IgG4-related disease with hypergammaglobulinemic hyperviscosity and retinopathy

IgG4-related hypophysitis: a retrospective cohort study

Purpose

IgG4-related hypophysitis (IgG4-RH) is a rare chronic inflammatory condition of the pituitary gland. This study reports the presentation, management and outcomes for patients with histologically proven IgG4-related hypophysitis.

Methods

A prospectively maintained electronic database was searched over a 14-year period from 1 January 2007 to 31 December 2020 at a single academic centre to identify all patients with a histological diagnosis of IgG4-RH. A retrospective case note review from electronic health records was conducted for each case to extract data on their presentation, management and outcomes.

Results

A total of 8 patients (5 male) with a median age of 51 years were identified. The most common presenting symptoms were headache (4/8; 50%), fatigue (3/8; 37.5%) and visual impairment (2/8; 25%). Three patients were initially treated with high-dose steroids aiming for reduction of the pituitary mass. However, ultimately all patients underwent transsphenoidal surgery. Post-operative changes included radiological reduction in pituitary mass in all patients that had imaging (7/7; 100%), improvement in vision (1/2; 50%), residual thick pituitary stalk (5/7; 71.4%), persistent anterior hypopituitarism (4/8; 50%) and panhypopopituitarism including diabetes insipidus (3/8; 37.5%).

Conclusions

IgG4-RH is an increasingly recognised entity presenting with a variety of symptoms and signs. Clinical presentation is similar to other forms of hypophysitis. It is therefore important to consider IgG4-RH as a differential and to have a low threshold for pituitary biopsy, the diagnostic gold standard. The diagnosis of IgG4-RH will guide decisions for additional workup for IgG4-related disease, multi-disciplinary team involvement and follow-up.

Polyclonal hypergammaglobulinaemia: assessment, clinical interpretation, and management

This Review outlines a practical approach to assessing and managing polyclonal hypergammaglobulinaemia in adults. Polyclonal hypergammaglobulinaemia is most commonly caused by liver disease, immune dysregulation, or inflammation, but can also provide an important diagnostic clue of rare diseases such as histiocyte disorders, autoimmune lymphoproliferative syndrome, Castleman disease, and IgG4-related disease. Causes of polyclonal hypergammaglobulinaemia can be divided into eight categories: liver disease, autoimmune disease and vasculitis, infection and inflammation, non-haematological malignancy, haematological disorders, IgG4-related disease, immunodeficiency syndromes, and iatrogenic (from immunoglobulin therapy). Measuring serum concentrations of C-reactive protein and IgG subclasses are helpful in diagnosis. IL-6-mediated inflammation, associated with persistently elevated C-reactive protein concentrations (≥30 mg/L), is an important driver of polyclonal hypergammaglobulinaemia in some cases. Although the presence of markedly elevated serum IgG4 concentrations (>5 g/L) is around 90% specific for diagnosing IgG4-related disease, mildly elevated serum IgG4 concentrations are seen in many conditions. In most cases, managing polyclonal hypergammaglobulinaemia simply involves treating the underlying condition. Rarely, however, polyclonal hypergammaglobulinaemia can lead to hyperviscosity, requiring plasmapheresis.

Challenges in Medicine: The Odyssey of a Patient with Isolated IgG4-Related Eosinophilic Angiocentric Fibrosis Presenting as a Locally Destructive Sinonasal Mass

Eosinophilic angiocentric fibrosis (EAF) is an exceeding rare clinical entity and is considered a part of the spectrum of IgG4-related disease (IgG4RD). We hereby present such an unusual case of a 60-year-old female who presented to us with recurrent sinonasal mass, after a decade long haul of multiple clinical evaluations, biopsies, and debulking surgery without a definitive diagnosis. Over this period, the mass eroded through the ethmoid cells along with nasal septal destruction leading to saddle nose deformity, extended superiorly through the cribriform plates to right frontal lobe, and compressed the optic nerve leading to visual loss. Although initial biopsy was negative, repeat biopsy was performed owing to high clinical suspicion due to all the classic histopathological findings compatible with the diagnosis of eosinophilic angiocentric fibrosis IgG4-related disease (EAF-IgG4RD). Steroids are the recommended first-line therapy; however, our case was resistant to steroids needing rituximab to halt the disease progression. Our case interestingly also had T-cell clonality and isolated isocitrate dehydrogenase 2 enzyme mutation on next-generation sequencing, suggesting a possible role of novel molecular-targeted therapies in this rare disease. This case highlights the clinical challenges physicians face towards diagnosing and treating EAF-IgG4RD, emphasizing the need for high clinical suspicion and the possible role of targeted therapies for this rare disease.

