Clinicopathological characteristics of immunoglobulin G4-related sialadenitis

A case of massive hemoptysis caused by immunoglobulin G4-related respiratory disease in adults: case report and review of literature

Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated chronic fibro-inflammatory condition, that can involve multiple systems. Immunoglobulin G4-related respiratory disease (IgG4-RRD) is relatively rare, with non-specific clinical symptoms. Hemoptysis is a rare clinical symptom of IgG4-RRD, and cases of massive hemoptysis in adults have not been reported. We present here a rare case of massive hemoptysis caused by IgG4-RRD in adults and review relevant literature. An 84-year-old female presented with recurrent cough and blood-streaked sputum, progressing to massive hemoptysis. Her chest CT showed patchy lesions in the lungs, initially misdiagnosed as a tumor. Ultimately, a biopsy confirmed the diagnosis of IgG4-RRD. The patient was treated with prednisone combined with leflunomide, which controlled her condition and maintained remission. However, after 13 months without hemoptysis, she experienced intermittent hemoptysis followed by a massive episode. Increasing the prednisone dose and continuing leflunomide treatment controlled the condition once again, with no recurrence in the subsequent year of follow-up. In patients with IgG4-RRD, particularly those with hemoptysis, it is essential to remain vigilant for massive hemoptysis. Similarly, in patients with lung patch lesions and no evidence of a tumor on biopsy, IgG4-RRD should not be overlooked. Early diagnosis and timely treatment can improve the patient's clinical prognosis.

Chronic Sclerosing Sialadenitis of the Submandibular Gland and its Histopathological Spectrum in the IgG4-Related Disease: a Series of 17 Cases

PURPOSE

This study aimed to characterize the histopathological immunohistochemical features of chronic sclerosing sialadenitis, emphasizing the IgG4-related disease.

METHODS

Seventeen cases of chronic sclerosing sialoadenitis were examined for histopathological aspects, (inflammation, fibrosis, glandular parenchyma, and lymphoid follicles) and immunohistochemistry (BCL2, CD3, CD20, CD34, CD163, p63, cyclin D1, mast cell, SMA, S100A4, IgG, and IgG4) which were scored. IgG4-related disease features were investigated. Demographic and clinical data were also collected.

RESULTS

Males predominated (10:7), with an average lesion size of 3.9 cm. Common histopathological findings included reduced acinar parenchyma, lymphoid follicle formation, and ductular proliferation. CD3-positive T lymphocytes and CD34- and SMA-positive stromal fibroblasts were abundant. Nine cases (53%) showed sialoliths and three cases met the criteria for IgG4-related disease.

CONCLUSION

CSS of the submandibular gland represents a reactive pattern rather than IgG4-RD as only 3 cases seemed to be related to IgG4-RD. The immunohistochemical profile revealed an abundant population of CD3-positive T lymphocytes, as opposed to regulatory proteins such as cyclin D1, demonstrating that populations of CD34- and SMA-positive stromal fibroblasts contribute to the fibrosis characteristic of CSS. In addition, our results provide a comprehensive insight into the study of CSS and its relationship with IgG4-RD.

New insights into chronic rhinosinusitis associated with IgG4-related disease

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

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

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

Current developments and opportunities of pluripotent stem cells-based therapies for salivary gland hypofunction

Salivary gland hypofunction (SGH) caused by systemic disease, drugs, aging, and radiotherapy for head and neck cancer can cause dry mouth, which increases the risk of disorders such as periodontitis, taste disorders, pain and burning sensations in the mouth, dental caries, and dramatically reduces the quality of life of patients. To date, the treatment of SGH is still aimed at relieving patients' clinical symptoms and improving their quality of life, and is not able to repair and regenerate the damaged salivary glands. Pluripotent stem cells (PSCs), including embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), and extended pluripotent stem cells (EPSCs), are an emerging source of cellular therapies that are capable of unlimited proliferation and differentiation into cells of all three germ layers. In recent years, the immunomodulatory and tissue regenerative effects of PSCs, their derived cells, and paracrine products of these cells have received increasing attention and have demonstrated promising therapeutic effects in some preclinical studies targeting SGH. This review outlined the etiologies and available treatments for SGH. The existing efficacy and potential role of PSCs, their derived cells and paracrine products of these cells for SGH are summarized, with a focus on PSC-derived salivary gland stem/progenitor cells (SGS/PCs) and PSC-derived mesenchymal stem cells (MSCs). In this Review, we provide a conceptual outline of our current understanding of PSCs-based therapy and its importance in SGH treatment, which may inform and serve the design of future studies.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Evaluation and management of dry mouth and its complications in rheumatology practice

INTRODUCTION

The symptom of dry mouth has multiple potential etiologies and can be a diagnostic clue to the presence of common systemic diseases encountered in rheumatology practice. The presence of decreased saliva flow (i.e. salivary hypofunction) defines a subset of dry mouth patients in whom there may be reversible drug effects, an iatrogenic insult such as head and neck irradiation, or a disease that directly involves the salivary glands (e.g. Sjögren's disease). The assessment of salivary hypofunction includes sialometry, salivary gland imaging, salivary gland biopsy, and an assessment for relevant systemic diseases. Optimal management of dry mouth requires accurate definition of its cause, followed by general measures that serve to alleviate its symptoms and prevent its complications.

AREAS COVERED

Through a literature search on xerostomia and salivary hypofunction, we provide an overview of the causes of dry mouth, highlight the potential impact of salivary hypofunction on oral and systemic health, detail routine evaluation methods and treatment strategies, and emphasize the importance of collaboration with oral health care providers.

EXPERT OPINION

Our Expert Opinion is provided on unmet needs in the management of dry mouth and relevant research progress in the field.

Unusual Presentation of Primary Hyper-IgE-Related Salivary Gland Disease in a 13-Year-Old Male

Adenomas are common pathologies of the salivary glands that are often associated with the major salivary glands and occur in the fourth to sixth decades of life. They are seldom seen in the pediatric age group and rarely in the minor salivary glands. Autoimmune sialadenosis of the minor salivary glands is a new phenomenon that has seldom been reported in the literature, with as few as three cases. Histopathological examination of the excised specimen is the definitive diagnosis, and these lesions have to be differentiated from adenomas and low-grade malignancies of the minor salivary glands. Management strategies of these lesions are extremely variable, ranging from wait-and-watch principle to the use of immunosuppressants and excision of the gland. This case report discusses the etiopathogenesis of the autoimmune sialadenosis and the management strategies.

Saliva biomarkers in oral disease

Saliva is a versatile biofluid that contains a wide variety of biomarkers reflecting both physiologic and pathophysiologic states. Saliva collection is noninvasive and highly applicable for tests requiring serial sampling. Furthermore, advances in test accuracy, sensitivity and precision for saliva has improved diagnostic performance as well as the identification of novel markers especially in oral disease processes. These include dental caries, periodontitis, oral squamous cell carcinoma (OSCC) and Sjögren's syndrome (SS). Numerous growth factors, enzymes, interleukins and cytokines have been identified and are the subject of much research investigation. This review highlights current procedures for successful determination of saliva biomarkers including preanalytical factors associated with sampling, storage and pretreatment as well as subsequent analysis. Moreover, it provides an overview of the diagnostic applications of these salivary biomarkers in common oral diseases.

