classification of hematopoietic tumors and the International Consensus Classification.

METHODS

We discuss the diagnosis of RDD using 2 illustrative cases, interpretative challenges, and a diagnostic algorithm.

RESULTS

Rosai-Dorfman disease involves nodal and extranodal sites, including skin, sinuses, salivary gland, orbit, central nervous system, kidney, and bone. In a subset, RDD can coexist with other neoplasms (lymphomas, other histiocytosis) or autoimmune disease. Morphologically, RDD histiocytes are characterized by enlarged round to oval nuclei, distinct nucleoli, and voluminous cytoplasm with engulfment of inflammatory cells (emperipolesis). By immunohistochemistry, they express CD68, CD163 (majority), S100, OCT2, and cyclin D1. Appropriate use of ancillary studies is important to support the diagnosis of RDD while excluding other histiocytic neoplasms and reactive histiocytic proliferations.

CONCLUSIONS

Management of RDD is dependent on the extent of organ involvement and clinical symptoms. In patients who require therapy, next-generation sequencing is recommended to identify MAPK/ERK pathway mutations for targeted therapy.

Patterns of Relapse and Complications of Immunoglobulin G4-Related Disease

BACKGROUND

Immunoglobulin G4-related disease (IgG4-RD) is a multisystemic fibroinflammatory condition potentially resulting in organ dysfunction. We aimed to evaluate imaging characteristics of disease relapse and complications in this cohort of patients.

METHODS

This was a cohort study of IgG4-RD patients imaged between 2010 and 2020. Radiological manifestations of disease activity (remission/stability vs. relapse and complications) were correlated with clinical symptoms. Univariate analyses were performed with χ2, Fisher exact, and Mann-Whitney U tests. Times to relapse and organ atrophy were studied with Kaplan-Meier analyses.

RESULTS

A total of 69 patients had imaging surveillance over a median duration of 47 months. Radiological relapse occurred in 50.7% (35/69) with median time to relapse at 74 months (95% confidence interval, 45-122 months); 42.8% (15/35) of this cohort had different-site relapse with the following recognized primary-secondary patterns: pancreas-hepatobiliary (p = 0.005), hepatobiliary-pancreas (p = 0.013), and periaortitis-mesenteric (p = 0.006). Clinical symptoms were significantly associated with imaging characteristics (p < 0.001). Abdominal complications were detected in 52.2% (36/69) of patients, mostly solid organ atrophy (97.2% [35/36]). New-onset diabetes was more likely in pancreatic IgG4-RD (n = 51) when accompanied by gland atrophy (4/21 vs. 0/30 nonatrophy, p = 0.024).

CONCLUSION

Radiological relapse of IgG4-RD is common over prolonged imaging surveillance and is significantly associated with symptomatic relapse. A multisystem review to detect new/different sites of disease and abdominal complications may help predict future organ dysfunction.

Carotid-Cavernous Fistula in a Patient With Unilateral Periorbital Swelling and Proptosis Initially Attributed to Possible Immunoglobulin G4-Related (IgG4-Related) Disease

The differential diagnosis for proptosis and periorbital swelling is broad and includes infectious, malignant, vascular, and rheumatologic etiologies. In this study, we report a case of carotid-cavernous fistula as the cause of acute-onset unilateral proptosis and periorbital swelling of the right eye in a 44-year-old female patient whose symptoms were initially attributed to possible immunoglobulin G4-related disease (IgG4-RD). The patient initially received antibiotics for presumed cellulitis and steroid treatment for a possible autoimmune cause, however; her autoimmune work-up was negative. Radiologic imaging later confirmed that she had a direct spontaneous carotid-cavernous fistula. She experienced significant improvement in her symptoms and vision after embolization treatment. Due to the risk that a carotid-cavernous fistula will progress quickly and cause neurological damage, this is a key diagnosis that should not be missed in patients with acute-onset periorbital and visual symptoms. Rheumatologists should include this condition in the differential for any patient who presents with periorbital swelling and vision disturbances.

Bilateral swelling of the salivary glands and sicca symptoms: an unusual differential diagnosis-Kimura's disease, a rare allergic condition with a high IgE serum level-a case report and review of the literature

A 68-year-old woman presented with bilateral swelling of the salivary glands, sicca symptoms of eyes and mouth, itching, fatigue and weight gain of about 5 kg in the last 2-3 years. As part of a careful diagnostic work up including lab tests for antinuclear antibodies (ANA), antibodies to extractable nuclear antigens (ENA), anti-neutrophilic cytoplasmatic antiobodies (ANCA), immunoglobulin (Ig)G4, a whole body computed tomography (CT) and a parotid biopsy several rheumatic diseases such as Sjoegren's syndrome, IgG4-related disease and sarcoidosis were ruled out and, considering a very high titre of IgE, Kimura's disease was diagnosed. The case and a short review of the literature are presented.