Clinical utility of serum IgG4 measurement

This article will review the structure and function of IgG4, methods of measuring serum IgG4 concentrations, clinical conditions associated with increased and decreased serum IgG4, and the test characteristics of serum IgG4 in the diagnosis and management of Immunoglobulin G4-Related Disease (IgG4-RD). The four subclasses of IgG were discovered in 1964 through experiments on monoclonal IgG in patients with myeloma. Since 2001, interest in measuring serum IgG subclasses has increased dramatically due to the emergence of IgG4-RD, a multisystem fibroinflammatory condition wherein polyclonal serum IgG4 concentration is increased in approximately 70% of cases. Increased serum IgG4 typically manifests as a restriction in the anodal gamma region on serum protein electrophoresis, often with beta-gamma bridging, and can be mistaken as a monoclonal protein or polyclonal increase in IgA. Limitations of current clinical methods used in quantitation of serum IgG4 concentrations will be discussed, including the common immunonephelometric assays and LC-MS/MS based assays. Polyclonal IgG4 elevation is not specific for IgG4-RD, and may also occur in conditions such as eosinophilic granulomatosis with polyangiitis (EGPA), lymphoma, and multicentric Castleman disease (MCD). Race and gender differences also affect interpretation of serum IgG4 concentrations, for instance Asians have a higher serum IgG4 concentration than Whites and males have a higher concentration than females.

The treatment outcomes in IgG4-related orbital disease: a systematic review of the literature

IgG4-related disease (IgG4-RD) is an immune-mediated systemic fibro inflammatory disease. Treatment of IgG4-related orbital disease (IgG4-ROD) is often indicated to relieve the symptoms and to prevent complications. For IgG4-ROD, no international formal treatment guidelines are available and the optimal treatment strategy is uncertain. In this systematic review, we describe the efficacy of conventional and biologic disease-modifying antirheumatic drugs (DMARDs) in IgG4-ROD. A systematic search of Embase, Medline, Web-of-Science, PubMed publisher, Cochrane and Google Scholar was performed for treatment outcomes in IgG4-ROD. Relevant articles on treatment of IgG4-ROD were retrieved to last date of inclusion 3 January 2018. The following inclusion criteria were used: articles in English or English translation, studies evaluating the use of DMARDs (conventional and biologic) in the treatment of IgG4-ROD. Meta-analysis and review articles were excluded. A final selection after full-text evaluation was made by independent reviewers, based on treatment of IgG4-ROD with DMARDs and the availability of treatment outcomes. With this systematic review, we identified 35 studies and case reports/series on IgG4-ROD, describing 95 patients, treated with conventional and/or biologic DMARDs. The success of conventional DMARDs varies between 36% and 75% in patients with IgG4-ROD, while rituximab is successful in the majority (93%) of the patients. Based on this systematic review, rituximab is the most effective DMARD in IgG4-ROD, while the efficacy of conventional DMARDs is limited. We propose early initiation of rituximab in case of refractory and organ- or life-threatening disease.

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: 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.

Acute hyperviscosity: syndromes and management

Plasma hyperviscosity is a rare complication of both monoclonal and polyclonal disorders associated with elevation of immunoglobulins. Asymptomatic patients with an elevation in the serum viscosity do not require plasma exchange, and the majority will have other indications for therapeutic intervention. For patients with hemorrhagic or central nervous system manifestations, plasma exchange is the therapy of choice and is relatively safe. Viscosity measurements are not required to initiate therapy if the index of suspicion is high and the clinical presentation is typical. However, patients should have a sample sent for confirmation of the diagnosis. Whole-blood hyperviscosity is seen in patients with extreme elevation of the red cell and white cell count. Phlebotomy of patients with primary and secondary elevation of the red cell count is a well-established therapy.

Utility of Serum IgG4 Levels in a Multiethnic Population

BACKGROUND

IgG4-related disease (IgG4-RD) is a recently recognized condition defined by characteristic histopathologic findings in affected organs. Serum IgG4 concentration is often but not always elevated. The sensitivity and specificity of serum IgG4 vary greatly across studies and has been anecdotally associated to ethnicity. Our study was conducted to investigate the difference in serum IgG4 levels between Asian and non-Asian patients with IgG4-RD.

METHODS

This is a single-center retrospective study of 26 Asian and 10 non-Asian patients with histologically confirmed IgG4-RD. Serum IgG4 levels, clinical features and other laboratory findings were compared between the 2 groups, 31 Asian and 11 non-Asian patients with non-IgG4-RD rheumatic diseases were randomly identified to evaluate test characteristics of serum IgG4 measurement.

