International Consensus Guidance Statement on the Management and Treatment of IgG4-Related Disease

Relapse patterns and predictors of IgG4-related diseases involved with autoimmune pancreatitis: A single-center retrospective study of 115 patients

OBJECTIVE

Autoimmune pancreatitis is an autoimmune disorder accompanied by clinicopathological manifestations that have been established as immunoglobulin (IgG)4-related diseases (IgG4-RD). Other IgG4-RD are often involved with autoimmune pancreatitis. They sometimes relapse despite a favorable response to steroid therapy. This study aimed to clarify the patterns and risk factors for extrapancreatic relapse.

METHODS

We reviewed the data of 115 patients diagnosed with definite autoimmune pancreatitis type 1 and followed up for > 1 year. We analyzed two items: the timing and pattern of extrapancreatic relapse, and risk factors for relapse with three common manifestations: IgG4-related sclerosing cholangitis (SC), IgG4-related dacryoadenitis and sialadenitis (DS), and IgG4-related retroperitoneal fibrosis (RF).

RESULTS

Remission was achieved in all patients, except one. The extrapancreatic relapse rates were 11.0%, 19.7%, and 40% within 3, 5, and 10 years, respectively. Of 26 patients with extrapancreatic relapse, nine (34.6%) relapsed with a new IgG4-RD. Based on multivariate analysis, the interval between symptom onset and steroid initiation, and the presence of RF at onset were significant risk factors for relapse with SC and RF, respectively.

CONCLUSIONS

Our results indicate that they may be various extrapancreatic relapse patterns especially in autoimmune pancreatitis with other organ involvement. Patients with a delayed initiation of steroids or RF at onset should be carefully followed up as high-risk groups for SC and RF relapse.

IgG4-related disease: what a hematologist needs to know

IgG4-related disease is a fibro-inflammatory condition that can affect nearly any organ system. Common presentations include major salivary and lacrimal gland enlargement, orbital disease, autoimmune pancreatitis, retroperitoneal fibrosis and tubulointerstitial nephritis. This review focuses on the hematologic manifestations of IgG4-related disease, including lymphadenopathy, eosinophilia, and polyclonal hypergammaglobulinemia. The disease can easily be missed by unsuspecting hematologists, as patients may present with clinical problems that mimic disorders such as multicentric Castleman disease, lymphoma, plasma cell neoplasms and hypereosinophilic syndromes. When IgG4-related disease is suspected, serum protein electrophoresis and IgG subclasses are helpful as initial tests but a firm histological diagnosis is essential both to confirm the diagnosis and to rule out mimickers. The central histopathological features are a dense, polyclonal, lymphoplasmacytic infiltrate enriched with IgG4-positive plasma cells (with an IgG4/IgG ratio >40%), storiform fibrosis, and obliterative phlebitis. Importantly for hematologists, the latter two features are seen in all tissues except bone marrow and lymph nodes, making these two sites suboptimal for histological confirmation. Many patients follow an indolent course and respond well to treatment, but a significant proportion may have highly morbid or fatal complications such as periaortitis, severe retroperitoneal fibrosis or pachymeningitis. Corticosteroids are effective but cause new or worsening diabetes in about 40% of patients. Initial response rates to rituximab are high but durable remissions are rare. More intensive lymphoma chemotherapy regimens may be required in rare cases of severe, refractory disease, and targeted therapy against plasmablasts, IgE and other disease biomarkers warrant further exploration.

IgG4-related disease in the head and neck

PURPOSE OF REVIEW

To summarize current evidence regarding the pathophysiology, diagnostic criteria, and management of IgG4 disease in the head and neck.

RECENT FINDINGS

The anti-CD20 antibody, rituximab is being used increasingly as a primary treatment modality in cases with a definitive diagnosis. Despite the favorable prognosis, it is now recognized that the incidence of cancer development within 3 years of diagnosis is higher than that of the general population.

SUMMARY

IgG4-related disease is a sclerosing, chronic inflammatory disease, that is benign, and usually occurs in middle-aged to elderly individuals. Definitive diagnosis of IgG4-related disease requires radiological confirmation of enlargement of the affected organ, elevated serum IgG4 levels, and characteristic histopathological findings. Treatment is primarily with systemic corticosteroids or the monoclonal anti-CD20 antibody rituximab, surgical excision, or a combination of treatment modalities. Prognosis is good with complete remission in up to 90% of patients.

Hepatic Inflammatory Pseudotumor: An Important Differential Diagnosis in Patients With a History of Previous Biliary Procedures

Hepatic inflammatory pseudotumors (IPTs) are rare lesions that mimic malignancy clinically, radiologically, and pathologically. The pathophysiology is unknown, and no criteria exist for diagnosis. This series includes 3 cases: 1 patient had recent biliary drainage with bile duct stent placement, and the other 2 patients had hepatic abscess formation before IPT development, which further supports that hepatic IPTs develop in patients with underlying triggers of liver inflammation and injury, including infections and/or bile leakage into the parenchyma. All 3 patients were successfully treated with antibiotics, sparing them surgical intervention. Follow-up showed complete resolution, and none developed recurrences or malignancies.

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.

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.

IgG4-related disease of the central and peripheral nervous systems

IgG4-related disease can involve nearly any organ system, including the central and peripheral nervous systems. The pathology findings are consistent from organ to organ, but careful clinicopathological correlation is necessary to establish the diagnosis. Many non-neurological and neurological inflammatory conditions, previously regarded as idiopathic in nature, are now recognised to fall within the spectrum of IgG4-related disease. The condition is highly treatable, but probably remains substantially under-recognised. In this Review, we offer an important and timely update on the current and emerging aspects of this neurological disease. Following a short overview of IgG4-related disease, we describe the current understanding of neurological findings, pathophysiology, approaches to diagnosis, and treatment of IgG4-related disease affecting the central and peripheral nervous systems.

