Antineutrophil cytoplasmic antibody positivity in IgG4-related disease: A case report and review of the literature

Common Characteristics of Sinonasal Inflammation Associated with IgG4-Related Disease and Other Chronic Inflammatory Diseases: A Retrospective Observational Study

INTRODUCTION

Immunoglobulin G4-related disease (IgG4-RD) is a systemic inflammatory disease characterized by elevated serum IgG4, tissue infiltration of IgG4-positive cells, and fibrosis. Although a number of IgG4-RD patients show sinonasal involvement, there is little known about sinonasal inflammation associated with IgG4-RD. This study aimed to describe the clinicopathological features of sinonasal inflammation associated with IgG4-RD and to compare with other inflammatory diseases, such as eosinophilic chronic rhinosinusitis (ECRS) and granulomatosis with polyangiitis (GPA).

METHODS

A retrospective analysis of clinicopathological features of patients with sinonasal lesions and high serum IgG4 was performed. Patient data were reviewed to determine whether they fulfilled the diagnostic criteria for other inflammatory diseases.

RESULTS

Six of 7 patients were diagnosed with IgG4-RD, while 1 patient was diagnosed with GPA. In the 6 patients with IgG4-RD, intranasal findings showed nasal polyps in 3 patients (50%) and nasal crusting in the 3 patients (50%). Computed tomography showed ethmoid sinus involvement in 5 patients (83%). Five of the 6 patients (83%) were diagnosed with IgG4-RD based on nasal biopsy, whereas 1 patient (17%) was diagnosed based on lacrimal gland biopsy. Four patients fulfilled the Japanese epidemiological survey of refractory ECRS (JESREC) criteria. However, none of the patients showed eosinophil infiltration. Although the patient with GPA showed high levels of serum IgG4 and tissue infiltration of IgG4-positive cells in the nasal biopsy, the patient showed common clinical features of GPA.

CONCLUSION

Patients with sinonasal inflammation associated with IgG4-RD had similar clinical characteristics with ECRS and GPA. Histopathological findings of the nasal biopsy from clinically diagnosed GPA was consistent with that of IgG4-RD. Sinonasal inflammation associated with IgG4-RD should be diagnosed based not only on tissue infiltration of IgG4-positive cells but in conjunction with clinical findings such as local nasal characteristics, involvement of other organs, and serum antineutrophil cytoplasmic antibody levels. IgG4-RD should be ruled out in patients with eosinophilia without histopathological eosinophil infiltration.

Coexistence of IgG4-related disease and ANCA-associated vasculitis: case report and review of the literature

IgG4-related disease (IgG4-RD) is a fibroinflammatory condition that is characterized by storiform fibrosis, infiltration of IgG4-positive lymphocytes, obliterative phlebitis, and high IgG4 levels. Since IgG4-RD affects a wide variety of organs, a differential diagnosis must include multiple conditions. IgG4-RD is also believed to coexist with certain diseases. In recent years, case reports and case series describing the co-occurrence of IgG4-RD and ANCA-associated vasculitis (AAV) have been published. We intended to evaluate patients with IgG4-RD and AAV overlap in the literature using a case similar to one that was diagnosed and monitored in our department. We searched the databases of Web of Science, Scopus, and Google Scholar as well as PubMed with the keywords ANCA, IgG4, IgG4-RD, granulomatosis with polyangiitis, Wegener's granulomatosis, microscopic polyangiitis, Eosinophilic granulomatosis with polyangiitis, and Churg-Strauss syndrome. Cases and Case series addressing the coexistence of IgG4-RD and AAV have been selected. Comprehensive diagnostic criteria are used to diagnose IgG4-RD. The Chapel Hill Consensus Conference nomenclature criteria were used for the inclusion of AAV. Out of a total of 910 publications, 20 articles, including 65 cases, were found to be eligible. Forty-seven cases with IgG4-RD were evaluated as definitive (71.2%), 10 cases as probable (15.1%), and 9 cases as possible IgG4-RD (13.6%). 26 patients were diagnosed with GPA, 1 patient with localized GPA, 23 patients with MPA, and 4 patients with EGPA. The aorta, lacrimal tissue, pancreas, and retroperitoneum are the sites of IgG4-RD rather than AAV. AAV and IgG4-RD might coexist in the same patient. IgG4-RD is mainly associated with GPA.

MPO-ANCA-positive granulomatosis with polyangiitis and concurrent IgG4-related disease with periaortitis and tubulointerstitial nephritis: A case report of a new overlap syndrome?

Immunoglobulin G4-related disease (IgG4-RD) is a fibroinflammatory condition that was first recognized as a unique disease entity in the early 2000s. Its diagnosis is based on specific pathologic, serologic, and clinical features, and the exclusion of several differential diagnoses, such antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). However, emerging evidence suggests that these 2 conditions may overlap in some cases. Here, we report a new case of overlapping IgG4-RD and AAV. The patient was diagnosed with IgG4-RD owing to the presence of periaortitis and IgG4 positive tubulointerstitial nephritis. Myeloperoxidase (MPO)-ANCA positivity, chronic paranasal sinusitis, and glomerulonephritis with granuloma led to a concurrent diagnosis of MPO-ANCA-positive granulomatosis with polyangiitis. Our case supports the hypothesis that diagnoses of IgG4-RD and AAV are not mutually exclusive but can overlap. It can be assumed that an overlap with IgG4-RD typically affects the granulomatous form of AAV, suggesting a common pathophysiological pathway for these 2 conditions.

Association of IgG4-related disease and systemic rheumatic disorders

PURPOSE

Autoimmune disorders can occur together especially in genetically predisposed individuals. We here aimed to assess the occurrence of IgG4-related disease (IgG4-RD) in association with other systemic immune-mediated conditions.

METHODS

We retrospectively analyzed the clinical records of patients with IgG4-RD followed at the IgG4-RD Clinic of San Raffaele Hospital (Milan, Italy) for pre-existing or concomitant immune-mediated disorders. IgG4-RD was diagnosed based on histological findings and on the 2011 Comprehensive Diagnostic criteria. Associated immune-mediated disorders were diagnosed based on available classification and/or diagnostic criteria.

RESULTS

Two-hundred and thirty-four patients with a definitive diagnosis of IgG4-RD were included in this study. A pre-existing immune-mediated connective tissue disease was reported in 6/234 patients (3%): one case each of sarcoidosis, Takayasu arteritis (TA), eosinophilic granulomatosis with polyangitis (EGPA), and rheumatoid arthritis; and two cases of granulomatosis with polyangitis (GPA). Organs involved by IgG4-RD included the lungs, the pancreas, the peritoneum, lacrimal glands, meninges and orbits. Sarcoidosis, EGPA, and TA preceded the onset of IgG4-RD. GPA preceded IgG4-RD onset in one case and occurred simultaneously in the other case. Rheumatoid arthritis occurred together with IgG4-RD in one case.

CONCLUSION

Our observation suggests that "secondary" IgG4-RD can present in the context of pre-existing systemic immune-mediated disorders and complicate systemic autoimmune diseases as well as chronic granulomatous conditions. Further studies are needed to define whether this peculiar clinical scenario is associated with different genetic backgrounds, pathological bases, and long-term outcomes.

Pachymeningitis associated with IgG4-related disease and ANCA positivity: Case report and review of the literature

OBJECTIVE

Hypertrophic pachymeningitis is a rare clinical disorder involving localized or diffuse thickening of the dura mater. Considering pachymeningitis is both in the clinical spectrum of IgG4-RD and ANCA vasculitis (specifically granulomatosis with polyangiitis), an overlap syndrome is discussed.