A case of IgG4-related interstitial nephritis with ureteral obstruction: case report and literature review

BACKGROUND

IgG4-related disease (IgG4-RD) is a newly discovered systemic disease that can affect any organ or tissue in the body. IgG4-related kidney disease (IgG4-RKD) is relatively rare but essential to IgG4-RD. However, there are few reports of IgG4-RD mimicking malignant ureteral tumors leading to hydronephrosis. We report here a rare case of IgG4-RD involving the ureter.

CASE PRESENTATION

An 87-year-old man presented to our nephrology department with anorexia, nausea, and acute kidney injury in November 2020. Urinary computed tomography (CT) examination revealed a right lower ureter mass with right renal and ureter hydronephrosis. The serum level of IgG4 was 1890 mg/dL, and the concurrently renal biopsy revealed extensive infiltration of IgG4-positive plasma cells in renal interstitium, which was diagnosed as IgG4-associated tubule-interstitial nephritis(IgG4-TIN). The renal function improved significantly after double-J tube implantation of the right ureter and moderate-dose hormone therapy. The serum IgG4 decreased to the normal range, and the right lower ureter mass almost disappeared after one year of low-dose hormone maintenance therapy.

CONCLUSION

IgG4-RD can present as a mass in the renal pelvis and (or) ureter, leading to hydronephrosis. Therefore, early recognition of this disease is significant. Most patients respond well to hormonal therapy to avoid surgical treatment due to misdiagnosis as malignant tumors, causing secondary harm to patients.

Hypertrophic pachymeningitis in ANCA-associated vasculitis: Clinical and immunopathological features and insights

Hypertrophic pachymeningitis (HP) is an inflammatory disorder characterized by intracranial and spinal thickened dura mater, leading to several neurological manifestations including headaches, cranial neuropathies, seizures, and sensorimotor disorders. Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a crucial disease that is implicated in the development of immune-mediated HP. HP is observed throughout the clinical course of AAV, and 3%-4% of patients with AAV experience HP as the initial clinical episode. However, patients with ANCA-related HP are unclassifiable in the classification criteria of AAV when HP is the only manifestation, suggesting that ANCA-related HP can be identified as a central nervous system-limited type of AAV. Among patients with AAV, those who develop HP have predominantly been classified as having granulomatosis with polyangiitis (GPA). Myeloperoxidase-ANCA positivity has been more frequently demonstrated than proteinase 3-ANCA positivity in patients with ANCA-related HP. The ear, nose, and throat manifestations, such as otitis media, sinusitis, and mastoiditis, as well as mucous membranes/eyes manifestations including sudden visual loss, are robustly associated with HP in AAV. The histology of thickened dura mater tissues includes fibrotic changes and infiltration of several immunocompetent cells, but the typical findings of GPA, such as granulomatous inflammation with necrotizing vasculitis, are not observed in all patients with ANCA-related HP. Corticosteroids are the first-line therapy for ANCA-related HP, while the concomitant use of immunosuppressive agents including cyclophosphamide, methotrexate, and mycophenolate mofetil, is an ideal strategy for achieving remission. Rituximab is a useful agent in refractory ANCA-related HP.

Pachymeningitis associated with IgG4-related disease and ANCA positivity: Case report and review of the literature

OBJECTIVE

Hypertrophic pachymeningitis is a rare clinical disorder involving localized or diffuse thickening of the dura mater. Considering pachymeningitis is both in the clinical spectrum of IgG4-RD and ANCA vasculitis (specifically granulomatosis with polyangiitis), an overlap syndrome is discussed.

METHODS

We report a case of hypertrophic pachymeningitis revealed by headache and cranial nerve dysfunction, and coexistence of biopsy-proven IgG4-RD pachymeningitis and MPO-ANCA positivity. Furthermore, all cases previously reported in the literature of pachymeningitis with IgG4-RD and presence of ANCA were analyzed.

