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]

[Clinical and laboratory characteristics of IgG4-realated disease and its diagnostic algorithm]

AIM

to propose diagnostic algorithm of IgG4-related disease (IgG4-RD).

MATERIALS AND METHODS

One center retrospective research. 52 pts with IgG4-RD were included. The diagnosis was proved histologically and immunohistochemically. 48 out of 52 pts received treatment. Treatment included one of the following schemes (along with low oral glucocorticoids): rituximab monotherapy, cyclophosphamide monotherapy or their combination.

RESULTS

The mean age was 47.4±5.9 years, the mean age of the disease onset was 43.9±16.0 years. Median time before the diagnosis was 24 months. The most often sites of IgG4-RD were lacrimal (63.5%), salivary (46.2%) glands, lungs (48%), lymph nodes (34.6%) and retroperitoneum (17.3%). In clinical picture the leading complain was organ enlargement, but not its dysfunction. Pain was characteristic for retroperitoneum localization. In 56.8% of pts with IgG4-related syalo - and/or dacryoadenitis there was association with ear - nose - throat organs affection. In 4 pts (7.7%) IgG4-RD was combined with some malignant disease, including MALT-lymphoma of lacrimal glands. Irreversible organ damage as an IgG4-RD outcome had 15.4% of pts. The main laboratory markers of IgG4-RD were ESR elevation (38.5%), blood eosinophilia (9.6%), immunological disturbances (serum total IgG and IgG4 elevation, IgE elevation, antinuclear antibodies, rheumatoid factor detection, hypocomplementemia). Serum IgG4 level >1.35 g/l was elevated in 88% of pts and correlated with the number of affected organs (Spearman correlation coefficient 0.39, Student's test, р=0.0056). Monoclonal serum secretion and B-cell clonality in the tissue was detected in 4 (23.5%) out of 17 pts, but not all of them had both signs.

CONCLUSION

Based on the analysis of clinical and laboratory characteristics of IgG4-RD a diagnostic algorithm was proposed that enhances the detection and examination of the patients with suspected IgG4-RD.

Retrospective single-centre analysis of IgG4-related disease patient population and treatment outcomes between 2007 and 2017

Objective

The aim was to gain a better understanding of the prevalence, organ involvement, clinical characteristics and long-term outcomes of medical and surgical treatments of IgG4-related disease (IgG4-RD).

Methods

Query of the Cleveland Clinic pathology database for IgG4 plasma cell staining between 2007 and 2017 yielded 1481 results, of which 57 cases were identified as highly likely (n = 28; 49%) or probable (n = 29; 51%) IgG4-RD by histopathological criteria and IgG4 serum concentrations. Patient demographics, type of treatment and outcomes were retrieved from medical records. Patients were designated as being in remission if indicated in the chart and/or symptom- and objective finding-free for >6 months, relapsed if symptoms/findings recurred after remission, active if no remission was achieved during follow-up, and as unable to determine if the duration of follow-up was <60 days or they were lost to follow-up.

Results

Of all patients who met the IgG4 staining criteria (n = 119), half (n = 57) satisfied the IgG4-RD histopathological criteria; 63% were males, age 57.9 ± 14.8 years. The average follow-up was 2.7 ± 2.2 years. The pancreas was the most affected organ in our cohort (26.4%). Almost half of the patients (45.6%; n = 26) were managed surgically, 21.1% (n = 12) medically, and 24.6% (n = 14) received both types of treatment. Medical treatment included prednisone (45.6%), MTX (5.3%), AZA (7%) and rituximab (8.8%). Remission was achieved by 77% of patients receiving surgical, 67% receiving medical and 72% receiving both treatments.

Conclusion

A histological diagnosis of IgG4-RD could be made in half of the patients who had IgG4⁺ plasma cells ≥10/high-power field or IgG4⁺/IgG⁺ ratio >40%. In our cohort, surgical treatment compared with medical treatment had a higher proportion of remission according to our outcome classification.

Pulmonary vascular involvement of IgG4-related disease: Case series with a PRISMA-compliant systemic review

BACKGROUND

Immunoglobulin G4-related disease (IgG4-RD) is a recently recognized, immune-mediated chronic fibrotic inflammation that can involve almost all organs, causing tumefaction and dysfunction. Its presence in pulmonary circulation is underestimated and has not yet been investigated.

OBJECTIVES

We describe a representative IgG4-RD patient with pulmonary artery stenosis and pulmonary embolism, leading to reversible pulmonary hypertension. Literature review of IgG4-RD with pulmonary circulation involvement was conducted.

DATA SOURCES

References for this review were identified through searches via PubMed, EBSCO, and Web of Science for published articles before November 2016.

RESULTS

There were 15 published cases of IgG4-RD with pulmonary vascular involvement, 3 with pulmonary arteritis, 2 with pulmonary artery aneurysm, 3 with pulmonary artery stenosis, 1 with obliterative phlebitis, and 1 with pulmonary embolism. Possible immunity and inflammation mechanisms were summarized.

CONCLUSIONS

IgG4-RD with pulmonary vascular involvement is rare. Echocardiogram and contrast-enhanced chest CT are helpful to screen the disease. Clinical manifestations were found from asymptomatic to dyspnea or even syncope. And nearly all cases had more than 1 organ affected, with significantly increased serum IgG4 levels. PET/CT aided in identifying affected organs and determining candidate biopsy sites. More awareness is urged to evaluate the pulmonary vascular manifestations of this disease.

Differences and similarities between IgG4-related disease with and without dacryoadenitis and sialoadenitis: clinical manifestations and treatment efficacy

Background

This study aimed to compare the differences and similarities in the clinical manifestations and treatment efficacy of IgG4-related disease (IgG4-RD) in patients with and without dacryoadenitis and sialoadenitis (DS).

Methods

A total of 121 untreated IgG4-RD patients in Peking Union Medical College Hospital were enrolled in this study. The patients were divided into three groups: DS-predominant (group A), non-DS (group B), and DS with other internal organs affected (group C). The patients were followed up for at least 15 months. Baseline and follow-up data were collected. The disease activity was evaluated according to the IgG4-RD responder index.

