Elevated polyclonal IgG4 mimicking a monoclonal gammopathy in IgG4-related disease-a case-based review

IgG4-related diseases (IgG-RDs) are a group of fibroinflammatory diseases that affect a variety of tissues, resulting in tumour-like effects and/or organ dysfunction. Monoclonal gammopathies (MGPs) are a group of disorders characterized by clonal proliferation of plasma cells or lymphoid cells resulting in the secretion of a monoclonal immunoglobulin. Cases of MGPs in IgG4-RDs coexisting with plasma cell dyscrasias and lymphoid neoplasms have been reported over the past few years. Therefore, the results of examinations of M protein in IgG4-RD patients should be interpreted with caution. Herein, we report the case of a 58-year-old male with a history of type 2 diabetes who presented with submandibular masses, anosmia, swollen lymph nodes, proteinuria, and renal impairment. Laboratory tests revealed hyperglobulinemia and elevated levels of IgG4 (124 g/L) and serum-free light chains (sFLCs). Serum protein electrophoresis (SPEP) revealed an M spike of 5.6 g/dL, and immunofixation electrophoresis (IPE) revealed biclonal IgG-κ and IgG-λ. The patient underwent bone marrow, lymph node, and kidney biopsy, which ruled out plasma cell disorders and lymphoma. He was finally diagnosed with an IgG4-RD comorbid with diabetic nephropathy. The findings in this case highlight that significant activation of B cells in IgG4-RD patients, especially those with multiorgan involvement can lead to significant hyperglobulinemia and high sFLC and IgG4 levels, which are more pronounced in the setting of renal impairment. Relatively high concentrations of polyclonal IgG4 can give rise to a focal band bridging the β and γ fractions, which may mimic the appearance of a monoclonal band on SPEP and monoclonal gammaglobulinemia in IFE. The patient experienced considerable improvement in his symptoms after rituximab combined with glucocorticoid therapy, and a monoclonal immunoglobulin was not detected.

Transcriptional profiling sheds light on the fibrotic aspects of idiopathic subglottic tracheal stenosis

Idiopathic subglottic stenosis (ISGS) is a rare fibrotic disease of the upper trachea with an unknown pathomechanism. It typically affects adult Caucasian female patients, leading to severe airway constrictions caused by progressive scar formation and inflammation with clinical symptoms of dyspnoea, stridor and potential changes to the voice. Endoscopic treatment frequently leads to recurrence, whereas surgical resection and reconstruction provides excellent long-term functional outcome. This study aimed to identify so far unrecognized pathologic aspects of ISGS using single cell RNA sequencing. Our scRNAseq analysis uncovered the cellular composition of the subglottic scar tissue, including the presence of a pathologic, profibrotic fibroblast subtype and the presence of Schwann cells in a profibrotic state. In addition, a pathology-associated increase of plasma cells was identified. Using extended bioinformatics analyses, we decoded pathology-associated changes of factors of the extracellular matrix. Our data identified ongoing fibrotic processes in ISGS and provide novel insights on the contribution of fibroblasts, Schwann cells and plasma cells to the pathogenesis of ISGS. This knowledge could impact the development of novel approaches for diagnosis and therapy of ISGS.

Unraveling the Clinical Features and Outcomes of IgG4-Related Ophthalmic Disease

Background/Objectives: IgG4-related ophthalmic disease (IgG4-ROD), characterized by lymphoplasmacytic infiltration, fibrosis, and elevated IgG4 levels, presents diagnostic challenges while offering insights into immune-mediated inflammatory disorders. The aim of this study was to comprehensively examine the clinical features and outcomes of IgG4-ROD. Materials and Methods: A retrospective study was conducted on 33 patients diagnosed with IgG4-ROD, fulfilling the American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) criteria. The demographic characteristics of the IgG4-ROD patients were compared with those of 37 patients diagnosed with IgG4-related disease (IgG4-RD) in departments other than ophthalmology (IgG4-nonROD) at the same hospital during the same period. The patients diagnosed with IgG4-ROD were initially treated with glucocorticosteroid (GCS) monotherapy, GCS combined with steroid-sparing agents (SSAs; mycophenolate mofetil, azathioprine, hydroxychloroquine), biologic agent (rituximab) monotherapy, or watchful waiting. The primary outcome was the assessed treatment response at 6 months, and the secondary outcome was the evaluation of recurrence at 1 year after initial treatment. A response was evaluated as the absence of ocular signs and symptoms, either clinically or radiologically. Results: Eyelid swelling (17 patients, 51.5%) was the most common symptom, and lacrimal gland (17 patients, 51.5%) was the most frequent site of involvement. The response rate for GCS monotherapy was 33.3% (3 out of 9 patients), while the response rate for GCS combined with SSA was 60.0% (9 out of 15 patients). The lacrimal gland group demonstrated a significantly higher treatment response compared to the non-lacrimal gland group (66.7% vs. 20.0%, p = 0.013), and the combination of GCS and SSA resulted in a significantly higher treatment response than the GCS monotherapy (77.8% vs. 33.3%, p = 0.045). The group including hydroxychloroquine (HCQ), which comprised 5 out of 33 patients (15.2%), showed no recurrence at 1 year. Conclusions: The combination therapy of GCS and SSA for IgG4-ROD can be considered an effective treatment approach and HCQ could be considered as a potential adjunctive therapy for IgG4-ROD.

Implications of Serum IgG4 Levels for Pancreatobiliary Disorders and Cancer

Background/Objectives: Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated disorder presenting as mass-like lesions with obstructions. An elevated serum IgG4 level is identified in more than half of affected patients and is considered a diagnostic criterion. IgG4-RD is still easily misdiagnosed as neoplastic or infectious disease. We aimed to conduct a hospital-based study to illuminate the association between serum IgG4 levels and pancreatobiliary disorders and cancer. Methods: In this study, serum IgG4 levels were assessed at our hospital's immunology laboratory, utilizing data from the hospital's computer center, and the diagnostic codes used were based on ICD-9-CM. We analyzed IgG4 level data collected between April 2013 and April 2020, including patients' age, gender, and diseases, but excluding the rationale for IgG4 level assessment. Employing propensity score matching (PSM) at a 1:1 ratio to mitigate age and gender confounding, we analyzed 759 patients divided into groups by IgG4 levels (≤140 and >140 mg/dL; and ≤140, 141-280, >280 mg/dL). We explored associations between IgG4 levels and conditions such as pancreatobiliary cancer (the group included cholangiocarcinoma, pancreatic cancer, and ampullary cancer), cholangitis, cholangiocarcinoma, pancreatitis, pancreatic cancer, and ampullary cancer. Results: Our study analyzed the demographics, characteristics, and serum IgG4 levels of participants and found no significant differences in serum IgG4 levels across various pancreatobiliary conditions. Nevertheless, the crude odds ratios (ORs) suggested a nuanced association between a higher IgG4 level > 280 mg/dL and increased risks of cancer and pancreatitis, with crude ORs of 1.52 (p = 0.03) and 1.49 (p = 0.008), respectively. After PSM matching, the further analysis of 759 matched patients showed no significant differences in IgG4 levels > 140 mg/dL between cancerous and non-cancerous groups, nor across other pancreatobiliary conditions. A higher serum IgG4 level > 280 mg/dL was significantly associated with pancreatobiliary cancer and cholangiocarcinoma, with crude ORs of 1.61 (p = 0.026) and 1.62 (p = 0.044), respectively. In addition, IgG4 > 280 mg/dL showed a greater association with pancreatic cancer compared with 141-280 mg/dL, with crude OR of 2.18 (p = 0.038). Conclusions: Our study did not find a clear association between serum IgG4 levels (>140 mg/dL) and pancreatobiliary cancer. We observed that higher IgG4 levels (>280 mg/dL) may be associated with cholangiocarcinoma and pancreatic cancer, as indicated by crude ORs. However, the adjusted analysis did not demonstrate the significant association between IgG4 level > 280 mg/dL and cancer. Considering IgG4-RD as a chronic and persistent inflammatory status, it is more closely associated with inflammatory diseases than with cancer. Therefore, further long-term cohort studies are necessary to evaluate the potential role of IgG4 levels in cancer risk among these patients.