RESULTS

Thirteen patients with pachymeningitis, IgG4-RD and ANCA were analyzed. Patients with HP-related IgG4 and ANCA are mainly male (8, 62%). Median age at diagnosis was 64 years. Main clinical manifestations at diagnosis were localized to the head and neck with headaches (10, 77%), cranial nerve dysfunction (7, 54%), hearing impairment (6, 46%) and vertigo (4, 31%). Except 1 patient with diffuse aortitis, no other systemic manifestation was observed at diagnosis and during follow-up. Serum IgG4 was often elevated (11, 85%) and ANCA was mainly with myeloperoxidase specificity (11, 85%). Seven patients had cerebrospinal fluid analyse with lymphocytic pleocytosis in 5 cases (71%), elevated proteins in 4 cases (57%), positive oligoclonal bands in 3 cases (42%) and decreased glucose in one case (14%). On the MRI, the thickening of the dura mater concerned most often the posterior fossa, in 7 cases (54%). Among 10 cases with histological findings, all showed increased IgG4-positivity of plasma cells, 50% lymphocytic infiltrate but none presented the three major histological criteria of IgG4-related disease. Three (30%) showed histological signs of vasculitis with vascular wall damage and/or giant cells. Among the 12 patients treated with steroid therapy, a clinical improvement was noted in 11 cases (92%). Relapse occurred during tapering in 4 patients (33%). An immunosuppressive drug was added in 2nd line for 7 cases (54%), with a clinical improvement in all.

CONCLUSION

Pachymeningitis with IgG4 and ANCA seems a localized disease to the head and neck. Leptomeningeal biopsy commonly found IgG4 criteria and no vasculitis. All patients responded well to steroid therapy and immunosuppressive drugs, especially rituximab, with clinical and radiological improvement but relapse and/or sequelae are not uncommon.

Progression to End-Stage Renal Disease Due to IgG4-Related Nephritis Refractory to Rituximab

An 81-year-old woman was referred to nephrology for a follow-up on progressive chronic kidney disease. She has a past medical history of hypertension, T2DM, breast cancer, and secondary hyperparathyroidism related to renal disease. A renal biopsy showed patchy interstitial fibrosis and tubular atrophy with an increased number of IgG4-positive plasma cells. A diagnosis of IgG4-related kidney disease was made based on clinical presentation and pathology. The patient ultimately required the initiation of hemodialysis, despite the administration of steroids and rituximab.

IgG4-related disease with kidney and lymph nodes involvement: a case-based review

IgG4-related disease (IgG4-RD), a rare immune-mediated chronic fibro-inflammatory condition, has various initial symptoms, thus posing diagnostic and therapeutic challenges. Here, we report a case of IgG4-RD in a 35-year-old man with initial clinical symptoms of facial edema and recent onset of proteinuria. It took more than 1 year from the onset of clinical symptoms to diagnosis. Pathological examination of renal biopsy revealed significant renal interstitial lymphoid tissue hyperplasia simulating growth pattern of lymphoma. Immunohistochemical (IHC) staining results showed that CD4 + T lymphocyte hyperplasia was dominant. There was no significant deletion of CD2/CD3/CD5/CD7. No monoclone was detected in TCR gene rearrangement. IHC staining showed that the number of IgG4-positive cells was greater than 100/HPF. The ratio of IgG4/IgG was greater than 40%. Combined with clinically examinations, IgG4-related tubulointerstitial nephritis was considered. Further cervical lymph node biopsy results suggested IgG4-related lymphadenopathy. He received methylprednisolone 40 mg/day intravenously for 10 days, leading to normal results of laboratory tests and clinical manifestations. The patient had a good prognosis without recurrence during 14 months of follow-up. This case report can be used as a reference for early diagnosis and treatment of such patients in the future.

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.

Lymph Nodes With Increased IgG4-positive Plasma Cells and Patterns Suspicious for IgG4-related Disease: Can Lymph Nodes Be the Only Site of Disease?