METHODS

We report a case of hypertrophic pachymeningitis revealed by headache and cranial nerve dysfunction, and coexistence of biopsy-proven IgG4-RD pachymeningitis and MPO-ANCA positivity. Furthermore, all cases previously reported in the literature of pachymeningitis with IgG4-RD and presence of ANCA were analyzed.

RESULTS

Thirteen patients with pachymeningitis, IgG4-RD and ANCA were analyzed. Patients with HP-related IgG4 and ANCA are mainly male (8, 62%). Median age at diagnosis was 64 years. Main clinical manifestations at diagnosis were localized to the head and neck with headaches (10, 77%), cranial nerve dysfunction (7, 54%), hearing impairment (6, 46%) and vertigo (4, 31%). Except 1 patient with diffuse aortitis, no other systemic manifestation was observed at diagnosis and during follow-up. Serum IgG4 was often elevated (11, 85%) and ANCA was mainly with myeloperoxidase specificity (11, 85%). Seven patients had cerebrospinal fluid analyse with lymphocytic pleocytosis in 5 cases (71%), elevated proteins in 4 cases (57%), positive oligoclonal bands in 3 cases (42%) and decreased glucose in one case (14%). On the MRI, the thickening of the dura mater concerned most often the posterior fossa, in 7 cases (54%). Among 10 cases with histological findings, all showed increased IgG4-positivity of plasma cells, 50% lymphocytic infiltrate but none presented the three major histological criteria of IgG4-related disease. Three (30%) showed histological signs of vasculitis with vascular wall damage and/or giant cells. Among the 12 patients treated with steroid therapy, a clinical improvement was noted in 11 cases (92%). Relapse occurred during tapering in 4 patients (33%). An immunosuppressive drug was added in 2nd line for 7 cases (54%), with a clinical improvement in all.

CONCLUSION

Pachymeningitis with IgG4 and ANCA seems a localized disease to the head and neck. Leptomeningeal biopsy commonly found IgG4 criteria and no vasculitis. All patients responded well to steroid therapy and immunosuppressive drugs, especially rituximab, with clinical and radiological improvement but relapse and/or sequelae are not uncommon.

Differential diagnosis of a local form of granulomatosis with polyangiitis: nasal cavity and paranasal sinuses lesions (part 1)

Granulomatosis with polyangiitis (GPA) is a primary vasculitis associated with antineutrophil cytoplasmic antibodies, characterized by necrotizing vasculitis with predominant involvement of small vessels of various localizations and necrotizing granulomatous inflammation with multiple clinical manifestations. GPA remains one of the most severe systemic vasculitis with unfavorable prognosis. When analyzing the course of the disease, there are two variants of GPA, local (with lesions of the upper respiratory tract, URT, organs of vision and hearing) and generalized (with lesions of the URT, organs of vision and hearing in combination with the lungs and/or kidneys, gastrointestinal tract, nervous systems, skin involvement).The article discusses the differential diagnosis of the disease with the nasal cavity and paranasal sinuses lesions onset, which requires an interdisciplinary approach and interaction of doctors of different specialties.

An overlap of IgG4-related tubulointerstitial nephritis and microscopic polyangiitis-associated glomerulonephritis: a case-based review

Because of some similarities in organ involvement, clinical manifestations, and histopathological features, IgG4-related disease (IgG4-RD) may occur concurrently with some clinicopathologic variants of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). An overlap syndrome of IgG4-RD and AAV has recently been proposed in clinical and/or histopathological studies, indicating that there may be some potential pathophysiological associations between the two disease entities; however, the mechanisms underlying these are incompletely understood. Here, we describe a rare case of a 63-year-old man with IgG4-related tubulointerstitial nephritis (IgG4-TIN) and microscopic polyangiitis-associated glomerulonephritis (MPA-GN) overlap syndrome. The clinical diagnosis of MPA was based on the 2022 American College of Rheumatology (ACR)/European League Against Rheumatology (EULAR) classification criteria. Remission induction therapy with intravenous methylprednisolone was initiated, followed by oral prednisone maintenance therapy with gradual tapering. The patient remained asymptomatic and his renal function was essentially normalized within 3.5 months of follow-up. The serum IgG4 levels decreased to 5 g/L. We also conducted a literature review to identify clinical findings, treatment options, and outcomes of patients with concurrent IgG4-RD and MPA and briefly discussed the potential pathophysiological association between IgG4-RD and MPA. Our findings enrich the database of this rare overlap syndrome and provide a basis for the diagnosis and early intervention in both diseases. These results provide some insights for clinicians to recognize and treat this overlap syndrome.

Granulomatosis with Polyangiitis Overlapping with IgG4-Related Disease

IgG4-related disease and granulomatosis with polyangiitis share several features as well as the presence of ANCA antibodies and serum IgG4 immunoglobulins. It is often difficult to distinguish between two entities. We hereby report the case of a patient portraying the clinical conundrum with clinical and biological features of the two diseases.

IgG4-related cholecystitis misinterpreted as gallbladder cancer, a case report

Introduction

Immunoglobulin G4-related disease (IgG4-RD) is a new defined entity with features that factually have been overlapped with other diseases with distinctly diverse treatments and prognoses.

Case presentation

This report describes a 50-year-old woman who presented with abdominal pain from 3 months ago. The patient underwent open cholecystectomy with Roux-en-Y hepaticojejunostomy due to suspicious of malignancy. The histological examinations revealed acute on chronic cholecystitis with extensive fibrosis and many inflammatory cells infiltration composed of plasmacells and eosinophils without any evidence of malignancy. Pathological and immunohistochemical examination for IgG4 compatible with IgG4-RD. So, pathological assessment is essential for the diagnosis.

Conclusion

IgG4-RD in gastrointestinal tract frequently misinterpret as malignancy before surgery, and surgeon should notice this disease in the differential diagnosis in order to choose the treatment.

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IgG4-related disease is rare fibroinflammatory condition.

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Gastrointestinal IgG4-related disease is problematic to establish previous surgery.

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Malignancy is main differential diagnosis of IgG4-related cholecystitis.

ANCA-associated vasculitis and IgG4-related disease overlap syndrome: a case report and literature review

Anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitides are infrequent autoimmune diseases characterized by inflammation of the walls of small vessels leading to tissue and endothelial damage. On the other hand, IgG4-related disease is a fibroinflammatory disease characterized histologically by lymphoplasmacytic infiltrates with IgG4+ plasma cells, storiform fibrosis, and obliterative phlebitis that may affect nearly every organ of the body. There are similarities in clinical, serological, radiological, and histopathological features between both diseases, and hence, they usually mimic each other complicating the differential diagnosis. Furthermore, reports of patients with the coexistence of both conditions (overlap syndrome) have been reported. We herein report a patient with an unequivocal diagnosis of ANCA-associated vasculitis, specifically granulomatosis with polyangiitis (posterior uveitis, polyneuropathy, pauci-immune glomerulonephritis with crescent formation and granulomas, and MPO-ANCA positivity) and IgG4-related disease (thoracic aortitis, tubulointerstitial nephritis with prominent IgG4+ plasma cell infiltration, fibrosis, and obliterative arteritis, high levels of serum IgG4, and eosinophilia) overlap syndrome.