The "great imitator": IgG4-related disease of the oral cavity. Two case reports and scoping review

This study aimed to review the lesser-known intraoral manifestations of immunoglobulin G4-related disease (IgG4-RD). In this paper we report an unprecedented case of oral IgG4-RD mimicking angiolymphoid hyperplasia with eosinophilia (ALHE), and another case presenting as plasma cell gingivitis. We then performed a scoping review of published cases of IgG4-RD involving the oral cavity. The following data were collected for each case: age, sex, intraoral site(s) involved, clinical appearance, imaging features, serum IgG4 values, histopathology, treatment, and follow-up duration. Fifty-one cases of oral IgG4-RD were published in literature. The hard palate and jaw bones were the two main locations reported, while the histological identification of a IgG4/IgG plasma cells ratio ≥40% was fundamental for diagnosis. Conversely, the pathological features of storiform fibrosis and obliterative phlebitis were not common. Future reports regarding oral IgG4-RD should report clear adherence to the recognized international diagnostic criteria of the disease.

When inflammation is not just inflammation-A review of systemic diseases of the nose and sinuses part 1: IgG4-related disease and sarcoidosis

BACKGROUND

Chronic rhinosinusitis is a very common condition. IgG4-related disease (IgG4-RD) and sarcoidosis are systemic diseases which can contribute to the development of chronic rhinosinusitis in select patients.

OBJECTIVE

Characterize the presenting features, diagnostic criteria, workup, and management of sinonasal IgG4-RD and sarcoidosis as they are encountered in otolaryngology clinics.

METHODS

Full length manuscripts published 2000 or later were reviewed. A separate search was conducted for each disease. Pertinent clinical features related to sinonasal manifestations of IgG4-RD and sarcoidosis were collected and reported in this review.

RESULTS

404 references were discovered during literature review process. In total, 42 references for IgG4-RD and 34 references for sarcoidosis were included in this review.

CONCLUSION

IgG4-RD and sarcoidosis are autoimmune inflammatory conditions that can affect many systems of the body. For both disease entities, sinonasal disease is a less common presentation which can lead to delayed diagnosis. Sinonasal IgG4-RD commonly presents in the setting of multisystem disease. All with other clinical features, biopsy plays a key role in the diagnosis for both diseases. Treatment for IgG4-RD consists primarily of steroids and rituximab which can lead to excellent and durable remission. A variety of immunosuppressive agents are used in the management of sarcoidosis. Surgery for IgG4-RD is primarily utilized for tissue biopsy, although resection or debulking may be considered. For sarcoidosis, surgery can be used for tissue biopsy and functional sinus surgery can offer symptomatic relief in many patients.

Mimickers of anterior uveitis, scleritis and misdiagnoses- tips and tricks for the cornea specialist

BACKGROUND

Anterior uveitis, inflammation of the anterior chamber and related structures, is a cohort of diseases that can present to almost any general or sub-specialty Ophthalmology practice. Its features classically involve anterior chamber cell and flare. Below the surface of these two signs exist a panoply of diagnoses. BODY: The purpose of this review is to provide a general framework for diagnoses of anterior uveitis that are often missed as well as non-uveitic pathologies that often mimic anterior uveitis. Diagnostic deviation in either direction can have vision-threatening and rarely life-threatening consequences for patients. Using a comprehensive literature review we have collected a broad spectrum of etiologies of anterior uveitis that are easily missed and non-uveitic pathologies that can masquerade as anterior uveitis.

CONCLUSIONS

We present a focused review on specific misdiagnosed anterior uveitis pathologies and some of the conditions that can masquerade as anterior uveitis and scleritis.

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

BACKGROUND

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

CASE PRESENTATION

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

CONCLUSIONS

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

A case with multiple nodules and mucosal oedema of the trachea and both bronchi induced by IgG4-related disease

BACKGROUND

IgG4-related disease is a systemic fibroinflammatory disease that is mainly seen in older men, and involves multiple organs, such as the pancreas and lungs. However, 75% of patients with IgG4-related lung disease are asymptomatic (if they are symptomatic, they mainly complain of nasal congestion, rhinorrhoea, chest pain, and cough) and are incidentally diagnosed through chest computed tomograph. Although, nodules in the airway and bronchial wall thickening are criteria for diagnosis, it is important that nodules have been reported in peripheral airways in several cases and rarely in the central airway.

CASE PRESENTATION

A 74-year-old woman previously diagnosed with Mikulicz's disease presented with swelling of the eyelid margin on both sides and visual disturbances. Computed tomography revealed extensive multiple nodules and mucosal oedema of the trachea and both bronchi. On flexible bronchoscopy under local anaesthesia, extensive lesions were observed from the middle of the trachea to the carina, extending into both segmental bronchi. The nodules were continuous with the normal respiratory tract mucosa, and the surfaces were smooth with minimal neovascularisation. Due to the solid nature of the lesion, obtaining an adequate amount of specimen was challenging. Therefore, we used a 1.9 mm cryoprobe under intubation, resulting in minimal bleeding. Subsequently, the patient was diagnosed with IgG4-related lung disease.

CONCLUSIONS

The present case is very rare because of the presence of multiple nodules, severe mucosal edema of the central airway and the absence of mediastinal lymphadenopathy, ground glass nodules, and lung masses. Therefore, it is important to consider differential diagnoses. Thus, we emphasise the importance of endobronchial cryobiopsy for obtaining an adequate number of tissue specimens in such cases to establish a definitive pathological diagnosis.

IgG4-related uveitis. A French cohort and literature review

INTRODUCTION

IgG4-related disease (IgG4-RD) is a fibro-inflammatory disorder that can affect almost any organ. IgG4-related ophthalmic disease is a protean condition involving the orbit and ocular adnexa. Although a few cases of uveitis have been reported, the exact pattern of IgG4-related intraocular manifestations remains unclear. Here, we report on a nationwide French multicenter cohort of patients with IgG4-RD and uveitis and conducted a literature review.

