ABSTRACT
TANK binding kinase 1 (TBK1) regulates IFN-I, NF-κB, and TNF-induced RIPK1-dependent cell death (RCD). In mice, biallelic loss of TBK1 is embryonically lethal. We discovered four humans, ages 32, 26, 7, and 8 from three unrelated consanguineous families with homozygous loss-of-function mutations in TBK1. All four patients suffer from chronic and systemic autoinflammation, but not severe viral infections. We demonstrate that TBK1 loss results in hypomorphic but sufficient IFN-I induction via RIG-I/MDA5, while the system retains near intact IL-6 induction through NF-κB. Autoinflammation is driven by TNF-induced RCD as patient-derived fibroblasts experienced higher rates of necroptosis in vitro, and CC3 was elevated in peripheral blood ex vivo. Treatment with anti-TNF dampened the baseline circulating inflammatory profile and ameliorated the clinical condition in vivo. These findings highlight the plasticity of the IFN-I response and underscore a cardinal role for TBK1 in the regulation of RCD.
Subject(s)
Inflammation/enzymology , Protein Serine-Threonine Kinases/deficiency , Tumor Necrosis Factor-alpha/pharmacology , A549 Cells , Adaptor Proteins, Signal Transducing/metabolism , Apoptosis , Autoimmunity/drug effects , Brain/diagnostic imaging , Cell Death/drug effects , Cytokines/metabolism , Deubiquitinating Enzyme CYLD/metabolism , Female , HEK293 Cells , Homozygote , Humans , I-kappa B Kinase/metabolism , Immunophenotyping , Inflammation/pathology , Interferon Type I/metabolism , Interferon-gamma/metabolism , Loss of Function Mutation/genetics , Male , Pedigree , Phosphorylation/drug effects , Protein Serine-Threonine Kinases/genetics , Protein Serine-Threonine Kinases/metabolism , Receptor-Interacting Protein Serine-Threonine Kinases/metabolism , Receptors, Pattern Recognition/metabolism , Toll-Like Receptor 3/metabolism , Transcriptome/genetics , Vesiculovirus/drug effects , Vesiculovirus/physiologyABSTRACT
In this retrospective study, BRAF mutation status did not correlate with disease extent or (event-free) survival in 156 adults with Langerhans cell histiocytosis. BRAFV600E was associated with an increased incidence of second malignancies, often comprising hematological cancers, which may be clonally related.
Subject(s)
Histiocytosis, Langerhans-Cell , Neoplasms, Second Primary , Humans , Adult , Neoplasms, Second Primary/epidemiology , Neoplasms, Second Primary/genetics , Proto-Oncogene Proteins B-raf/genetics , Retrospective Studies , Incidence , Histiocytosis, Langerhans-Cell/epidemiology , Histiocytosis, Langerhans-Cell/genetics , Histiocytosis, Langerhans-Cell/pathology , MutationABSTRACT
Langerhans cell histiocytosis (LCH) can affect children and adults with a wide variety of clinical manifestations, including unifocal, single-system multifocal, single-system pulmonary (smoking-associated), or multisystem disease. The existing paradigms in the management of LCH in adults are mostly derived from the pediatric literature. Over the last decade, the discovery of clonality and MAPK-ERK pathway mutations in most cases led to the recognition of LCH as a hematopoietic neoplasm, opening the doors for treatment with targeted therapies. These advances have necessitated an update of the existing recommendations for the diagnosis and treatment of LCH in adults. This document presents consensus recommendations that resulted from the discussions at the annual Histiocyte Society meeting in 2019, encompassing clinical features, classification, diagnostic criteria, treatment algorithm, and response assessment for adults with LCH. The recommendations favor the use of 18F-Fluorodeoxyglucose positron emission tomography-based imaging for staging and response assessment in the majority of cases. Most adults with unifocal disease may be cured by local therapies, while the first-line treatment for single-system pulmonary LCH remains smoking cessation. Among patients not amenable or unresponsive to these treatments and/or have multifocal and multisystem disease, systemic treatments are recommended. Preferred systemic treatments in adults with LCH include cladribine or cytarabine, with the emerging role of targeted (BRAF and MEK inhibitor) therapies. Despite documented responses to treatments, many patients struggle with a high symptom burden from pain, fatigue, and mood disorders that should be acknowledged and managed appropriately.