Results

The mean ± SD age at disease onset was 53.2 ± 14.1 years, and 71.9% of the patients were male. The prevalence of allergies was higher in groups A (21, 61.8%) and C (32, 69.6%) than group B (14, 34.1%). More patients with DS (17, 50.0%, and 17, 37.0%) had sinonasal lesions than those without DS (5, 12.2%). Moreover, an increased number of eosinophils were more common in patients with DS than in those without, as were increased serum IgG, IgG4, and IgE levels. More patients in group B and group C (28, 68.3%, and 31, 67.4%) received a combination therapy of corticosteroid and immunosuppressant. During the 15-month follow-up, 28 (23.1%) patients had disease relapse.

Conclusion

Results demonstrated that IgG4-RD patients with DS had distinctive clinical features compared with non-DS. Allergy and sinonasal involvement were more common in patients with DS. Patients with DS showed higher serum IgG4 levels than those without DS.

Electronic supplementary material

The online version of this article (10.1186/s13075-019-1828-8) contains supplementary material, which is available to authorized users.

Isolated IgG4-related gastric disease presenting as diffuse gastric wall thickening with ulcer

An 81-year-old male presented with loss of appetite, early satiety and iron deficiency anaemia. A computed tomography (CT) scan of the abdomen and pelvis during initial work-up revealed diffuse gastric mural thickening associated with a large ulcer and adjacent gastro-hepatic lymphadenopathy. The CT appearances, together with the clinical features, were highly suspicious for an infiltrative type of gastric malignancy. Endoscopic biopsy however showed erosive inflammation, IgG4 plasmacytosis and fibrosis, raising the possibility of IgG4-related disease. A serologic assay for IgG showed normal IgG4 and elevated IgG2 serum levels. After appropriate steroid treatment, endoscopy and CT scan showed resolution of the ulcer and gastric wall thickening. This case shows yet another possible appearance of gastric involvement in IgG4-related disease on the current evolving spectrum of this disease presentation. Greater awareness and education of this disease would help in patient care, ensuring earlier diagnosis, prevention of severe organ damage and morbidity, as well as unnecessary surgery.

A novel model for treatment of hypertrophic pachymeningitis

Objective

Immunoglobulin (Ig)G4‐related disease is a major cause of hypertrophic pachymeningitis (HP), presenting as a progressive thickening of the dura mater. HP lacks an animal model to determine its underlying mechanisms. We developed a suitable animal model for the treatment of HP.

Methods

We longitudinally evaluated dura in mice with a mutation (Y136F) in the linker for activation of T cells (LAT), which induced type 2 T helper (Th2) cell proliferation and IgG1 (IgG4 human equivalent) overexpression. Mice were therapeutically administered daily oral irbesartan from 3 to 6 weeks of age. Human IgG4‐related, anti‐neutrophil cytoplasmic antibody‐related, and idiopathic HP dura were also immunohistochemically examined.

Results

LATY136F mice showing dural gadolinium enhancement on magnetic resonance imaging had massive infiltration of B220⁺ B cells, IgG1⁺ cells, CD138⁺ plasma cells, CD3⁺ T cells, F4/80⁺ macrophages, and polymorphonuclear leukocytes in the dura at 3 weeks of age, followed by marked fibrotic thickening. In dural lesions, transforming growth factor (TGF)‐β1 was produced preferentially in B cells and macrophages while TGF‐β receptor I (TGF‐βRI) was markedly upregulated on fibroblasts. Quantitative western blotting revealed significant upregulation of TGF‐β1, TGF‐βRI, and phosphorylated SMAD2/SMAD3 in dura of LATY136F mice aged 13 weeks. A similar upregulation of TGF‐βRI, SMAD2/SMAD3, and phosphorylated SMAD2/SMAD3 was present in autopsied dura of all three types of human HP. Irbesartan abolished dural inflammatory cell infiltration and fibrotic thickening in all treated LATY136F mice with reduced TGF‐β1 and nonphosphorylated and phosphorylated SMAD2/SMAD3.

Interpretation

TGF‐β1/SMAD2/SMAD3 pathway is critical in HP and is a potential novel therapeutic target.

Resection of lesions in the ileum of patients with IgG4-related disease may ameliorate disease progression without steroid administration

Background

IgG4-related disease (IgG4-RD) is a pathological condition that is characterized by an infiltrate composed of IgG4-positive plasma cells and recently recognized as an immune-mediated condition. It causes tissue throughout the body to become stiff and thickened due to autoimmune reactions that cause fibrosis and scarring. Disease-related changes commonly occur in the salivary glands, bile duct, pancreas, and lungs, but are seldom seen in the small bowel. A diagnosis of IgG4-RD is suspected if a high level of IgG4 is found on a blood test. The ideal diagnostic method is pathological examination, but because the clinical manifestations of IgG4-RD are very diverse and nonspecific, the disease may often go undiagnosed until an unrelated biopsy or resection specimen is obtained. The most common treatment for IgG4-RD is steroid use. However, tapering or stopping steroid administration is seen to result in recurrence in approximately 50% of cases. A complete cure is therefore considered extremely difficult.

Case presentation

A 69-year-old man with gastrointestinal obstruction underwent small bowel resection for two lesions. On histopathological examination, the specimen showed features of IgG4-RD. We performed several tests to detect other characteristics of IgG4-RD, but were unable to find any. The patient is being followed up regularly for a year and is being observed for any symptoms of recurrence.

Conclusions

We present a case of IgG4-RD wherein the ileum wall was significantly sclerosed, leading to gastrointestinal tract obstruction; therefore, we resected two sections of the ileum. We believe that resection of IgG4-RD lesions can help avoid long-term steroid use in patients, because the surgery completely eliminates the pathological origins of the condition.

Eosinophilia and Kidney Disease: More than Just an Incidental Finding?