METHODS

Patients with uveitis and a concomitant definite diagnosis of IgG4-RD (Revised Comprehensive Diagnostic criteria, American College of Rheumatology/European League Against Rheumatism classification criteria for IgG4-RD, International Consensus Diagnostic Criteria for auto-immune pancreatitis, or diagnostic criteria for IgG4-related hypophysitis), were screened from our national IgG4-RD and systemic fibrosis database. Concomitantly, we conducted a PubMed literature review and selected cases of definite IgG4-RD with uveitis.

RESULTS

We reported on 16 patients (8 from our database and 8 from the literature) and a total of 30 episodes of uveitis. Uveitis cases represented 3 % of total IgG4-RD patients in the national database on IgG4-RD and systemic fibrosis. Uveitis was inaugural in IgG4-RD in 4/16 cases (25 %) (appearing before any other IgG4-related symptom, at a median of 9 months), occurred concurrently to other IgG4-related symptoms in 9/16 cases (56 %) (at a median of 15 months before IgG4-RD diagnosis), and appeared during follow up in 3/16 patients (19 %) (at a median of 57 months after first IgG4-related symptoms). When uveitis occurred during follow up, it was associated with IgG4-RD manifestations in other organs in 6/9 patients (67 %). Uveitis was bilateral in 8/16 cases (50 %) and granulomatous in 5/10 cases (50 %). It was anterior in 8/13 (62 %), intermediate in 3/13 (23 %), and global (panuveitis) in 4/13 patients (31 %). Median serum IgG4 at diagnosis was 3.2 g/L. Median follow up time was of 6 years, during which 8/16 patients (50 %) experienced at least one relapse of uveitis. Treatment data was available for 29/30 uveitis flares. Steroids were used in 28/29 episodes of uveitis (97 %), leading to remission of uveitis in 16/28 cases (57 %). Methotrexate and rituximab (in combination with systemic steroids) were administered as second- or third-line therapy in 6/29 (21 %) and 5/29 (17 %) episodes of uveitis, respectively, and led to remission of uveitis in 4/6 cases (67 %) and 4/5 cases (80 %), respectively. One third of uveitides required at least two different lines of treatment for remission induction (mainly a combination of both systemic steroids and methotrexate or rituximab).

DISCUSSION AND CONCLUSIONS

Uveitis may be one of the initial symptoms of IgG4-RD, and IgG4-RD should be considered in the diagnostic workup of uveitis. Its early onset in IgG4-RD may help with early diagnosis and treatment of the disease. Steroid monotherapy may be sufficient to treat IgG4-related uveitis, yet relapses were frequent (50 %) and ultimately a third of patients required at least two lines of treatment. Hence, steroid-sparing agents can be considered at early stages of the disease, particularly for patients with a high risk of relapse or steroid-related complications.

Significant CA 19-9 elevation in IgG4-related autoimmune pancreatitis - A diagnostic dilemma

IgG4-related disease (IgG4-RD) is a systemic fibroinflammatory disorder characterized by dense infiltration of IgG4-positive plasma cells in the affected tissue along with characteristic storiform fibrosis that can lead to the development of tumefactive lesions in any organ. CA19-9 is a marker for pancreato-biliary malignancy, however mild to moderate elevation of CA 19-9 can also be observed in IgG4-RD autoimmune pancreatitis (AIP) and sclerosing cholangitis (IgG4-SC). Therefore, it becomes difficult to differentiate between these entities. We describe the case of a 65-year-old male with history of IgG4-RD, presenting with jaundice and abdominal pain. He was found to have a pancreatic mass with significantly elevated IgG4 162 (2-96 mg/dL and CA19-9 levels 2830 (0-35 U/ml). Patient underwent ERCP and biopsy, which ruled out pancreatic cancer and cholangiocarcinoma. He was diagnosed with IgG4-RD autoimmune pancreatitis (AIP) and sclerosing cholangitis. Treatment with steroids and rituximab resulted in significant improvement in the bilirubin and a dramatic decrease in CA19-9 levels.

Immunoglobulin G4-related disease: Multiple organ occupation on CT

One case involved a 61-year-old woman who was admitted to hospital with liver occupation, subsequently found multiple organ occupation, and was eventually pathologically identified as having immunoglobulin G4-related disease.

Navigating the Spectrum: Atypical Pulmonary Involvement in Immunoglobulin G4-Related Disease

Immunoglobulin G4-related disease (IgG4-RD) is a systemic condition known to affect multiple organ systems. While its manifestations are diverse, pulmonary involvement, especially of the pleura, remains less common. We report the case of a 99-year-old Saudi male with a medical history of diabetes mellitus, chronic kidney disease, and hypertension. He presented with dyspnea and syncope, with radiological findings revealing pleural effusion and a mass in the right hemidiaphragm. Laboratory investigations highlighted elevated serum IgG4 levels, and histopathological evaluation confirmed the diagnosis of IgG4-RD. Notably, the patient's thoracic histopathology differed from typical IgG4-RD presentations, emphasizing the variability of the disease. This case underscores the significance of recognizing IgG4-RD as a potential cause of unexplained pleural effusion. It also highlights the need for a comprehensive diagnostic approach, integrating laboratory values, histopathological findings, and clinical context. Given the potential variability in thoracic IgG4-RD histopathology, clinicians should maintain a heightened awareness of this condition to avoid missed diagnoses.

IgG4-related digestive diseases: diagnosis and treatment

IgG4-related digestive diseases encompass a group of chronic inflammatory disorders characterized by autoimmune reactions and fibrosis affecting multiple digestive organs. These diseases are identified by elevated serum levels of IgG4 and the presence of IgG4-positive plasma cell infiltration in the affected sites, along with storiform fibrosis, obliterative phlebitis, and eosinophilic infiltration. Although extensive research has been conducted, a comprehensive understanding of these conditions remains elusive. Current clinical diagnosis often relies on the application of integrated diagnostic criteria for IgG4-related diseases, combined with specific organ involvement criteria. Distinguishing them from malignancies poses considerable challenges. Moreover, further investigations are required to elucidate the underlying pathogenic mechanisms and explore potential therapeutic interventions. This review provides a systematic classification of IgG4-related digestive diseases while discussing their diagnostic strategies, clinical presentations, and treatment modalities. The comprehensive insights shared herein aim to guide clinicians in their practice and contribute to the advancement of knowledge in this field.

Value of High-Frequency Ultrasonography in the Qualitative and Semi-Quantitative Assessment of Immunoglobulin G4-Related Submandibular Sialadenitis

OBJECTIVE

To assess the value of high-frequency ultrasonography in the evaluation of immunoglobulin G4-related submandibular sialadenitis (IgG4-SS).

METHODS

Thirty-four submandibular glands in 17 patients with IgG4-SS were retrospectively enrolled, as well as 34 submandibular glands in 17 healthy control subjects. Qualitative ultrasonic features including submandibular gland size, border, echogenicity, and vascularity were reviewed. Two different scoring systems (0-16 and 0-48, respectively) were used for semi-quantitative analysis of imaging features. Comparison of both qualitative and semi-quantitative ultrasonic analysis were made between patients with IgG4-SS and healthy controls. Spearman correlation was used to explore relationships between variables.