Hyperosmolar environment and salivary gland epithelial cells increase extra-cellular matrix remodeling and lymphocytic infiltration in Sjögren's syndrome

Salivary gland epithelial cells (SGECs) play an active role in primary Sjogren's syndrome (pSS) pathogenesis. Quantitative and qualitative abnormalities of saliva might expose SGECs to chronic hyperosmolarity. We aimed to decipher the links between hyperosmolar stimulation of SGECs and lymphocytic infiltration of the salivary glands (SG) observed in pSS. RNAseq was performed on NS-SV-AC cells stimulated with hyperosmolar media containing NaCl (100 mM) or sucrose (200 mM), or with iso-osmolar (Iso) medium. RNAseq was performed on primary cultured SGECs from pSS and controls, in the presence or not of B cells. Hyperosmolar stimulation of NS-SV-AC-cells identified an upregulation of interferon-induced (MX1, IFIT2) and MMPs genes. Enrichment analysis revealed an over-representation of fibrosis pathway. In parallel, RNAseq of SGECs comparing pSS to controls identified an over-representation of a pathway involving MMPs. Given the unexpected upregulation of collagen (COL3A1, COL1A2) and ADAMTS genes in pSS SGECs, we hypothesized that SGECs might undergo epithelial-mesenchymal transition. ZEB2 was upregulated and SLUG was down regulated in SGECs from pSS versus controls. MMP24 and ZEB2 were higher in SGECs from pSS with a focus score ≥1 versus <1. Lastly, SGECs cocultured with B cells expressed higher levels of COL1A2. These results suggest the existence of a vicious circle. Alteration of SGECs in pSS participates in the establishment of a hyperosmolar microenvironment, which in turn promotes SGECs transcriptomic modifications. These modifications include extracellular matrix remodeling and promote SG lymphocytic infiltration.

Implication of allergy and atopy in IgG4-related disease

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

IgG4-RD in a Unilateral Parotid Mass: A Rare Manifestation and Review of the Literature

IgG4 related disease (IgG4-RD) is a rare, immune-mediated inflammatory disease that varies widely in its presentation because it can affect nearly any organ. We present a case of a 73-year-old male who presented with an ill-defined mass of the parotid gland, found to be IgG4-RD, after several months of work up and tissue sampling. Most cases of salivary gland involvement in IgG4-RD present as bilateral swelling of the submandibular glands. We present this case as a unique manifestation of salivary gland disease in IgG4-RD as a persistent, non-discrete unilateral mass in the parotid gland. It is critical that clinicians who regularly treat salivary gland pathologies are familiar with this rare disease and its potential manifestations in the oral cavity.

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

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

Comparison of Clinical Manifestations and Pathology between Kimura Disease and IgG4-Related Disease: A Report of Two Cases and Literature Review

Kimura disease (KD) is a rare, chronic proliferative condition presenting as a subcutaneous mass predominantly located in the head and neck region; it is characterized by eosinophilia and elevated serum IgE levels. IgG4-related disease (IgG4RD) is a fibroinflammatory condition characterized by swelling in single or multiple organs and the infiltration of IgG4 plasma cells. Herein, we presented two cases. Case 1 is a 38-year-old man with a painless mass in his right postauricular region, and Case 2 is a 36-year-old man with painless lymphadenopathy in his bilateral postauricular region. After surgical excision, they showed good recovery with no relapse. Although Cases 1 and 2 shared several overlapping pathological manifestations, there were a few differences that allowed the differentiation of KD and IgG4RD.

[Establishment and application of new techniques for submandibular gland preservation]

The saliva secreted from submandibular gland (SMG) accounts for 60%-65%. It plays an important role in maintaining the human function of swallow, digestion, testing, speech, protection of oral mucosa, and prevention from dental carries. The SMG is frequently resected during the treatment for various kinds of oral and maxillofacial diseases, resulting in xerostomia and decreased quality of life. During the past 15 years, Research Center of Salivary Gland Diseases in Peking University School and Hospital of Stomatology conducted a series of studies on new techniques for preservation of SMG and achieved remarkable results. The clinicopathologic and imaging characteristics of IgG4-related sialadenitis (IgG4-RS) were clarified based on systematic studies. The results of studies on the pathogenesis of IgG4-RS showed that unbalance of inflammatory factors mediated the abnormality of secretion of SMG. IL-4 participates in occurring and development of glandular fibrosis of SMG. Regulation of tumor necrosis factor α (TNF-α) and cleaning of senescent cells might be taken as the targets for treatment of IgG4-RS. The combination of glucocorticoid and steroid-sparing agents showed effective results for treating IgG4-RS, clinical remission was achieved in all the patients, serum IgG4 levels decreased, and salivary gland secretion significantly increased. Sialoendoscopy-assisted sialolithectomy was applied in the treatment of about 1 000 cases with submandibular hilar calculi with a success rate of more than 90%. Transfer of SMG was used for prevention from radiation-induced xerostomia in the patients with head and neck carcinoma. SMG was transferred to the submental region before radiotherapy and was kept away from the ra-diation field. The results of prospective clinical controlled study showed this technique could effectively preserve the function of SMG and prevent from xerostomia. Based on the micro-anatomical study on the blood vessels and ducts of SMG, partial sialoadenectomy was applied for treatment of benign tumors in the SMG. A clinical controlled study confirmed its safety for control of the tumors and its advantage of preservation of SMG function. The studies on the involvement of SMG in oral squamous cell carcinoma (OSCC) provided the anatomical and histopathological basis for preservation of SMG during neck dissection for early cases with OSCC. A innovated surgical modality "four preservations including SMG" was used during the neck dissection for the early cases with OSCC. A prospective randomized clinical controlled study confirmed its safety, feasibility, effectiveness for control of the carcinoma, and advantages of preservation of SMG function.

Immunological characteristics of IgG4-related Kuttner tumors

Immunoglobulin G4-related disease (IgG4-RD) has recently been well recognized and Kuttner tumor is known to be a chronic sclerosing sialadenitis, representing the focal manifestation of IgG4-RD, in the submandibular gland (SMG). This study is to evaluate the immunologic features of IgG4-related Kuttner tumor in the SMG. We retrospectively chose 13 patients who were confirmed as having Kuttner tumor by surgical biopsy between May 2012 and January 2019. The fine-needle aspiration cytology, serum antibody levels (anti-Ro antibodies, anti-La antibodies), IgG serum levels (total IgG and IgG4), and immunohistochemical findings for IgG and IgG4-positive plasma cells were reviewed. The cytologic results found that 7 of the 9 cases were reported as chronic sialoadenitis, and the other 3 as benign lymphoproliferative lesion. The serum levels of autoantibodies, Sjögren-syndrome-related antigen A/Ro-Ab and Sjögren-syndrome-related antigen A/Ro-La, showed all normal values of serum level. The serum level of IgG was increased in only 4 among the cases. However, the IgG4 levels were significantly increased in 11 among the cases. In all the patients who received resection of SMG, immunohistochemical findings showed all positive for IgG4-RD, with elevated numbers of IgG and IgG4-positive plasma cells. The evaluation of IgG4 serum level should be very informative for the diagnosis of this tumor before surgery. Fine-needle aspiration cytology with ultrasound guidance are not conclusive in this study. The immunological study including IgG4 serum level should be required for proper diagnosis and treatment, with clinical features of the Kuttner tumor. The level of evidence was IV.

IgG4-Related Disease: Mimickers and Diagnostic Pitfalls

BACKGROUND

The tendency of IgG4-related disease (IgG4-RD) to form pseudotumors, as well as its multisystemic nature, makes it the perfect mimicker of many conditions. Moreover, some clinical, serological, radiological, or histological features of the disease might be shared with some mimickers.Recently, 4 clinical phenotypes have been identified, and patients grouped in each phenotype have distinctive demographic, clinical, and serological features and outcomes, and, as expected, for each phenotype, a set of differential diagnoses should be considered.