Subject(s)
Histiocytosis, Langerhans-Cell , Adult , Child , Cladribine/therapeutic use , Consensus , Histiocytosis, Langerhans-Cell/diagnosis , Histiocytosis, Langerhans-Cell/genetics , Histiocytosis, Langerhans-Cell/therapy , Humans , MAP Kinase Signaling System , MutationABSTRACT
ALK-positive histiocytosis is a rare subtype of histiocytic neoplasm first described in 2008 in 3 infants with multisystemic disease involving the liver and hematopoietic system. This entity has subsequently been documented in case reports and series to occupy a wider clinicopathologic spectrum with recurrent KIF5B-ALK fusions. The full clinicopathologic and molecular spectra of ALK-positive histiocytosis remain, however, poorly characterized. Here, we describe the largest study of ALK-positive histiocytosis to date, with detailed clinicopathologic data of 39 cases, including 37 cases with confirmed ALK rearrangements. The clinical spectrum comprised distinct clinical phenotypic groups: infants with multisystemic disease with liver and hematopoietic involvement, as originally described (Group 1A: 6/39), other patients with multisystemic disease (Group 1B: 10/39), and patients with single-system disease (Group 2: 23/39). Nineteen patients of the entire cohort (49%) had neurologic involvement (7 and 12 from Groups 1B and 2, respectively). Histology included classic xanthogranuloma features in almost one-third of cases, whereas the majority displayed a more densely cellular, monomorphic appearance without lipidized histiocytes but sometimes more spindled or epithelioid morphology. Neoplastic histiocytes were positive for macrophage markers and often conferred strong expression of phosphorylated extracellular signal-regulated kinase, confirming MAPK pathway activation. KIF5B-ALK fusions were detected in 27 patients, whereas CLTC-ALK, TPM3-ALK, TFG-ALK, EML4-ALK, and DCTN1-ALK fusions were identified in single cases. Robust and durable responses were observed in 11/11 patients treated with ALK inhibition, 10 with neurologic involvement. This study presents the existing clinicopathologic and molecular landscape of ALK-positive histiocytosis and provides guidance for the clinical management of this emerging histiocytic entity.
Subject(s)
Anaplastic Lymphoma Kinase/antagonists & inhibitors , Anaplastic Lymphoma Kinase/analysis , Histiocytic Disorders, Malignant/drug therapy , Histiocytic Disorders, Malignant/pathology , Protein Kinase Inhibitors/therapeutic use , Adolescent , Adult , Anaplastic Lymphoma Kinase/genetics , Child , Child, Preschool , Female , Histiocytic Disorders, Malignant/complications , Histiocytic Disorders, Malignant/genetics , Humans , Infant , Male , Nervous System Diseases/etiology , Nervous System Diseases/genetics , Nervous System Diseases/pathology , Oncogene Proteins, Fusion/analysis , Oncogene Proteins, Fusion/antagonists & inhibitors , Oncogene Proteins, Fusion/genetics , Retrospective Studies , Young AdultABSTRACT
During the last decades the efficacy of biologic agents, mainly of anti-TNFs, in controlling the activity of serious manifestations of Behcet's Disease (BD) has been established. On the other hand, the clinical heterogeneity of BD has precluded the validation of a widely-accepted composite index for disease assessment and for target disease-state definitions, such as low disease activity and remission, and the testing of their implementation in clinical practice. Therefore, in contrast to other systemic rheumatic diseases, a treat-to-target strategy has not yet been developed in BD. There are several challenges towards this approach, including standardization of outcome measures for assessing the disease activity in each-affected organ and construction of a composite disease activity index. The challenges for the development of a treat-to-target strategy and possible solutions are discussed in this position paper, which stemmed from a round table discussion that took place in the 19th International Conference on BD.