RESULTS

The submandibular glands with IgG4-SS presented with enlarged size, rough border, increased vascularity, and abnormal echogenicity (All P < .05). The most common echogenicity pattern for IgG-SS was diffuse hypoechoic foci pattern (44.1%), followed by superficial hypoechoic pattern (20.6%), tumor-like pattern (14.7%), and diffuse hypoechogenicity pattern (11.8%). Most IgG4-SS glands presented linear hyperechogenicity in parenchyma (91.2%). Based on both scoring system, scores of IgG4-SS were significantly higher than those of the controls (All P < .05). Association analysis of both scoring systems showed positive correlation of scores with vascularity in the gland parenchyma (All P < .05).

CONCLUSION

The ultrasonic features of IgG4-SS comprise enlarged gland, rough border, increased vascularity, and abnormal echogenicity, which correlate with its pathological characteristics. The most common echogenicity pattern for IgG4-SS was diffuse hypoechoic foci pattern. Semi-quantitative analysis systems could be useful in the assessment of IgG4-SS. Ultrasound is a potential, valuable, and non-invasive tool for the diagnosis and evaluation of IgG4-SS.

Clinical significance of the detection of serum IgG4 and IgG4/IgG ratio in patients with thyroid-associated ophthalmopathy

To evaluate the clinical significance of detecting serum IgG4 and the IgG4/IgG ratio in patients with thyroid-associated ophthalmopathy (TAO) and to explore whether high serum IgG4 levels and the IgG4/IgG ratio are associated with the severity and activity of TAO, we retrospectively assessed the records of 78 TAO patients and 32 controls collected in our hospital from July 2020 to July 2022. The TAO patients were divided into TAO inactive and TAO active phase groups according to the clinical activity score (CAS), and we evaluated the association between the serum IgG4 levels, the IgG4/IgG ratio, and the clinical data of the participants. The levels of IgG4 significantly increased in the TAO active group compared to those in the inactive and control groups (P < 0.05). Additionally, the number of patients with increased IgG4 levels (≥135 mg/dL) in the TAO active group was markedly higher than that in the inactive and control groups (P < 0.05). The IgG4/IgG ratio was also significantly enhanced in the TAO active group compared to the inactive and control groups (P < 0.05). CAS was identified as an independent factor influencing IgG4 levels in patients with TAO. The levels of serum IgG4, as well as the IgG4/IgG ratio, were significantly increased in some patients with active TAO, and they were related to the CAS, suggesting that the pathogenesis of TAO may be heterogeneous.

Coronary artery ectasia associated with IgG4-related disease: a case report and literature review

BACKGROUND

Coronary artery ectasia is defined as a local or diffuse dilatation of the coronary artery more than 1.5 times the diameter of the adjacent normal segment. The etiology of coronary artery ectasia is diverse, and rarely complicated with immunoglobulin G4-related disease (IgG4-related disease). A limited number of cases have been reported, with insidious onset, slow progression but poor prognosis.

CASE PRESENTATION

we report a patient with coronary artery ectasia combined with IgG4-related disease. He has been diagnosed with IgG4-related disease 5 years after his first percutaneous coronary intervention (PCI). Despite routine treatment with steroids, he develops a large coronary aneurysm and eventually died.

CONCLUSIONS

It is suggested that a thorough evaluation should be performed when coronary artery ectasia is diagnosed. The factors such as manifestations of coronary artery thickening, typical imaging features, other aortas involvement, increased serum IgG4 level, etc. should be considered for early diagnosis of key etiologies.

Neurosarcoidosis: Diagnostic Challenges and Mimics A Review

PURPOSE OF REVIEW

Neurosarcoidosis is a rare manifestation of sarcoidosis that is challenging to diagnose. Biopsy confirmation of granulomas is not sufficient, as other granulomatous diseases can present similarly. This review is intended to guide the clinician in identifying key conditions to exclude prior to concluding a diagnosis of neurosarcoidosis.

RECENT FINDINGS

Although new biomarkers are being studied, there are no reliable tests for neurosarcoidosis. Advances in serum testing and imaging have improved the diagnosis for key mimics of neurosarcoidosis in certain clinical scenarios, but biopsy remains an important method of differentiation. Key mimics of neurosarcoidosis in all cases include infections (tuberculosis, fungal), autoimmune disease (vasculitis, IgG4-related disease), and lymphoma. As neurosarcoidosis can affect any part of the nervous system, patients should have a unique differential diagnosis tailored to their clinical presentation. Although biopsy can assist with excluding mimics, diagnosis is ultimately clinical.

Focal IgG4-related periprostatic "PI-RADS 5" pseudotumor mimicking prostatic adenocarcinoma

Immunoglobulin G4-related disease (IgG4-RD) is a systemic fibroinflammatory disease characterized by raised serum IgG4 levels and tumefactive inflammation affecting multiple organ systems, typically involving the pancreas and biliary tree. Though rare, prostatic involvement has been reported in a few cases and is suspected to be an underreported entity. Our patient is a 63-year-old gentleman who has presented with an incidental "PI-RADS 5" (Prostate Imaging Reporting & Data System) prostate lesion and perivascular soft tissue cuffing of the superior rectal vessels on MRI rectum performed for surveillance of rectal neuroendocrine tumor. He had a history of lacrimal gland IgG4-RD. The lentiform prostate lesion subtly indents the prostate capsule, reminiscent of a periprostatic rather than an intraprostatic lesion. Perivascular cuffing of superior rectal vessels suggest inflammatory vasculitis of IgG4-RD. Differential diagnosis of periprostatic inflammatory IgG4-RD was considered, subsequently proven on MRI-ultrasound fusion targeted biopsy. Reported radiological findings of prostate IgG4-RD typically show diffuse chronic inflammation of the prostate, with a minority of the reports describing focal involvement, often mimicking focal prostate adenocarcinoma. Focal periprostatic involvement of IgG4-RD is an unusual manifestation which should be considered in patients with IgG4-RD who present with a periprostatic pseudotumor. IgG4-RD of the prostate usually responds well to steroid treatment without the need for surgery.

Investigation of the value of hematological biomarkers in the clinical differential diagnosis of IgG4-RD

BACKGROUND

IgG4- related disease (IgG4- RD) is a systemic fibroinflammatory disease whose pathogenesis has not been completely elucidated. Due to the novelty and complexity of the diagnostic criteria, it is difficult to distinguish from the diseases included in the differential diagnosis without tissue biopsy. This study aimed to discover new biomarkers that can help for disease diagnosis and its differential diagnosis by reviewing the relationships between neutrophil-lymphocyte ratio (NLR), platelet lymphocyte ratio (PLR), systemic immune-inflammation index (SII), and systemic inflammation response index (SIRI).

METHODS

Thirty IgG4- RD, 38 granulomatous polyangiitis (GPA), and 46 sarcoidosis patients presenting to the Rheumatology Clinic meeting the criteria of 2019 American College of Rheumatology, 2012 International Chapel Hill and 1999 American Thoracic Society meeting, respectively, and 27 healthy control subjects were included. We collected data on complete blood count with automated differential values including NLR, PLR, SII, and SIRI.

