Mechanisms and assessment of IgG4-related disease: lessons for the rheumatologist. Nat Rev Rheumatol. 2014;10:148-159. [PMID: 24296677 DOI: 10.1038/nrrheum.2013.183]

Interferon-gamma increased epithelial barrier function via upregulating claudin-7 expression in human submandibular gland duct epithelium

Tight junctions (TJs) are necessary for salivary gland function and may serve as indicators of salivary gland epithelial dysfunction. IgG4-related disease (IgG4-RD) is a newly recognized fibro-inflammatory condition which disrupts the TJ associated epithelial barrier. The salivary glands are one of the most frequently involved organs in IgG4-RD, however, changes of the TJ associated epithelial barrier in salivary gland duct epithelium is poorly understood. Here, we investigated the regulation and function of TJs in human submandibular gland ductal epithelial cells (HSDECs) in normal and IgG4-RD. We examined submandibular gland (SMG) tissue from eight control individuals and 22 patients with IgG4-RD and established an HSDEC culture system. Immunohistochemistry, immunocytochemistry, western blotting, and measurement of transepithelial electrical resistance (TER) were performed. Claudin-4, claudin-7, occludin, and JAM-A were expressed at the apical side of the duct epithelium in submandibular gland (SMG) tissue and at the cell borders in HSDECs of normal and IgG4-RD. The expression and distribution of TJs in SMG tissue were not different in control individuals and patients with IgG4-RD in vivo and in vitro. Although interferon-gamma (IFNγ) generally disrupts the integrity and function of TJs, as manifested by decreased epithelial barrier function, IFNγ markedly increased the epithelial barrier function of HSDECs via upregulation of claudin-7 expression in HSDECs from patients with IgG4-RD. This is the first report showing an IFNγ-dependent increase in epithelial barrier function in the salivary gland duct epithelium. Our results provide insights into the functional significance of TJs in salivary gland duct epithelium in physiological and pathological conditions, including IgG4-RD.

IgG4-Related Neuromyopathy Associated With Recurrent Pleural Effusion

OBJECTIVE

Immunoglobulin G4-related disease (IgG4-RD) is an increasingly recognized idiopathic systemic disorder associated with elevated serum IgG4 level and tissue infiltration by IgG4-positive plasma cells. Multiple neurological manifestations, including peripheral neuropathy, have been described in IgG4-RD. Our objective is to discuss a case report and review of the literature, which would expand the spectrum of IgG4-RD.

METHODS

We describe the clinical features and biopsy findings in a patient with IgG4-RD who presented with features suggestive of neuromyopathy in the setting of recurrent pleural effusion and weight loss.

RESULTS

Electrodiagnostic findings were suggestive of an irritable myopathy and polyradiculoneuropathy with primary demyelination and secondary axonal degeneration. Pleural biopsy and laboratory studies confirmed the diagnosis. Improvement was sustained with steroid therapy.

CONCLUSIONS

We describe the first case, to our knowledge, of IgG4-related neuromyopathy associated with recurrent pleural effusion. Our case expands the clinical spectrum of IgG4-RD. Neurologists should be aware of this treatable disorder and in the appropriate clinical context consider it in the differential diagnosis of neuromyopathy.

Intracranial spread of IgG4-related disease via skull base foramina

IgG4-related disease (IgG4-RD) is a newly recognised, multiorgan, inflammatory disease, and its full clinical spectrum remains undefined. We present a biopsy-proven case of IgG4-RD presenting with a parapharyngeal mass with intracranial extension and possible involvement of the brain parenchyma. We highlight the importance of considering the diagnosis in those presenting with tumefactive lesions, leptomeningitis or pachymeningitis and emphasise the value of securing a tissue diagnosis so that appropriate long-term treatment can be instigated and complications avoided.

IgG4-related disease: A relatively new concept for clinicians

IgG4-related disease (IgG4-RD) is a recently recognized chronic fibrotic inflammation, which can affect almost every organ, and may come to clinical attention first due to visible organ swelling or organ dysfunction, or is identified incidentally by imaging and specific biopsy. The disorder has an allergic background and is immune-mediated. Up-regulated responses of T helper 2 and T regulatory cells and their cytokines play a major role in disease progression. About 30-50% of patients are atopic or have mild eosinophilia. IgG4-RD predominantly affects middle-aged male patients. The cornerstones of diagnosis of the disease are compatible clinical features and typical histopathology. Swelling of salivary and lacrimal glands, lymphadenopathy, and type 1 autoimmune pancreatitis (AIP) are the most common manifestations of the disease. However, other tissues and organs, such as retroperitoneum, lung, kidney, aorta, upper airways, thyroid gland, meninges, heart, mesenterium and skin may be involved. Typical histopathology is lymphoplasmacytic infiltration abundant in IgG4-positive plasma cells, storiform-type fibrosis, and obliterative phlebitis. Elevated serum IgG4 concentration supports the diagnosis. Characteristic imaging features such as a "capsule-like rim" surrounding the pancreatic lesions is highly specific to type 1 AIP. 18F-fluorodeoxyglucose positron emission tomography/computed tomography enables mapping the sites of inflammation, permits evaluation of the extent of the disease, helps in guiding biopsy decision, and may be used in monitoring response to treatment. Glucocorticoids alone or in combination with B-cell depletion with rituximab induces prompt clinical response to IgG4-RD. This article reviews the current understanding, different clinical manifestations, and approaches to diagnosis and treatment of IgG4-RD.