Anti-Neuronal IgG4 Autoimmune Diseases and IgG4-Related Diseases May Not Be Part of the Same Spectrum: A Comparative Study

Background

IgG4 is associated with two emerging groups of rare diseases: 1) IgG4 autoimmune diseases (IgG4-AID) and 2) IgG4-related diseases (IgG4-RLD). Anti-neuronal IgG4-AID include MuSK myasthenia gravis, LGI1- and Caspr2-encephalitis and autoimmune nodo-/paranodopathies (CNTN1/Caspr1 or NF155 antibodies). IgG4-RLD is a multiorgan disease hallmarked by tissue-destructive fibrotic lesions with lymphocyte and IgG4 plasma cell infiltrates and increased serum IgG4 concentrations. It is unclear whether IgG4-AID and IgG4-RLD share relevant clinical and immunopathological features.

Methods

We collected and analyzed clinical, serological, and histopathological data in 50 patients with anti-neuronal IgG4-AID and 19 patients with IgG4-RLD.

Results

A significantly higher proportion of IgG4-RLD patients had serum IgG4 elevation when compared to IgG4-AID patients (52.63% vs. 16%, p = .004). Moreover, those IgG4-AID patients with elevated IgG4 did not meet the diagnostic criteria of IgG4-RLD, and their autoantibody titers did not correlate with their serum IgG4 concentrations. In addition, patients with IgG4-RLD were negative for anti-neuronal/neuromuscular autoantibodies and among these patients, men showed a significantly higher propensity for IgG4 elevation, when compared to women (p = .005). Last, a kidney biopsy from a patient with autoimmune paranodopathy due to CNTN1/Caspr1-complex IgG4 autoantibodies and concomitant nephrotic syndrome did not show fibrosis or IgG4+ plasma cells, which are diagnostic hallmarks of IgG4-RLD.

Conclusion

Our observations suggest that anti-neuronal IgG4-AID and IgG4-RLD are most likely distinct disease entities.

[Recurrent myelitis in a case of IgG4-related respiratory disease]

We report an 80-year-old man with IgG4-related pleuritis who had been treated with a low dose oral steroid for two years and developed recurrent myelitis. He was admitted to our hospital with gradually worsening numbness in the lower body and difficulty in walking due to mild weakness and loss of proprioception in the legs. T₂-weighted MR images of the spinal cord showed a high signal intensity lesion, located centrally in the spinal cord at the Th2-4 spine levels. Laboratory data revealed an elevated serum IgG4 level and cerebrospinal fluid protein level. Anti-aquaporin 4 antibody, anti-myelin oligodendrocyte glycoprotein antibody and other autoantibodies were negative. He showed a good response to the administration of steroid pulse therapy with almost resolution of the neurological symptoms and MRI findings. He was followed with the maintenance therapy with a low dose oral steroid. After one year, he developed recurrence of myelitis in the lower end of the medulla oblongata and in the central to dorsal area at the C2 spine level. Each lesion of recurrent myelitis was located within 3 vertebral segments length and improved without focal spinal atrophy. Recently, IgG4-related disease (IgG4-RD)-associated inflammation involving brain parenchyma and spinal cord were reported. Further investigations are needed to elucidate the relationship between IgG4-RD and seronegative recurrent myelitis.

Development of Myeloperoxidase Anti-neutrophil Cytoplasmic Antibody-positive Necrotizing Crescentic Glomerulonephritis in an Elderly Patient with Immunological Kidney Disease

A 78-year-old man presented with hypercalcemia and renal disease with high serum IgG4 and positive myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA), exhibiting sarcoidosis-like chest findings. A renal biopsy revealed tubulointerstitial nephritis, membranous nephropathy (MN), and sub-capsular lymphoid aggregates without fulfilling the diagnostic criteria of IgG4-related disease or sarcoidosis. Steroid therapy ameliorated the serological and renal abnormalities. After 5 years, following gradual increases in the neutrophil count and upper respiratory infection (URI), necrotizing crescentic glomerulonephritis (NCGN) developed with an increased serum MPO-ANCA level. These results suggest that in the presence of MPO-ANCA in immune senescence, the persistent neutrophil increase with URI may lead to the development of NCGN.

Rituximab for treatment of non-infectious and non-malignant orbital inflammatory disease

PURPOSE

To provide a comprehensive review of rituximab use for the treatment of non-infectious/non-malignant orbital inflammation.

METHODS

Review of literature through January 2021.

RESULTS

Individual data was available for 167 patients with refractory non-infectious/non-malignant orbital inflammation who received treatment with rituximab (RTX). Rituximab was generally utilized as third-line or later treatment (108/149, 72.5%) at a mean of 44.6 months following the diagnosis of orbital inflammation (range = 0 to 360 months; median = 13.7 months). Patients with non-infectious/non-malignant orbital inflammation either received prior treatment with corticosteroids only (27/122, 22.1%), or with one (31/122, 25.4%), two (25/122, 20.5%), or three or more (25/122, 20.5%) corticosteroid-sparing immunosuppressive agents with or without corticosteroids before initiation of RTX treatment. The rheumatologic protocol (two infusions of 1 gram of RTX separated by 14 days) was utilized most frequently (80/144, 55.6%), followed by the oncologic protocol (four weekly infusions of 375 mg/m2 RTX; 51/144, 35.4%). Various other off-label regimens were used infrequently (13/144, 9.0%). Rituximab treatments resulted in a positive therapeutic response for the majority of patients with orbital inflammation (146/166, 88.0%). Commonly treated diagnoses included granulomatosis with polyangiitis (99/167, 59.3%), IgG-4 related disease (36/167, 21.6%), and orbital inflammation of indeterminate cause (25/167, 15.0%). No side effects were reported in 83.3% (55/66) of cases. The most common RTX-induced adverse event was an infusion-related temporary exacerbation of orbital disease (4/66, 6.1%), which occurred prior to the routine use of systemic corticosteroids as pre-conditioning.

CONCLUSIONS

Overall, RTX appears to be both efficacious and well-tolerated as second- or third-line therapy for patients with non-infectious/non-malignant orbital inflammation.

Rituximab for non-infectious Uveitis and Scleritis

Purpose

To provide a comprehensive review of rituximab use for the treatment of non-infectious uveitis and scleritis.

Methods

Review of literature through December 2020.

Results

Individual data was available for 229 patients with refractory non-infectious uveitis (n = 108) or scleritis (n = 121) who received treatment with rituximab (RTX). Rituximab was generally utilized as third-line or later treatment (uveitis: 67/90, 74.4%; scleritis: 90/96, 93.8%) at a mean of 33.5 months following the diagnosis of uveitis (range = 0 to 168.0 months; median = 24.0 months) and 39.4 months after diagnosis of scleritis (range = 1.0 to 168.0 months; median = 21.0 months). Patients with non-infectious uveitis and scleritis either received prior treatment with corticosteroids only (uveitis: 18/90, 20%; scleritis: 4/94, 4.3%), or with one (uveitis: 19/90, 21.1%; scleritis: 30/94, 31.9%), two (uveitis: 11/90, 12.2%; scleritis 27/94, 28.7%), or three or more (uveitis: 37/90, 41.1%; scleritis: 31/94, 33.0%) corticosteroid-sparing immunosuppressive agents with or without corticosteroids before initiation of RTX treatment. The rheumatologic protocol (two infusions of 1 gram of RTX separated by 14 days) was utilized most frequently (uveitis: 45/87, 51.7%; scleritis: 87/114, 76.3%), followed by the Foster protocol (eight weekly infusions of 375 mg/m² RTX; uveitis: 18/87, 20.7%; scleritis: 10/114, 8.8%), and the oncologic protocol (four weekly infusions of 375 mg/m² RTX; uveitis: 5/87, 5.7%; scleritis: 6/114, 5.3%). Various other off-label regimens were used infrequently (uveitis: 19/87, 21.8%; scleritis 11/114, 9.6%). Rituximab treatments resulted in a positive therapeutic response for the majority of patients with non-infectious uveitis (81/97, 83.5%). Commonly treated uveitic diagnoses included non-paraneoplastic autoimmune retinopathy (30/107, 28.0%), juvenile idiopathic arthritis (21/107, 19.6%), Vogt-Koyanagi-Harada disease (12/107, 11.2%), and Behçet disease (11/107, 10.3%). Cases of non-infectious scleritis were most commonly attributed to granulomatosis with polyangiitis (75/121, 62.0%) and rheumatoid arthritis (15/121, 12.4%), and showed an even greater rate of positive therapeutic response (112/120, 93.3%) following RTX treatment. No side effects were reported in 76.3% (74/97) of uveitis and 85.5% (71/83) scleritis cases. Of those cases associated with RTX-induced adverse events, the most common were infusion reactions of various severity (11/35, 31.4%).