RESULTS

The SII and PLR values were significantly higher in patients with IgG4-RD compared to healthy controls, (SII median (minmax) 572 (102-5583) vs. 434 (172-897), PLR median (min-max) 130 (56.8-546) vs. 104 (57.5- 253) p < 0.001). SII value was found to have a significant positive correlation with CRP in IgG4-RD disease (r = 0.371; p = 0.043). While SII, SIRI, NLR, PLR parameters were not significant between the IgG4-RD and sarcoidosis groups, SII, SIRI, NLR, PLR were significantly higher in patients with GPA than in IgG4-RD patients (p < 0.001).

DISCUSSION

This is the first study to review the SII, SIRI, NLR, and PLR in IgG4-RD. The obtained results suggest that the SII could beused as a new tool, for differential diagnosis and activity of the IgG4-RD.

IgG4-Related Spinal Hypertrophic Pachymeningitis With Neurological Deficit: A Report of 2 Cases

CASE

Immunoglobulin G4 (IgG4)-related spinal hypertrophic pachymeningitis (IgG4-RHP) is a rare disease characterized by diffuse inflammatory fibrosis of the spinal dura mater that can cause myelopathy and neurological deficits. Here, we report 2 cases in which both patients presented with myelopathy and paraplegia. They underwent decompressive laminectomy, and the diagnoses were confirmed through histopathologic examination. Both patients received prednisolone postoperatively, which was subsequently switched to methotrexate for maintenance.

CONCLUSION

Two cases of IgG4-RHP were successfully treated with decompressive laminectomy and combined therapy with steroids and other immunosuppressive agents.

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.

New-onset retroperitoneal fibrosis following COVID-19 mRNA vaccination: Coincidental or vaccine-induced phenomenon?

The Pfizer-BioNTech mRNA vaccine is a US Food and Drug Administration-approved coronavirus disease 2019 (COVID-19) vaccine. Although it is reported to be safe and effective, immune dysregulation leading to autoimmunity has become an area of concern. Retroperitoneal fibrosis (RPF) is an immune-mediated fibroinflammatory disease characterized by the deposition of fibrous tissues, primarily around the abdominal aorta and iliac arteries. Herein, we report a case of RPF following Pfizer BioNTech COVID-19 mRNA vaccination. To the best of our knowledge, there have been no published reports on RPF after COVID-19 mRNA vaccination. A 58-year-old woman with no history of autoimmune diseases presented with acute onset of epigastric pain 5 weeks after the second dose of the Pfizer-BioNTech vaccine. She had been diagnosed with stage I breast cancer 9 years ago and was in complete remission on admission. Abdominal computed tomography showed preaortic soft-tissue infiltration around the origin of the superior mesenteric artery but no evidence of breast cancer recurrence. Considering the temporal relationship between current symptoms and vaccination and the absence of other possible causes, she was diagnosed with RPF secondary to Pfizer-BioNTech vaccine-induced autoimmunity. This case may raise awareness of the possibility of RPF development following COVID-19 mRNA vaccination.

Id4 modulates salivary gland homeostasis and its expression is downregulated in IgG4-related disease via miR-486-5p

Salivary glands are physiologically orchestrated by the coordinated balance between cell differentiation, proliferation, apoptosis, and interactions between epithelial, mesenchymal endothelial, and neuronal cells, and they are frequent sites of manifestations of Sjögren's syndrome (SS) or IgG4-related disease (IgG4-RD). However, little is known about salivary gland homeostasis and its involvement in those diseases. Inhibitor of DNA binding/differentiation 4 (Id4) is an Id protein involved in the transcriptional control of many biological events, including differentiation. Studies of Id4-deficient mice revealed that Id4-deficient submandibular glands were smaller and exhibited accelerated differentiation, compared with those from wild-type littermates. In addition, dry mouth symptoms and Th17 expansion in splenocytes were also observed in the absence of Id4. Furthermore, Id4 levels in the salivary glands of patients with IgG4-RD, but not SS, were significantly decreased compared with those of healthy controls. miRNA-mRNA integrated analysis demonstrated that miR-486-5p was upregulated in IgG4-RD patients and that it might regulate Id4 in the lesion sites. Together, these results provide evidence for the inhibitory role of Id4 in salivary differentiation, and a critical association between Id4 downregulation and IgG4-RD.

IgG4-related disease mimicking gynecologic malignancy

Immunoglobulin G4 (IgG4) related disease is a systemic disease that causes fibrosis, tumor-like nodules, and lymphoid hyperplasia with infiltration of IgG4 positive plasma cells. It can manifest in many organ systems; however, there are few cases that report gynecologic organ involvement. It is crucial to correctly diagnose IgG4-related disease versus malignancy because the former is treated with glucocorticoids or rituximab. In this case report, we describe two patients in which IgG4-related disease mimics gynecologic cancer. In the first case, an 85 year old woman presented with diffuse lymphadenopathy and a uterine mass concerning for malignancy. Biopsies were negative for carcinoma. Inguinal lymph node biopsy demonstrated IgG4 positive plasma cells and the patient was treated with rituximab therapy given concurrent severe rheumatoid arthritis. In the second case, a 35 year old woman under surveillance for Stage IB2 squamous cell carcinoma of the cervix (status post definitive chemoradiation therapy) presented with fluorodeoxyglucose (FDG) avid paraaortic lymph nodes on positron emission tomography (PET) imaging with subsequent negative paraaortic lymph node biopsies. Serial imaging and biopsies remained inconclusive despite ongoing diffuse lymphadenopathy and clinical concern for recurrence. Supraclavicular lymph node excision was performed which demonstrated lymphoid hyperplasia with increased IgG4 plasma cells and no evidence of carcinoma, supporting the diagnosis of IgG4-related disease. The patient was treated with high dose steroids with clinical improvement and resolution of abnormal imaging findings. We demonstrate that IgG4-related disease can present with FDG-avid lesions on PET imaging and lymphadenopathy that mimics primary or recurrent gynecologic malignancy. While rare, we conclude the IgG4-related disease is an important differential diagnosis to consider in the workup of primary or recurrent gynecologic malignancy and highlights the value of PET imaging to identify unusual patterns of lymphadenopathy and guide histologic confirmation of disease.

Differential CpG DNA methylation of peripheral B cells, CD4+ T cells, and salivary gland tissues in IgG4-related disease

OBJECTIVES

Immunoglobulin-G4-related disease (IgG4-RD) is a distinct systemic autoimmune-mediated disease manifesting as chronic inflammation and tissue fibrosis. Since the role of DNA methylation in the pathogenesis of IgG4-RD is still unclear, we conduct this study to investigate epigenetic modifications in IgG4-RD.

METHODS

A genome-wide DNA methylation study was conducted with B cells, CD4⁺ T cells, and salivary gland tissues from IgG4-RD patients and matched controls by using the Illumina HumanMethylation 850K BeadChip. We further performed pyrosequencing and immunohistochemistry assays to validate the methylation status of some targets of interest.