Peripheral blood eosinophilia (PBE), defined as 500 eosinophils or above per microliter (µL) blood, is a condition that is not uncommon but often neglected in the management of patients with chronic kidney disease (CKD), acute kidney injury (AKI), or patients on renal replacement therapy (RRT). The nature of PBE in the context of kidney diseases is predominantly secondary or reactive and has to be distinguished from primary eosinophilic disorders. Nonetheless, the finding of persistent PBE can be a useful clue for the differential diagnosis of underdiagnosed entities and overlapping syndromes, such as eosinophilic granulomatosis with polyangiitis (EGPA), IgG4-related disease (IgG4-RD), acute interstitial nephritis (AIN), or the hypereosinophilic syndrome (HES). For patients on RRT, PBE may be an indicator for bio-incompatibility of the dialysis material, acute allograft rejection, or Strongyloides hyperinfection. In a subset of patients with EGPA, eosinophils might even be the driving force in disease pathogenesis. This improved understanding is already being used to facilitate novel therapeutic options. Mepolizumab has been licensed for the management of EGPA and is applied with the aim to abrogate the underlying immunologic process by blocking interleukin-5. The current article provides an overview of different renal pathologies that are associated with PBE. Further scientific effort is required to understand the exact role and function of eosinophils in these disorders which may pave the way to improved interdisciplinary management of such patients.

Interleukin 5-producing ST2+ memory Th2 cells in IgG4-related dacryoadenitis and sialadenitis

Objectives: Immunoglobulin (Ig) G4-related disease (IgG4-RD) is often complicated by allergic disorders. This study was conducted to investigate the mechanism of type 2 helper T-inflammation (Th2-inflammation) in IgG4-related dacryoadenitis and sialadenitis (IgG4-DS). Methods: We separated and analyzed the proportion of growth stimulation expressed gene 2 (ST2)⁺ memory Th2 cells among the peripheral blood mononuclear cells by flow cytometry in cases with IgG4-DS and healthy individuals. Finally, we identified the role of ST2⁺ memory Th2 cells in the involved tissues. Results: The proportion of circulating ST2⁺ memory Th2 cells was much higher in the patients with IgG4-DS than in the healthy controls. Abundant infiltration of ST2⁺ memory Th2 cells was detected in the involved salivary glands and lymph nodes, and these cells produced interleukin-5. Conclusion: We demonstrated that there is an increase of interleukin-5 producing ST2⁺ memory Th2 cells in the involved tissues in IgG4-DS. This subset of cells is considered to be an important player in inducing the inflammatory Th2 environment characteristic of IgG4-DS.

Macrophage migration inhibitory factor contributes to the pathogenesis of benign lymphoepithelial lesion of the lacrimal gland

Background

Benign Lymphoepithelial Lesion (BLEL) is a rare disease observed in the adult population. Despite the growing numbers of people suffering from BLEL, the etiology and mechanisms underlying its pathogenesis remain unknown.

Methods

In the present study, we used gene and cytokines expression profiling, western blot and immunohistochemistry to get further insight into the cellular and molecular mechanisms involved in the pathogenesis of BLEL of the lacrimal gland.

Results

The results showed that Macrophage Migration Inhibitory Factor (MIF) was the most highly expressed cytokine in BLEL, and its expression positively correlated with the expression of Th2 and Th17 cells cytokines. MIF was found to regulate biological functions and pathways involved in BLEL pathogenesis, such as proliferation, resistance to apoptosis, MAPK and PI3K/Akt pathways. We also found that MIF promotes fibrosis in BLEL by inducing BLEL fibroblast differentiation into myofibroblasts as well as the synthesis and the deposit of extracellular matrix in BLEL tissues.

Conclusions

Our findings demonstrate the contribution of MIF to the pathogenesis of BLEL of the lacrimal gland and suggested MIF as a promising therapeutic target for its treatment.

Electronic supplementary material

The online version of this article (10.1186/s12964-018-0284-4) contains supplementary material, which is available to authorized users.

Circulating PD-1+CXCR5-CD4+ T cells underlying the immunological mechanisms of IgG4-related disease

Objective

The aim was to study the pathological role of lymphocytes with a peripheral T helper-cell-like phenotype (PD-1⁺CXCR5⁻CD4⁺) in IgG4-related disease (IgG4-RD).

Methods

PD-1⁺CXCR5⁻CD4⁺ T cells in the blood of patients with IgG4-RD (n = 53), patients with SS (n = 16) and healthy volunteers (n = 34) as controls were analysed by flow cytometry. Correlations between results obtained by flow cytometry and clinical parameters relevant to IgG4-RD were also analysed.

Results

The percentage and absolute number of PD-1⁺CXCR5⁻ cells within total CD4⁺ T cells in IgG4-RD patients were significantly increased compared with those in healthy volunteers. Further analysis showed that there were marked positive correlations of the percentage of PD-1⁺CXCR5⁻CD4⁺ T cells with the serum level of IgG4 and the number of organs involved. Interestingly, granzyme A (GZMA)⁺ cells were enriched in PD-1⁺CXCR5⁻CD4⁺ T cells, and the percentage and absolute number of GZMA⁺PD-1⁺CXCR5⁻CD4⁺ T cells were significantly elevated in IgG4-RD patients. Although no obvious change was observed in the percentage of total CD4⁺ T cells, the percentage and absolute number of PD-1⁺CXCR5⁻CD4⁺ T cells decreased in accordance with a reduction of serum IgG4 level after treatment with glucocorticoids.

Conclusion

In IgG4-RD, circulating CD4⁺ T-cell populations were composed of PD-1⁺CXCR5⁻ cells, and the ratios of these cells were correlated with clinical manifestations of IgG4-RD. Further analysis of GZMA⁺PD-1⁺CXCR5⁻CD4⁺ T cells might lead to a deeper understanding of the pathogenesis of ectopic lymphoid follicles and the persistent inflammation in IgG4-RD.

[Histological and clinical characteristics of cases of immunoglobulin G4-related disease in a tertiary hospital, in Cali, Colombia]

INTRODUCTION

Immunoglobulin G4 (IgG4)-related disease has been described in the last decade. It is a fibro-inflammatory condition capable of affecting almost every organ and diagnosis requires both clinical and paraclinical confirmation. We present the largest study to date in Colombia.

OBJECTIVE

To describe the clinical and histopathological characteristics of patients diagnosed with IgG4-related disease at the Fundación Valle del Lili.