IgG4-related diseases: state of the art on clinical practice guidelines

Immunoglobulin G4-related diseases (IgG4-RD) are a group of chronic relapsing–remitting inflammatory conditions, characterised by tissue infiltration with lymphocytes and IgG4-secreting plasma cells, fibrosis and a usually favourable response to steroids.

In this narrative review, we summarise the results of a systematic literature research, which was performed as part of the European Reference Network ReCONNET, aimed at evaluating existing clinical practice guidelines (CPGs) and recommendations in IgG4-RD. From 167 publications initially obtained from a systematic literature search, only one was identified as a systematic multispecialist, evidence-based, consensus guidance statement on diagnosis and treatment of IgG4-RD, which may be recommended for use as CPG in IgG4-RD.

With the recognition of a limited evidence based in this increasingly recognised disease, the group discussion has identified the following unmet needs: lack of shared classification criteria, absence of formal guidelines on diagnosis, no evidence-based therapeutic recommendations and lack of activity and damage indices. Areas of unmet needs include the difficulties in diagnosis, management and monitoring and the scarcity of expert centres.

IgG4-related disease: Is rituximab the best therapeutic strategy for cases refractory to conventional therapy? Results of a systematic review

INTRODUCTION

IgG4 related disease is a fibroinflammatory condition characterised by lymphoplasmocytic infiltration with predominance of IgG4+ plasma cells, fibrosis, and in most cases elevated IgG4 serum levels. It can affect any organ and result in varying clinical manifestations. Steroids are the cornerstone of treatment, however there is a high percentage of relapse. Recent studies have demonstrated favourable effects with rituximab.

OBJECTIVE

To evaluate effectiveness related to the response to treatment with rituximab in patients with IgG4 related disease refractory to steroids and other immunosuppressant therapies.

MATERIALS AND METHODS

We undertook a systematic search of the specialist databases EMBASE, LILACS, PUBMED and OVID-Cochrane for publications up until December 2017.

RESULTS

After the quality analysis, we selected 27 articles (264 patients in total) for the final review, of which 23 were case reports and case series (105 patients), 3 were observational follow-up cohort studies (129 patients), and there was one clinical trial (30 patients). IgG4 related disease presents predominantly in male patients aged between 50 and 70 years on average. Multiple organs are compromised with an average of 3.5 compromised organs. Orbital, glandular and lymph-node compromise is most frequent. Patients in the different studies we included had received various treatments prior to starting rituximab, including glucocorticoids and disease-modifying anti-rheumatic drugs. There was 90.7% response in the cases where rituximab was used as second line therapy; rituximab was used as first line treatment for 10% of the patients with a 100% response rate.

CONCLUSION

The use of rituximab for patients refractory to first-line treatments was associated with a high response percentage and less dependence on glucocorticoids.

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.

Clinical practice guidelines for IgG4-related sclerosing cholangitis

IgG4‐related sclerosing cholangitis (IgG4‐SC) is a distinct type of cholangitis frequently associated with autoimmune pancreatitis and currently recognized as a biliary manifestation of IgG4‐related disease. Although clinical diagnostic criteria of IgG4‐SC were established in 2012, differential diagnosis from primary sclerosing cholangitis and cholangiocarcinoma is sometimes difficult. Furthermore, no practical guidelines for IgG4‐SC are available. Because the evidence level of most articles retrieved through searching the PubMed, Cochrane Library, and Igaku Chuo Zasshi databases was below C based on the systematic review evaluation system of clinical practice guidelines MINDS 2014, we developed consensus guidelines using the modified Delphi approach. Three committees (a guideline creating committee, an expert panelist committee for rating statements according to the modified Delphi method, and an evaluating committee) were organized. Eighteen clinical questions (CQs) with clinical statements were developed regarding diagnosis (14 CQs) and treatment (4 CQs). Recommendation levels for clinical statements were set using the modified Delphi approach. The guidelines explain methods for accurate diagnosis, and safe and appropriate treatment of IgG4‐SC.

Immunophenotype involved in IgG4-related disease

As stated in the comprehensive diagnostic criteria for IgG4-related disease (IgG4-RD), IgG4-RD is characterized by elevated serum IgG4 level and pathological findings, characterized by infiltration of IgG4-positive plasma cells. In addition to fibrotic changes, dysregulated activation of lymphocytes is considered as one of major pathogenic events in IgG4-RD. Among lymphocytes, the importance of plasmablast, T follicular helper (Tfh) cells, T type 2 helper (Th2) cells, T regulatory (Treg) cells, and CD4 positive T cells with cytotoxic activity has been reported. Conversely, comprehensive immunophenotyping in patients with IgG4-RD revealed that there are two different axes consisting plasmablast-Tfh cells and Treg cells. There is need for research to seek out molecules associated with these immunocompetent cell interactions. It is believed that this will contribute to the future application to disease-specific treatment for IgG4-RD.

Clinical outcomes and pathological characteristics of immunoglobulin G4-related ophthalmic disease versus orbital inflammatory pseudotumor

BACKGROUND/AIMS

This study investigated the clinical and pathological features of immunoglobulin G4 (IgG4)-related ophthalmic disease. To clarify the features, we compared IgG4-related ophthalmic disease and orbital inflammatory pseudotumor.

METHODS

We retrospectively reviewed the medical records of 103 patients who were initially diagnosed with orbital inflammatory pseudotumor, and identified 16 cases in which the diagnosis was based on surgical biopsy and for which data in medical records were sufficient for analysis. Immunohistochemical staining of pathological specimens for IgG and IgG4 was performed. Finally, six of IgG4-related ophthalmic disease patient and 10 of orbital inf lammatory pseudotumor patient were analyzed.