RESULTS

We identified differentially methylated CpG sites including 44 hypomethylated and 166 hypermethylated differentially methylated probes (DMPs) in B cells and 260 hypomethylated and 112 hypermethylated DMPs in CD4⁺ T cells from 10 IgG4-RD patients compared with 10 healthy controls. We also identified 36945 hypomethylated and 78380 hypermethylated DMPs in salivary gland tissues of 4 IgG4-RD patients compared with 4 controls. DPM2 (cg21181453), IQCK (cg10266221), and ABCC13 (cg05699681, cg04985582) were hypermethylated and MBP (cg18455083) was hypomethylated in B cells, CD4⁺ T cells, and salivary gland tissues of IgG4-RD patients. We also observed the hypomethylated HLA-DQB2 in CD4⁺ T cells from IgG4-RD patients. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of DMPs in salivary gland tissues of IgG4-RD patients revealed enrichment of pathways involved in the regulation of immune cell responses and fibrosis.

CONCLUSION

This is the first DNA methylation study in peripheral B cells, CD4⁺ T cells, and salivary gland tissues from IgG4-RD patients. Our findings highlighted the role of epigenetic modification of DNA methylation and identified several genes and pathways possibly involved in IgG4-RD pathogenesis.

Eosinophilic granulomatosis with polyangiitis: A review

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare, multi-system, inflammatory disease, belonging to the group of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV). Previously known as Churg-Strauss syndrome, EGPA is characterised by late-onset asthma, eosinophilia and vasculitis affecting small-to-medium vessels. This disease behaves differently in many aspects to the other AAV and is often excluded from AAV studies. The disease is poorly understood and, due to it rarity and unique manifestations, there has been limited research progress to optimise our understanding of its complex pathogenesis and ability to develop management options - although the success of interleukin-5 inhibitors such as Mepolizumab has been a welcome development. The pathophysiology also appears to be different to other forms of AAV and hence management strategies that work for AAV may not fully apply to this condition. There is no current standard therapy for EGPA although corticosteroids are almost universally used for treatment alongside other agents and encouraging modes of treatment continue to evolve beyond glucocorticoid immunosuppression (including interleukin-5 inhibition). There is therefore a significant ongoing unmet need for efficacious steroid-sparing immunosuppressing agents. The prognosis also diverges from other forms of AAV, and we discuss the pathophysiology, clinical features and diagnosis, management and prognosis in this article.

Serum ANCA as Disease Biomarkers: Clinical Implications Beyond Vasculitis

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

Advantages of an alternate-day glucocorticoid treatment strategy for the treatment of IgG4-related disease: A preliminary retrospective cohort study

Alternate-day glucocorticoid (GC) therapy is a treatment option that can reduce GC-associated adverse events. We investigated the safety and efficacy of alternate-day GC therapy in patients with immunoglobulin G4-related disease (IgG4-RD). Medical records of patients with IgG4-RD who were followed for at least one year at St. Luke's International Hospital, Tokyo, Japan, from 2004 to 2020 were reviewed. Patients who fulfilled comprehensive IgG4-RD diagnostic criteria were divided into alternate-day or daily GC treatment groups based on their treatment protocol. The effect of alternate-day GC therapy on glucocorticoid toxicity index (GTI) score was evaluated using multilinear analysis with adjustments for cumulative GC doses until each assessment point and propensity scores (PS) for alternate-day GC therapy. Kaplan-Meier curves and Cox proportional hazard models were used to assess the efficacy of alternate-day GC therapy for disease control. Among the 67 patients with IgG4-RD, patients with alternate-day (n = 13) and daily (n = 31) GC treatments were analyzed after excluding 23 ineligible patients. The median (interquartile range) age was 64 (60-70) years, 29 (65.9%) were male patients, 26 (59.1%) patients had positive biopsy results, and the median follow-up period was 1643 days. Significantly more patients with alternate-day GC treatment used concomitant immunosuppressants (11 [84.6%] vs 11 [35.5%]; P = .007). The alternate-day strategy significantly lowered the GTI score after adjusting for cumulative GC dose until the assessment and PS (adjusted coefficient: -29.5 [-54.3, -4.8], P = .021 at 12 months; -20.0 [-39.8, -0.1], P = .049 at 24 months). Serious infections were numerically less frequent in the alternate-day group (incidence ratio [95% confidence interval [CI]: 0.45 [0.05, 3.63], P = .45). Most patients (92.3%) in the alternate-day GC treatment group and all patients in the daily GC treatment group showed treatment responses in the remission induction therapy. The PS-adjusted hazard ratio of alternate-day GC treatment for disease flares was not significant (1.55 [0.53, 4.51]; P = .43). The alternate-day treatment strategy significantly reduced GC-related adverse events regardless of the cumulative GC dose. Alternate-day GC treatment is a feasible option for patients with IgG4-RD, without a significant increase in disease flares particularly when combined with immunosuppressants.

Report of Two Cases of Pediatric IgG4-Related Lymphadenopathy (IgG4-LAD): IgG4-Related Disease (IgG4-RD) or a Distinct Clinical Pathological Entity?

IgG4-related disease (IgG4-RD) is a recently discovered immune-mediated fibroinflammatory condition, uncommon in the pediatric population, that could involve multiple organs and induce cancer-like lesions and organ damage. Its main features are multiple injuries in different sites, a dense lymphoplasmacytic infiltrate rich in IgG4 plasma cells, storiform fibrosis, and often high serological concentrations of IgG4. Autoimmune pancreatitis is the most common manifestation, mainly in adults. Two cases of IgG4-RD in children with lymph node localization of disease are reported. Localized or systemic lymph node involvement is common, but lymph node enlargement as the first and only manifestation of IgG4-RD is unusual, and therefore, hard to differentiate from other diseases. IgG4-related lymphadenopathy (IgG4-LAD) is most likely a distinct disease, described as isolated lymphadenopathy, related to the presence of elevated numbers of IgG4-positive plasma cells. Both disorders are likely to be misdiagnosed in children because they are characterized by rare and polymorphic features. IgG4-RD and IgG4-LAD should be considered in the differential diagnosis of disorders characterized by lymphadenopathy of uncertain etiology.

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

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

The role of PET/CT in large vessel vasculitis and related disorders: diagnosis, extent evaluation and assessment of therapy response

Large vessel vasculitides (LVV) are defined as chronic inflammatory disorders that affect the arteries with two major variants being distinguished: giant cell arteritis (GCA) and Takayasu's arteritis (TAK). These often present with nonspecific constitutional symptoms which makes an accurate diagnosis often challenging. Nevertheless, timely diagnosis is of utmost importance to initiate treatment and to avoid potential life-threatening complications. [¹⁸F]FDG-PET/CT is nowadays widely accepted as useful tool to aid in the diagnosis of large vessel vasculitis. However, its role to monitor disease activity and to predict disease relapse during follow-up is less obvious since vascular [¹⁸F]FDG uptake can be detected in the absence of clinical or biochemical signs of disease activity. In addition to the two major variants, [¹⁸F]FDG-PET/CT has shown promise in (peri-)aortitis and related disorders. This article aims to provide an update on the current knowledge and limitations of [¹⁸F]FDG-PET/CT for the diagnosis and assessment of treatment response in LVV. Furthermore, other radiopharmaceuticals targeting key components of the vascular immune system are being discussed which could provide an interesting alternative to image vascular inflammation in LVV.

IL-7 Promotes the Expansion of Circulating CD28- Cytotoxic T Lymphocytes in Patients With IgG4-Related Disease via the JAK Signaling

Objectives

This study aimed to elucidate the changes and associated mechanisms of circulating CD28- cytotoxic T lymphocytes (CTLs) in patients with IgG4-related disease (IgG4-RD).