SUMMARY OF THE LITERATURE

The main differential diagnoses for the pancreato-hepato-biliary phenotype are pancreatic adenocarcinoma and cholangiocarcinoma. Other differential diagnoses include type 2 autoimmune pancreatitis and primary sclerosing cholangitis. In patients with retroperitoneal/aortic phenotype, inflammatory conditions such as idiopathic retroperitoneal fibrosis and large vessel vasculitides should be ruled out, and most of the time, a biopsy will be needed to exclude malignancies. In head and neck limited phenotype, autoimmune conditions (eg, granulomatosis with polyangiitis, Graves orbitopathy, sarcoidosis), malignancies, and histiocytosis should be ruled out, whereas the main differential diagnoses of the Mikulicz/systemic phenotype are Sjögren syndrome, granulomatosis with polyangiitis, and multicentric Castleman disease.

CONCLUSIONS

Approaching a patient with probable IgG4-RD through a clinical phenotype framework will ease the diagnostic algorithm and facilitate the prompt recognition of the disease. There are certain clinical, serological, radiological, and histological features in each clinical phenotype that, if present, increase the likelihood that a patient may have IgG4-RD instead of the mimicker condition. Those clues that point toward IgG4-RD diagnosis should be actively sought in the workup of patients.

Primary Hyper-IgE-Related Salivary Gland Disease: A New Disease Entity

OBJECTIVES

To clarify the clinicopathological characteristics of primary hyper-IgE-related salivary gland disease (PHIESD), which is a newly proposed entity.

METHODS

Fifteen consecutive patients pathologically diagnosed with chronic sialadenitis were enrolled, and their clinicopathological features were comprehensively analyzed.

INCLUSION CRITERIA

(1) multiple salivary gland enlargement; (2) elevated serum IgE and/or IgE-positive cell infiltration in salivary gland tissues; (3) histology-confirmed lymphoplasmacytic infiltration; (4) exclusion of other known diseases.

RESULTS

The male-to-female ratio was 5:10. The median age was 21 (range, 3-63) years. The average number of affected glands was 3.7 ± 1.4. Submandibular, parotid, and sublingual glands were involved in 15, 8, and 2 patients, respectively. Comorbid diseases included allergic diseases in seven patients and autoimmune diseases in two. Elevated serum IgE (median 175 kU/L) was seen in all patients. Serum IgG4 was slightly elevated in three patients. Histologically, most patients had mild lesions, including mild lymphocyte infiltration (60%) and focal fibrosis (66.7%). Lymphoid follicular formation (53.3%), moderate to severe lymphocytic inflammation (40%) and severe fibrosis (33.3%) were also observed. Immunohistochemically, IgE-positive cells infiltrated mainly around the ducts, with scattered infiltration of IgG4-positive, mast, and interleukin-4 positive cells. During follow-up (median, 46 months) of ten patients without intervention and two with immunosuppressive therapy, no significant changes in gland size or serum IgE level were noted.

CONCLUSIONS

PHIESD manifests as homogeneous enlargement of multiple salivary glands and elevated serum IgE. Histopathology further verifies the diagnosis. It might be associated with anaphylaxis or autoimmune dysfunction. Conservative treatment is suggested.

LEVEL OF EVIDENCE

4 Laryngoscope, 2022.

The Contribution of the Interleukin-4-Induced Epithelial Cell Senescence to Glandular Fibrosis in IgG4-Related Sialadenitis

OBJECTIVE

Immunoglobulin G4-related sialadenitis (IgG4-RS) is a chronic fibro-inflammatory disease characterized by glandular fibrosis and hyposalivation. Here we aimed to explore the role of cellular senescence in the pathogenesis of IgG4-RS-related fibrosis.

METHODS

The expression of senescence markers and proinflammatory cytokines in the submandibular glands (SMGs) of IgG4-RS patients (n = 18) and controls (n = 14) was determined by proteomics, real-time polymerase chain reaction (PCR), western blot, and immunohistochemistry. After interleukin-4 (IL-4) treatment, high-throughput RNA-sequencing was performed to identify the differentially expressed genes in SMG-C6 cells. A glandular fibrosis model was established by the intraglandular injection of IL-4 into mouse SMGs (n = 8 per group).

RESULTS

Salivary acinar and ductal epithelial cells underwent senescence in IgG4-RS patients, as indicated by the elevated activity of senescence-associated β-galactosidase, lipofuscin accumulation, enhanced expression of senescence markers (p53 and p16^INK4A ), and upregulation of senescence-associated secretory phenotype factors. Moreover, there was a significant increase in IL-4 levels in SMGs of IgG4-RS patients, which positively correlated with p16^INK4A expression and the fibrosis score. Incubation with IL-4 exacerbated salivary epithelial cell senescence by increasing the expression of p16^INK4A through ROS-p38 mitogen-activated protein kinase (MAPK) pathway. The supernatant collected from IL-4-induced senescent SMG-C6 cells enhanced fibroblast activation and matrix protein production. Furthermore, injecting IL-4 promoted fibrosis and senescence phenotypes in the SMGs in vivo.

CONCLUSION

The cellular senescence induced by IL-4 through the ROS-p38 MAPK-p16^INK4A pathway promoted fibrogenesis during IgG4-RS. Our data suggest that cellular senescence could serve as a novel therapeutic target for treating IgG4-RS.

Abnormal [18F]fluorodeoxyglucose accumulation to tori tubarius in IgG4-related disease

OBJECTIVES

Tubarial glands (TGs) are recently refocused gland tissues localized near the tori tubarius in the nasopharynx and their clinical relevance is not clear yet. IgG4-related disease (IgG4-RD) is a progressive fibrosing condition and salivary glands are well-affected lesions. The aim of the present study is to examine [¹⁸F]fluorodeoxyglucose ([¹⁸F]FDG) accumulation to the tori tubarius in IgG4-related disease (IgG4-RD).

METHODS

48 patients with IgG4-RD who underwent positron emission tomography (PET) scanning with [¹⁸F]FDG were included and semi-quantitative analysis of [¹⁸F]FDG accumulation to tori tubarius was performed along with the clinical features and histopathological analysis.

RESULTS

Of the 48 patients, abnormal [¹⁸F]FDG accumulation (metabolic tumour volume ≥ 1) to tori tubarius was observed in 15 (31.3%), all of whom had lesions in other head and neck glands. IgG4-RD patients with abnormal [¹⁸F]FDG accumulation to tori tubarius showed swollen nasopharyngeal walls around tori tubarius and forceps biopsy of the lesion revealed acinar cells and IgG4-positive plasma cells histologically. Abnormal [¹⁸F]FDG accumulation (maximum standard uptake value, metabolic tumour volume and total lesion glycolysis) to tori tubarius correlated with higher IgG4 and lower IgA serum concentrations.

CONCLUSIONS

Abnormal [¹⁸F]FDG accumulation to tori tubarius can be observed in patients with IgG4-RD and the abnormal [¹⁸F]FDG accumulation to tori tubarius can be a clue of TG involvement in IgG4-RD.

Clinical and histopathologic characteristics of submandibular gland in Stevens-Johnson syndrome: A comparative study

OBJECTIVE

The objective of this study was to investigate the clinical manifestations and pathologic appearances of the submandibular gland (SMG) in Stevens-Johnson syndrome (SJS).