Lymphadenopathy with increased immunoglobulin (Ig) G4 + plasma cells can be a nonspecific finding or a manifestation of immunoglobulin G4-related disease (IgG4-RD). It remains unclear whether there are characteristic pathologic features of IgG4-RD involving lymph nodes, or if IgG4-RD lymphadenopathy can occur without other manifestations of IgG4-RD. In this study, we assessed 55 lymph node biopsy specimens (44 men and 11 women with a mean age of 55 y) with increased IgG4 + plasma cells that had 1 of the 6 well-described pathologic patterns. We also correlated these findings with IgG4 serum levels and followed these patients for 7 to 108 months (mean, 34.9 mo) for the occurrence of extranodal IgG4-RD. We further compared lymphadenopathy in patients who developed other manifestations of IgG4-RD (RD + , n=20, 36%) versus those who did not (RD - , n=35, 64%). We found that there were only minor significant differences between 2 groups, including frequency of receiving treatment (RD + , 90% vs. RD - , 60%, P =0.021) and higher serum levels of C-reactive protein (>8 mg/L, RD + , 53% vs. RD - , 13%, P =0.007). Other differences were either borderline or not significant, including mean age (RD + , 59.8 y vs. RD - , 51.9 y, P =0.097), male-to-female ratio (RD + , 16:4 vs. RD - , 28:7, P =1), constitutional symptoms (RD + , 25% vs. RD - , 9%, P =0.096), multiple enlarged lymph nodes (RD + , 45% vs. RD - , 26%, P =0.143), good response to therapy (RD + , 94% vs. RD - , 94%, P =1); higher serum IgG4 levels (>280 mg/dL, RD + , 75% vs. RD - , 51%, P =0.086), anemia (RD + , 45% vs. RD - , 43%, P =0.877), leukopenia (RD + , 0% vs. RD - , 3%, P =0.446), thrombocytopenia (RD + , 10% vs. RD - , 6%, P =0.556), positivity for antinuclear antibody (RD + , 24% vs. RD - , 29%, P =0.688), elevated serum levels of lactate dehydrogenase (>225 U/L, RD + , 0% vs. RD - , 20%, P =0.064), elevated serum IgE level (>100 IU/mL, RD + , 75% vs. RD - , 92%, P =0.238), and hypergammaglobulinemia (RD + , 90% vs. RD - , 86%, P =0.754). There were also no differences in morphologic patterns ( P =0.466), IgG4 + cell location ( P =0.104), eosinophil counts (RD + , 10.3±11.3 vs. RD - , 13.4±17.5, P =0.496), Epstein-Barr virus positivity (RD + , 35% vs. RD - , 60%, P =0.074), and Epstein-Barr virus-positive cell location ( P =0.351). Our findings suggest that there are minimal differences between stringently defined IgG4-RD lymphadenopathy with versus without other manifestations of IgG4-RD. These findings also suggest the existence of IgG4-RD lymphadenopathy as the sole presentation of IgG4-RD.

Anatomic and Functional Imaging of Immunoglobulin G4-related Disease and Its Mimics

Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) is an immune-mediated fibrosclerosing disease with tumefactive lesions infiltrated by IgG4-positive plasma cells. Initially described as autoimmune pancreatitis, IgG4-RD is now recognized as a discrete entity and is found to affect virtually any organ in the body. Common extrapancreatic sites include the biliary tree, salivary glands, periorbital tissue, lungs, kidneys, lymph nodes, aorta, retroperitoneum, and thyroid gland. Diagnosis-which relies on histopathologic, serologic, and radiologic features-can be challenging with the disease underdiagnosed, as IgG4-RD often mimics malignancy, infectious processes, or other immune-mediated conditions. Patients may present with signs of compression of nearby structures due to mass effect or with organ failure when the disease is left untreated. The clinical course is complex, with single- or multiorgan involvement and metachronous or synchronous occurrence of lesions. IgG4-RD responds well to glucocorticoid therapy, disease-modifying antirheumatic drugs, and B-cell-depleting biologic agents; prompt diagnosis is important to avoid delay in treatment and unnecessary pharmacologic or surgical intervention. While imaging features may not be specific for IgG4-RD, functional whole-body imaging with fluorine 18-fluorodeoxyglucose PET/CT is a useful adjunct for localizing extrapancreatic sites for biopsy, monitoring therapeutic response, and demonstrating disease relapse. The authors describe the pancreatic and extrapancreatic sites of involvement in IgG4-RD, with imaging features and patterns to aid in distinguishing IgG4-RD from its mimics through a multimodality approach with emphasis on functional imaging evaluation. ^©RSNA, 2023 Quiz questions in the supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.

Roles of IgG4 and IgG4/IgG ratio to IgG4-related disease in patients with elevated serum IgG4 level

OBJECTIVE

To evaluate the performance of elevated serum IgG4 and IgG4/IgG in IgG4-related disease (IgG4-RD) and other diseases.

METHODS

Seven hundred seventy-three patients with elevated serum IgG4 level (> 2.01 g/L) were reviewed in Zhongda Hospital of Southeast University from 1 July 2016 to 31 December 2021. Demographic, disease distribution and the role of elevated serum IgG4 and IgG4/IgG in IgG4-RD and other diseases were analysed. The alteration of IgG4 and IgG4/IgG in pre-therapy and post-treatment were also assessed in IgG4-RD.