RESULTS

Median serum IgG4 at time of diagnosis was significantly higher in Asian (median = 11.2g/L, interquartile range: 4.6-19.7) than non-Asian patients (median = 2.9g/L, interquartile range: 0.7-5.4, P = 0.0094), as well as the median serum IgG and total protein. Asian patients had more eosinophilia and polyclonal hypergammaglobulinemia than non-Asian patients (P = 0.016 and 0.001, respectively). Test sensitivity was higher in Asian (96%) than non-Asian patients (67%), whereas test specificity was higher in non-Asian patients (91% versus 71%).

CONCLUSION

Asian patients with IgG4-RD have more exuberant serum IgG4, IgG and polyclonal hypergammaglobulinemia than non-Asian patients; the mechanism of this difference requires further study. These findings have significant clinical importance and must be accounted for in the diagnostic workup of patients in multiethnic settings.

IgG4-Related Ophthalmic Disease: Pooling of Published Cases and Literature Review

In recent years, IgG4-related ophthalmic disease (IgG4-ROD) has emerged as a common cause of orbital inflammation, accounting for a substantial proportion of idiopathic orbital inflammation and lymphoid hyperplasia. The last pooled analysis of published cases was conducted in 2012, but a large number of new cases have been added to the literature since then. In this review, we present the demographic, clinical, histological, and treatment data for 172 published cases of biopsy-confirmed IgG4-ROD. Results are accompanied by a review of the relevant literature.

Immunology of IgG4-related disease

Immunoglobulin G4-related disease (IgG4-RD) is a fibroinflammatory condition that derives its name from the characteristic finding of abundant IgG4(+) plasma cells in affected tissues, as well as the presence of elevated serum IgG4 concentrations in many patients. In contrast to fibrotic disorders, such as systemic sclerosis or idiopathic pulmonary fibrosis in which the tissues fibrosis has remained largely intractable to treatment, many IgG4-RD patients appear to have a condition in which the collagen deposition is reversible. The mechanisms underlying this peculiar feature remain unknown, but the remarkable efficacy of B cell depletion in these patients supports an important pathogenic role of B cell/T cell collaboration. In particular, aberrant T helper type 2 (Th2)/regulatory T cells sustained by putative autoreactive B cells have been proposed to drive collagen deposition through the production of profibrotic cytokines, but definitive demonstrations of this hypothesis are lacking. Indeed, a number of unsolved questions need to be addressed in order to fully understand the pathogenesis of IgG4-RD. These include the identification of an antigenic trigger(s), the implications (if any) of IgG4 antibodies for pathophysiology and the precise immunological mechanisms leading to fibrosis. Recent investigations have also raised the possibility that innate immunity might precede adaptive immunity, thus further complicating the pathological scenario. Here, we aim to review the most recent insights on the immunology of IgG4-RD, focusing on the relative contribution of innate and adaptive immune responses to the full pathological phenotype of this fibrotic condition. Clinical, histological and therapeutic features are also addressed.

Polyclonal hyperviscosity syndrome in IgG4-related disease and associated conditions

Polyclonal hyperviscosity syndrome (HVS) is rare and has been reported in various disorders of immune dysregulation and lymphoid hyperplasia. IgG4-Related Disease (IgG4-RD) is an emerging disorder often associated with exuberant hypergammaglobulinemia, and this review of seven cases establishes IgG4-RD as an important cause of polyclonal HVS.

Rituximab for the treatment of IgG4-related orbital disease: experience from five cases

PURPOSE

To review the clinical efficacy and safety of rituximab for treatment of IgG4-related orbital disease (IgG4-ROD).

DESIGN

Retrospective multicentre interventional case series.

METHODS

Chart review for five cases of biopsy-confirmed IgG4-ROD (IgG4+>10/HPF, ratio of IgG4+/IgG+>40%) treated with rituximab. Information retrieved included the dosing schedule, adverse events and the magnitude, temporality, and duration of the clinical response.

RESULTS

All cases of IgG4-ROD were either steroid dependent or steroid resistant. Rituximab doses for induction therapy included two doses of 1000 mg at 2-weekly intervals, and four doses at 375 mg/m(2) at weekly intervals. Two months after starting rituximab, three cases achieved complete clinical resolution and two cases achieved partial clinical resolution. Complete radiological resolution occurred in one case, and partial radiological resolution in three cases. Three cases received rituximab maintenance therapy and one case was commenced on mycophenolate. No relapse occurred during a mean follow-up of 33 months (range: 7-65 months). One disease relapse occurred when the dosing interval of rituximab maintenance therapy was extended to 6-monthly intervals; remission was swiftly achieved with rituximab reinduction therapy. The only adverse effects reported were one episode of fatigue lasting 1 week and two episodes of orbital discomfort.