Methods

Fifty IgG4-RD patients and 15 healthy controls (HCs) were recruited. Peripheral blood mononuclear cells (PBMCs) were isolated, the levels of circulating CD28- CTLs were detected by flow cytometry, and the proportions of CD127lo or GZMB+CD28- CTL subsets were analyzed in the meantime. Mechanistically, PBMCs isolated from IgG4-RD patients were stimulated with IL-7 in the presence or absence of the JAK inhibitor tofacitinib. Flow cytometry was used to analyze the proliferation of CD28- CTLs and the changes in related subpopulations.

Results

Circulating CD4+CD28- CTLs and CD8+CD28- CTLs were significantly increased in IgG4-RD patients compared with HCs, accompanied by an elevation of CD127lo or GZMB+ CTL subsets. The ex vivo culture of PBMCs showed that IL-7 could induce the amplification of CD4+CD28- CTLs and CD8+CD28- CTLs in IgG4-RD. Furthermore, IL-7 promotes the proliferation and functional subset changes of these CD28- CTLs in this disease. The selective JAK inhibitor tofacitinib significantly inhibited the effects of IL-7 on CD4+CD28- CTLs and CD8+CD28- CTLs.

Conclusion

IL-7 can affect the immune balance of IgG4-RD patients by promoting the expansion and function of CD4+CD28- and CD8+CD28- CTLs in IgG4-RD through the JAK pathway. Blockade of the IL-7 signaling pathway may be a new therapeutic strategy for IgG4-RD.

Case Series of Autoimmune Pancreatitis and IgG4-Related Sclerosing Cholangitis

IgG4-related disease (IgG4-RD) is an emerging immune-mediated disease that can involve any organ. The involvement of the pancreas and biliary tract is the most common and well-studied in the literature. It is characterized by a non-specific presentation, mimicking a malignant process. The goal was to look at the different clinical and paraclinical aspects of this disease, as well as the challenges that come from its management. It was made up of three observations of patients with IgG4-RD involving the biliary tract and pancreas. The first observation concerned intrahepatic biliary cholangitis that was accompanied by porto-mesenteric thrombosis, which was discovered by cholestatic jaundice on the 15th day after an appendectomy, and the patient improved under corticosteroids and anticoagulants. The second observation concerned an acute revelation of the disease. It was an acute attack of chronic pancreatitis of IgG4-RD. The main symptoms were pancreatic pain and exocrine pancreatic insufficiency, and corticosteroid therapy allowed remission. The third observation was related to autoimmune pancreatitis (AIP) and IgG4-related sclerosing cholangitis, revealed by jaundice with cholestasis. The patient acquired corticosteroid resistance and an adverse progression to decompensated cirrhosis, and liver transplantation was indicated. The clinical presentation of IgG4-RD is heterogeneous, as evidenced by our three clinical observations. There are still significant gaps in our understanding, particularly in terms of pathogenesis and factors that influence therapy response. Further observational and interventional research is needed to better manage this disease.

Case Report: A Programmed Cell Death-1 Inhibitor-Related Abdominal Fibroinflammatory Reaction Affecting Multiple Organs in A Non-Small-Cell Lung Cancer Patient

Immunotherapy utilizing programmed cell death-1 (PD-1)/PD-L1 inhibitors has been regarded as a rising hope for tumor patients, and their effects have been demonstrated in many clinical trials. However, immune-related adverse events also occur in patients and can sometimes have severe consequences. Pembrolizumab (Keytruda) is a humanized monoclonal anti-PD-1 antibody that has been approved by the US Food and Drug Administration for non-small-cell lung cancer. Here, we report a rare case of an abdominal fibroinflammatory reaction that affected multiple organs during anti-PD-1 immunotherapy using pembrolizumab in a non-small-cell lung cancer patient. The patient’s case demonstrates that immunotherapy-related abdominal fibroinflammatory reactions need to be considered, especially for patients with a history of pre-existing conditions in the abdomen. Glucocorticoids may be useful as a treatment when a diagnosis is confirmed.

A case of simultaneous onset of highly active systemic lupus erythematosus and IgG4-related renal disease

The patient was a 73-year-old woman who had hair loss, purpura, and numbness of the soles for past 1 year. Three months prior, she was diagnosed with interstitial lung disease (ILD) and was admitted to our department. She was diagnosed with systemic lupus erythematosus (SLE) based on positive antinuclear antibodies 1280× (speckled type), hair loss, low white blood cell count, positive anti-cardiolipin and anti-ds-DNA antibodies, and lupus retinopathy. In addition, the patient was also diagnosed with immunoglobulin G (IgG)4-related disease (IgG4RD) based on high serum IgG4 levels, ILD, urine occult blood, protein, and cast, and renal histological findings showed endocapillary proliferative glomerulonephritis, increased IgG4 positive plasma cells, and characteristic storiform fibrosis. High-dose glucocorticoid therapy, hydroxychloroquine, and belimumab were administered, which improved the SLE symptoms of lupus retinopathy and peripheral neuropathy, as well as the IgG4RD symptoms of ILD and urinary findings. Herein, we report a rare case of simultaneous onset of IgG4-related nephropathy with active glomerular lesions and SLE, in which renal histology, including fluorescent antibodies, was crucial for diagnosis.

18F-fluorodeoxyglucose PET and PET/computed tomography for the evaluation of immunoglobulin G4-related disease: a systematic review

BACKGROUND

In the last years, 18F-fluorodeoxyglucose PET/computed tomography (18F-FDG PET/CT) has demonstrated its utility for the evaluation of immunoglobulin G4 (IgG4)-related disease (IgG4RD). The studies are, however, really heterogeneous and different. The aim of this review is, therefore, to analyze the diagnostic performance of 18F-FDG PET and PET/CT for the assessment of IgG4RD.

METHODS

A wide literature search of the PubMed/MEDLINE, Scopus, Embase and Cochrane library databases was made to find relevant published articles about the diagnostic performance of 18F-FDG PET or PET/CT for the evaluation of IgG4RD.

RESULTS

The comprehensive computer literature search revealed 779 articles. On reviewing the titles and abstracts, 756 articles were excluded because the reported data were not within the field of interest. Twenty-three studies were included in the review.

CONCLUSION

Despite some limitations that affect our review, 18F-FDG PET or PET/CT demonstrated the ability to assess IgG4RD both at initial evaluation and after therapy. In general, no correlation between PET/CT parameters and IgG4 serum levels has been reported. A possible role for 18F-FDG PET/CT to drive differential diagnosis with other disease is starting to emerge.

Single-Cell Sequencing of Immune Cell Heterogeneity in IgG4-Related Disease

Background

The IgG4-related disease (IgG4-RD) is an immune-mediated disorder with fibrotic manifestations. However, the transcriptional profiles of immune cell subsets at single-cell level are unknown. Herein, single-cell sequencing was used to assess the specific cell subpopulations and pathways in peripheral blood mononuclear cells (PBMCs) of IgG4-RD.