RESULTS

Patients with elevated serum IgG4 were principally observed in older males. Chronic diseases of various organs (21.7%), rheumatic immune diseases (19.4%), bacterial infection disease (11.5%) and malignant tumor (5.2%) were the common diseases with elevated serum IgG4, but only 3.2% was IgG4-RD. The level of IgG4 and IgG4/IgG in IgG4-RD was significantly higher than that in various diseases except for eosinophilia group. Serum IgG4 and IgG4/IgG manifested a similar diagnostic capacity for IgG4-RD among this study cohort and the optimal cut-off values were 3.345 g/L and 0.295 respectively. The sensitivity and specificity were 96% and 71% for the optimal cut-off value of IgG4, and 80% and 88.8% for the optimal cut-off value of IgG4/IgG4. IgG4 and IgG4/IgG both were remarkably reduced in IgG4-RD after therapy compared with prior treatment (P < 0.05).

CONCLUSIONS

Elevated serum IgG4 was found in a variety of diseases, especially in chronic diseases of various organs. IgG4 and IgG4/IgG manifest a great value for IgG4-RD diagnosis, and are available for the treatment evaluation of IgG4-RD. Key Points • Elevated serum IgG4 level was not a specific marker to IgG4-related disease and can be observed in various diseases. • Patients with IgG4-related disease or eosinophilia manifest a higher level of serum IgG4 and IgG4/IgG. • Both of IgG4 and IgG4/IgG are available for the diagnosis and the clinical treatment evaluation of IgG4-related disease.

IgG4-related autoimmune liver disease

The term IgG4-related autoimmune liver disease (AILD) refers to hepato-biliary manifestations of Immunoglobin G4-related disease (IgG4-RD) including IgG4-related sclerosing cholangitis and IgG4-related pseudotumor. The association of some forms of autoimmune hepatitis to IgG4-RD remains controversial. Although autoimmune phenomena have not been clearly observed in IgG4-AILD, perturbation of the adaptive immune system and activation of the humoral response represent established pathophysiological hallmarks and potential therapeutic targets. Clinical manifestations of IgG4-AILD are virtually indistinguishable from bile duct cancer or primary sclerosing cholangitis and are due to mass forming lesions and thickening of the biliary tract that progressively lead to biliary ducts obstruction. There are no current reliable biomarkers for IgG4-AILD and diagnosis should rely on the integration of clinical, serological, radiological, and histological findings. In analogy to most IgG4-RD manifestations, and in contrast to its major mimickers, IgG4-AILD promptly responds to glucocorticoids but frequently relapses, thus requiring long-term maintenance therapy to avoid progressive fibrosclerotic disease and liver cirrhosis. Accumulating evidence on the efficacy of B-cell depletion therapy in patients with systemic IgG4-RD is gradually changing the treatment paradigm of IgG4-AILD and biologics will be increasingly used also for gastroenterological manifestations of IgG4-RD to spare glucocorticoids and traditional immunosuppressive agents. Looking ahead, identification of reliable biomarkers and of mini-invasive strategies to obtain informative biopsies from the biliary tree represent unavoidable priorities to optimize diagnosis and management of IgG4-AILD.

Development of an algorithm for IgG4-related disease management

OBJECTIVES

IgG4-related disease (IgG4-RD) is a rare fibro-inflammatory condition affecting multiple organs lacking standardized management. In this article, we review the evidence available to provide European expert-based statements on the management of IgG4-RD which were integrated in a final algorithm.

METHODS

A panel of nine European experts in IgG4-RD from different specialties was asked to elaborate a set of consensus statements through a Delphi exercise. Three rounds of survey were taken. Consensus was reached when ≥75% of the responders agreed with a statement.

RESULTS

Thirty-one statements on induction treatment, maintenance treatment, non-pharmacological treatment, and general considerations were assessed. Patients should be treated promptly in situations when there is an immediate organ threatened, or when organ damage is anticipated. Glucocorticoids (GC) are considered the first line of treatment and should be progressively tapered. Maintenance treatment is recommended for patients with high disease activity or with risk factors for relapse. Rituximab is effective for induction and maintenance of remission, but its use can be limited by economics. Low dose GC with or without GC-sparing agents can be used for maintenance therapy. Stenting or surgery should be ancillary to pharmacological treatment. Follow up should be based on physical examination, blood works, and imaging studies. Furthermore, it should be tailored on individual patient clinical history. 18-fluorodeoxyglucose positron emission tomography/computerized tomography may provide additional information over other imaging modalities.