Subject(s)
Behcet Syndrome , Rheumatic Diseases , Humans , Behcet Syndrome/drug therapy , Biological Factors , Rheumatic Diseases/drug therapyABSTRACT
Autosomal recessive mutations in RAB27A are associated with Griscelli syndrome type 2 (GS2), characterized by hypopigmentation and development of early-onset, potentially fatal hemophagocytic lymphohistiocytosis (HLH). We describe a 35-year old male who presented with recurrent fever, was diagnosed with Epstein-Barr virus-driven chronic lymphoproliferation, fulfilled clinical HLH criteria, and who carried a novel homozygous RAB27A c.551G > A p.(R184Q) variant. We aimed to evaluate the contribution of the identified RAB27A variant in regard to the clinical phenotype as well as cellular and biochemical function. The patient displayed normal pigmentation as well as RAB27A expression in blood-derived cells. However, patient NK and CD8+ T cell exocytosis was low. Ectopic expression of the RAB27A p.R184Q variant rescued melanosome distribution in mouse Rab27a-deficient melanocytes, but failed to increase exocytosis upon reconstitution of human RAB27A-deficient CD8+ T cells. Mechanistically, the RAB27A p.R184Q variant displayed reduced binding to SLP2A but augmented binding to MUNC13-4, two key effector proteins in immune cells. MUNC13-4 binding was particularly strong to an inactive RAB27A p.T23N/p.R184Q double mutant. RAB27A p.R184Q was expressed and could facilitate melanosome trafficking, but did not support lymphocyte exocytosis. The HLH-associated RAB27A variant increased Munc13-4 binding, potentially representing a novel mode of impairing RAB27A function selectively in hematopoietic cells.
Subject(s)
Epstein-Barr Virus Infections , Lymphohistiocytosis, Hemophagocytic , Adult , Humans , Male , CD8-Positive T-Lymphocytes , Herpesvirus 4, Human , Lymphohistiocytosis, Hemophagocytic/diagnosis , Lymphohistiocytosis, Hemophagocytic/genetics , Protein Binding , rab GTP-Binding Proteins/genetics , rab GTP-Binding Proteins/chemistry , rab GTP-Binding Proteins/metabolism , rab27 GTP-Binding Proteins/genetics , rab27 GTP-Binding Proteins/metabolismABSTRACT
OBJECTIVE: Hemophagocytic lymphohistiocytosis is a hyperinflammatory syndrome that often requires critical care support and remains difficult to diagnose. These guidelines are meant to aid in the early recognition, diagnosis, supportive care, and treatment of patients with hemophagocytic lymphohistiocytosis in ICUs. DATA SOURCES: The literature searches were performed with PubMed (MEDLINE). STUDY SELECTION: Keywords and medical subject headings terms for literature search included "macrophage activation syndrome," hemophagocytic lymphohistiocytosis," and "hemophagocytic syndrome." DATA EXTRACTION: The Histiocyte Society developed these consensus recommendations on the basis of published reports and expert opinions with level of evidence provided for each recommendation. They were endorsed by the Society of Critical Care Medicine. DATA SYNTHESIS: Testing for hemophagocytic lymphohistiocytosis should be initiated promptly in all patients admitted to ICUs with an unexplained or disproportionate inflammatory response, especially those with rapid clinical deterioration. Meeting five or more of eight hemophagocytic lymphohistiocytosis 2004 diagnostic criteria serves as a valuable diagnostic tool for hemophagocytic lymphohistiocytosis. Early aggressive critical care interventions are often required to manage the multisystem organ failure associated with hemophagocytic lymphohistiocytosis. Thorough investigation of the underlying triggers of hemophagocytic lymphohistiocytosis, including infections, malignancies, and autoimmune/autoinflammatory diseases, is essential. Early steroid treatment is indicated for patients with familial hemophagocytic lymphohistiocytosis and is often valuable in patients with acquired hemophagocytic lymphohistiocytosis (i.e., secondary hemophagocytic lymphohistiocytosis) without previous therapy, including macrophage activation syndrome (hemophagocytic lymphohistiocytosis secondary to autoimmune/autoinflammatory disease) without persistent or relapsing disease. Steroid treatment should not be delayed, particularly if organ dysfunction is present. In patients with macrophage activation syndrome, whose disease does not sufficiently respond, interleukin-1 inhibition and/or cyclosporine A is recommended. In familial hemophagocytic lymphohistiocytosis and severe, persistent, or relapsing secondary macrophage activation syndrome, the addition of prompt individualized, age-adjusted etoposide treatment is recommended. CONCLUSIONS: Further studies are needed to determine optimal treatment for patients with hemophagocytic lymphohistiocytosis in ICUs, including the use of novel and adjunct therapies.