RESULTS

The IgG4-related ophthalmic disease group had more IgG4-positive plasma cells and a higher IgG4/IgG plasma cell ratio than the orbital inflammatory pseudotumor group. Collagenous fibrosis and lacrimal gland involvement were significantly more frequent in the IgG4-related ophthalmic disease group. Dense lymphocyte infiltration, obliterative phlebitis, and bilateral lesions were more frequent in IgG4-related ophthalmic disease, but the differences were not significant. The recurrence-free period was shorter in the IgG4-related ophthalmic disease group (p = 0.035).

CONCLUSION

The location of the lesion (lacrimal gland), count and ratio of IgG4-positive plasma cells, and collagenous fibrosis aid the diagnosis of IgG4-related ophthalmic disease in patients with idiopathic orbital mass-like lesions. In addition, maintenance therapy should be considered in patients with IgG4-related ophthalmic disease to prevent recurrence.

Sclerosing Cholangitis Related to IgG4: Not Always a Curable Entity

IgG4-related disease is a recently-described fibro-inflammatory condition with characteristic histopathological findings in the organs involved. The most commonly affected organs are pancreas, lymph nodes, and retroperitoneum. Liver disease usually involves bile structures and therefore IgG4-related disease is considered a cause of secondary sclerosing cholangitis. One out of three patients with IgG4 sclerosing cholangitis also presents autoimmune pancreatitis, although it can be associated with manifestations in other organs. One of the main features of IgG4-related disease is its good prognosis due to the great response to glucocorticoid therapy. However, relapse of the disease is not uncommon, especially when steroid therapy is decreased or stopped. Rituximab seems to be an effective treatment to achieve remission of the disease. We report the case of a 74 year-old man diagnosed with IgG4-related disease based on increase of serum IgG4 levels, imaging and histopathological findings, with systemic involvement including sclerosing cholangitis. Despite the absence of liver fibrosis at onset, the early use of glucocorticoids and rituximab therapy, the patient presented clinical and analytical deterioration, leading to secondary biliary cirrhosis. In conclusion, this clinical case highlights the importance of prompt diagnosis and therapeutics for sclerosing cholangitis secondary to IgG4-related disease in order to avoid progression of the disease and development of liver cirrhosis, as well as the refractory, aggressive nature of the disease in some cases as this one.

IgG4-related disease in endocrine practice

IgG4-related disease is a set of symptoms resulting from a chronic, usually multiple organ inflammatory condition which affects various organs. It consists of lymphoplasmacytic infiltrations with attendant fibrosis and deep vein thrombosis. Frequently observed tissue lesions are accompanied by elevated IgG4 levels in serum. The etiopathogenesis of the lesions is of multifactor character and the clinical manifestation of the disease is highly diverse. The diagnostic process is based on the patient's medical history, clinical examination and additional tests, including a histopathological examination of the infected organ's tissues. Almost forty different locations of the disease have been reported, including disorders of the endocrine system. IgG4-related endocrinopathies are quite rare. However, it is likely that the diagnosis is under-reported due to lack of awareness of this clinical entity. Despite increasing interest in the subject, there are not enough reliable studies evaluating the link between IgG4-RD and endocrine disorders.

Spontaneous Regression of Swollen Submandibular Glands in IgG4-Related Disease

Background

IgG4-related disease is a new clinical entity frequently associated with swelling of the submandibular glands (SMGs). The long-term outcome of SMG swelling without steroid therapy remains unknown.

Objective

To examine whether swollen SMGs spontaneously regress without steroid therapy in the context of IgG4-related disease and to identify biomarkers that can predict the spontaneous regression of SMG swelling.

Methods

The SMG volume of 49 patients diagnosed with IgG4-related disease was calculated by measuring the axial and coronal planes of computed tomography scans. The change in SMG volume over time was measured and examined by treatment regimen, clinical data, and serum complement level.

Results

We found 28 of 49 (57%) IgG4-related disease patients to have swollen SMGs, with 15 of 20 (75%) of the swollen SMGs regressing without steroid therapy. The time required for the SMGs swelling to regress was significantly shorter in the steroid therapy group than in the no-steroid therapy group. Serum complement components at the initial visit were significantly lower in the regressed SMG group than in the nonregressed SMG group.

Conclusion

We observed 75% of swollen SMGs spontaneously regressed in patients with IgG4-related disease. The time required for the swollen SMGs to regress was longer in patients without steroid therapy than in those with steroid therapy. Serum complement level could be used as a predictor for the spontaneous regression of swollen SMGs in patients with IgG4-related disease.

Rituximab treatment for isolated IgG4-related hypophysitis in a teenage female

IgG4-related hypophysitis is an important diagnostic consideration in patients with a pituitary mass or pituitary dysfunction and can initially present with headaches, visual field deficits and/or endocrine dysfunction. Isolated IgG4-related pituitary disease is rare, with most cases of IgG4-related disease involving additional organ systems. We report the case of a teenage female patient with isolated IgG4-related hypophysitis, diagnosed after initially presenting with headaches. Our patient had no presenting endocrinologic abnormalities. She was treated with surgical resection, prednisolone and rituximab with no further progression of disease and sustained normal endocrine function. This case, the youngest described patient with isolated IgG4-related hypophysitis and uniquely lacking endocrinologic abnormalities, adds to the limited reports of isolated pituitary disease. The use of rituximab for isolated pituitary disease has never been described. While IgG4-related hypophysitis has been increasingly recognized, substantial evidence concerning the appropriate treatment and follow-up of these patients is largely lacking. Learning points: IgG4-related hypophysitis most often occurs in the setting of additional organ involvement but can be an isolated finding. This diagnosis should therefore be considered in a patient presenting with pituitary abnormalities. Most patients with IgG4-related hypophysitis will have abnormal pituitary function, but normal functioning does not exclude this diagnosis. Corticosteroids have been the mainstay of therapy for IgG4-related disease, with other immunosuppressive regimens being reserved for refractory cases. Further research is needed to understand the effectiveness of corticosteroid-sparing regimens and whether there is utility in using these agents as first-line therapies.