STUDY DESIGN

Patients with autologous transplantation of SMG for treatment of severe dry eye between March 1998 and May 2018 were divided into the SJS group (70 cases) and non-SJS group (50 cases) according to the history of SJS. The SMG weight and computed tomography volume and salivary flow rate were measured. The concentration index and secretion index were estimated using scintigraphy with technetium-99m-pertechnetate. Histopathology studies of SMG tissues were conducted, and the acini parameters were measured using a digital image analyzer.

RESULTS

A decreased computed tomography volume and weight was observed in 48.57% the SJS group and 2% in the non-SJS group (P < .01). The rest whole, acid-stimulated whole, and SMG rest salivary flow rates decreased in the SJS group (P < .05). The normal SMG concentration index (37.5% vs 96.67%, P < .001) and secretion index (35% vs 96.67%, P < .001) rates were lower in the SJS group than in the non-SJS group. The glandular parenchyma was reduced, the acinar space was widened, and the fat content was increased in the SJS group.

CONCLUSION

SMG atrophic and degenerative changes occurred in the SJS group, with a decrease in salivary secretion function in more than half of the patients.

Salivary gland involvement in ANCA-associated vasculitis

OBJECTIVE

Salivary gland involvement in anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis is rare, but can lead to the misdiagnosis of other diseases. The objective of this study was to clarify the characteristics of patients with salivary gland involvement.

METHODS

We conducted a systematic literature review of articles reporting salivary gland involvement in ANCA-associated vasculitis from the inception dates until May 2, 2021.

RESULTS

We identified 58 patients with salivary gland involvement. The mean age was 52 years, and men were predominantly affected (59%). Half of the patients presented with fever. Swelling of the salivary gland was the initial manifestation in 88% of the patients, unilaterally affected in 53%, and painful in 47%. The affected salivary glands were as follows: parotid gland alone (53%), submandibular gland alone (33%), and both parotid and submandibular glands (14%). Additionally, two patients had sublingual gland involvement. The most frequent clinical diagnosis was granulomatosis with polyangiitis (83%), followed by eosinophilic granulomatosis with polyangiitis (17%), while no patient was diagnosed with microscopic polyangiitis. PR3-ANCA positivity (72%) was predominant to MPO-ANCA positivity (6%), and ANCA was negative in 22% of the patients. Among 37 ANCA-positive patients, 6 patients (16%) were initially ANCA-negative, but subsequently became positive during the clinical course. The serum C-reactive protein levels were elevated in all the examined patients. On contrast-enhanced computed tomography, a finding suggestive of necrosis, which was heterogeneous enhancement with low-density areas, was found in 33% of the patients. Vasculitis, granulomatous inflammation, necrosis, or the presence of multinucleated giant cells was found in 83% of the biopsy samples of the affected salivary gland. Glucocorticoids with or without other immunosuppressive agents, such as cyclophosphamide were effective in most patients, but twelve patients (21%) experienced a relapse of the disease and nine patients (16%) died during the clinical course.

CONCLUSION

Salivary gland involvement can be an initial manifestation of ANCA-associated vasculitis. The recognition of this unusual atypical presentation is important for the early and accurate diagnosis and treatment.

Natural developing process of immunoglobulin G4-related sialadenitis after submandibular gland excision: a retrospective cohort study

OBJECTIVE

This study aimed to evaluate the long-term outcome and quality of life of IgG4-related sialadenitis (IgG4-RS) patients after submandibular gland (SMG) excision without immunomediate therapy.

MATERIALS AND METHODS

This retrospective review included patients with IgG4-RS who did not undergo further treatment following SMG excision. All patients diagnosed with IgG4-RS between January 1955 and December 2012 at the Department of Oral and Maxillofacial Surgery, Peking University School of Stomatology, were enrolled. The main outcome measures included postoperative IgG4-RS progression rate and differences between patients with and without recurrent disease. The degree of subjective oral dryness was evaluated using the summated xerostomia inventory (SXI); the objective secretory function was assessed by whole saliva flow rate measurements. Serological findings were analyzed during the follow-up.

RESULTS

SMG excision was adopted in all of the 83 patients. The median follow-up period was 108 (range 7-396) months. Clinical progression was observed in 54.2% of cases. Patients with other organ involvement (OOI) indicated higher progression rate to a significant extent (P = 0.015, HR = 2.108). The annual progression rate was 20.7% in the group with OOI and was 14.1% in the group without OOI. All cases showed higher levels of serum IgG4; the level was in positive correlation with follow-up time when no therapy was added. 82.4% of cases experienced xerostomia after the surgery, and the degree of dry mouth in patients underwent bilateral resection was significantly more severe than those in unilateral resection.

CONCLUSIONS

Surgical excision of involved SMG cannot control the disease progression, which is not recommended for treatment of IgG4-RS. Differential diagnosis is crucial in order to prevent irreversible organ loss and relevant salivary gland dysfunction. Key Points • Surgical excision of involved SMG cannot control progression of IgG4-RS.

IgG4-Related Disease and the Salivary Glands: A Review of Pathophysiology, Diagnosis, and Management

IgG4-related disease is a rare, immune-mediated, systemic disease that is characterized by soft tissue lymphocyte infiltration and resultant fibrosis. The salivary glands are among the most commonly affected organs. Patients present with subacute submandibular and/or parotid swelling and sialadenitis. Diagnosis incorporates clinical, serologic, radiologic, and pathologic findings. Most cases respond quickly to systemic glucocorticoids. IgG4-related disease mimics many infectious, inflammatory, and neoplastic diseases. Therefore, IgG4-related disease is frequently misdiagnosed. A knowledge of the pathophysiology, diagnosis, and management of IgG4-related disease is important for providers who treat salivary gland diseases.

Rare Diseases of the Salivary Glands and of Facial Nerve

Salivary gland diseases are rare. In the European Union (EU) a disease is considered to be rare if not more than 5 of 10,000 people are affected by it. According to estimates in Germany are about 4 million people with a rare disease. In the EU are about 30 million people with rare diseases [1]. In the present work most of the described diseases of salivary glands and of the facial nerve fall in this category. They form a very heterogeneous group whose treatment takes place mainly in specialized centers. Still, it is essential for the otolaryngologist to identify and to diagnose these diseases in order to initiate the right therapeutic steps. The work is a compilation of innate andacquired rare salivary gland disorders and of rare facial nerve disorders. The etiologies of inflammatory diseases, autoimmune disorders and tumors are taken into account. For the individual topics, the current literature, if available, was evaluated and turned into summarized facts. In this context the development of new processes, diagnostics, imaging and therapy are considered. Genetic backgrounds of salivary gland tumors and the trends in the treatment of tumorous lesions of the facial nerve are picked up. Furthermore, also rare diseases of the salivary glands in childhood are described. Some of them can occur in adults as well, but differ in frequency and symptoms. Due to the rarity of these diseases, it is recommended to tread these in centers with special expertise for it. Finally, the difficulties of initiation of studies and the problems of establishing disease registries concerning salivary gland disorders are discussed. This is very relevant because these pathologies are comparatively seldom.

Lesions that mimic malignant tumors in nasopharyngeal biopsies: case series of 10 years

INTRODUCTION

Lesions mimicking malignancies in the nasopharynx are frequently seen in adult patients. These include inflammatory, metaplastic, and cystic lesions. We aimed to draw attention to rare tumor-like lesions that can be confused with malignancies and cause diagnostic difficulties clinically and radiologically.