Non-IgG4-related Multifocal Fibrosclerosis

Multifocal fibrosclerosis (MFS), which causes systemic and chronic connective tissue inflammation, has been associated with IgG4 and regarded as an identical entity with "IgG4-related disease (IgG4-RD)". Although a few cases of MFS mimicking IgG4-RD histopathologically, despite the absence of a serum IgG4 elevation and IgG4-positive plasma cell infiltration, have been reported, there is, so far, little information regarding such exceptional cases. We herein demonstrate a case of non-IgG4-related MFS presenting with periaortitis and parotiditis, whose histological findings were consistent with IgG4-RD despite the absence of elevated serum and tissue IgG4 levels.

Plasmacytoid Dendritic Cell Activation and IFN-α Production Are Prominent Features of Murine Autoimmune Pancreatitis and Human IgG4-Related Autoimmune Pancreatitis

The abnormal immune response accompanying IgG4-related autoimmune pancreatitis (AIP) is presently unclear. In this study, we examined the role of plasmacytoid dendritic cell (pDC) activation and IFN-α production in this disease as well as in a murine model of AIP (MRL/Mp mice treated with polyinosinic-polycytidylic acid). We found that the development of AIP in treated MRL/Mp mice occurred in parallel with pancreatic accumulation of pDCs producing IFN-α, and with pDC depletion and IFN-α-blocking studies, we showed that such accumulation was necessary for AIP induction. In addition, we found that the pancreas of treated MRL/Mp mice contained neutrophil extracellular traps (NETs) shown previously to stimulate pDCs to produce IFN-α. Consistent with these findings, we found that patients with IgG4-related AIP also exhibited pancreatic tissue localization of IFN-α-expressing pDCs and had significantly higher serum IFN-α levels than healthy controls. In addition, the inflamed pancreas of these patients but not controls also contained NETs that were shown to be capable of pDC activation. More importantly, patient pDCs cultured in the presence of NETs produced greatly increased levels of IFN-α and induced control B cells to produce IgG4 (but not IgG1) as compared with control pDCs. These data suggest that pDC activation and production of IFN-α is a major cause of murine AIP; in addition, the increased pDC production of IFN-α and its relation to IgG4 production observed in IgG4-related AIP suggest that this mechanism also plays a role in the human disease.

Clinical Evaluation of Sinonasal Lesions in Patients With Immunoglobulin G4-Related Disease

Objectives:

Immunoglobulin G4-related disease (IgG4-RD) is a systemic disease entity characterized by elevated serum IgG4 and extensive IgG4-positive plasma cell infiltration of various organs. Patients with IgG4-RD show nasal manifestations with chronic rhinosinusitis. The objective of this study was to evaluate the clinical characteristics of sinonasal lesions in patients with IgG4-RD.

Methods:

We evaluated radiological findings of sinonasal lesions in 79 patients with IgG4-RD who were divided into 3 groups according to severity. We also compared serological findings, including serum IgG4 and IgE levels, and eosinophil counts.

Results:

Rhinosinusitis was found in 41 patients (51.9%). Although there were no significant differences in the serum IgG4 and IgE levels of the groups, there was a significant increase in eosinophil counts (445 ± 311.9/mm3) in Group C. Furthermore, 14 of the 41 patients with rhinosinusitis (34.1%) showed improvement after prednisolone administration. Patients with IgG4-RD and serum eosinophilia tend to also have sinonasal lesions.

Conclusions:

Rhinosinusitis is common in patients with IgG4-RD, and its pathogenesis can be similar to eosinophilic chronic rhinosinusitis.

IgG4-related disease in the sinonasal cavity accompanied by intranasal structure loss

IgG4-related disease was recently proposed under the classification of systemic chronic inflammatory disease. In the field of otolaryngology, organ-specific diagnostic criteria have been established for the occurrence of this condition in the salivary glands, but not in the sinonasal cavity. Here we report a case involving a 70-year-old man with IgG4-related disease in the sinonasal cavity. The patient, with the chief complaint of nasal bleeding, first visited a physician. However, the patient experienced recurrent bleeding with intranasal structure loss and was subsequently referred to our hospital. His IgG4 level was elevated, and histopathological examination of a tissue sample obtained from the edematous sphenoid sinus showed increased IgG4-positive plasma cells and storiform fibrosclerosis. A definitive diagnosis of IgG4-related rhinosinusitis was made on the basis of comprehensive criteria for IgG4-related disease. The disease showed a progressively destructive course that was clearly different from that of chronic sinusitis and represented a very rare case of IgG4-related rhinosinusitis. IgG4-related disease originating in the sinonasal cavity is rare, and, to the best of our knowledge, this is the first primary case of IgG4-related disease that originated in one side of the sinonasal cavity and showed progressive destruction.