Subject(s)
Lymphohistiocytosis, Hemophagocytic , Macrophage Activation Syndrome , Adult , Child , Consensus , Critical Illness/therapy , Humans , Lymphohistiocytosis, Hemophagocytic/diagnosis , Lymphohistiocytosis, Hemophagocytic/therapy , Macrophage Activation Syndrome/diagnosis , Macrophage Activation Syndrome/etiology , Macrophage Activation Syndrome/therapy , Neoplasm Recurrence, Local/complications , SteroidsABSTRACT
OBJECTIVES: The aim of this study is to investigate the cumulative incidence and the severity of COVID-19 infections in patients with Behçet's disease. METHODS: A retrospective cohort study of patients with Behçet's disease was conducted. We obtained the data systematically from electronic patient files and through telephone interviews between February 2020 and May 1, 2021. Main outcomes were COVID-19 infection, disease duration, hospitalisation, intensive care admission and mortality. Secondary outcome was adherence to quarantine measures as recommended by the government. RESULTS: 185 Behçet's disease patients were included (mean age 42.2 years, 54% female); 58% of the patients were receiving colchicine, 30% anti-TNFα, 16% azathioprine and 8% systemic steroids. 30 patients (16.2%) were positive for COVID-19. Within our cohort, the cumulative incidence of COVID-19 was therefore 16.2% (95% CI 11.2-22.3%), which is significantly increased when compared to the general Dutch population (8.7% (95% CI 8.72-8.73%)) (p < 0.001). Four out of 30 (13%) patients were admitted to the hospital. There was no COVID-19 related mortality observed. Patients adhered to government measures; except in the period between the 1st of June and the 28th of September, this cohort received more visitors than in period 1 and 3. CONCLUSIONS: In this cohort, Behçet's disease patients have a higher risk for COVID-19 infection, without an increase of virus-related mortality. The course of COVID-19 disease in this cohort is relatively mild, with a lower admission rate than expected of patients using immunosuppressive medication.
Subject(s)
Behcet Syndrome , COVID-19 , Adult , Azathioprine/therapeutic use , Behcet Syndrome/diagnosis , Behcet Syndrome/drug therapy , Behcet Syndrome/epidemiology , COVID-19/epidemiology , Female , Humans , Male , Netherlands/epidemiology , Retrospective StudiesABSTRACT
Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) is a chronic, clinically heterogenous fibroinflammatory condition, characterised by an accumulation of IgG4 secreting plasma cells in affected tissues and associated with increased serum IgG4 concentrations. Despite a growing recognition of the disease among clinicians from different specialties worldwide, its indolent nature, lack of a single diagnostic test and ability to mimic other malignant, infective and inflammatory conditions, makes the diagnosis challenging. As treatment options evolve, biomarkers correlating with disease activity, predicting prognosis and response to treatment are deemed required. A multidisciplinary panel of experts from the European Reference Network for Rare and Complex Connective tissue diseases (ERN ReCONNET) and affiliated international partners have performed a narrative literature search and reviewed the current evidence of biomarkers in IgG4-RD, including immunoglobulins, cytokines, chemokines and other soluble immune mediators, and cellular components of the immune system. The aim of this paper is to provide useful information for clinicians as to the utility of biomarkers for diagnosing and monitoring IgG4-RD in clinical routine and sets out recommendations for clinical decision making.