METHODS

A total of 538 patients who underwent nasopharyngeal biopsy in our center between January 2010 and June 2020 were evaluated. Patient information was obtained from patient files and evaluated retrospectively.

RESULTS

A total of 19 of the 538 patients had tumor-like lesions that were included in the study. Granulomatous inflammation was present in seven cases, oncocytic metaplasia in four cases, benign cyst in five cases, fungal infection in two cases, and immunoglobulin G4-related disease in one case.

CONCLUSIONS

The nasopharynx is a region where various lesions can be seen. Some lesions form tumor-mimicking mass effect, cause increased thickness, and lead to increased metabolic activity in positron emission tomography-computed tomography that create the illusion of a malignant tumor and histopathologic verification is crucial. We aimed to present these rare tumor-like lesions that should be kept in mind in the differential diagnosis.

Imaging of IgG4-Related Disease in the Head and Neck: A Systematic Review, Case Series, and Pathophysiology Update

This systematic review aims to clarify and comprehensively detail the sometimes variable published imaging features as well as the pathogenesis, clinical diagnostic criteria, and treatment options of IgG4-Related Diseases (IgG4-RD) in the head and neck to aid the radiologist in diagnosing relapse and new sites of disease. A literature search in PubMed and EMBASE for reported cases of IgG4-RD was performed in December 2019. Case reports or series of IgG4-RD in the head and neck in adults that included sufficient imaging and pathology findings were included. This yielded 50 reports. IgG4-RD locations included the orbits, thyroid, pituitary gland, paranasal sinuses, salivary and parotid glands, larynx, pharynx, cervical lymph nodes, meninges, and skull base. Most lesions demonstrated non-specific homogenous CT attenuation, diffuse enhancement, isointense/low T2 signal intensity, and low T1 signal intensity. 6 cases from our institution followed previously reported imaging patterns.

Differential diagnosis of immunoglobulin G4-related sialadenitis and Kimura's disease of the salivary gland: a comparative case series

The aim of this study was to investigate key points for the differential diagnosis of immunoglobulin G4-related sialadenitis (IgG4-RS) and Kimura's disease (KD) involving the salivary glands. The clinical, serological, radiological, histological, and immunohistochemical features of 85 IgG4-RS cases and 52 KD cases were evaluated comparatively. Seventy-two IgG4-RS cases had enlargement of multiple salivary and/or lacrimal glands; 67 patients had bilateral submandibular gland (SMG) involvement. Unilateral parotid gland involvement (59.6%) and comorbid skin lesions (61.5%) were common in KD. Serum IgG4 was elevated in 94.1% of IgG4-RS cases versus 19.0% of KD cases (cut-off value=266.5mg/dl). KD was more commonly associated with elevated eosinophil counts (86% vs 23.1%) and elevated IgE concentrations (95.5% vs 76.6%). Storiform fibrosis, irregular lymphoid follicles, and increased IgG4-positive cells (112.9±37.6/high-power field (HPF)) were common in IgG4-RS. Acellular fibrosis, regular lymphoid follicles, IgE-positive reticular networks, increased IgE-positive cells (43.4±26.7/HPF), and tryptase-positive mast cells (29.7±13.3/HPF) were usually detected in KD. Computed tomography showed that 85.7% of KD cases involved subcutaneous fat tissue. A superficial hypoechoic and reticular pattern with multiple hypoechoic foci were the sonographic features of the SMG in IgG4-RS. Despite numerous overlapping manifestations, histopathological examination showed meaningful differences in the types of fibrosis, eosinophils, and IgG4-positive cell counts. Comprehensive evaluation of clinical, serological, radiological, and histopathological features are crucial for the differential diagnosis.

Pathology of IgG4-related sclerosing mastitis

Immunoglobulin G4-related sclerosing mastitis (IgG4-RM) is a recently recognised member of the IgG4-related disease (IgG4-RD) family, a multisystem fibroinflammatory condition that can affect any organ system. IgG4-RM is rare and predominantly occurs in middle-aged women. It may present with painless palpable mass and/or lymphadenopathy thereby mimicking breast cancer. Although there is an abundance of literature describing the clinicopathological characteristics of IgG4-RD in a variety of organs, data on IgG4-RM are limited due to its rarity. This review describes the manifestation of the disease in the breast based on reported cases, emphasising the clinicopathological features, pathophysiology, differential diagnosis, treatment and prognosis.

Prediction of 3-month treatment outcome of IgG4-DS based on BP artificial neural network

OBJECTIVE

The study aimed to establish an effective back-Propagation artificial neural network (BP-ANN) model for automatic prediction of 3-month treatment outcome of IgG4-DS.

METHODS

A total of 26 IgG4-DS patients at Shanghai Ninth People's Hospital from January 2018 to December 2019 were involved in the study. They were all followed for >3 months. The primary outcome was reduction of serum IgG4 (sIgG4) after 3-month treatment. The association between risk factors and reduction of sIgG4 was analyzed by Spearman's rank correlation test. According to the R values, we built a BP-ANN model by MATLAB R2019b.

RESULTS

The average reduction of sIgG4 was 5.55 ± 5.03. After Spearman's rank correlation test, ESR, sIgG4, and sIgG were independently associated with reduction of sIgG4 (p < .05) and were selected as input variables. Take into account these parameters, BP-ANN model was developed and the coefficient of determination (R² ) model was 0.95512.

CONCLUSION

The BP-ANN model based on ESR, sIgG4, and sIgG could predict the 3-month reduction of sIgG4 for IgG4-DS patients. It showed potential clinical application value.

Eosinophilic Sialodochitis: A Type of Chronic Obstructive Sialadenitis Related to Allergy

OBJECTIVES

To investigate the clinical, laboratory, radiological, histopathological, and immunohistochemical features, and the expression of allergy-related cytokines in eosinophilic sialodochitis (ES).

METHODS

Thirty-eight patients diagnosed with chronic obstructive sialadenitis (COS) who had undergone glandular excision or incisional biopsy were enrolled. Seventeen patients with comorbid atopic disease and increased ductal tissue eosinophils comprised the ES group, while 21 patients comprised the COS group. The clinicopathological features and allergy-related cytokine expression were compared between groups.

RESULTS

The ES group frequently involved multiple, bilateral major salivary glands, and the number of glands was significantly greater than the COS group (2.8 ± 1.1 vs. 1.2 ± 0.4, P < .001). Serum immunoglobulin (Ig) E was elevated in 91% of patients in ES group (419 ± 357 kU/L) and peripheral blood eosinophil was significantly greater compared with the COS group (7.6% ± 4.6% vs. 2.5% ± 1.4%, P < .001). Histologically, eosinophil infiltration in ES group was observed around the main and interlobular ducts (50 ± 39/high power field [HPF]). Follicular hyperplasia (76%), epithelial mucous metaplasia (82%), and mucus plugs with eosinophils (41%) were observed. IgE-positive cell count was 20.7 ± 18.3/HPF and tryptase-positive mast cell count was 23.5 ± 15.1/HPF, which was significantly greater than the respective cell counts in COS group, which mainly infiltrated around the ducts. The levels of interleukin-4, interleukin-13, and eotaxin in tissue were significantly greater in ES than the COS group.

CONCLUSIONS

The clinicopathological characteristics of ES are significantly different from COS and ES might have an allergy-related pathogenesis.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E800-E806, 2021.