Conclusions

Overall, RTX appeared to be both effective and well-tolerated as second or third-line therapy for patients with non-infectious uveitis and scleritis.

Utility of the "2019 ACR/EULAR classification criteria" for the management of patients with IgG4-related disease

BACKGROUND

The 2019 ACR/EULAR Classification Criteria for IgG4-related disease (IgG4-RD) represent a fundamental tool for patient enrollment in research studies and in clinical trials but their usefulness in daily clinical practice remains unknown.

OBJECTIVE

To validate the 2019 ACR/EULAR Classification Criteria for IgG4-RD in a real-life setting and to anticipate their utility for orienting disease diagnosis and patient management.

METHODS

Four experts were asked to classify 200 patients diagnosed with IgG4-RD according to the 2019 ACR/EULAR Classification Criteria for IgG4-RD. Agreement between experts was calculated and the Classification score of each patient was correlated with the following variables and outcomes: serum IgG4 and IgE; inflammatory markers; eosinophils; plasmablasts; IgG4-RD responder index; diabetes, osteoporosis, relapses; and use of rituximab.

RESULTS

Among the 157/200 cases equally rated by at least three experts, 94 (59.9%) achieved IgG4-RD classification and 63 (40.1%) did not. Strong agreement among IgG4-RD experts was observed in classifying patients (k = 0.711, p<0.0001). Clinical presentations not included in the classification algorithm and lack of informative histology were the most common reasons for not achieving classification. In patients achieving classification, the Classification score did not correlate with variables of disease activity and was not associated with specific outcomes.

CONCLUSIONS

The ACR/EULAR Classification Criteria represent a replicable instrument for classifying patients and a useful framework for orienting diagnosis but are of limited utility for assessing IgG4-RD activity, for predicting disease outcomes, and for defining personalized therapeutic approaches.

Renal involvement in eosinophilic granulomatosis with polyangiitis (EGPA): a multicentric retrospective study of 63 biopsy-proven cases

OBJECTIVE

Eosinophilic granulomatosis with polyangiitis (EGPA) is a systemic small-vessel vasculitis characterized by asthma, hypereosinophilia and ANCA positivity in 40% of patients. Renal involvement is rare and poorly described, leading to this renal biopsy-proven based study in a large EGPA cohort.

METHODS

We conducted a retrospective multicentre study including patients fulfilling the 1990 ACR criteria and/or the 2012 revised Chapel Hill Consensus Conference criteria for EGPA and/or the modified criteria of the MIRRA trial, with biopsy-proven nephropathy.

RESULTS

Sixty-three patients [27 women, median age 60 years (18-83)] were included. Renal disease was present at vasculitis diagnosis in 54 patients (86%). ANCA were positive in 53 cases (84%) with anti-MPO specificity in 44 (83%). All patients had late-onset asthma. Peripheral neuropathy was present in 29 cases (46%), alveolar haemorrhage in 10 (16%). The most common renal presentation was acute renal failure (75%). Renal biopsy revealed pauci-immune necrotizing GN in 49 cases (78%). Membranous nephropathy (10%) and membranoproliferative GN (3%) were mostly observed in ANCA-negative patients. Pure acute interstitial nephritis was found in six cases (10%); important interstitial inflammation was observed in 28 (44%). All patients received steroids with adjunctive immunosuppression in 54 cases (86%). After a median follow-up of 51 months (1-296), 58 patients (92%) were alive, nine (14%) were on chronic dialysis and two (3%) had undergone kidney transplantation.

CONCLUSION

Necrotizing pauci-immune GN is the most common renal presentation in ANCA-positive EGPA. ANCA-negative patients had frequent atypical renal presentation with other glomerulopathies such as membranous nephropathy. An important eosinophilic interstitial infiltration was observed in almost 50% of cases.

Renal Involvement in IgG4-Related Disease: From Sunlight to Twilight

IgG4-Related Disease (IgG4-RD) is a fibroinflammatory condition characterized by a typical histopathological pattern (dense lymphoplasmacytic infiltrate with prevalent IgG4+ plasma cells and storiform fibrosis), which may involve the kidney both directly (IgG4-related kidney disease, IgG4-RKD) or indirectly, as a consequence of post-renal ureteral obstruction due to retroperitoneal fibrosis (IgG4-RD RF). The most frequent presentation of IgG4-RKD is IgG4-related tubulointerstitial nephritis (TIN), but a glomerular disease can be present, in most of the cases a membranous nephropathy. Albeit steroid-responsive, in some cases renal manifestations may lead to progressive and permanent organ damage. In this review we describe four clinical cases representative of typical and less typical renal manifestations of IgG4-RD, emphasizing a potential, subclinical, early involvement of the kidney in the disease.

Emerging therapy options for IgG4-related disease

INTRODUCTION

Awareness of IgG4-related disease (IgG4-RD) is increasing worldwide and specialists are now familiar with most of its clinical manifestations and mimickers. IgG4-RD promptly responds to glucocorticoids and repeated courses are typically used to induce and maintain remission because the disease relapses in most patients. If left untreated, it can lead to organ dysfunction, organ failure and death. Advancement in our understanding of IgG4-RD pathogenesis is leading to the identification of novel therapeutic targets and emerging treatments are now setting the stage for personalized therapies for the future.

AREAS COVERED

This review focuses on emerging treatment options for IgG4-RD based on our advancing understanding of disease pathophysiology. Research was performed in the English literature on Pubmed and clinicaltrials.gov databases.

EXPERT OPINION

Glucocorticoids remain the first-line induction treatment for the multi-organ manifestations of IgG4-RD. Alternative immunosuppressive agents for maintaining remission are warranted in order to avoid long-term steroid toxicity, and to offer a more mechanistic and personalized therapeutic strategy. Targeting B and T-lymphocyte activation represents the most promising approach, but randomized controlled trials are eagerly awaited to confirm positive preliminary experiences reported in case series and small cohort studies.