Elevated Serum IgG4 Complicated by Pericardial Involvement with a Patchy (18)F-FDG Uptake in PET/CT: Atypical Presentation of IgG4-related Disease

IgG4-related pericardial involvement has rarely been reported and its clinical features remain unknown. We herein report a case of a 50-year-old woman with pericarditis who presented with a fever, elevated C-reactive protein levels, elevated serum IgG4 concentrations, and thickened pericardium with a patchy (18)F-fluorodeoxyglucose (FDG) uptake. A biopsy specimen of (18)F-FDG accumulated in the mediastinal lymph nodes revealed an abundant infiltration of IgG4-bearing plasma cells without fibrosis. Moderate-dose glucocorticoids promptly resolved the physical, serological, and imaging abnormalities, thus indicating a relatively acute and reversible nature of IgG4-related pericardial involvement.

IgG4-related disease: a new kid on the block or an old aquaintance?

IgG4-related systemic disease is a recently recognized systemic condition characterized by unique pathological features that can affect a variety of organs. It includes a growing number of medical conditions which have the following features in common: diffuse organ swelling or focal mass formation, sclerosing storiforme (whirl-shaped) fibrosis with a lymphoplasmacytic infiltrate rich in IgG4-bearing plasma cells, as well as elevated levels of serum IgG4. It invariably responds to steroid treatment and is mostly diagnosed in elderly men. Well-known syndromes like Mikulicz's disease of the salivary or lacrimal gland, Küttner's tumour of the submandibular gland, Riedel's thyroiditis, or retroperitoneal fibrosis, as well as novel entities such as autoimmune pancreatitis type 1, are now regarded to be manifestations of this systemic disease. This article provides an overview of the epidemiology, concepts of pathogenesis, clinical presentation, proposed diagnostic approaches, treatment options, and differential diagnosis of IgG4-related disease.

Preferential M2 macrophages contribute to fibrosis in IgG4-related dacryoadenitis and sialoadenitis, so-called Mikulicz's disease

IgG4-related dacryoadenitis and sialoadenitis (IgG4-DS) is characterized by bilateral swelling of glandular tissues with extensive fibrosis, and is immunologically considered a Th2-predominant disease. Recent studies reported that alternatively activated (M2) macrophages enhanced Th2 immune responses and fibrosis by production of pro-fibrotic factors (IL-10, IL-13 and CCL18). Therefore, we examined the association between M2 macrophages and fibrosis in submandibular glands from 7 patients with IgG4-DS, 10 patients with chronic sialoadenitis, 10 patients with Sjögren's syndrome, and 10 healthy subjects. The number of M2 macrophages in SMGs from patients with IgG4-DS was also significantly higher than in the other groups. Double immunofluorescence staining showed that IL-10 and CCL18 expression co-localized with M2 macrophage-marker (CD163). Furthermore, the SMG fibrosis score was positively correlated with the frequency of M2 macrophages in only IgG4-DS. These results indicate that IL-10 and CCL18 secreted by preferential M2 macrophages possibly play a key role in the development of severe fibrosis in IgG4-DS.

Identification of relapse predictors in IgG4-related disease using multivariate analysis of clinical data at the first visit and initial treatment

OBJECTIVES

Inducting clinical remission by glucocorticoid treatment is relatively easy in IgG4-related disease (IgG4-RD), but relapse also occurs easily with tapering of the steroid dose. The present study tried to analyse the cases to extract predictors of relapse present at the diagnosis of IgG4-RD.

METHODS

Subjects comprised 79 patients with IgG4-related dacryoadenitis and sialadenitis, known as Mikulicz's disease, who were diagnosed between April 1997 and October 2013 and followed-up for >2 years from the initial induction treatment. They were applied to Cox proportional hazard modelling, based on the outcome of interval to relapse. We performed multivariate analysis for the clinical factors of these cases and identified predictors of relapse.

RESULTS

Identified factors were male sex and younger onset in cases without organ involvement at diagnosis and low levels of serum IgG4 in cases with organ dysfunction at diagnosis. Complication with autoimmune pancreatitis and low steroid dose at initial treatment also tended to be associated with recurrence.

CONCLUSION

Follow-up is important in cases with recognized risk factors for relapse, including male sex and younger onset in cases without organ damage.