Sex disparities in clinical characteristics and prognosis of immunoglobulin G4–related disease: a prospective study of 403 patients

Objectives

To study the impact of sex on the clinical presentation of IgG4-related disease (IgG4-RD).

Methods

We prospectively enrolled 403 newly diagnosed IgG4-RD patients. We compared the demographic features, clinical manifestations, organ involvement, laboratory tests and treatment outcomes between female and male patients. The organs involved were divided into superficial organs (salivary glands, lacrimal glands, orbit, sinus and skin) and internal organs (all the other organs). The patients treated with glucocorticoids with or without additional immunosuppressants were included in the assessment of treatment outcomes, and potential confounding factors were corrected by propensity score matching or multivariate Cox regression analysis.

Results

Female patients showed younger age at both symptom onset and diagnosis, and a longer interval between symptom onset and diagnosis. Allergy history, Mikulicz’s disease and thyroiditis were more common in female patients, while autoimmune pancreatitis, sclerosing cholangitis and retroperitoneal fibrosis were more common in male patients. In accordance, female patients more frequently presented with superficial organ involvement, while male patients more frequently had internal organ involvement, and the discrepancy was more prominent in the patients with older age. Male sex was associated with higher peripheral eosinophils, CRP and IgG4 levels at baseline. In response to glucocorticoid-based therapies, male sex was associated with a higher IgG4-RD responder index during follow-up as well as a greater risk of relapse (hazard ratio 3.14, P = 0.003).

Conclusion

Our study revealed the sex disparities in clinical characteristics of IgG4-RD, and indicated that male sex was independently associated with worse prognosis in response to glucocorticoid-based therapies.

No overlap between IgG4-related disease and microscopic polyangiitis and granulomatosis with polyangiitis despite elevated serum IgG4 at diagnosis: a retrospective monocentric study

OBJECTIVES

We investigated whether elevated serum IgG4 at the time of diagnosis of microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA) may be associated with concurrent IgG4-related disease (IgG4-RD) in immunosuppressive drug-naïve patients.

METHODS

We retrospectively reviewed the medical records of 46 MPA and GPA patients with results on serum IgG4 and histology at diagnosis. Elevated serum IgG4 was defined as IgG4 > 135 mg/dL. We collected clinical and laboratory data at diagnosis including ANCA, white blood cell (WBC) count, haemoglobin, platelet, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and serum IgG4, and calculated Birmingham vasculitis activity score (BVAS) at diagnosis. We compared variables between patients with MPA and GPA and assessed the correlation of serum IgG4 and other continuous variables.

RESULTS

Twenty-eight patients (60.9%) were classified as MPA and 18 patients (39.1%) as GPA. The mean age at diagnosis was 61.0 years and 17 patients (37.0%) were men. The serum IgG4 at diagnosis was 1202.7 mg/dL and 37 patients (80.4%) had elevated serum IgG4 at diagnosis. We found no patients, who could be classified as IgG4-RD according to comprehensive diagnostic criteria for IgG4-RD among 46 patients. The mean serum IgG at diagnosis was not different between the two groups. Serum IgG4 was significantly correlated with inflammation-related variables at diagnosis including BVAS (r = 0.367), platelet (r = 0.398), ESR (r = 0.327), and CRP (r = 0.373).

CONCLUSIONS

Elevated serum IgG4 is not associated with concurrent IgG4-RD, and it may reflect activity and inflammatory burden of vasculitis in patients with MPA and GPA at diagnosis.

Hybrid treatment of an isolated immunoglobulin G4-related internal thoracic artery aneurysm

True aneurysms of the internal thoracic artery (ITA) are rare and are associated with vasculitides, connective tissue diseases, and infections. We report a case of a 3-cm immunoglobulin G4-positive ITA aneurysm that was excised by a hybrid approach involving open ligation of the ITA origin and video-assisted thoracoscopic aneurysmectomy. This novel technique was able to acquire tissue for histopathologic diagnosis through a minimally invasive means.

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.

IgG4-Related Disease, the Malignancy Mimicker: Case Series from Bahrain

IgG4-related disease is an evolving immune-mediated condition. The hallmark of this condition is IgG4(+) plasma cells infiltration of the affected organs accompanied by a variable degree of fibrosis and occasionally elevated serum IgG4 level. It links many conditions that were once recognized as isolated unrelated idiopathic single organ disorders (e.g., autoimmune pancreatitis, Mikulicz syndrome, and retroperitoneal fibrosis) under one umbrella. It usually presents clinically as tumor-like swelling of the involved organs that can be misdiagnosed as neoplasia. In this case series, we present four cases that were considered as neoplasia but turned out to be IgG4-related disease, we demonstrate the protean manifestations of this condition and variable organs involvement, and we share our experience in using rituximab as the steroid sparing immunosuppressant agent to control this disease.