CONCLUSION

Rituximab may be an effective treatment option for IgG4-ROD that is steroid dependent or steroid intolerant. Rituximab therapy resulted in swift clinical and radiological improvement, many months free of relapse, and few side effects.

T helper 2 and regulatory T-cell cytokine production by mast cells: a key factor in the pathogenesis of IgG4-related disease

IgG4-related disease is a systemic disorder with unique clinicopathological features and uncertain etiological features and is frequently related to allergic disease. T helper 2 and regulatory T-cell cytokines have been reported to be upregulated in the affected tissues; thus, the production of these cytokines by T helper 2 and regulatory T cells has been suggested as an important factor in the pathogenesis of IgG4-related disease. However, it is not yet clear which cells produce these cytokines in IgG4-related disease, and some aspects of the disorder cannot be completely explained by T-cell-related processes. To address this, we analyzed paraffin-embedded sections of tissues from nine cases of IgG4-related submandibular gland disease, five cases of submandibular sialolithiasis, and six cases of normal submandibular gland in order to identify potential key players in the pathogenesis of IgG4-related disease. Real-time polymerase chain reaction analysis confirmed the significant upregulation of interleukin (IL)4, IL10, and transforming growth factor beta 1 (TGFβ1) in IgG4-related disease. Interestingly, immunohistochemical studies indicated the presence of mast cells expressing these cytokines in diseased tissues. In addition, dual immunofluorescence assays identified cells that were double-positive for each cytokine and for KIT, which is expressed by mast cells. In contrast, the distribution of T cells did not correlate with cytokine distribution in affected tissues. We also found that the mast cells were strongly positive for IgE. This observation supports the hypothesis that mast cells are involved in IgG4-related disease, as mast cells are known to be closely related to allergic reactions and are activated in the presence of elevated non-specific IgE levels. In conclusion, our results indicate that mast cells produce T helper 2 and regulatory T-cell cytokines in tissues affected by IgG4-related disease and possibly have an important role in disease pathogenesis.

IgG4- related disease: an orphan disease with many faces

Immunoglobulin G4- related disease (IgG4-RD) is a rare systemic fibro-inflammatory disorder (ORPHA284264). Although patients have been described more than 100 years ago, the systemic nature of this disease has been recognized in the 21^st century only. Type 1 autoimmune pancreatitis is the most frequent manifestation of IgG4-RD. However, IgG4-RD can affect any organ such as salivary glands, orbits, retroperitoneum and many others. Recent research enabled a clear clinical and histopathological description of IgG4-RD. Typically, lymphoplasmacellular inflammation, storiform fibrosis and obliterative phlebitis are found in IgG4-RD biopsies and the tissue invading plasma cells largely produce IgG4. Elevated serum IgG4 levels are found in many but not all patients. Consequently, diagnostic criteria for IgG4-RD have been proposed recently. Treatment is largely based on clinical experience and retrospective case series. Glucocorticoids are the mainstay of therapy, although adjunctive immunosuppressive agents are used in relapsing patients. This review summarizes current knowledge on clinical manifestations, pathophysiology and treatment of IgG4-RD.

Hypophysitis due to IgG4-related disease responding to treatment with azathioprine: an alternative to corticosteroid therapy

PURPOSE

Fifteen cases of lymphocytic hypophysitis due to IgG4-related disease have been reported demonstrating marked improvement with corticosteroid therapy. This is the first case of IgG4-related hypophysitis demonstrating improvement with azathioprine, where corticosteroids were initially tried but ceased due to concern regarding enlargement of the pituitary infiltrate.

METHODS

Case description and review of 15 cases reported in the literature. A 40 year old male was diagnosed with IgG-4 related disease based on pituitary and lacrimal gland biopsies associated with raised serum concentration of IgG4. The patient was commenced on prednisolone 30 mg/day, as rapid response to prednisolone treatment has been described in the literature for other cases of IgG4-related hypophysitis. Over the next 3 months, prednisolone treatment resulted in a reduction of serum IgG4 levels, but repeat MRI scan showed an enlarging pituitary mass with new optic nerve compression. Azathioprine 75 mg twice daily was commenced and in the subsequent 3 months, IgG4 levels normalised (0.58 g/L) and MRI scan showed 50% shrinkage of the pituitary mass. After 10 months of azathioprine treatment the MRI showed a normal sized pituitary but persistence of the infraorbital nerve thickening.

CONCLUSIONS

Hypophysitis due to IgG4-related disease usually demonstrates prompt response to corticosteroids. This case highlights the need to image promptly after starting treatment to exclude an enlarging pituitary mass despite corticosteroid treatment. Alternative therapy with azathioprine can result in marked improvement. It should be remembered that IgG-4 related hypophysitis is part of a multi-organ disease.