Salivary gland involvement disparities in clinical characteristics of IgG4-related disease: a retrospective study of 428 patients

OBJECTIVES

IgG4-related disease (IgG4-RD) has recently been recognized as a fibro-inflammatory condition featuring tumefactive lesions in multiple organs, and the salivary gland is one of the most commonly involved sites. We undertook this study to compare detailed demographic, clinical and laboratory characteristics of IgG4-RD patients with salivary gland lesions (IgG4-RD SG+) and salivary-gland-free IgG4-RD (IgG4-RD SG-) in a large cohort.

METHODS

We carried out a retrospective review of the medical records of 428 cases of IgG4-RD diagnosed at Peking University People's Hospital between March 2006 and May 2018.

RESULTS

Among 428 patients, 249 had salivary glands that were affected. IgG4-RD SG+ patients showed younger age at disease onset and diagnosis, and a longer interval between symptom onset and diagnosis. The IgG4-RD SG+ group involved more female patients, and allergic diseases were more common in this group. In terms of organ involvement, the IgG4-RD SG+ group were more frequently presented with lacrimal gland involvement, while lymph node, retroperitoneal fibrosis, pancreas, biliary system, kidney and aorta were more prominent in the IgG4-RD SG- group. In addition, the serum IgG4 level, IgG4/IgG ratio and IgE level were significantly higher in IgG4-RD SG+ patients. Patients with eosinophilia were more common in the IgG4-RD SG+ group, while elevated ESR, CRP and positive ANA were more common in the IgG4-RD SG- group.

CONCLUSION

We have revealed demographic, clinical and laboratory differences between IgG4-RD SG+ and SG- patients, which indicated potential differences in pathogenesis and important implications for the diagnosis and management of these two phenotypes.

Diagnostic utility of submandibular and labial salivary gland biopsy in IgG4-related sialadenitis

OBJECTIVE

The diagnostic utility of labial salivary gland (LSG) biopsy for IgG4-related sialadenitis remains undetermined. The purpose of the present study was to determine whether submandibular gland biopsy could be replaced by LSG biopsy for diagnosing IgG4-RS.

PATIENTS AND METHODS

Medical records of two groups of patients were reviewed. Group A contained 45 patients suspected to have IgG4-RS who underwent both SMG and LSG biopsies. Group B contained 25 patients who were clinically and pathologically diagnosed with Sjögren syndrome (SS). Biopsy samples were stained using hematoxylin and eosin (HE) and immunohistochemical techniques and observed under an optical microscope. Relevant data describing histopathological characteristics were collected and analyzed.

RESULTS

SMG of IgG4-RS patients presented typical histopathological characteristics of fibrosis and IgG4-positive plasmacytic infiltration, while LSG showed varied characteristics. The sensitivity and accuracy of SMG for diagnosing IgG4-RS were greater than those of LSG (100% and 100% versus 55.3% and 75.7%, respectively, P < 0.05).

CONCLUSIONS

Biopsy of SMG showed greater sensitivity and specificity, whereas LSG biopsy showed varied histopathological and immunohistochemical characteristics; thus, SMG biopsy cannot be replaced by LSG biopsy for diagnosis of IgG4-RS.

Sclerosing sialadenitis of the submandibular gland is rarely an immunoglobulin G4-related disease in the Finnish population

Chronic sclerosing sialadenitis may represent one of many manifestations of an immunoglobulin G4-related disease. However, existing studies typically consist of small patient cohorts rarely conducted in Western populations. The clinical behavior of chronic sclerosing sialadenitis, including follow-up data, warrants further study. Thus, we aimed to determine whether chronic sclerosing sialadenitis always presents as IgG4-related disease or associates with autoimmune diseases and to determine which additional examinations patients may require. Between 2000 and 2017, 51 patients undergoing submandibular gland resection within the Helsinki University Hospital area were diagnosed with chronic sclerosing sialadenitis. We re-evaluated all specimens and performed immunostaining for IgG4. IgG and CD31 stainings were performed for IgG4-positive specimens. IgG4-related disease diagnosis was defined by the Boston consensus statement criteria. We revised clinical data, distributing a follow-up questionnaire to patients to register symptoms of IgG4-related disease or autoimmune disease during follow-up. The chronic sclerosing sialadenitis criteria were fulfilled in 34 patients, whereby 17 were diagnosed as non-sclerosing chronic sialadenitis. In 19 cases, a sialolith associated with a salivary gland lesion. In total, 12 of 51 cases were recognized as IgG4-positive, while two met the criteria for IgG4-related disease. These two cases belonged to the non-sclerosing chronic sialadenitis group, and both involved other organs. The histopathological features between chronic sclerosing sialadenitis and non-sclerosing chronic sialadenitis overlapped regarding the degree of fibrosis and inflammatory infiltrates. In the Finnish population, chronic sclerosing sialadenitis of the submandibular gland does not appear to present as IgG4-related disease. Non-sclerosing chronic sialadenitis can associate with IgG4-related disease. A histopathological distinction between chronic sclerosing sialadenitis and non-sclerosing chronic sialadenitis is not always unequivocal and the presence of a sialolith does not exclude IgG4-positivity. Therefore, immunostaining for IgG4 should be performed when dense plasma cell infiltration is present in either non-sclerosing chronic sialadenitis or chronic sclerosing sialadenitis.

Review of a novel disease entity, immunoglobulin G4-related disease

Immunoglobulin G4 (IgG4)-related dacryoadenitis and sialoadenitis (IgG4-DS) are part of a multiorgan fibroinflammatory condition of unknown etiology termed IgG4-related disease (IgG4-RD), which has been recognized as a single diagnostic entity for less than 15 years. Histopathologic examination is critical for diagnosis of IgG4-RD. CD4+ T and B cells, including IgG4-expressing plasma cells, constitute the major inflammatory cell populations in IgG4-RD and are thought to cause organ damage and tissue fibrosis. Patients with IgG4-RD who have active, untreated disease exhibit significant increase of IgG4-secreting plasmablasts in the blood. Considerable insight into the immunologic mechanisms of IgG4-RD has been achieved in the last decade using novel molecular biology approaches, including next-generation and single-cell RNA sequencing. Exploring the interactions between CD4+ T cells and B lineage cells is critical for understanding the pathophysiology of IgG4-RD. Establishment of pathogenic T cell clones and identification of antigens specific to these clones constitutes the first steps in determining the pathogenesis of the disease. Herein, the clinical features and mechanistic insights regarding pathogenesis of IgG4-RD were reviewed.

Disruption of tight junction structure contributes to secretory dysfunction in IgG4-related sialadenitis

IgG4-related sialadenitis (IgG4-RS) is a chronic fibro-inflammatory disease characterized by swelling of salivary glands and varying degrees of xerostomia. Tight junctions (TJs) play an essential role in maintaining secretory function by regulating the paracellular flow of ions and water. However, whether TJs are altered and contribute to the hyposecretion in IgG4-RS is not fully understood. Here, a total of 399 differentially expressed proteins were identified in IgG4-RS submandibular glands (SMGs) and enriched in the regulation of actin cytoskeleton and the salivary secretion. Real-time PCR results showed that the mRNA levels of claudin-3, -4, -6, -7, -8, -10, -12, occludin, and ZO-1 were significantly lower, whereas claudin-1 and -5 were higher in IgG4-RS SMGs. Immunohistochemical and immunofluorescence staining revealed that claudin-1, -3, -4, occludin, and ZO-1 were mainly distributed at apicolateral membranes in acini and ducts of SMGs from controls, whereas claudin-1 protein intensity at apicolateral membrane was elevated, while the staining of claudin-3, -4, and ZO-1 were reduced in IgG4-RS SMGs. Occludin was dispersed into cytoplasm of acini and ducts in SMGs of patients. Among them, claudin-3 and ZO-1 protein levels were positively correlated with saliva flow rate. Furthermore, the decreased fluorescence intensity of F-actin at peri-apicolateral membranes and the loss of ZO-1 staining at the same location were observed in acinar and ductal cells of IgG4-RS SMGs, which might be responsible for disorganization of TJ complex. Taken together, these findings indicate that the integrity of TJ complex of SMGs is impaired and might contribute to hyposalivation of IgG4-RS patients.