Primary hypophysitis and other autoimmune disorders of the sellar and suprasellar regions

The pituitary gland and the hypothalamus can be affected by autoimmune-mediated structural and functional disruption. These autoimmune-mediated diseases occur more commonly in females and are often found during pregnancy or in the post-partum period. Autoimmune diseases can either affect parts of the pituitary or hypothalamus, or can involve both sellar and suprasellar structures. Most of these cases comprise primary hypophysitis (PRH). Over the years, there has been a tremendous increase in the number of reported PRH cases and related disorders, including hypophysitis induced by immune checkpoint inhibitors. With this increasing data, more light is being shed on the spectrum of clinical presentations, biochemical and imaging abnormalities of these disorders. Regardless, these disorders are still relatively rare. The clinical presentation can vary vastly, based on the type of pituitary cell or the area of the suprasellar region affected. The severity can range from clinically silent disease to progressive and rapid deterioration and death, likely due to unrecognized central adrenal insufficiency. Although biopsy remains a gold standard for diagnosing these disorders, the current standard of practice is biochemical assessment for hormonal deficiencies and imaging studies. In several instances, these disorders spontaneously resolve, but medical or surgical intervention might be necessary to treat symptomatic disease. Due to the subtlety and a vast spectrum of clinical manifestations which could often be asymptomatic, and the rarity of the occurrence of these diseases in clinical practice, the diagnosis can be easily missed which could potentially lead to substantial morbidity or mortality. Therefore, it is crucial to have a strong clinical suspicion and pursue timely biochemical and imaging studies to initiate prompt treatment. In this article, we review the various autoimmune conditions that affect the sellar and suprasellar structures, their diagnostic approach and management of these disorders.

Long-Lived Plasma Cells in Mice and Men

Even though more than 30 years have passed since the eradication of smallpox, high titers of smallpox-specific antibodies are still detected in the blood of subjects vaccinated in childhood. In fact, smallpox-specific antibody levels are maintained in serum for more than 70 years. The generation of life-long immunity against infectious diseases such as smallpox and measles has been thoroughly documented. Although the mechanisms behind high persisting antibody titers in the absence of the causative agent are still unclear, long lived plasma cells (LLPCs) play an important role. Most of the current knowledge on LLPCs is based on experiments performed in mouse models, although the amount of data derived from human studies is increasing. As the results from mouse models are often directly extrapolated to humans, it is important to keep in mind that there are differences. These are not only the obvious such as the life span but there are also anatomical differences, for instance the adiposity of the bone marrow (BM) where LLPCs reside. Whether these differences have an effect on the function of the immune system, and in particular on LLPCs, are still unknown. In this review, we will briefly discuss current knowledge of LLPCs, comparing mice and humans.

Neuro-surgical considerations for treating IgG4-related disease with rare spinal epidural compression

Background:

Immunoglobulin G4-related disease (IgG4-RD) is a group of distinct autoimmune disorders affecting nearly every organ system in the body. Although central nervous system involvement is quite rare, it may present as hypertrophic pachymeningitis more frequently affecting the brain than the spine. In this study, we provide a case of spinal IgG4-RD pseudotumor resulting in cord compression, and a comprehensive review of the literature.

Case Description:

A patient presented with an extradural mass causing spinal cord compression at the L2-L3 level. Pathologically this proved to be an IgG4-RD pseudotumor. The patient was treated with thecal sac decompression and post-operative steroids that resulted in complete resolution of his symptoms.

Conclusion:

IgG4-RD is typically under-recognized and under-reported in the spinal literature. The clinical spinal presentation and non-surgical vs. surgical treatment are relatively straightforward. Although most cases can be managed with a course of steroids, surgical decompression may be required in patients presenting with spinal cord and/or nerve root compression. The differential diagnoses for these spinal tumors or pseudotumors should include IgG4-RD. Early detection and appropriate treatment can lead to satisfactory outcomes.

A Case of IgG4-Related Aortitis and Pericarditis: Diagnostic Challenges and Natural History

BACKGROUND IgG4-related disease (IgG4-RD) is a systemic inflammatory condition with a myriad of presentations related to the pattern of organ involvement. Diagnostic workup for IgG4-RD requires a high index of suspicion, and further workup often includes the results of serological testing for elevated levels of IgG4. Correlation of presentation, past medical history, and histopathologic analysis are required to make a diagnosis. CASE REPORT In this case, incidental discovery of non-infectious aortitis and pulmonary mass lesions were the specific signs that led to the consideration of IgG4-RD. It was only after careful consideration of the patient's past medical history and examination of previously stored surgical specimens (pericardial tissue) that a conclusive, retrospective diagnosis of IgG4-related disease was reached. CONCLUSIONS This case demonstrates that the natural history of IgG4-related disease can be indolent and variable in presentation. Appropriate diagnosis requires consideration of all manifestations of the disease, sometimes with surveillance over several years.

Never forget the aorta: a case report of IgG4-related disease causing aortitis

Background

Chest pain is a common reason for admission to the Emergency Department and aortic disease is a relatively frequent cause amongst the total number of admissions due to chest pain. IgG4-related disease (IgG4-RD) is a multi-organ immune-mediated condition that mimics several malignant, infectious, and inflammatory disorders.

Case summary

We report a rare case of IgG4-related aortitis complicated with severe aortic regurgitation and multivessel coronary artery disease in a 64-year-old man with a history of atypical chest pain. The diagnosis was made performing transthoracic echocardiography, transoesophageal echocardiography, and left heart catheterization; the aortitis was an incidental finding discovered by computed tomography angiography. Unusually, the positron emission tomography-computed tomography (PET-CT) scans did not reveal metabolic activity in the aortic wall. This last finding prompted us to exclude more aggressives arteritis (such as Horton's disease or Takayasu arteritis); syphilis infection and other infective or autoimmune diseases were excluded with laboratory tests. The patient underwent cardiac surgery with replacement of both the aortic valve and the ascending aorta, also performing a coronary aortic bypass graft (CABG). Despite the PET-CT scans were negative in the aortic wall, the histological specimens showed diffuse lymphoid infiltration, fibro-atheromatosis lesions, and medium-interstitial hyperplasia compatible with aortic atherosclerosis and IgG4-RD. The post-surgery course was free of complications and the patient was discharged in good clinical condition. He was referred to the Rheumatologic Department and a corticosteroid therapy has been started.