METHODS

Observational-descriptive retrospective study. The clinical and pathological records of patients diagnosed with IgG4-related disease at the Fundación Valle del Lili were reviewed and a descriptive statistical analysis made.

RESULTS

From 2013-2016, 16 patients were diagnosed. Median age was 44 years (RIC 30-58) and 10 (62.5%) were women. The most common clinical presentation was a combination of a tumefactive mass, constitutional symptoms and site-related symptoms (43.8%) (n=7). No preference for any organ was seen. Histopathology revealed all cases had dense lymphoplasmacytic infiltrate and storiform-type fibrosis; 75% also had obliterative phlebitis. In all cases≥10 cells/HPF of IgG4+ were found and 81% had a ratio of IgG4+/IgG+>50%.

CONCLUSION

IgG4-related disease appears to be underdiagnosed, probably due to its broad clinical spectrum as well as a low index of awareness among clinicians. We recommend that, when dense lymphoplasmacytic infiltrates, storiform-type fibrosis or obliterative phlebitis are found, immunohistochemistry for IgG and IgG4should be requested. Positive results then must be correlated with complementary studies to confirm the disease.

Unique properties of IgG4 antibody and its clinical application in autoimmune pancreatitis

BACKGROUND

Autoimmune pancreatitis (AIP) is defined as a unique form of chronic pancreatitis characterized by clinical presentation with obstructive jaundice, a dense lymphoplasmacytic infiltrate and fibrosis histologically, and a dramatic response to steroids therapeutically. The possible role of IgG4 in driving the pathology of AIP is a controversial subject that has not been addressed satisfactorily.  Objective: The purpose of this review is to discuss the unique biology of IgG4 that are important for its role and the clinical applications for serologic detection.

METHODS

Review of current literature about IgG4 antibody in the clinical application in AIP.

RESULTS

High serum levels of IgG4 are an important biomarker and broadly used for diagnosis, differentiation from diseases especially pancreatic cancer, and as a parameter to indicate disease activity, extra-pancreatic lesions, and treatment monitoring. However, some controversial studies show it has a limited specificity and sensitivity in these conditions.  Conclusion: Although increasing studies have promoted our understanding of the structure and function of IgG4, there is still dilemma between the beneficial and the adverse aspect of IgG4 in the pathogenesis of AIP.

Case of Primary Isolated Subconjunctival IgG4-Related Disease

PURPOSE

To report a case of isolated subconjunctival ocular adnexal IgG4-related disease that met the diagnostic criteria according to the Japanese Ministry of Health, Labour and Welfare's 2011 guidelines.

METHODS

We report a case of a 56-year-old woman with a left subconjunctival mass for 3 months. Excisional biopsy was performed. Postoperatively, the patient underwent systemic and radiologic evaluations for IgG4-related disease.

RESULTS

The clinicopathologic study revealed storiform fibrosis and lymphoplasmacytic infiltration, with increased IgG4-positive plasma cells and an IgG4/IgG-positive plasma cell ratio of 40%. Serum IgG4 and IgG levels were slightly elevated. Systemic involvement was not detected.

CONCLUSIONS

IgG4-related disease is well known in the orbit and ocular adnexa, particularly the lacrimal gland. However, subconjunctival involvement should be recognized as a possible presentation for this entity.

Perirenal capsule and scrotal involvement in immunoglobulin G4-related kidney disease: case-based review

Immunoglobulin G4-related disease (IgG4-RD) is a chronic, immune-mediated-, systemic disease that is characterized by IgG4 plasma cell infiltration with fibrotic changes in various organs. The most affected organs are pancreas and salivary glands. Kidney can be rarely involved, and is usually represented as a renal mass and organomegaly. Usually, elevated levels of serum IgG4 more than 135 mg/dl with organ-specific features and biopsy results showing enriched infiltration of IgG4-positive plasma cells are needed to diagnose the disease. However, we experienced two unusual cases of IgG4-RD involving kidney. IgG4-related kidney disease (IgG4-RKD) was first reported as an extra pancreatic feature of autoimmune pancreatitis(AIP) in 2004. Herein, we describe two cases of such unique presentation of IgG4RKD and a literature review focusing on clinicopathologic features of IgG4RKD. Our cases are distinct in the fact that IgG4RD invades unusual organs such as perinephric capsule or scrotum. We reported the patient who showed extinct perirenal capsule invasion with multi-organ involvement including exocrine glands in comparison to previous IgG4RKD that often involved in renal parenchyma and renal pelvis lesions. And the other patient had scrotal invasion with multifocal renal parenchymes. Referring to the features observed in these two cases, we could propose that as every organ can be related to IgG4RD, we propose clinicians to confirm the disease using imaging, serologic, and pathologic studies. We also reviewed previous reports of IgG4-RKD and summarized diverse imaging findings and pathologic features.

The Clinicopathologic Spectrum of IgG4-Related Disease

Immunoglobulin G4-related disease is a fibroinflammatory systemic disease that is characterized by focal or diffuse organ infiltration by immunoglobulin G4-bearing plasma cells. Immunoglobulin G4-related disease may affect any organ, and a high index of suspicion is necessary for early detection to avoid irreversible fibrosis, organ dysfunction, and death. Tumor-forming lesions are common radiological features of immunoglobulin G4-related disease that need to be differentiated from malignancies. The diagnostic approach requires the integration of clinical, biochemical, and radiographic manifestations with classic histopathologic features, which remain crucial to diagnosis. The histology of immunoglobulin G4-related disease is determined by a dense lymphoplasmacytic infiltrate, storiform fibrosis, and obliterative phlebitis in the presence of increased immunoglobulin G4-positve plasma cells. Although immunoglobulin G4-related disease forms a distinct, clinically independent disease category, many questions and problems remain unanswered, especially on its pathogenesis and the role of immunoglobulin G4. Advances in the understanding of immunoglobulin G4-related disease are likely to change the diagnostic approach in the future and create potential targets for therapeutic purposes. Here we describe the concept of immunoglobulin G4-related disease and the most recent knowledge in the clinico-pathological characteristics on this emerging disease. This study can guide clinicians in early diagnosis and prevent unnecessary surgical resections.