TNF-α Suppresses Autophagic Flux in Acinar Cells in IgG4-Related Sialadenitis

IgG4-related sialadenitis (IgG4-RS) is a newly recognized immune-mediated systemic fibroinflammatory disease that affects salivary glands and leads to hyposalivation. Tumor necrosis factor-α (TNF-α) is a critical proinflammatory cytokine involved in several salivary gland disorders, but its role and mechanism regarding acinar cell injury in IgG4-RS are unknown. Here, we found that TNF-α level was significantly increased in serum and submandibular gland (SMG) of patients and that serum TNF-α level was negatively correlated with saliva flow rate. Ultrastructural observations of IgG4-RS SMGs revealed accumulation of large autophagic vacuoles, as well as dense fibrous bundles, decreased secretory granules, widened intercellular spaces, swollen mitochondria, and expanded endoplasmic reticulum. Expression levels of LC3 and p62 were both increased in patients' SMGs. TNF-α treatment led to elevated levels of LC3II and p62 in both SMG-C6 cells and cultured human SMG tissues but did not further increase their levels when combined with bafilomycin A1 treatment. Moreover, transfection of Ad-mCherry-GFP-LC3B in SMG-C6 cells confirmed the suppression of autophagic flux after TNF-α treatment. Immunofluorescence imaging revealed that costaining of LC3 and the lysosomal marker LAMP2 was significantly decreased in patients, TNF-α-treated SMG-C6 cells, and cultured human SMGs, indicating a reduction in autophagosome-lysosome fusion. Furthermore, the ratio of pro/mature cathepsin D was elevated in vivo, ex vivo, and in vitro. TNF-α also appeared to induce abnormal acidification of lysosomes in acinar cells, as assessed by lysosomal pH and LysoTracker DND-26 fluorescence intensity. In addition, TNF-α treatment induced transcription factor EB (TFEB) redistribution in SMG-C6 cells, which was consistent with the changes observed in IgG4-RS patients. TNF-α increased the phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, and inhibition of ERK1/2 by U0126 reversed TNF-α-induced TFEB redistribution, lysosomal dysfunction, and autophagic flux suppression. These findings suggest that TNF-α is a key cytokine related to acinar cell injury in IgG4-RS through ERK1/2-mediated autophagic flux suppression.

[Clinicopathological characteristics and diagnosis of IgG4related sialadenitis]

Immunoglobulin G4-related sialadenitis (IgG4-RS) is a newly recognized immune-mediated disease and one of immunoglobulin G4-related diseases (IgG4-RD). Our multidisciplinary research group investigated the clinicopathological characteristics and diagnosis of IgG4-RS during the past 10 years. Clinically, it showed multiple bilateral enlargement of major salivary glands (including sublingual and accessory parotid glands) and lacrimal glands. The comorbid diseases of head and neck region including rhinosinusitis, allergic rhinitis, and lymphadenopathy were commonly seen, which could occur more early than enlargement of major salivary glands. Internal organ involvements, such as autoimmune pancreatitis, sclerosing cholangitis, and interstitial pneumonia could also be seen. Thirty-five (38.5%) patients had the symptom of xerostomia. Saliva flow at rest was lower than normal. Secretory function was reduced more severely in the submandibular glands than in the parotid glands. Serum levels of IgG4 were elevated in almost all the cases and the majority of the patients had increased IgE levels. CT, ultrasonography, and sialography showed their imaging characteristics. Histologically it showed marked lymphoplasmacytic inflammation, large irregular lymphoid follicles with expanded germinal centers, prominent cellular interlobular fibrosis, eosinophil infiltration, and obliterative phlebitis. Their immunohistological examination showed marked IgG-positive and IgG4-positive plasma cell infiltration and high IgG4/IgG ratio. The disease could be divided into three stages according to severity of glandular fibrosis. The serum IgG4 level was higher and the saliva secretion lower as glandular fibrosis increased. IgG4-RS should be differentiated from other diseases with enlargement of major salivary gland and lacrimal gland, such as primary Sjögren syndrome, chronic obstructive submandibular sialadenitis, and eosinophilic hyperplastic lymphogranuloma.

Clinical features and mechanistic insights regarding IgG4-related dacryoadenitis and sialoadenitis: a review

Immunoglobulin G4-related disease (IgG4-RD), recognized only recently as a single diagnostic entity, is a chronic inflammatory condition of unknown etiology. The diagnosis of IgG4-RD relies heavily on histopathological analysis and the correlation of histology findings with clinical, serological, and radiological data. CD4⁺ T and B cells, including IgG4-expressing plasmablasts, constitute the major inflammatory cell populations in IgG4-RD and are believed to cause organ damage and tissue fibrosis. Patients with IgG4-RD, who have active, untreated disease, exhibit marked expansion of IgG4-secreting plasmablasts in the blood. Important mechanistic insights correlated with the pathogenesis of IgG4-RD have been disclosed in recent years through the application of novel molecular biology approaches, including next-generation and single-cell RNA sequencing. Exploration of the interactions between these CD4⁺ T cells and cells of the B lymphocyte lineage is critical to understanding the pathophysiology of IgG4-RD. The establishment of pathogenic T cell clones and the identification of antigens specific to these clones constitute the first steps in determining the pathogenesis of this disease. This review focuses on clinical features and mechanistic insights regarding IgG4-related dacryoadenitis and sialoadenitis, from a perspective suitable for oral and maxillofacial surgeons.

Contribution of HIV Infection, AIDS, and Antiretroviral Therapy to Exocrine Pathogenesis in Salivary and Lacrimal Glands

The structure and function of exocrine glands are negatively affected by human immunodeficiency virus (HIV) infection and its co-morbidities, including innate and adaptive immune responses. At the same time, exocrine function may also be influenced by pharmacotherapies directed at the infectious agents. Here, we briefly review the role of the salivary glands and lacrimal glands in normal physiology and exocrine pathogenesis within the context of HIV infection and acquired immune deficiency syndrome (AIDS), including the contribution of antiretroviral therapies on both. Subsequently, we discuss the impact of HIV infection and the types of antiretroviral therapy on disease management and therapy development efforts.

Sialendoscopic management of autoimmune sialadenitis: a review of literature

Autoimmune diseases of major salivary glands include Sjögren's syndrome and a complex of disorders classified as immunoglobulin G4-related diseases. These pathologies are characterised by an autoimmune reaction mediated by T-helper lymphocytes that targets the ducts of exocrine glands in Sjögren's syndrome and glandular parenchyma in immunoglobulin G4-related diseases. Immunoglobulin G4-related diseases represent recently introduced multi-organ diseases that also involve the salivary glands. However, the morbid conditions once known as Mikulicz's disease and Kuttner's tumour were recently considered as two variants of immunoglobulin G4-related diseases affecting the major salivary glands ( immunoglobulin G4-related sialadenitis). This review briefly summarises the pathogenesis and clinical features of autoimmune diseases of the major salivary glands, focusing on the diagnostic and therapeutic role of sialendoscopy.