CONCLUSIONS

These new statements and algorithm reached a high degree of agreement and may help guiding the clinical management of IgG4-RD.

Lung and Pleural Immunoglobulin G4-Related Disease: Two Contrasting Case Reports

Immunoglobulin G4-related disease (IgG4-RD) is an immunomediated disease that can virtually affect any organ. Despite the pancreas being known as the most frequently involved organ, pulmonary and pleural IgG4-RD is being increasingly reported. The authors present two cases of IgG4-RD diagnosed in the same year, with different presentations and outcomes, in which the lung and pleural involvement were essential for the diagnosis. Recognizing IgG4-RD as a possible cause of chronic pleural effusion and/or thickening and lung abnormalities is important for an early diagnosis and prognosis improvement.

Differential diagnosis of a local form of granulomatosis with polyangiitis: nasal cavity and paranasal sinuses lesions (part 1)

Granulomatosis with polyangiitis (GPA) is a primary vasculitis associated with antineutrophil cytoplasmic antibodies, characterized by necrotizing vasculitis with predominant involvement of small vessels of various localizations and necrotizing granulomatous inflammation with multiple clinical manifestations. GPA remains one of the most severe systemic vasculitis with unfavorable prognosis. When analyzing the course of the disease, there are two variants of GPA, local (with lesions of the upper respiratory tract, URT, organs of vision and hearing) and generalized (with lesions of the URT, organs of vision and hearing in combination with the lungs and/or kidneys, gastrointestinal tract, nervous systems, skin involvement).The article discusses the differential diagnosis of the disease with the nasal cavity and paranasal sinuses lesions onset, which requires an interdisciplinary approach and interaction of doctors of different specialties.

Performance of classification and diagnostic criteria for IgG4-related disease and comparison of patients with and without IgG4-related disease

IgG4-related disease (IgG4-RD) was recently described in Japan. It is characterised by extensive organ involvement with tissue fibrosis. We assessed the performance of the 2019 American College of Rheumatology and European League Against Rheumatism (ACR/EULAR) classification criteria and the 2020 revised comprehensive diagnostic (RCD) criteria as well as differences between patients with and without IgG4-RD. In this retrospective, single-centre study of 50 patients admitted with suspected IgG4-RD, we evaluated the sensitivity and specificity of both criteria. We also compared clinical characteristics and laboratory data of patients with IgG4-RD (n = 42) and patients without IgG4-RD (n = 8). The ACR/EULAR classification criteria had 88.1% sensitivity and 87.5% specificity for IgG4-RD diagnosis. The RCD criteria had 100% sensitivity and 50% specificity. Patients with IgG4-RD had significantly more affected organs (p = 0.002). Patients with a single affected organ and IgG4-RD had significantly higher serum IgG4/IgG ratios (p = 0.027), lower serum C-reactive protein levels (p = 0.020), and lower total haemolytic complement activity (p = 0.044) than those without IgG4-RD. The ACR/EULAR classification criteria have high specificity and the RCD criteria have high sensitivity for diagnosing IgG4-RD. The number of affected organs is important for diagnosing IgG4-RD.

IgG4 related disease and aortitis: an up-to-date review

Aortic involvement in immunoglobulin G4-related disease (IgG4-RD) is extremely rare and is often overlooked during the aortitis work-up. IgG4-related aortitis differs from non-IgG4-related aortitis in its histopathological features, site of involvement, laboratory markers, and treatment options. The histopathological examination of the vessel walls characteristically reveals adventitial thickening with intimal sparing, typically affecting the infrarenal abdominal aorta. In addition, inadequate knowledge about the disease often leads to delayed or missed diagnosis and undermanagement of a potentially treatable condition. Hence, in this paper, we review the unique clinical manifestations, laboratory markers, diagnostic features, current treatment strategies, and novel experimental therapeutic options in the management of IgG4-related aortitis.