Hashimoto's thyroiditis with elevated serum IgG4 concentrations is not equivalent to IgG4 Hashimoto's thyroiditis

BACKGROUND

Hashimoto's thyroiditis (HT) with serum IgG4 concentrations greater than 135 mg/dL can be diagnosed as elevated serum IgG4 HT. HT can also be classified into IgG4 HT and non-IgG4 HT based on an immunohistochemistry analysis of IgG4. The aim of our study was to determine the relationship between elevated serum IgG4 HT and IgG4 HT.

METHOD

Both thyroid tissues and serum samples stored before pathological examination from 93 patients with HT were collected. The serum levels of IgG, IgG4, TgAb IgG, TgAb IgG4, TPOAb IgG and TPOAb IgG4 were measured by ELISAs. The expression levels of IgG4, IgG and TGF-β1 in thyroid tissues were detected by immunohistochemistry.

RESULTS

Patients with HT were divided into two groups: elevated serum IgG4 HT (n = 12) and nonelevated serum IgG4 HT (n = 81). Hypothyroidism was found in 5 of 12 cases (41.7%) in the elevated serum IgG4 HT group and 10 of 81 cases (12.3%) in the nonelevated serum IgG4 HT group (P = .023). Serologically, there were no significant differences in the levels of TgAb IgG, TPOAb IgG, TgAb IgG4 and TPOAb IgG4 between the two groups, and the expression of TGF-β1 in thyroid tissues was not significantly different between the groups. Most importantly, the frequency of patients who satisfied the criteria for IgG4 HT diagnosis was comparable (25% vs 20.9%, P = .756).

CONCLUSIONS

The measurement of serum IgG4 allows the identification of patients with HT closely associated with hypothyroidism. However, our study demonstrated that elevated serum IgG4 HT is not equivalent to IgG4 HT.

IgG4-related kidney disease: the effects of a Rituximab-based immunosuppressive therapy

IgG4-related disease (IgG4-RD) is a recently recognized disorder, characterized by elevated serum IgG4 concentrations, dense tissue infiltration of IgG4-positive plasma cells and storiform fibrosis. Treatment is usually based on steroids, however, relapses and long-term adverse effects are frequent. We prospectively studied 5 consecutive patients with histologically-proven IgG4-RD and renal involvement, treated with an extended Rituximab protocol combined with steroids. Two doses of intravenous cyclophosphamide were added in 4 patients. Five patients with IgG-RD were investigated: three had tubulointerstitial nephritis (TIN), while two had retroperitoneal fibrosis (RPF). In the patients with TIN, renal biospy was repeated after 1 year. In the patients with TIN, estimated glomerular filtration rate (eGFR) at 12 months increased from 9 to 24 ml/min per 1.73 m²; IgG/IgG4 decreased from 3,236/665 to 706/51 mg/dl; C3/C4 increased from 49/6 to 99/27 mg/dl; CD20⁺ B-cells decreased from 8.7% to 0.5%; Regulatory T-cells decreased from 7.2% to 2.5%. These functional and immunologic changes persisted at 24 months and in two patients at 36 months. A repeat renal biopsy in the patients with TIN showed a dramatic decrease in interstitial plasma cell infiltrate with normalization of IgG4/IgG positive plasma cells. The patients with RPF showed a huge regression of retroperitoneal tissue. In this sample of patients with aggressive IgG4-RD and renal involvement, treatment aimed at depleting B cells and decreasing antibody and cytokine production was associated with a substantial, persistent increase in eGFR, and a definite improvement in immunologic, radiologic and histological parameters.

Idiopathic Sclerosing Orbital Inflammation in a Relapsing Polychondritis Patient With Impaired Vision

A 55-year-old woman with relapsing polychondritis had progressively enlarged right retro-orbital tumor invading the optic nerve, followed by left retrobulbar infiltrating lesions despite prescription of high-dose corticosteroids and pulse methylprednisolone. Repeated histopathologic analyses showed dense collagen fibers with scanty inflammatory cells, consistent with the diagnosis of idiopathic sclerosing orbital inflammation. This disorder has been recognized as a distinct entity with unique clinical features and coexisting rheumatologic disorders, requiring more focused diagnostic strategies and therapeutic regimens. In summary, we demonstrate a rare ocular manifestation in relapsing polychondritis and emphasize the importance of serial radiological and pathological evaluations in such patients presenting with exophthalmos.

Immunoglobulin G4-related kidney diseases: An updated review

This review will encompass definition, pathogenesis, renal clinical manifestations and treatment of immunoglobulin G4-related diseases (IgG4-RDs). IgG4-RD is a recently recognized clinical entity that often involves multiple organs and is characterized by high levels of serum immunoglobulins G4, dense infiltration of IgG4⁺ cells and storiform fibrosis. Cellular immunity, particularly T-cell mediated immunity, has been implicated in the pathogenesis of IgG4-RDs. The most frequent renal manifestations of IgG4-RD are IgG4-related tubulointerstitial nephritis, membranous glomerulopathy and obstructive nephropathy secondary to urinary tract obstruction due to IgG4-related retroperitoneal fibrosis. IgG4-RD diagnosis should be based on specific histopathological findings, confirmed by tissue immunostaining, typical radiological findings and an appropriate clinical context. The first line treatment is the steroids with two warnings: Steroid resistance and relapse after discontinuation. In the case of steroid resistance, B cell depleting agents as rituximab represent the second-line treatment. In the case of relapse after discontinuation, steroid treatment may be associated with steroid sparing agents. Since the disease has been only recently identified, more prospective, long-term studies are needed to an improved understanding and a more correct and safe treatment.