Subject(s)
Autoimmune Diseases , Immunoglobulin G4-Related Disease , Autoimmune Diseases/diagnosis , Biomarkers , Chemokines , Humans , Immunoglobulin G , Immunoglobulin G4-Related Disease/diagnosis , Plasma Cells/pathologyABSTRACT
Hemophagocytic lymphohistiocytosis (HLH) is a severe hyperinflammatory syndrome induced by aberrantly activated macrophages and cytotoxic T cells. The primary (genetic) form, caused by mutations affecting lymphocyte cytotoxicity and immune regulation, is most common in children, whereas the secondary (acquired) form is most frequent in adults. Secondary HLH is commonly triggered by infections or malignancies but may also be induced by autoinflammatory/autoimmune disorders, in which case it is called macrophage activation syndrome (MAS; or MAS-HLH). Most information on the diagnosis and treatment of HLH comes from the pediatric literature. Although helpful in some adult cases, this raises several challenges. For example, the HLH-2004 diagnostic criteria developed for children are commonly applied but are not validated for adults. Another challenge in HLH diagnosis is that patients may present with a phenotype indistinguishable from sepsis or multiple organ dysfunction syndrome. Treatment algorithms targeting hyperinflammation are frequently based on pediatric protocols, such as HLH-94 and HLH-2004, which may result in overtreatment and unnecessary toxicity in adults. Therefore, dose reductions, individualized tailoring of treatment duration, and an age-dependent modified diagnostic approach are to be considered. Here, we present expert opinions derived from an interdisciplinary working group on adult HLH, sponsored by the Histiocyte Society, to facilitate knowledge transfer between physicians caring for pediatric and adult patients with HLH, with the aim to improve the outcome for adult patients affected by HLH.
Subject(s)
Lymphohistiocytosis, Hemophagocytic/diagnosis , Lymphohistiocytosis, Hemophagocytic/therapy , Adult , Female , Humans , MaleABSTRACT
OBJECTIVES: To investigate whether the auto-inflammatory nature and the pathergic reaction in Behçet's disease (BD) are driven by a disturbed toll-like receptor (TLR) response. METHODS: We compared both TLR expression by flow-cytometry and TLR response by stimulation assay in 18 BD patients (both pathergy positive and pathergy negative) with 15 healthy controls. RESULTS: Expression of TLR1 and 2 was significantly elevated in B-lymphocytes of BD patients compared with healthy controls. TLR1, 2 and 4 were significantly more highly expressed in both CD4+ and CD8+ T-lymphocytes of BD patients. Granulocytes of BD patients displayed significantly higher expression of TLR1, 2, 4 and 6. TLR2, 4 and 5 expression was significantly increased on classical monocytes of BD patients. Intermediate monocytes of BD patients showed an increase in expression of TLR2. Furthermore, TLR2 and 5 were significantly more highly expressed in non-classical monocytes of BD patients. In pathergy positive patients, TLR5 was even more highly expressed compared with pathergy negative patients on B- and T-lymphocytes and granulocytes. Furthermore, TLR2 and 5 showed an elevated TNF-α response to stimulation with their cognate ligands. CONCLUSION: Immune cells of BD patients overexpress TLR1, 2, 4, 5 and 6. Furthermore, after stimulation of TLR2 and 5, BD patients demonstrate a more potent TNF-α response. Although this is a small cohort, in the pathergy positive patients, TLR5 expression is even further augmented, suggesting that a microbial (flagellin) or damage (HMGB1) associated signal may trigger the exaggerated immune response that is characteristic for the pathergy phenomenon in BD. In conclusion, these results point to an exaggerated TLR response in the auto-inflammatory nature of BD.