IgG4-related disease and ANCA positive vasculitis in childhood: a case-based review

Autoimmune pancreatitis (AIP) type 1 is an IgG4-related disease (IgG4-RD), characterized by inflammatory pseudotumors and histologically by dense lymphoplasmacytic infiltrates rich in IgG4 positive plasma cells, storiform fibrosis, and obliterative phlebitis. Although quite rare, IgG4-RD was found to be associated with medium or small vessel vasculitides. A new overlap syndrome between IgG4-RD and ANCA-associated vasculitis (AAV) has recently been described in the adult population. Here we present a 16-year-old adolescent girl admitted with abdominal pain, episcleritis, palpable purpura, salivary gland enlargement, and bloody diarrhea. Laboratory investigations revealed findings of glomerulonephritis. Abdominal imaging surprisingly revealed a focal mass in the pancreatic tail, while the c-ANCA level was found to be quite high as well as serum IgG4 level. Biopsy of the pancreatic mass showed lymphoplasmacytic IgG4 positive cells infiltrating the pancreas with storiform fibrosis compatible with IgG4-related AIP. The renal biopsy that was done simultaneously showed necrotizing granulomatous vasculitis indicating AAV. Renal biopsy showed IgG4 positive plasma cells very rarely by immunohistochemical examination, which does not indicate any significance for IgG4-RD. Our diagnosis was IgG4-related AIP and AAV overlap syndrome, which has not been reported in the pediatric populations yet. IgG4-RD should be investigated in patients with ANCA-associated vasculitis who shows atypical organ involvement. We searched the Pubmed/Medline and Google Scholar databases to identify clinical findings, treatment, and outcome of the patients with IgG4-related AIP and AAV.

What is the meaning of ANCA positivity in IgG4-related disease?

Objectives

To evaluate the prevalence and meaning of antineutrophil cytoplasmic antibodies (ANCA) positivity in a cohort of IgG4-related disease (IgG4-RD).

Methods

We identified patients with ANCA determination from a retrospective cohort of 69 patients with IgG4-RD. ANCA were measured by indirect immunofluorescence microscopy (IIF) and/or proteinase 3 (PR3)-ANCA and MPO-ANCA by ELISA. IIF patterns were classified as perinuclear (P-ANCA), cytoplasmic (C-ANCA) and atypical (X-ANCA). We compared the ANCA-positive vs the ANCA-negative IgG4-RD group.

Results

Out of 69 patients, 31 IgG4-RD patients had an ANCA determination. Four patients with concomitant systemic autoimmune diseases were excluded. We found positive ANCA by IIF in 14 (56%) of 25 patients tested. The most common IIF pattern was C-ANCA in eight (57.1%), followed by dual C-ANCA/X-ANCA in four (28.6%) and P-ANCA and dual C-ANCA/P-ANCA in one each (7.1%). Of the 20 patients with ANCA determination by both IIF and ELISA, four have positive ANCA by ELISA (three for MPO-ANCA and one for PR3-ANCA). Of the two patients with only ELISA determination, one was positive for MPO-ANCA. The prevalence of ANCA positivity by ELISA was 22.7% (5 out of 22 patients). ANCA was more frequent in the Mikulizc/systemic phenotype (42.9%) compared with other phenotypes (P = 0.04). ANCA-positive IgG4-RD patients had more frequently lymph node and kidney involvement, high IgG1 levels and erythrocyte sedimentation rate, and positive antinuclear antibodies.

Conclusion

ANCA are found in a significant number of patients with IgG4-RD and differed from the ANCA-negative group in terms of clinical and serological features.

Camacho M, Cunha B, Alkatan H, Xavier N. Plasma cell IgG4 positivity in orbital biopsies of non-IgG4-related conditions

The IgG4-related disease (IgG4-RD) is a systemic condition defined as a fibro-inflammatory disorder, characterized by the occurrence of tumor-like lesions in multiple organs including the eye adnexa. The main diagnostic criterion is based on histopathological findings, especially on the IgG4⁺/IgG⁺ plasma cell ratio. In this article, we reviewed the literature of non-IgG4-RD orbital conditions with IgG4 positivity. There were 20 reports of inflammatory non-IgG4-RD orbital lesions and 14 reports of orbital lymphoid proliferations with significant IgG4 positivity. The role of plasma cells IgG4 in the pathogenesis of non-IgG4-RD is not clear. Considering the large spectrum of diseases caused by a variety of different etiopathogenic mechanisms, we think that the common denominator of IgG4⁺ in these conditions might be related to the peculiar properties of down regulation of immune response of the IgG4 and not to a specific link to IgG4-RD.

[Management of orbital inflammatory disorders in internal medicine: New findings resulting from a retrospective study of 31 consecutive patients]

PURPOSE

To describe a case series of patients investigated in internal medicine for orbital inflammation (OI) since the individualization of the clinical entity of the IgG4-related orbital disease (IgG4 ROD).

PATIENTS AND METHODS

Thirty four patients were consecutively referred by a specialized center where orbital biopsy was performed when the lesion was surgically accessible. Fourteen patients were excluded in case of missing data or lymphoma, periocular xanthogranuloma or Graves' orbitopathy. Patients with systemic or auto-immune disease according to the international criteria, or presenting with idiopathic orbital inflammation syndrome (IOIS), were included. Knowing the histological similarities between IOIS and IgG4 ROD, immunohistochemical assessment of plasma cells for IgG4 positivity was performed for every patient with available biopsy. Clinical and biological characteristics, treatment and response to treatment of included patients are reported.

RESULTS

Among 22 included patients, 10 presented with orbital manifestation of a systemic or autoimmune disease including 2 sarcoidosis (9%) and 8 (36%) cases of non specific OI which were reclassified in IgG4 ROD. Finally, IOIS of various clinicopathological presentation was diagnosed for 12 patients including 10 with histological documentation. Whereas relapse and resistance were not found to be related to IgG4 positivity (50% in both IOIS and IgG4 ROD groups), another treatment in addition to corticosteroids was more often necessary in IgG4 ROD patients (50%) than in IOIS patients (25%).

CONCLUSION

After ruling out auto-immune orbital diseases, especially IgG4 ROD, IOIS should be discussed. Factors conditioning the corticosteroid response are yet to be determined.

Update on IgG4-mediated autoimmune diseases: New insights and new family members

Antibodies of IgG4 subclass are exceptional players of the immune system, as they are considered to be immunologically inert and functionally monovalent, and as such may be part of classical tolerance mechanisms. IgG4 antibodies are found in a range of different diseases, including IgG4-related diseases, allergy, cancer, rheumatoid arthritis, helminth infection and IgG4 autoimmune diseases, where they may be pathogenic or protective. IgG4 autoimmune diseases are an emerging new group of diseases that are characterized by pathogenic, antigen-specific autoantibodies of IgG4 subclass, such as MuSK myasthenia gravis, pemphigus vulgaris and thrombotic thrombocytopenic purpura. The list of IgG4 autoantigens is rapidly growing and to date contains 29 candidate antigens. Interestingly, IgG4 autoimmune diseases are restricted to four distinct organs: 1) the central and peripheral nervous system, 2) the kidney, 3) the skin and mucous membranes and 4) the vascular system and soluble antigens in the blood circulation. The pathogenicity of IgG4 can be validated using our classification system, and is usually excerted by functional blocking of protein-protein interaction.