Current approach to the diagnosis of IgG4-related disease - Combination of comprehensive diagnostic and organ-specific criteria

IgG4-related disease (IgG4-RD) is a fascinating clinical entity proposed by Japanese investigators, and includes a wide variety of diseases, formerly diagnosed as Mikulicz's disease (MD), autoimmune pancreatitis (AIP), interstitial nephritis, prostatitis, retroperitoneal fibrosis, etc. Although all clinicians in every field of medicine may encounter this new disease, a unifying diagnostic criterion has not been established. In 2011, the Japanese IgG4 team, organized by the Ministry of Health, Labor and Welfare (MHLW) of Japan, published comprehensive diagnostic criteria for IgG4-RD. Several problems with these criteria have arisen in clinical practice, however, including the difficulty obtaining biopsy samples from some patients, and the sensitivity and the specificity of techniques used to measure serum IgG4 concentrations. Although serum IgG4 concentration is an important clinical marker for IgG4-RD, its diagnostic utility in differentiating IgG4-RD from other diseases, called IgG4-RD mimickers, remains unclear. This review describes the current optimal approach for the diagnosis of IgG4-RD, based on both comprehensive and organ-specific diagnostic criteria, in patients with diseases such as IgG4-related pancreatitis (AIP), sclerosing cholangitis, and renal, lung and orbital diseases.

The autoimmune IgG4 -associated endocrine pathology

Immunoglobulin G4-associated diseases (IgG4-AD) arethe group of chronic progressive autoimmune fibro-inflammatory pathology of various organs and tissues, characterized by their enlargement and abundant infiltration of immunoglobulin G4-positive plasma cells, as well as an increase in the level of serum immunoglobulin G4 (IgG4).In most patients, the disease is characterized by a mild course.However, there is evidence of a high incidence of malignancies in patients with IgG4-AD.Among endocrine IgG4-associated pathologies, pancreatitis with outcome in diabetes mellitus, hypophysitis and thyroiditis are described. Laboratory examination usually reveals an increased level of IgG4. However, the concentration of IgG4 could not be used as the only diagnostic criterion.The possibility of plasmablastsdetermining as a marker of the disease is discussed.Among the imaging techniques CT, MRI and 18F-FDG-PET/CT are used.However, the most informative method of diagnosis is biopsy. Randomized clinical trials to determine clear recommendations for the treatment of IgG4-AD were not conducted.In most cases, glucocorticoids are prescribed, and immunosuppressive therapy is sometimes used.According to the results of recent studies, the genetically engineered drug rituximab is relatively effective in inducing remission of the disease.Given the high recurrence rate and the risk of malignancy, patients with IgG4-AD require careful long-term follow-up. Thus, the review describes the clinical manifestations of IgG4-AD, examines the possibilities of their diagnosis and presents the existing methods of treatment.However, given the fact that IgG4-AD became a separate group of autoimmune pathology less than 20 years ago, there are insufficient data on these diseases. Researches related to epidemiology, pathophysiology, diagnosis and effective treatment of IgG4-AD are actual.

The variety of clinical presentations in IgG4-related disease in Rheumatology

IgG4-related disease (IgG4-RD) belongs to the group of rare diseases in which the identification of the characteristic histology and immunohistochemistry provides with the gold standard in the diagnosis. The variable organ dysfunction reflects the clinical presentation. The examples of different IgG4-RD presentations in the Rheumatology Unit were discussed in this article. The spectrum of IgG4-RD is wide-ranging and manifested in one or more organs synchronously or metachronously. In the presented article, we described five different cases of IgG4-RD. Four cases were reaffirmed in the histopathological assessment. The clinical and laboratory findings were analyzed and the assigned therapy was discussed. According to our experience, the diagnosis of IgG4-RD requires the careful clinicopathological correlation. The diagnosis relies on the coexistence of various clinical, laboratory, radiological, and histopathological findings, although none of them is pathognomonic itself. The time needed for the diagnosis and variety of clinical forms of IgG4-RD shows that there is need of the cooperation among many specialists for the better and earlier recognition of the disease.

Serum IgG4:IgG Ratio Predicts Recurrence of Patients with Hepatocellular Carcinoma after Curative Resection

Aim: IgG4 is associated with a Th1-to-Th2 switch, which plays a vital role in metastasis, in patients with malignances; thus, we aimed to investigate its clinical significance in predicting hepatocellular carcinoma (HCC) recurrence in the present study.

Methods: The correlation between serum IgG4:IgG ratio and recurrence was analyzed in a cohort of 195 patients undergoing curative resection in 2012. Another 100 patients were analyzed in a prospective independent cohort during 2012-2013 to validate the value of serum IgG4. Serum IgG4 and total IgG concentrations were measured with an automatic immune analyzer and the optimal cutoff value for serum IgG4 levels was determined by X-tile software.

Results: Our data revealed that serum IgG4:IgG were significantly elevated in patients with tumor recurrence (P<0.05). A cutoff IgG:IgG4 ratio of 0.08 was set to stratify HCC patients into high (>0.08) and low (≤0.08) groups. High serum IgG4:IgG ratio correlated with significantly shorter time-to-recurrence (median 11.85 months vs. 39.20, P=0.005). Univariate and multivariate analyses demonstrated that serum IgG4:IgG ratio is an independent indicator of tumor recurrence and this retained its clinical significance even in conventional low-recurrence-risk subgroups, including patients with low α-fetoprotein and early-stage diseases.

Conclusion: Our results demonstrated that elevated serum IgG4:IgG ratio is associated with poor clinical outcomes in HCC patients and therefore, and can serve as a novel prognostic predictor for HCC patients undergoing resection. Analyzing serum IgG4 would be useful to tailor individualized therapies for patients.