Discussion

The growing recognition of IgG4-related systemic disease as a clinical entity underscores the importance of considering this diagnosis in patients with any type of idiopathic aortitis and aortic valve disease. Noteworthy, the PET-CT scans could be negative in this disease, so histological exams are mandatory to make the diagnosis; in our case an unusual post-surgery histopathological finding prompted us to diagnose a rare, unrecognized disease and allowed us to treat the patient properly.

IgG4-related disease presenting with combined pulmonary fibrosis and emphysema (CPFE)

A 64-year-old man was admitted to our hospital with an abnormal chest shadow. The patient was a current-smoker and had a past illness of autoimmune pancreatitis with a high serum level of IgG4, 348 mg/dL. Chest CT showed upper-lobe emphysema, and lower-lobe reticulation with honeycombing, suggestive of combined pulmonary fibrosis with emphysema (CPFE). Surgical lung biopsy was revealed a usual interstitial pneumonia pattern with marked infiltration of IgG4-positive plasma cells. The patient was diagnosed with IgG4 related disease (IgG4-RD) presenting with CPFE. Pulmonary manifestation was improved by corticosteroid therapy. IgG4-RD may be an underlying condition in patient with CPFE.

Increase of circulating memory B cells after glucocorticoid-induced remission identifies patients at risk of IgG4-related disease relapse

BACKGROUND

Immunoglobulin G4-related disease (IgG4-RD) promptly responds to glucocorticoids but relapses in a considerable fraction of patients. Reliable biomarkers of flare are currently lacking because the pathophysiology of IgG4-RD remains largely elusive. In the present work, we aimed to identify perturbations of B-cell subpopulations that might predict IgG4-RD relapse.

METHODS

Thirty patients were treated with glucocorticoids according to international guidelines. Circulating CD19+ and CD20+ cells, naive B cells, memory B cells, plasmablasts, and plasma cells were measured by flow cytometry at baseline and every 6 months for 2 years after the initiation of corticosteroid therapy.

RESULTS

Patients with active untreated IgG4-RD showed significantly reduced CD19+ B cells, CD20+ B cells, and naive B cells compared with healthy subjects (p < 0.05), but significantly expanded plasmablasts and plasma cells (p < 0.01). After 6 months of corticosteroid treatment, all patients achieved clinical improvement. Naive B cells, plasmablasts, and plasma cells significantly decreased compared with disease onset, whereas memory B cells significantly increased compared with baseline (p < 0.01). Increase of memory B cells was observed only in patients who relapsed within 2 years of follow-up, however (HR, 12.24; 2.99 to 50.2; p = 0.0005). In these patients, the relapse rates at 12 and 24 months were 30% and 100%, respectively. No abnormalities of other B-cell subpopulations at disease onset or after 6 months of glucocorticoid treatment were found to predict IgG4-RD relapse at 2 years.

CONCLUSIONS

Increase of circulating memory B cells after 6 months of glucocorticoid treatment might predict IgG4-RD relapse.

[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.

Management of Autoimmune Pancreatitis

Type 1 autoimmune pancreatitis (AIP) is an IgG-4-related systemic disease that can manifest as a pancreatic disorder or another disorder of presumed autoimmune origin. Type 2 disease is typically characterized by absent IgG-4-positive cells. As patients often present with acute pancreatitis, obstructive jaundice, or pancreatic mass, it is imperative to exclude malignancy, a more common diagnosis. AIP may respond to corticosteroids, and has a strong association with other immune-mediated diseases. Recent literature suggests the benefit of immune-modulating therapy, including rituximab, although no consensus exists. This review covers the essentials of diagnosis, but focuses primarily on management of AIP.

Gastrointestinal and Extra-Intestinal Manifestations of IgG4-Related Disease

IgG4-related disease (IgG4-RD) is a chronic relapsing multi-organ fibro-inflammatory syndrome of presumed autoimmune etiology. It is characterized by increased serum levels of IgG4 and tissue infiltration by IgG4⁺ cells. Increased titers of autoantibodies against a spectrum of self-antigens and response to steroids have led to its characterization as an autoimmune disease. However, the pathognomonic antigens probably differ among manifestations, and different antigens or autoantibodies produce similar immune reactions in different organs. Little is known about the pathogenic effects, if any, of serum IgG4 or IgG4⁺ plasma cells in tissues. Despite several animal models of the disease, none truly recapitulates human IgG4-RD. Histologic analyses of tissues from patients with IgG4-RD reveal a dense lymphoplasmacytic infiltrate rich in IgG4⁺ plasma cells, storiform fibrosis, and obliterative phlebitis, although these features vary among organs. Typical presentation and imaging findings include mass-forming synchronous or metachronous lesions in almost any organ, but most commonly in the pancreas, bile duct, retroperitoneum, kidneys, lungs, salivary and lacrimal glands, orbit, and lymph nodes. In all organs, inflammation can be reduced by corticosteroids and drugs that deplete B cells, such as rituximab. Patients with IgG4-RD have relapses that respond to primary therapy. Intense fibrosis accompanies the inflammatory response, leading to permanent organ damage and insufficiency. Death from IgG4-RD is rare. IgG4-RD is a multi-organ disease with predominant pancreatico-biliary involvement. Despite its relapsing-remitting course, patients have an excellent prognosis.