Clinical characteristics, the diagnostic criteria and management recommendation of otitis media with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (OMAAV) proposed by Japan Otological Society

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a form of necrotizing vasculitis with few or no immune deposits. It primarily affects small and medium blood vessels. AAV is classified into three categories, granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA) and eosinophilic granulomatosis with polyangitis (EGPA), and two major ANCAs, proteinase 3 (PR3)-ANCA or myeloperoxidase (MPO)-ANCA are involved in their pathogenesis. Intractable otitis media frequently occurs in patients with GPA, MPA or EGPA, although all patients show similar clinical features, regardless of the type of AAV. Furthermore, approximately 15% patients with otitis media caused by AAV do not show ANCA positivity, histopathological evidence, or any other AAV-related lesions at the initial visit; therefore, these patients do not fulfill the ordinary diagnostic criteria for systemic AAV. Thus, we first proposed that this condition could be categorized as "otitis media with AAV (OMAAV)". Subsequently, the Japanese Otological Society (JOS) conducted a nationwide survey between December 2013 and February 2014 and identified 297 patients with OMAAV. The survey revealed that OMAAV is a disease that initially occurs in the middle ear and subsequently spreads to other organs such as the lungs and kidneys, with eventual involvement of all body organs. Severe sequelae such as facial palsy, hypertrophic pachymeningitis, complete deafness, and subarachnoid hemorrhage resulting in death can also occur. In this review, we introduce the clinical features, diagnostic criteria, and treatment strategies recommended by JOS for early diagnosis and treatment of OMAAV.

An unusual presentation of propylthiouracil-induced anti-MPO and PR3 positive ANCA vasculitis with associated anti-GBM antibodies, IgA nephropathy and an IgG4 interstitial infiltrate: a case report

Background

A number of disease processes can culminate in rapidly progressive glomerulonephritis, including pauci-immune focal segmental necrotising glomerulonephritis, usually seen with positive serum antineutrophil cytoplasmic antibodies (ANCA). Propylthiouracil (PTU) has been associated with drug-induced ANCA-associated vasculitis (AAV), with antibodies against myeloperoxidase (MPO) and proteinase 3 (PR3) present individually and together having been recognised. ‘Double-positive’ vasculitis with ANCA and anti-glomerular basement membrane (GBM) antibodies has also been reported in association with PTU treatment. We present a case of PTU-induced anti-MPO and PR3 positive ANCA vasculitis with associated anti-GBM antibodies, IgA nephropathy and an IgG4 interstitial infiltrate.

Case presentation

A 51-year-old man presented 2 weeks after re-commencing propylthiouracil (PTU) treatment for Graves’ disease, with a severe acute kidney injury and haemato-proteinuria. He demonstrated positive titres for autoantibodies to PR3 (76.9 IU/mL), MPO (28.8 IU/mL) and GBM (94 IU/mL). Renal biopsy demonstrated numerous glomerular crescents, widespread IgG4-positive lymphoplasmacytic infiltrate and mesangial positivity for IgA. PTU was stopped and he was treated with steroids, plasma exchange and cyclophosphamide with sustained improvement in his renal function.

Conclusions

This case of drug-induced AAV presented a unique and intriguing collection of serological and histological features. We propose that the PTU-induced AAV resulted in epiphenomena of anti-GBM antibody production and an IgG4-cell-rich tubulointerstitial infiltrate. It is uncertain whether the mesangial IgA deposition preceded or resulted from the AAV.

2020 international consensus on ANCA testing beyond systemic vasculitis

This document follows up on a 2017 revised international consensus on anti-neutrophil cytoplasm antibodies (ANCA) testing in granulomatosis with polyangiitis and microscopic polyangiitis and focuses on the clinical and diagnostic value of ANCA detection in patients with connective tissue diseases, idiopathic interstitial pneumonia, autoimmune liver diseases, inflammatory bowel diseases, anti-glomerular basement membrane (GBM) disease, infections, malignancy, and during drug treatment. Current evidence suggests that in certain settings beyond systemic vasculitis, ANCA may have clinical, pathogenic and/or diagnostic relevance. Antigen-specific ANCA targeting proteinase-3 and myeloperoxidase should be tested by solid phase immunoassays in any patient with clinical features suggesting ANCA-associated vasculitis and in all patients with anti-GBM disease, idiopathic interstitial pneumonia, and infective endocarditis associated with nephritis, whereas in patients with other aforementioned disorders routine ANCA testing is not recommended. Among patients with autoimmune liver diseases or inflammatory bowel diseases, ANCA testing may be justified in patients with suspected autoimmune hepatitis type 1 who do not have conventional autoantibodies or in case of diagnostic uncertainty to discriminate ulcerative colitis from Crohn's disease. In these cases, ANCA should be tested by indirect immunofluorescence as the target antigens are not yet well characterized. Many questions concerning the optimal use of ANCA testing in patients without ANCA-associated vasculitis remain to be answered.

Localized Granulomatous with Polyangiitis (GPA): Varied Clinical Presentations and Update on Treatment

PURPOSE OF REVIEW

Granulomatosis with polyangiitis is a primary systemic vasculitis commonly described with the typical triad of upper airway, lung, and kidney involvement. Upper and lower airway involvement is characteristic in patients with granulomatosis with polyangiitis and can sometimes represent the initial or in some instances the sole manifestation. The objective of this review is to summarize the various clinical manifestations of localized disease in GPA and their treatment.

RECENT FINDINGS

Sinonasal disease is seen in up to 90% of patients. Otologic and ocular involvement is also commonly seen. Laryngeal and tracheal disease although less common is associated with significant morbidity and can be therapeutically challenging. Clinicians need to be aware of these localized GPA manifestations as they may be presenting disease features in the absence of other systemic findings. Treatment of localized GPA involves both immunosuppressive and surgical interventions for specific manifestations. Collaboration between specialists including rheumatologists, otolaryngologists, and ophthalmologists is often crucial to ensure optimal outcomes for patients. This is a narrative review that provides a comprehensive overview of localized granulomatosis with polyangiitis and current treatment options.

Simultaneous presentation of granulomatosis with polyangiitis (GPA) and immunoglobulin G4-related disease (IgG4-RD). Leaving an open question: widening the spectrum of a single disease or real overlap?

Because of a similar organ involvement and histopathological features, IgG4-related disease (IgG4-RD) may mimic some forms of granulomatosis with polyangiitis (GPA). However, several cases of clear coexistence or overlap of both diseases have been reported. We describe a case of a 47-year-old man presenting with a renal mass and a nasal crusting showing histopathological features of IgG4-RD in both territories. Cytoplasmic/proteinase 3 (PR3) antineutrophil cytoplasmic antibodies (ANCA) were positive and the patient subsequently developed kidney failure and nephritic syndrome that led to a renal biopsy re-evaluation revealing changes compatible with segmental necrotising glomerulonephritis and GPA. Remission induction therapy with prednisone and rituximab was started and clinical and laboratory parameters returned to normal. After administering a maintenance regimen based in rituximab 500 mg every six month the patient remained asymptomatic during 4 years of follow-up and free of prednisone the last 18 months. Although coexistence or overlap of GPA and IgG4-RD may be established in some clinical scenarios, the possibility of widening the spectrum of a single disease is also postulated.

Advances in the diagnosis and management of IgG4 related disease

IgG4 related disease was recognized as a unified disease entity only 15 years ago. Awareness of IgG4 related disease has increased worldwide since then, and specialists are now familiar with most of its clinical manifestations. Involvement of the pancreato-biliary tract, retroperitoneum/aorta, head and neck, and salivary glands are the most frequently observed disease phenotypes, differing in epidemiological features, serological findings, and prognostic outcomes. In view of this multifaceted presentation, IgG4 related disease represents a great mimicker of many neoplastic, inflammatory, and infectious conditions. Histopathology remains key to diagnosis because reliable biomarkers are lacking. Recently released classification criteria will be invaluable in improving early recognition of the disease. IgG4 related disease is highly treatable and responds promptly to glucocorticoids, but it can lead to end stage organ failure and even death if unrecognized. Prolonged courses of corticosteroids are often needed to maintain remission because the disease relapses in most patients. Rapid advancement in our understanding of the pathophysiology of IgG4 related disease is leading to the identification of novel therapeutic targets and possible personalized approaches to treatment.