Methods

Single-cell sequencing was performed using the PBMCs from four patients with IgG4-RD and three healthy controls (HCs). Functional enrichment and cell analysis were performed through re-clustering of PBMCs to assess functional pathways and intercellular communication networks in IgG4-RD. Western blot and flow cytometry were used to verify sequencing and functional enrichment results.

Results

Four major cell types and 21 subtypes were identified. Further subclustering demonstrated that plasma B-cell proportions increased with increasing glycolysis/gluconeogenesis activity in IgG4-RD. Re-clustering of myeloid cells showed that EGR1 and CD36 expressions were significantly increased in CD14⁺ monocytes of IgG4-RD, as validated by Western blot analysis. Moreover, tumor necrosis factor (TNF) production pathways were positively regulated in CD14⁺ monocytes of IgG4-RD. In vitro stimulation showed that CD14⁺ monocytes of IgG4-RD could secrete higher levels of TNF-α . Notably, the proportions of CD8 central memory T (TCM) and TIGIT⁺ CD8 cytotoxic T (CTL) increased in patients with IgG4-RD compared with HCs. Further interaction analysis showed that B cell activation factor (BAFF) signaling pathways were enriched from myeloid cells subsets to B cells.

Conclusion

This study enhances the understanding of the cellular heterogeneity and transcriptional features involved in the pathogenesis of IgG4-RD, providing key clinical implications.

Oral and maxillofacial manifestations of IgG4-related disease: A clinicopathological study

BACKGROUND

IgG4-related disease is a fibroinflammatory and immune-mediated condition, which has extremely variable clinical manifestations. In this study, we aim to investigate the clinicopathological features of IgG4-related disease involving the oral and maxillofacial region.

METHODS

Cases of IgG4-related disease manifesting in the oral and maxillofacial region were retrieved from three Brazilian institutions. Clinical and serological data were obtained from the patients' medical charts, while microscopic and immunohistochemical findings were revised by oral pathologists. Diagnosis followed the American College of Rheumatology/European League against Rheumatism criteria.

RESULTS

Seven patients diagnosed with IgG4-related disease were included in this study. Women were affected in all analysed cases, with a mean age of 55.4 years. Two patients presented with the clinical involvement of more than one oral and maxillofacial anatomic site. Therefore, our sample comprised nine oral and maxillofacial anatomic sites affected by IgG4-related disease. The submandibular gland was affected in four cases, the tongue and the parotid gland in two cases each, and the palate in one case. In a few cases, exploratory lower lip biopsy was used as a diagnostic approach. A moderate-to-severe lymphoid infiltrate containing plasma cells and lymphocytes, with an increased IgG4/IgG ratio, was common. Treatment varied and steroids were the most frequently used (57.4%). Six patients remained alive, while one died from unknown causes.

CONCLUSION

Although major salivary glands are commonly affected by IgG4-related disease, the oral cavity can also be involved, and lower lip biopsy may be an auxiliary diagnostic tool.

Cardiac manifestations of IgG4-related disease: a case series

Background

IgG4-related disease (IgG4-RD) is an autoimmune condition affecting almost every organ system, with an early inflammatory phase and later fibrotic consequences. Vascular manifestations, particularly, large-vessel involvement in IgG4-RD, are well described. However, important IgG4-related effects on medium-sized arteries and the pericardium are less well recognized. These less frequently reported cardiovascular effects of IgG4-RD include coronary artery stenosis, pericardial disease, cardiac masses, and valvular heart disease.

Case summary

This case series focuses on three patients that demonstrate the cardiovascular effects of IgG4-RD and the pitfalls and importance of early diagnosis. Cases 1 and 2 presented with cardiac manifestations prior to more typical organ systems being affected which led to a delay in diagnosis. Case 1 presented with an acute myocardial infarction secondary to IgG4-RD of the coronary arteries and Case 2 presented with pericarditis which progressed to pericardial constriction due to IgG4-RD. Case 3 already had a diagnosis of IgG4-RD from a prior renal biopsy which raised the index of suspicion that his pericardial disease and thoracic mass were also related to IgG4-RD.

Discussion

Cardiac manifestations of IgG4-RD remain under-recognized and include coronary artery and pericardial disease. These manifestations often precede more typical manifestations in other organ systems. Recognizing cardiac manifestations of IgG4-RD on cardiac imaging can raise clinical suspicion and act as a catalyst to ascertain a confirmatory diagnosis. Early diagnosis and treatment are crucial to prevent potentially fatal outcomes and irreversible fibrosis.

IgG4-related prostatitis manifesting as urinary obstruction in a 28-year-old male

Background

Immunoglobulin G4-related disease (IgG4-RD) is a systemic lymphoproliferative disorder characterized by elevated serum IgG4 levels and tumefactive lesions that can involve nearly every organ system. Involvement of the prostate is rare but has been reported in limited cases.

Case presentation

A 28-year-old man of Asian descent with a history of sinusitis and priapism presented to hospital with rigors and voiding symptoms. He was diagnosed with IgG4-RD one month prior to presentation, following pathological analysis of a submandibular mass that demonstrated chronic sclerosing sialadenitis. On presentation, white blood cell count, C-reactive protein, and prostate serum antigen levels were all within normal limits. Examination was notable for a large, firm prostate, and a foley catheter was inserted. Contrast CT of the abdomen was unremarkable. Further workup revealed elevated serum IgG4 levels (9.22 g/L) and he was subsequently started on prednisone 35 mg daily. Imaging to screen for systemic IgG4-RD involvement demonstrated paravertebral soft tissue involvement and he was given rituximab 1000 mg IV × 2 doses. MRI revealed diffuse prostatitis. Five days after starting prednisone and one day after his first dose of rituximab, he successfully passed trial of void and was discharged home.

Conclusions

IgG4-related prostatitis is a rare and underrecognized manifestation of IgG4-RD. Our case highlights the need to consider IgG4-related prostatitis as an etiology of urinary obstruction in young individuals. Resolution of symptoms following treatment with steroids may be diagnostic of IgG4-related prostatitis, and may potentially avoid the need for invasive diagnostic procedures such as prostate biopsy.

Hypercalcemia in IgG4-related disease: coincidental or associated? Case based review

Immunoglobulin (Ig) G4-related disease (IgG4RD) is a chronic autoimmune disorder characterized by dense lymphoplasmacytic infiltrations and fibrosis of storiform pattern. The most typical manifestations include major salivary or lacrimal gland involvement, autoimmune pancreatitis, and retroperitoneal fibrosis. While the increase in IgG4 is the typical feature of the disease, hypercalcemia has been rarely reported in IgG4RD so far, only one of these cases has been shown parathyroid gland involvement (isolated involvement). In this study, we present a 43-year-old female patient with weight loss, pancreatic mass, lymphadenopathy, nodular lesion in the lung, hypercalcemia, and also increased level of serum IgG4. Histopathological investigation following parathyroidectomy revealed a dense lymphoplasmacytic infiltrate with an IgG4 to IgG ratio of > 50% in the fat tissue surrounding the parathyroid gland, particularly at the perivascular areas. This is the first systemic IgG4RD case in combination with hypercalcemia in the literature who was detected to have parathyroid adenoma. Our aim in this review is to emphasize that, although rarely, IgG4RD may be accompanied by hypercalcemia and parathyroid gland may be one of its target sites.