A Refractory Case of Secondary Membranous Nephropathy Concurrent with IgG4-related Tubulointerstitial Nephritis

A 58-year-old man with type 1 autoimmune pancreatitis was referred to nephrologists for severe proteinuria. Laboratory data revealed a high serum IgG4 level, hypoalbuminemia, and massive proteinuria, which were compatible with nephrotic syndrome. The renal pathological findings confirmed the diagnosis of secondary membranous nephropathy concurrent with IgG4-related tubulointerstitial nephritis. Despite the improvement of interstitial markers, the proteinuria was refractory to prednisolone, requiring cyclosporine to achieve complete remission. Membranous nephropathy is a rare manifestation of IgG4-related kidney disease. This case shows that the therapeutic response to prednisolone significantly differs between glomerular lesions and interstitial lesions of IgG4-related kidney disease.

Immunoglobulin G4-related sclerosing cholangitis

Immunoglobulin G4-related disease (IgG4-RD) is a systemic fibroinflammatory condition of which IgG4-related sclerosing cholangitis (IgG4-SC) is the biliary manifestation. In this review, we provide an overview of IgG4-RD, with a focus on the biliary manifestations. In particular, we describe the important differential diagnoses of IgG4-SC, namely, primary sclerosing cholangitis and cholangiocarcinoma, outline diagnostic criteria for IgG4-SC, provide insight into possible pathophysiological mechanisms underlying the disease and discuss short and long-term management options of this recently described disease.

Aberrant Expansion and Function of Follicular Helper T Cell Subsets in IgG4-Related Disease

Objective

To determine the number and function of follicular helper T (Tfh) cell subsets in IgG4‐related disease (IgG4‐RD).

Methods

Mononuclear cells from the peripheral blood and involved tissue of patients with IgG4‐RD were assessed for Tfh cells and their subsets, and levels of B cell lymphoma 6 (Bcl‐6), B lymphocyte–induced maturation protein 1 (BLIMP‐1), and interleukin‐21 (IL‐21) messenger RNA (mRNA). Immunohistochemical and immunofluorescence techniques were used to assess the involved tissue of patients to determine the location of IL‐21, Bcl‐6, and CD4+CXCR5+ Tfh cells. Furthermore, the ability of circulating Tfh (cTfh) cell subsets to induce B cell proliferation, apoptosis, and differentiation and to produce IgG4 was explored in cell cocultures in vitro.

Results

Frequencies of cTfh cells were significantly increased in the peripheral blood of patients with IgG4‐RD, and even higher frequencies were observed in the involved tissue. Percentages of programmed cell death protein 1 in CD4+CXCR5+ICOS+ cTfh cells were positively correlated with the serum levels of IgG and IgG4, IgG4:IgG ratio, number of involved organs, and frequency of CD19+CD24−CD38^high plasmablasts/plasma cells. Levels of BLIMP‐1 and IL‐21 mRNA in peripheral CD4+ T cells were increased in patients with IgG4‐RD compared to healthy controls, and this was correlated with the levels of serum IgG4. Moreover, in the involved tissue, Bcl‐6, IL‐21, and Tfh cells were highly expressed. Compared to cTfh cells from healthy controls, cTfh cells from patients with IgG4‐RD could facilitate B cell proliferation and inhibit B cell apoptosis more efficiently, and enhanced the differentiation of naive B cells into switched memory B cells and plasmablasts/plasma cells, with a resultant increase in the secretion of IgG4. Notably, the cTfh1 and cTfh2 cell subsets were the most effective at providing B cell help.

Conclusion

Tfh cell subsets are expanded in IgG4‐RD and may play pivotal roles in the pathogenesis of the disease.

IgG4-Related Disease: Beyond Glucocorticoids

IgG4-related disease is a heterogeneous immune-mediated fibroinflammatory condition that can affect every single organ. This disease is more prevalent in the elderly (the mean age of patients is above 60 years) and the prevalence rate is estimated to be over 4.6 per 100,000 population. Before making a diagnosis, the exclusion of malignancies, lymphoma, anti-neutrophil cytoplasmic antibody-associated vasculitis, multicentric Castleman disease, and other mimickers is crucial for appropriate treatment. Broad management guidelines have been published emphasizing the need for prompt treatment and the use of glucocorticoids as first-line drug therapy for induction of remission. However, the toxic effects of glucocorticoids are problematic because IgG4-related disease is more prevalent in patients above 60 years of age, a population with frequent comorbid conditions and polypharmacy. Immunosuppressants (cyclophosphamide, methotrexate, leflunomide, and tacrolimus) and targeted immunomodulators (rituximab, XmAb5871, and abatacept) are appealing to overcome potential toxic effects of glucocorticoids and as emerging glucocorticoid-sparing and/or maintenance treatments. In this review, we provide an overview of our understanding of the pathophysiology of the disease (T follicular helper cells, CD4⁺ cytotoxic T cells, plasmablasts, and alternatively activated M2 macrophages) and clinical characteristics, and highlight the potential targets for treatment intervention.

IgG4-related mastopathy: A case report and literature review

IgG4-related sclerosing disease (IgG4-RD) occasionally involves breast entity, which is often difficult to distinguish from malignant tumor, as both radiologically resembles. We report a case of a breast mass diagnosed as IgG4-related mastopathy (IgG4-RM) through needle biopsy, which responded well to glucocorticoid therapy. Unnecessary excision should be avoided.

IgG4-related disease mimicking pancreatic cancer: Case report and review of the literature

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Pancreatic masses pose a diagnostic challenge, and cancer has to be always considered.

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IgG4-related disease is a rare cause of pancreatic masses.