Concurrent anti-neutrophil cytoplasmic antibody-associated glomerulonephritis and IgG4-associated tubulointerstitial nephritis with C3 glomerulonephritis: A case report

RATIONALE

IgG4-related disease (IgG4-RD) is a slowly progressing inflammatory disease that can involve multiple organ systems. There is considerable overlap between IgG4-RDs and anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). Herein, we present an unusual case of IgG4-associated tubulointerstitial nephritis (IgG4-TIN) and ANCA-associated glomerulonephritis (ANCA-GN) co-occurring with C3 glomerulonephritis (C3GN).

PATIENT CONCERNS

A 72-year-old male was admitted to hospital because of fever and fatigue. He was diagnosed with elevated serum creatinine and IgG4 levels, and was positive for ANCA.

DIAGNOSIS

Initially, the pathology supported a diagnosis of IgG4-TIN and ANCA-GN; however, further examination revealed he also had C3GN.

INTERVENTIONS

The patient was treated with methylprednisolone and cyclophosphamide and received regular follow-up care.

OUTCOMES

After treatment, the patient no longer exhibited fever or fatigue and had no complications. The seven-month follow-up showed downward trends in IgG4 and MPO-ANCA levels and stable 24-hour urine protein, serum creatinine levels.

LESSONS

Anti-neutrophil cytoplasmic antibody-associated glomerulonephritis and IgG4-associated tubulointerstitial nephritis with C3glomerulonephritis rarely occur simultaneously. Laboratory analysis and pathology are both needed to ensure diagnostic accuracy. However, in this case, the three diseases overlapped to such a large extent that achieving a definitive diagnosis was particularly challenging. Timely and accurate diagnosis is crucial for selecting the best treatment course and optimizing patient outcome.

Consideration concerning similarities and differences between ANCA-associated vasculitis and IgG-4-related diseases: case series and review of literature

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) and immunoglobulin G4-related diseases (IgG4-RD) are regarded as entirely different disease types with different etiological mechanisms. However, we experienced two cases that had clinical features of both AAV and IgG4-RD. The first case is an 81-year-old woman who showed periaortitis and retroperitoneal fibrosis and periarteritis with elevation of myeloperoxidase-anti-neutrophil cytoplasmic antibody and IgG4 levels. The second case is a 63-year-old woman who had dura mater, ear, nose, lung, and kidney involvement with serum negative for ANCA and elevated IgG4. Renal biopsy revealed tubulointerstitial nephritis involving IgG4⁺ plasma cells (IgG4⁺/IgG⁺ cell ratio of ≥ 40%). On the other hand, lung biopsy showed features of granulomatosis with polyangiitis (GPA). These two cases suggested that AAV and IgG4-RD might overlap. To investigate the similarities and differences between AAV and IgG4-RD, we retrospectively analyzed 13 cases of typical GPA, a subtype of AAV, and 13 cases of typical IgG4-RD at our hospital for comparison of clinical features and found some differences that can be useful in the differential diagnosis between the two diseases. Although AAV and IgG4-RD are distinguishable based on characteristic findings in many cases, the diagnosis can be unclear in rare cases, in which clinicians should consider possible coexistence of AAV and IgG4-RD when performing further workup. Here, we discuss the similarities and differences between AAV and IgG4-RD on the basis of our results and past literature.

An overlap of antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis and IgG4-related kidney disease

BACKGROUND

We investigated the characteristics of antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis (ANCA-GN) and immunoglobulin G4 (IgG4)-related kidney disease (IgG4-RKD) overlap syndrome.

METHODS

This is a 2-center study with 19 patients.

RESULTS

Fifteen patients were classified as microscopic polyangiitis (MPA). The initial serum creatinine levels were 320.9 ± 191.4 μmol/l and the BVAS was 19.7 ± 7.4 at diagnosis. Hematuria was absent or slight in 13 (68.4%) cases. Renal histology of these patients revealed concurrent ANCA-GN and IgG4-RKD. Regarding the histological classification of ANCA-GN, 9 (47.4%), 8 (42.1%), 1 (5.3%) and 1 (5.3%) patients were classified as focal, crescentic, mixed and sclerotic ANCA-GN, respectively. MPO-ANCA could be detected in 17/19 (89.5%) patients. IgG subclasses of MPO-ANCA were tested in 10 patients, and all were positive for IgG4-MPO-ANCA. In patients with combined ANCA-GN and IgG4-RKD, the percentage of positive IgG1-MPO-ANCA was significantly lower than the control group of 20 AAV patients without IgG4-RKD (P = 0.002), and the percentage of positive IgG4-MPO-ANCA was higher than the control group, but this difference was not statistically significant (P = 0.14).

CONCLUSIONS

ANCA-GN and IgG4-RKD overlap syndrome concerned mainly MPO-ANCA positive patients. The IgG subclass analysis of MPO-ANCA showed lower percentage of IgG1 subclass. The association between ANCA-GN and IgG4-RKD is possible and represents a special entity.

[Vasculitides and eosinophilic pulmonary diseases]

Eosinophilic granulocytes form peripheral effector cells controlled by Th2 lymphocytes, which cause local cell, tissue, and functional disorders of infiltrated organs via the release of cytotoxic basic proteins and oxygen radicals. Diseases associated with eosinophilia include systemic and organ-related forms. The lungs are involved in eosinophilic granulomatosis with polyangiitis (EGPA, formerly known as Churg-Strauss syndrome), acute and chronic eosinophilic pneumonia, as well as in an organ manifestation in hypereosinophilic syndrome and certain parasitic diseases. In particular, the lungs are frequently affected in vasculitis of small vessels, including EGPA, granulomatosis with polyangiitis (GPA), and microscopic polyangiitis (MPA). Among these, EGPA is the most frequent pulmonary eosinophil vasculitis representative. In addition, there are various overlap syndromes in which characteristic features of EGPA can be detected in the context of other anti-neutrophil cytoplasmic antibody (ANCA-)associated vasculitides. Occasionally, non-ANCA-associated pulmonary vasculitides occur with eosinophilia (e.g., Schönlein-Henoch purpura, Kawasaki disease, drug-induced hypersensitivity, and paraneoplastic syndrome). Herein, the pulmonary vasculitides accompanying eosinophilia are presented with respect to both the lung manifestations and pulmonary eosinophilia.

Granulomatosis with polyangiitis in a patient with biopsy-proven IgG4-related pulmonary disease and coincident small cell lung cancer

Granulomatosis with polyangiitis (GPA) was diagnosed in a patient with a 16-month history of IgG4-related lung disease that spontaneously became asymptomatic. Cytoplasmic antineutrophil cytoplasmic antibody (ANCA) was positive at the time of diagnosis of IgG4-related disease (IgG4-RD), but there was no vasculitis or kidney disease. Sixteen months later he developed rapidly progressive glomerulonephritis that responded to cyclophosphamide treatment. While undergoing treatment for GPA, he was found to have a lung mass identified as small cell lung cancer. This mass was present at the time of the IgG4-RD diagnosis. GPA can be confused with IgG4-RD histologically and they rarely coexist. ANCA antibodies are primarily IgG4 subclass. IgG4-RD has been associated with cancer and may improve prognosis. We speculate that this patient may have had small cell lung cancer that incited an IgG4 predominant immune response with coexistent ANCA antibodies that eventually resulted in GPA. Immunosuppressive treatment of GPA likely accelerated the progression of the lung cancer.