Chronic Fibro-Inflammatory Responses in Autoimmune Pancreatitis Depend on IFN-α and IL-33 Produced by Plasmacytoid Dendritic Cells

In previous studies, we found that human IgG4-related autoimmune pancreatitis (AIP) and murine AIP are driven by activation of plasmacytoid dendritic cells (pDCs) producing IFN-α. In the present studies we examined additional roles of pDC-related mechanisms in AIP pathogenesis, particularly those responsible for induction of fibrosis. We found that in murine AIP (MRL/Mp mice treated with polyinosinic-polycytidylic acid) not only the pancreatic infiltration of immune cells but also the development of fibrosis were markedly reduced by the depletion of pDCs or blockade of type I IFN signaling; moreover, such treatment was accompanied by a marked reduction of pancreatic expression of IL-33. Conversely, polyinosinic-polycytidylic acid-induced inflamed pancreatic tissue in murine AIP exhibited increased expression of type I IFNs and IL-33 (and downstream IL-33 cytokines such as IL-13 and TGF-β1). pDCs stimulated by type I IFN were the source of the IL-33 because purified populations of these cells isolated from the inflamed pancreas produced a large amount of IL-33 upon activation by TLR9 ligands, and such production was abrogated by the neutralization of type I IFN. The role of IL-33 in murine AIP pathogenesis was surprisingly important because blockade of IL-33 signaling by anti-ST2 Ab attenuated both pancreatic inflammation and accompanying fibrosis. Finally, whereas patients with both conventional pancreatitis and IgG4-related AIP exhibited increased numbers of acinar cells expressing IL-33, only the latter also exhibited pDCs producing this cytokine. These data thus suggest that pDCs producing IFN-α and IL-33 play a pivotal role in the chronic fibro-inflammatory responses underlying murine AIP and human IgG4-related AIP.

Serum IgG2 and tissue IgG2 plasma cell elevation in orbital IgG4-related disease (IgG4-RD): Potential use in IgG4-RD assessment

AIMS

To determine the role of serum and tissue IgG2 in orbital biopsies with the histological features of IgG4-related disease (IgG4-RD) in comparison with non-IgG4-related orbital inflammatory disorders (OID), including autoimmune disorders.

METHODS

This is an international (Sheffield, UK, and Singapore) collaborative, retrospective case review of 69 patients (38 from Singapore National Eye Centre and 31 from Royal Hallamshire Hospital, Sheffield) with orbital inflammatory biopsies between 2002 and 2016. Clinical information and histology were reviewed and cases were classified into three groups: Group 1: IgG4-RD orbital inflammation (n=43); Group 2: idiopathic OID (n=12) and Group 3: autoimmune OID (n=14). Serum IgG1, IgG2, IgG3 and IgG4 levels were collated where available and immunohistochemistry (IHC) for tissue IgG2 plasma cells was performed.

RESULTS

Dual IHC showed IgG2 plasma cells as a distinct population from IgG4 plasma cells. Significant (twofold) serum IgG2 elevation was noted among IgG4-RD (group 1), idiopathic (group 2) and autoimmune OID (group 3). Similarly, significant elevation of tissue IgG2 plasma cells was also seen among IgG4-RD (group 1), idiopathic and autoimmune OID (groups 2 and 3).

CONCLUSIONS

Significant elevations of serum IgG2 and tissue IgG2 plasma cells are present in orbital IgG4-RD in comparison with non-IgG4 orbital inflammation (idiopathic and autoimmune OID), suggesting that IgG2 may play a role in IgG4-RD. A serum IgG2 cut-off >5.3 g/L was found to be 80% sensitive and 91.7% specific for orbital IgG4-RD, with an accuracy of 0.90. Tissue IgG2 and IgG4 subclass reporting may provide additional insight regarding the 'IgG4-RD' pathogenesis.

Immunoglobulin G4-Related Disease: Recent Advances in Pathogenesis and Imaging Findings

Immunoglobulin G4-related disease (IgG4-RD) is a novel, immune-mediated, multisystem disease characterized by the development of tumefactive lesions in multiple organs. IgG4-RD encompasses many fibroinflammatory diseases that had been thought to be confined to single organs. Delayed diagnosis or misdiagnosis as malignancies leading to aggressive treatment may be averted by identification of the multisystem nature of IgG4-RD. Most cases show exquisite response to steroid therapy; steroid-resistant cases are being treated by novel therapeutic agents, including B-cell depleting agents such as rituximab. Cross-sectional imaging studies play a pivotal role in the initial diagnosis, assessing response to therapy and long-term surveillance.

IgG4-Related Kidney Disease in a Patient With History of Breast Cancer: Findings on 18F-FDG PET/CT

A 64-year-old African American woman with history of stage III breast carcinoma, 3 years after complete response to therapy, presents with progressive fatigue, increasing arthralgia, and unintentional weight loss of 15 lb in 3 months. An F-FDG PET demonstrated new diffuse FDG avidity of the renal parenchyma, new FDG-avid foci in pancreas and lungs, and new FDG-avid lymph nodes above and below the diaphragm. While a retroperitoneal lymph node biopsy was inconclusive, a kidney biopsy resulted in diagnosis of diffuse, severe, IgG4-related tubulointerstitial nephritis. Treatment with corticosteroid led to complete resolution of the symptoms and PET findings.

New strategies for the treatment of IgG4-related disease

IgG4-related disease is a chronic and fibroinflammatory disorder, which is characterized with elevated levels of serum IgG4, and prominent infiltration of IgG4-bearing plasma cells in the involved organs. It often affects with lacrimal glands, salivary glands, pancreas, kidneys, lungs, and retroperitoneal cavity. Now, the first line of the induction therapy for IgG4-related disease is glucocorticoid, but almost patients need the maintenance treatment and experience the relapse. It is recently reported that biologic agents, including rituximab and abatacept, are effective for the relapse of IgG4-related disease. It is clear that the tapering effect of glucocorticoid is better than conventional oral immunosuppressants. We can use it in safely if we choose the appropriate cases. The investigator-initiated trial of rituximab for IgG4-related disease is scheduled in Japan. This article reviews the new strategies for the treatment of IgG4-related disease with our data of SMART registry, and discuss the problems of each biologic agents for IgG4-related disease.