Salivary Gland Pathology in IgG4-Related Disease: A Comprehensive Review

IgG4-related disease (IgG4-RD) is a rare fibroinflammatory condition that can affect almost any organ, characterized by swollen lesions and often by eosinophilia and elevated serum IgG4 concentrations. The diagnosis of IgG4-RD is a challenging task: in fact, single or multiple organs can be affected and clinical, serological, and histological findings can be heterogeneous. In IgG4-RD, the involvement of salivary glands is observed in 27% to 53% of patients. Several organ-specific conditions, now recognized as different manifestations of IgG4-related sialadenitis (IgG4-RS), were viewed in the past as individual disease entities. The study of salivary glands may sometimes be complex, because of the number of pathological conditions that may affect them, often with overlapping clinical pictures. Integration of different imaging techniques is often required in the case of swelling of salivary glands, even though biopsy remains the gold standard for a definite diagnosis of IgG4-RS. Thus, in this review, we discuss new insights in the pathogenesis of IgG4-RD, focusing on its clinical aspects and the tools that are currently available for a correct differential diagnosis when the salivary glands are involved.

Treatment of immunoglobulin G4-related sialadenitis: outcomes of glucocorticoid therapy combined with steroid-sparing agents

Background

Immunoglobulin G4-related sialadenitis (IgG4-RS) is a newly recognized immune-mediated systemic disease. Despite its good response to steroid therapy, its treatment protocol is not standardized and the long-term outcome is controversial. The study was conducted to determine the short-term and long-term outcomes of IgG4-RS patients treated with glucocorticoids and steroid-sparing immunosuppressive agents, to analyze secretory function, serological and radiological changes in salivary glands and to assess the usefulness of serum IgG4 level as an indicator of disease activity.

Methods

IgG4-RS patients who were treated for more than 3 months were enrolled. Serological tests, salivary gland function assessment and computed tomography (CT) were performed before treatment and during follow up. The treatment outcomes in the short and the long term were evaluated, and the relationship between serum IgG4 level and salivary gland volume was analyzed.

Results

Glucocorticoids were used in all 43 patients and steroid-sparing immunosuppressive agents in 38 patients (88.4%). The follow-up period was 24.6 ± 14.9 months. Clinical remission was achieved in all patients after induction therapy. During short-term observation, salivary gland secretion significantly increased, and the serum IgG4 levels, the volumes and CT values of submandibular and parotid gland decreased significantly (P < 0.001). For long term, relapse occurred in 32.5% patients within 55 months in the regularly treated group, while all seven irregularly treated patients relapsed. However, the relapse-free survival curves were not significantly different between the steroid monotherapy and the combination therapy groups (P = 0.566). Submandibular glands, lacrimal glands, sublingual glands, nasal and paranasal cavity were commonly relapsing organs. In clinically stable patients, a serologically unstable condition occurred in 54.9% patients within 55 months and medication adjustment was performed accordingly. Volume changes in the submandibular and parotid glands were associated with serum IgG4 levels and time of follow up (R²_adjusted = 0.905, P < 0.0001 and R²_adjusted = 0.9334, P < 0.0001, respectively).

Conclusions

The combination of glucocorticoid and steroid-sparing agents could be effective for treating IgG4-RS, and restoring salivary gland function. Serum IgG4 levels could predict disease activity.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-017-1507-6) contains supplementary material, which is available to authorized users.

Imaging of IgG4-related disease of the head and neck

IgG4-related disease is a systemic, inflammatory disorder typically involving multiple organ systems. Several eponymous conditions described previously in the clinical and radiology literature are now recognised to be part of the IgG4-related disease spectrum. This includes multiple manifestations in the head and neck region, which are the subject of this review. Imaging can occasionally suggest the specific diagnosis of IgG4 disease. More commonly, it will be included in a limited differential diagnosis that requires clarification with the aid of image-guided biopsy. There are strict histopathological criteria for the diagnosis of IgG4-related disease.

Differential diagnosis of IgG4-related sialadenitis, primary Sjögren syndrome, and chronic obstructive submandibular sialadenitis

Our aim was to differentiate IgG4-related sialadenitis, primary Sjögren syndrome, and chronic obstructive submandibular sialadenitis by analysing clinical, radiographic, and pathological features. Fifty-five patients, 50, and 50 were enrolled, respectively and their baseline characteristics and serological, sialographic, and pathological findings compared. The male:female ratio for IgG4-related sialadenitis was 1:1.2 for primary Sjögren syndrome 1:15.7, and for chronic obstructive submandibular sialadenitis1:0.92. Numbers with enlarged salivary glands were 55, 16, and 50; with xerostomia 26, 48, and 0; with a history of allergy 26, 4, and 6, and with coexisting systemic disease 12, 19, and 0 (p=0.14). Mean (SD) serum IgG4 concentrations were 109.1 (97.9), 4.9. (1.9) g/L, and 5.3 (1.6) g/L, p<0.001 in all cases. Sialography showed enlargement of the gland, dilatation of the duct, and slightly decreased secretory function in IgG4-related disease; obvious sialectasia and decreased secretory function in Sjögren syndrome; and dilatation of Wharton's duct and filling defects in obstructive sialadenitis. Histopathological examination showed lymphoplasmacytic infiltration with storiform fibrosis, lymphoplasmacytic inflammation and lymphoepithelial lesions, and dilatation of the duct with epithelial metaplasia in the three groups, respectively. The number of IgG4-positive plasma cells was 123 (45)/HPF, 8 (3)/HPF, and 5 (4)/HPF, while the IgG4-/IgG-positive cell ratio was 71.7 (13.9)%, 4.6 (2.5)%, 18.9 (19.7)%, respectively (p<0.001). The three conditions have different clinical, radiographic, and pathological features that provide important clues to the differential diagnosis. Serological and histological tests are important, and comprehensive consideration is necessary.

Clinicopathology of Immunoglobulin G4–Related Chronic Sclerosing Sialadenitis

Objectives

To investigate the clinicopathologic characteristics of patients with immunoglobulin G4–related chronic sclerosing sialadenitis (IgG4-RCSS), a recently recognized disease.

Study Design

Case series with chart review and pathology study.

Settings

Tertiary care hospital.

Subjects and Methods

We evaluated chronic sialadenitis specimens obtained over 11 years using pathologic examination and IgG4 immunohistochemistry staining. The specimens were assigned a revised diagnosis of IgG4-RCSS or chronic sialadenitis not otherwise specified, and clinicopathologic data from each group were compared.

Results

Of the 84 patients, 21 were diagnosed with IgG4-RCSS and 63 with chronic sialadenitis not otherwise specified. IgG4-RCSS patients were older (68.2 ± 13.9 vs 54.2 ± 15.8 years, P = .001), predominantly male (85.7% vs 61.9%, P = .036), and more likely to present with painless swelling (75% vs 44.3%, P = .001) and bilateral involvement (52.4% vs 6.3%, P < .001). Ratio of IgG4-positive plasma cells to IgG-positive plasma cells in IgG4-RCSS tissues was 0.81 ± 0.14. The mean value of serum IgG4 in IgG4-RCSS patients was 918.8 mg/dL.

Conclusion

IgG4-RCSS is more common in older male patients and frequently presents with bilateral involvement. Informing head and neck surgeons of the clinical features of IgG4-RCSS and promoting a combined approach of clinical evaluation, imaging, and biopsy can improve the accuracy of preoperative diagnoses.