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Biopsy from the pancreas is not always required if histopathology from a more accessible peripheral site lesion confirms the diagnosis.

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Multiorgan involvement and aortitis should raise suspicion of IgG4-related disease.

Introduction

Most patients with pancreatic masses pose a diagnostic challenge when a benign lesion is suspected, and often, resection is needed before a benign diagnosis is confirmed.

Presentation of case

A 57 years old male patient presented with a pancreatic head mass, obstructive jaundice and submandibular lymph node enlargement. He also had a history of recurrent eye pain and redness, skin lesions, and benign prostatic hypertrophy. MRI showed a pancreatic head mass with double duct sign, aortic thickening, bilateral renal lesions, diffuse lymph node enlargement, and prostatic enlargement. FDG-PET/CT demonstrated abnormal uptake corresponding to the MRI lesions, and there were elevated IgG4 levels on blood investigations. Biopsy of an inguinal lymph node revealed infiltrates with IgG4 plasma cells, consistent with the diagnosis of IgG4 disease. The patient was treated with IV steroids and showed significant improvement.

Discussion

IgG4 related disease is a rare entity that is characterized by lesions that show heavy infiltration with IgG4 positive plasma cells, storiform fibrosis, and obliterative phlebitis. The pancreas is the most commonly involved organ, but several other organ systems are involved, and this helps in clinical suspicion of the diagnosis. A biopsy from any easily accessible site that shows the characteristic histological features is sufficient for diagnosis. Patients respond quickly to steroids, but recurrence is frequent.

Conclusion

IgG4 related disease is a rare cause of pancreatic tumorous lesions that need a high index of suspicion for diagnosis and should be differentiated from pancreatic neoplastic lesions.

Recurrent IgG4-related tubulointerstitial nephritis concurrent with chronic active antibody mediated rejection: A case report

IgG4-related disease is a relatively newly described entity that can affect nearly any organ, including the kidneys, where it usually manifests as tubulointerstitial nephritis (IgG4-TIN). The diagnosis can be suggested by characteristic histological features, including an inflammatory infiltrate with increased IgG4-positive plasma cells associated with "storiform" fibrosis. Serum IgG4 is usually elevated. In the native kidney and other organs, there is typically a brisk response to treatment with immunosuppression. Recurrence of IgG4-TIN after renal transplant has not been described in the literature. Here, we describe the first case of recurrent IgG4-TIN in a young patient concomitant with chronic active antibody mediated rejection five years after kidney transplant. Recurrent IgG4-TIN could be diagnosed by the characteristic histopathologic features and increased IgG4-positive plasma cells. Despite maintenance immunosuppression, this disease may recur in the kidney allograft.

A CD8α- Subset of CD4+SLAMF7+ Cytotoxic T Cells Is Expanded in Patients With IgG4-Related Disease and Decreases Following Glucocorticoid Treatment

OBJECTIVE

An unconventional population of CD4+ signaling lymphocytic activation molecule family member 7-positive (SLAMF7+) cytotoxic effector memory T (TEM ) cells (CD4+ cytotoxic T lymphocytes [CTLs]) has been linked causally to IgG4-related disease (IgG4-RD). Glucocorticoids represent the first-line therapeutic approach in patients with IgG4-RD, but their mechanism of action in this specific condition remains unknown. We undertook this study to determine the impact of glucocorticoids on CD4+ CTLs in IgG4-RD.

METHODS

Expression of CD8α, granzyme A, perforin, and SLAMF7 within the effector memory compartment of CD45RO+ (TEM ) and CD45RA+ effector memory T (TEMRA ) CD4+ cells was quantified by flow cytometry in 18 patients with active IgG4-RD, both at baseline and after 6 months of glucocorticoid treatment. Eighteen healthy subjects were studied as controls. Next-generation sequencing of the T cell receptor α- and β-chain gene was performed on circulating CD4+ CTLs from patients with IgG4-RD before and after treatment and in affected tissues.

RESULTS

Circulating CD4+ TEM and TEMRA cells were not expanded in IgG4-RD patients compared to healthy controls. CD4+SLAMF7+ TEM cells (but not TEMRA cells) were significantly increased among IgG4-RD patients. Within CD4+SLAMF7+ TEM cells, CD8α- cells but not CD8αlow cells were elevated in IgG4-RD patients. The same dominant clones of CD8α-CD4+SLAMF7+ TEM cells found in peripheral blood were also identified in affected tissue. CD8α- and CD8αlow CD4+SLAMF7+ TEM cells both expressed cytolytic molecules. Clonally expanded CD8α- but not CD8αlow CD4+SLAMF7+ TEM cells decreased following glucocorticoid-induced disease remission.

CONCLUSION

A subset of CD8α-CD4+SLAMF7+ cytotoxic TEM cells is oligoclonally expanded in patients with active IgG4-RD. This TEM cell population contracts following glucocorticoid-induced remission. Further characterization of this cell population may provide prognostic information and targets for therapeutic intervention.

IgG4-related disease: review of the histopathologic features, differential diagnosis, and therapeutic approach

Immunoglobulin G4-related disease (IgG4-RD) is an uncommon disorder that demonstrates characteristic clinicopathologic features including sclerosing lesions with storiform fibrosis, increased IgG4+ plasma cells with an increased IgG4+/IgG+ plasma cell ratio, obliterative phlebitis, and often an increased serum IgG4 level. This review summarizes the characteristic histopathologic and clinical features of IgG4-RD with detailed discussion of the histopathologic characteristics of the most commonly involved anatomic sites. We also present recent advances in our understanding of the pathophysiologic mechanisms of IgG4-RD and discuss updates on the treatment, prognosis, and outcomes of this rare disease, including discussion of the possible association between IgG4-RD and malignancy.