Recent advances in knowledge regarding the head and neck manifestations of IgG4-related disease

IgG4-related disease (IgG4-RD) is a chronic inflammatory disorder, characterized by elevated serum IgG4 levels as well as abundant infiltration of IgG4-positive plasmacytes and fibrosis in various organs, including the head and neck region. In particular, the salivary glands, orbit, and thyroid are common sites of disease involvement. IgG4-RD is diagnosed based on various clinical, serological, and histopathological findings, none of which are pathognomonic. Hence, various differential diagnoses, which exhibit elevated serum IgG4 levels and infiltration of IgG4-postive cells into tissues, need to be excluded, especially malignant diseases and mimicking disorders. Systemic corticosteroids are generally effective in inducing IgG4-RD remission; however, recurrent or refractory cases are common. In addition, although the pathogenic mechanisms of IgG4-RD remain unclear, an antigen-driven inflammatory condition is believed to be involved. Recent studies have indicated the important pathogenic role of B cell/T cell collaboration and innate immunity in this disease. Nevertheless, additional research and discussions are needed to resolve many remaining questions. In this review, we provide an overview of the recent insights on the history, clinical features, diagnosis, and treatment of IgG4-RD in the head and neck region. Furthermore, we have also addressed the pathogenesis of this disease.

Clinicopathological analysis of salivary gland tissue from patients with IgG4-related disease

Conclusion The diagnosis of immunoglobulin G4-related disease (IgG4-RD) should be based on the morphology of tissue biopsy, and this study recommends a submandibular gland (SMG) biopsy for accurate diagnosis and to exclude malignant disease. Objective To clarify which type of biopsy specimen (SMG or labial salivary gland [LSG]) should be taken from patients with IgG4-RD. Methods This study included 33 patients with IgG4-RD (21 women; 12 men) who were subjected to both SMG and LSG biopsies at Sapporo Medical University between 2011-2015. Tissues obtained from the SMG and LSG specimens were evaluated. Results All SMG specimens satisfied the diagnostic criteria for IgG4-RD, whereas 19 (57.6%) LSG specimens satisfied the diagnostic criteria for IgG4-RD. Histological evaluation showed fibrosis in all the SMG specimens and in eight LSG specimens (24.2%). Obliterative phlebitis was seen in nine SMG specimens (27.3%), but it was absent in all the LSG specimens.

Characterization of NF-κB Reporter U937 Cells and Their Application for the Detection of Inflammatory Immune-Complexes

Our study tested the hypothesis that immunoglobulins differ in their ability to activate the nuclear factor-κB pathway mediated cellular responses. These responses are modulated by several properties of the immune complex, including the ratio of antibody isotypes binding to antigen. Immunoassays allow the measurement of antigen specific antibodies belonging to distinct immunoglobulin classes and subclasses but not the net biological effect of the combination of these antibodies. We set out to develop a biosensor that is suitable for the detection and characterization of antigen specific serum antibodies. We genetically modified the monocytoid U937 cell line carrying Fc receptors with a plasmid encoding NF-κB promoter-driven GFP. This clone, U937-NF-κB, was characterized with respect to FcR expression and response to solid-phase immunoglobulins. Human IgG3, IgG4 and IgG1 induced GFP production in a time- and dose-dependent manner, in this order of efficacy, while IgG2 triggered no activation at the concentrations tested. IgA elicited no response alone but showed significant synergism with IgG3 and IgG4. We confirmed the importance of activation via FcγRI by direct stimulation with monoclonal antibody and by competition assays. We used citrullinated peptides and serum from rheumatoid arthritis patients to generate immune complexes and to study the activation of U937-NF-κB, observing again a synergistic effect between IgG and IgA. Our results show that immunoglobulins have distinct pro-inflammatory potential, and that U937-NF-κB is suitable for the estimation of biological effects of immune-complexes, offering insight into monocyte activation and pathogenesis of antibody mediated diseases.

Clinical implications of serum IgG4 levels in patients with IgG4-related ophthalmic disease

AIMS

The present study aimed to investigate the clinical implications of serum IgG₄ levels in patients with IgG₄-related ophthalmic disease (ROD).

METHODS

The medical records of 31 patients who met the diagnostic criteria for IgG₄-ROD were retrospectively reviewed. Twenty-five patients whose serum IgG₄ levels could be identified were included. Clinical manifestations and serum IgG₄ levels before and after corticosteroid treatment were obtained. Factors associated with relapse were evaluated by comparing the features of patients with disease relapse with those of patients without relapse.

RESULTS

Twenty-four patients were 'definite' and one was 'probable' for IgG₄-ROD according to the diagnostic criteria. Serum IgG₄ levels were higher in patients with systemic involvement (p=0.046). All patients improved clinically after corticosteroid treatment. Serum IgG₄ levels decreased after steroid treatment (p=0.005) and normalised in nine patients. In cases of relapse, serum IgG₄ levels increased along with the aggravation of symptoms (p=0.047). Serum IgG₄ levels that were still elevated (≥135 mg/dL) after steroid treatment (p=0.034) and cessation of steroid treatment during disease remission (p=0.043) were predictive factors for IgG₄-ROD relapse.

CONCLUSIONS

Serum IgG₄ level can be considered an adjunctive marker for treatment response in IgG₄-ROD. Patients with serum IgG₄ levels that remain elevated after steroid treatment should be carefully observed for relapse. A continuing maintenance dose of oral steroid is recommended to prevent relapse, even when clinical remission is achieved.

Immunoglobulin G4-related disease presenting with prurigo: Circulating T-helper 2 cells may be involved in the pathogenesis

We report a case of immunoglobulin G4-related disease (IgG4-RD) which presented with prurigo on the trunk and extremities. A 66-year-old man had a 2-month history of itchy erythematous papules on his trunk and extremities. Bilateral eyelid swelling and enlargement of the submandibular and parotid glands were also observed. Computed tomography revealed pleural thickening and diffuse pancreatic enlargement. Serum levels of IgG4 were markedly increased. A biopsy specimen obtained from an erythematous papule showed a perivascular inflammatory infiltrate of lymphocytes with eosinophils in the dermis, whereas a parotid gland biopsy revealed an infiltrate of abundant IgG4-positive plasma cells. Treatment with prednisolone resulted in improvement of the skin and other lesions along with a decrease in IgG4 serum levels. A flow cytometric assay revealed that percentages of interleukin (IL)-4- and IL-13-producing CD4(+) T cells were markedly higher in the circulation of the IgG4-RD patient than in that of healthy subjects. Moreover, those populations dramatically decreased after treatment. Thus, prurigo may be a skin manifestation of IgG4-RD and T-helper 2 cells may contribute to the pathogenesis.