Thoracic manifestations of IgG4-related disease

Immunoglobulin G4-related disease (IgG4-RD) is a recently described rare systemic fibroinflammatory disease with an estimated incidence of less than 1 in 100,000 persons per year. The disease can affect virtually any organ and is characterized by unifying histopathological findings. Recently, four subgroups of patients have been characterized: hepatobiliary, head and neck, Mikulicz syndrome and retroperitoneal fibrosis, who illustrate the mainly abdominal and ENT tropism of the disease. Yet, thoracic involvement is not uncommon. It can be detected in up to 30% of patients with systemic IgG4-RD and is the exclusive manifestation of the disease in about 10% of cases. Clinical symptoms are nonspecific and may include dyspnoea, cough or chest pain. Chest CT findings are heterogeneous and primarily include peribronchovascular thickening, nodules, ground-glass opacities and lymphadenopathy. There is no specific diagnostic test for IgG4-RD thoracic involvement, which may mimic malignancy or vasculitis. Therefore, a cautious approach is needed to make an accurate diagnosis: a search for extra-thoracic manifestations, elevated serum IgG4 levels, circulating levels of plasmablasts and pathologic evidence of disease is warranted. Although very suggestive, neither the presence of a polyclonal IgG4 lymphoplasmacytic infiltrate, storiform fibrosis or obliterative phlebitis are sufficient to confirm the histological diagnosis. Steroids are recommended as first-line therapy. Rituximab or disease-modifying antirheumatic drugs may be used in relapsed or rare cases of steroid-refractory disease. In this review, we summarize current knowledge regarding the pathophysiology, epidemiology, diagnostic modalities (clinical-biological-imaging-histopathology) and treatment of IgG4-RD thoracic involvement.

IgG4-related ophthalmic disease in association with adult-onset asthma and periocular xanthogranuloma: a case report

A 54-year-old male presented with a three-year history of bilateral upper eyelid and peri-orbital swelling and adult-onset asthma. Histopathology of a left orbital biopsy showed lymphoid follicles with foamy macrophages and Touton giant cells. Clinical, histological and radiological features were consistent with adult-onset asthma and periocular xanthogranuloma. Treatment with rituximab led to a complete clinical and radiological remission. Nine years later, his condition relapsed with a biopsy of the left orbit and lacrimal gland demonstrating features of IgG4-related disease and adult-onset asthma and periocular xanthogranuloma. Immunohistochemistry showed increased numbers of IgG4+ plasma cells (290 per high power field) and an elevated IgG4+/IgG+ plasma cell ratio of 480%. Involvement by both disorders in the orbit and ocular adnexa of a single patient has not previously been reported in the literature, to the best of our knowledge, and suggests a possible aetiologic or pathophysiologic association.

Difficulties of diagnosing idiopathic hypertrophic pachymeningitis in children: Case report and literature review

Hypertrophic pachymeningitis (HP) is a rare inflammatory disorder characterised by local or diffuse thickening of the cranial and spinal dura mater. HP occurs owing to idiopathic or secondary causes, including autoimmune disease, infection, and trauma. HP has mainly been reported in adults, with few reported cases in children. We encountered an 11-year-old boy with idiopathic HP who presented with chronic inflammation and daily occipital headache. Gadolinium (Gd)-enhanced magnetic resonance imaging (MRI) helped us to diagnose him with HP. He was successfully treated with corticosteroids and azathioprine with no recurrence. We also conducted a literature review of childhood-onset HP and found only 16 cases, including our patient. Seven patients had idiopathic HP, and the remaining nine had secondary HP, including two with rheumatic disease. The most common clinical symptoms were headache (68.8%) and cranial nerve-related symptoms (68.8%). Inflammatory laboratory markers were elevated in 60% of patients with available data. Fifteen cases were diagnosed using Gd-enhanced MRI. The main initial treatment was steroids and/or immunosuppressants, to which 87.5% of patients responded. However, two patients with HP associated with trauma and neuroblastoma (12.5%) died, and seven patients (43.8%) had left cranial nerve-related sequelae. As the prognosis for childhood HP is poor, early diagnosis and treatment are essential. Children with headache, cranial nerve symptoms, and elevated inflammatory marker levels should be suspected of having HP and Gd-enhanced MRI should be considered.

A case of aortoduodenal fistula caused by IgG4-related periaortitis

An 86-year-old man who underwent endovascular aortic repair for impending rupture of an abdominal aortic aneurysm a year ago presented to our hospital because of fatigue and black stools. Multiple bacterial specimens were detected in blood cultures, and computed tomography following oral administration of gastrografin demonstrated gastrografin in the abdominal aorta. The diagnosis of aortic duodenal fistula was confirmed and emergency abdominal aortic replacement was performed. The pathological findings of the aorta included a large number of immunoglobulin G4 (IgG4)-positive plasma cells infiltrating all layers of the aortic wall, with particularly marked thickening of the adventitia. The serum IgG4 level was 241 mg/dl and IgG4-related periaortitis was diagnosed. Aortoduodenal fistula is a rare but fatal complication of IgG4-related periaortitis. Patients should be followed carefully after endovascular aortic repair for inflammatory abdominal aortic aneurysms.