IgG4:IgG RNA ratio differentiates active disease from remission in granulomatosis with polyangiitis: a new disease activity marker? A cross-sectional and longitudinal study

OBJECTIVES

An important limitation in granulomatosis with polyangiitis (GPA) is the lack of disease activity markers. Immunoglobulin G4-positive (IgG4+) B cells and plasma cells are implicated in the pathogenesis of GPA. We hypothesized that the presence of these cells in peripheral blood could serve as disease activity parameter in GPA.

METHODS

We included 35 proteinase 3-antineutrophil cytoplasmic antibodies-positive patients with GPA in a cross-sectional study. Active disease was defined as Birmingham Vasculitis Activity Score (BVAS) ≥ 3 (n = 15), remission as BVAS of 0 (n = 17), and low disease activity (LDA) as BVAS of 1-2 and clinical remission (n = 3). Healthy subjects (n = 10), patients with systemic lupus erythematosus (n = 24), and patients with rheumatoid arthritis (n = 19) functioned as control subjects. An additional longitudinal study was performed in ten patients with GPA. Using a validated qPCR test, we measured the IgG4:IgG RNA ratio in all groups and compared the results with known biomarkers.

RESULTS

The median qPCR score was higher in active GPA (21.4; IQR 12.1-29.6) than in remission/LDA (3.3; IQR 1.6-5.6) (Mann-Whitney U test, p < 0.0001) and outperformed other known disease activity parameters in detecting activity. A cutoff qPCR score of 11.2% differentiated active disease from remission/LDA accurately (AUC 0.993). The qPCR test correlated well with the BVAS (Spearman r = 0.77, p < 0.0001). In the longitudinal study, a decrease in BVAS correlated with qPCR score reduction (paired t test, p < 0.05).

CONCLUSIONS

The IgG4:IgG RNA ratio in GPA accurately distinguishes active disease from remission and correlates well with disease activity in these single-center studies. If these results are confirmed in larger longitudinal studies, this test might help to steer treatment decisions in patients with GPA.

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.

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.

[Vasculitides and eosinophilic pulmonary diseases]

Eosinophilic granulocytes form peripheral effector cells controlled by Th2 lymphocytes, which cause local cell, tissue, and functional disorders of infiltrated organs via the release of cytotoxic basic proteins and oxygen radicals. Diseases associated with eosinophilia include systemic and organ-related forms. The lungs are involved in eosinophilic granulomatosis with polyangiitis (EGPA, formerly known as Churg-Strauss syndrome), acute and chronic eosinophilic pneumonia, as well as in an organ manifestation in hypereosinophilic syndrome and certain parasitic diseases. In particular, the lungs are frequently affected in vasculitis of small vessels, including EGPA, granulomatosis with polyangiitis (GPA), and microscopic polyangiitis (MPA). Among these, EGPA is the most frequent pulmonary eosinophil vasculitis representative. In addition, there are various overlap syndromes in which characteristic features of EGPA can be detected in the context of other anti-neutrophil cytoplasmic antibody (ANCA-)associated vasculitides. Occasionally, non-ANCA-associated pulmonary vasculitides occur with eosinophilia (e.g., Schönlein-Henoch purpura, Kawasaki disease, drug-induced hypersensitivity, and paraneoplastic syndrome). Herein, the pulmonary vasculitides accompanying eosinophilia are presented with respect to both the lung manifestations and pulmonary eosinophilia.

Prevalence of overlap of antineutrophil cytoplasmic antibody associated vasculitis with systemic autoimmune diseases: an unrecognized example of poliautoimmunity

We aimed to estimate the frequency of overlap of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) with systemic autoimmune diseases. Retrospective single-center study to identify patients with AAV diagnosis and concomitant autoimmune systemic diseases, simultaneously, before or after the diagnosis of AAV. Sociodemographic characteristics, such as comorbidities; follow-up time; type of AAV; disease duration; relapses; treatment and response; clinical, serological, and histological characteristics; disease activity and damage; prognosis; dialysis requirements, and death were assessed. Twenty-eight of two hundred and forty-seven patients (11.3%) with AAV had a concomitant diagnosis of autoimmune disease. The predominant AAV type was renal-limited vasculitis (39%), followed by granulomatosis with polyangiitis (29%), mycroscopic polyangiitis (25%), and eosinophilic granulomatosis with polyangiitis (7%). Mean age at AAV diagnosis was 50 ± 17 years and 24/28 were ANCA positive. The main clinical manifestations were renal (79%), otorhinolaryngologic (43%), and pulmonary and peripheral neuropathy (32%). Sixteen patients (57%) experienced partial or total remission at a median follow-up of 34 months, and four patients (14%) died. The most frequent autoimmune disease overlapped was rheumatoid arthritis (39%), followed by Sjögren's syndrome and systemic sclerosis (14%), mixed connective tissue disease (11%), systemic lupus erythematosus and juvenile idiopathic arthritis (7%), and ankylosing spondylitis and IgG4-related disease (4%). In nine patients (32%), both diagnoses were simultaneous; in the rest, median time elapsed between the autoimmune disease and AAV diagnosis was 173 months. The prevalence of overlap AAV with other autoimmune diseases was low. The most common AAV phenotype was renal-limited vasculitis, and the most frequent overlap disease was rheumatoid arthritis.

Lung Manifestations of IgG4-related Disease. A multifaceted disorder. Presentation of two cases and short review of the literature

Immunoglobulin (Ig) G4-related disease (IgG4-RD) is a recently described systemic inflammatory disease associated with elevated circulating levels of IgG4. IgG4-RD may affect one or more organs and lesions can present synchronously or metachronously in different organs. Pulmonary involvement of IgG4-related disease includes airway, lung parenchyma, pleura and mediastinum. In this article, we report two cases of IgG4-RD to show the multifaceted manifestations of this disease in the lungs. (Sarcoidosis Vasc Diffuse Lung Dis 2018; 35: 74-80).

The Lung in Dysregulated States of Humoral Immunity

In common variable immunodeficiency, lung manifestations are related to different mechanisms: recurrent pneumonias due to encapsulated bacteria responsible for diffuse bronchiectasis, diffuse infiltrative pneumonia with various patterns, and lymphomas, mostly B cell extranodal non-Hodgkin type. The diagnosis relies on significant serum Ig deficiency and the exclusion of any primary or secondary cause. Histopathology may be needed. Immunoglobulin (IgG) replacement is crucial to prevent infections and bronchiectasis. IgG4-related respiratory disease, often associated with extrapulmonary localizations, presents with solitary nodules or masses, diffuse interstitial lung diseases, bronchiolitis, lymphadenopathy, and pleural or pericardial involvement. Diagnosis relies on international criteria including serum IgG4 dosage and significantly increased IgG4/IgG plasma cells ratio in pathologically suggestive biopsy. Respiratory amyloidosis presents with tracheobronchial, nodular, and cystic or diffuse interstitial lung infiltration. Usually of AL (amyloid light chain) subtype, it may be localized or systemic, primary or secondary to a lymphoproliferative process. Very rare other diseases due to nonamyloid IgG deposits are described. Among the various lung manifestations of dysregulated states of humoral immunity, this article covers only those associated with the common variable immunodeficiency, IgG4-related disease, amyloidosis, and pulmonary light-chain deposition disease. Autoimmune connective-vascular tissue diseases or lymphoproliferative disorders are addressed in other chapters of this issue.