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.

Large lung mass lesion with spontaneous regression in a patient with IgG4-related lung disease

IgG4-related lung disease (IgG4-RLD) may present with a variety of radiological findings, but large lung mass lesion are rare. Although steroid therapy is strongly recommended for IgG4-RLD with or without symptoms, respirologists should be aware that some patients may not need steroid therapy.

Serum IgG4 level during initial treatment as a predictor of relapse in IgG4-related disease

INTRODUCTION

We aimed to investigate the predictors of relapse in immunoglobulin G4-related disease (IgG4-RD), focusing on the serum IgG4 levels during initial treatment.

METHODS

We retrospectively recruited 57 patients with IgG4-RD who were treated with immunosuppressants and elevated serum IgG4 levels in a tertiary hospital between January 2011 and December 2020. They were followed up for ≥ 6 months after initiation of immunosuppressive therapy. Clinical and laboratory findings including serum IgG4 levels (reference value: 6-121 mg/dL) were compared between relapsed (n = 13) and non-relapsed (n = 44) groups. Multivariate Cox regression analysis was used to assess the predictors for relapse. We performed a Kaplan-Meier analysis with a log-rank test to evaluate the cumulative relapse rate for two years.

RESULTS

Median serum IgG4 levels at baseline were 321 mg/dL in the relapsed group and 299 mg/dL in the non-relapsed group. Serum IgG4 levels were normalized after six months in five (38.5%) relapsed and 28 (63.6%) non-relapsed patients. In multivariate Cox regression analysis, the normalization of serum IgG4 levels at six months was associated with a lower risk of relapse, with a hazard ratio of 0.232 (p = 0.019). Central nervous system involvement was associated with the relapse, with a hazard ratio of 21.130 (p = 0.015). The cumulative relapse rate for two years was lower in the normal serum IgG4 group at six months than in the elevated serum IgG4 group at six months (p = 0.027).

CONCLUSION

Our study suggests that normalization of serum IgG4 levels during immunosuppressive treatment for IgG4-RD independently predicts relapse-free outcomes. Thus, monitoring serum IgG4 levels might be used as a marker of prognosis.

Bibliometric analysis of IgG4-related disease research from 2003 to 2022 based on Web of Science Core Collection Databases

This study aimed to perform a bibliometric analysis of the IgG4-related disease (IgG4-RD) research field over the past 20 years to explore its research hotspots and trends. The literature of IgG4-RD published in the Web of Science Core Collection databases was reviewed from January 1, 2003, to April 30, 2022. A bibliometric analysis was carried out using CiteSpace software to evaluate and visualize the evolving dynamics and hotspots in the field of IgG4-RD. A total of 3174 IgG4-RD articles were reviewed. Since 2011, there has been a rapid increase in published literature. Japan is the highest yielding country and Kanazawa University the highest yielding institution. The USA has the highest centrality (0.34) and plays a critical role in cooperation and communication of IgG4-RD research. Nine highly connected clusters of IgG4-RD were observed by keyword analysis. Research hotspots included IgG4-RD involved organs and differentiation from Rosai-Dorfman disease and primary sclerosing cholangitis. Further research topics include pathogenesis, relapse, and malignancy. As a cross-discipline systemic disease, IgG4-RD requires attention by clinicians in multiple fields. This bibliometric analysis can help researchers grasp trends and provide new perspectives for future research on IgG4-RD.

[Differential diagnosis of IgG4-related disease]

IgG4-related disease is a chronic autoimmune fibro-inflammatory disease characterized by the presence of lymphoplasmacytic infiltrate, storiform fibrosis, obliterating phlebitis, increased number of IgG4+ cells in tissue, and, in most cases, an elevated serum IgG4 level. This disease often affects the pancreas, salivary glands and lymph nodes, but can involve almost any tissue. Its etiology is still unclear, the central role in the pathogenesis belongs to B-lymphocytes, T2-helpers, interleukins 1-β, 4, 5, 10, 13 and tumor growth factor 1-β. The ambiguous clinical picture and frequent simultaneous involvement of several organs make it difficult to diagnose, so biopsy plays a leading role in making a diagnosis. The characteristic microscopic picture, the presence of certain populations of lymphocytes are key criteria in establishing the correct diagnosis.