Subject(s)
Behcet Syndrome/metabolism , Toll-Like Receptors/metabolism , Adult , B-Lymphocytes/metabolism , Behcet Syndrome/pathology , CD4-Positive T-Lymphocytes/metabolism , CD8-Positive T-Lymphocytes/metabolism , Case-Control Studies , Female , Flow Cytometry , Humans , Male , Middle Aged , Toll-Like Receptor 1/metabolism , Toll-Like Receptor 2/metabolism , Toll-Like Receptor 4/metabolism , Young AdultABSTRACT
In this both narrative and systematic review, we explore the role of TNF-α in the immunopathogenesis of Behçet's disease (BD) and the effect of treatment with TNF-α blockers. BD is an auto-inflammatory disease, characterized by recurrent painful oral ulcerations. The pathogenesis of BD is not yet elucidated; it is assumed that TNF-α may play a key role. In the narrative review, we report an increased production of TNF-α, which may be stimulated via TLR-signaling, or triggered by increased levels of IL-1ß and IFN-γ. The abundance of TNF-α is found in both serum and in sites of inflammation. This increased presence of TNF-α stimulates T-cell development toward pro-inflammatory subsets, such as Th17 and Th22 cells. Treatment directed against the surplus of TNF-α is investigated in the systematic review, performed according to the PRISMA guideline. We searched the Pubmed and Cochrane database, including comparative studies only. After including 11 studies, we report a beneficial effect of treatment with TNF-α blockers on the various manifestations of BD. In conclusion, the pivotal role of TNF-α in the immunopathogenesis of BD is reflected in both the evidence of their pro-inflammatory effects in BD and in the evidence of the positive effect of treatment on the course of disease in BD.
Subject(s)
Behcet Syndrome/etiology , Behcet Syndrome/metabolism , Disease Susceptibility , Molecular Targeted Therapy , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Tumor Necrosis Factor-alpha/metabolism , Animals , Behcet Syndrome/drug therapy , Disease Management , Disease Susceptibility/immunology , Humans , Molecular Targeted Therapy/methodsABSTRACT
OBJECTIVES: The TNF-blocker adalimumab can be effective in Behçet's disease (BD), a multisystem auto-inflammatory disorder. Unfortunately, the therapeutic efficacy of TNF-blockers can be hampered by the formation of anti-drug antibodies. We present an observational study of adalimumab in refractory BD with measurement of anti-drug antibodies. METHODS: The effect of fortnightly 40mg adalimumab in nine patients with therapy refractory mucocutaneous, non-ocular or organ threatening BD was studied up to 60 months. Primary endpoint was a decrease in disease activity, measured by the BD Current Activity Form (BDCAF) within 6 months. Secondary endpoints included serum cytokines and the long-term formation of anti-adalimumab antibodies. RESULTS: BDCAF improved significantly in all nine patients from 5.4 (SD=1.4) to 2.4 (SD=1.4) (p=0.007) within one month up to 6 months and after prolonged follow up of 5 years. All patients could either taper or stop concomitant therapy. Symptoms of mucocutaneous lesions, erythema nodosum and joint involvement decreased or disappeared. Serum TNF-alpha levels were elevates in five patients and decreased upon treatment (p=0.017). Adalimumab was save and none of the patients experienced therapy failure or antibodies against adalimumab. CONCLUSIONS: We present an observational study on patients with BD treated with adalimumab and provide a basis for long-term use in refractory mucocutaneous BD. These findings show that adalimumab can safely be administered yielding sustainable clinical effects in refractory BD patients with mucocutaneous disease without formation of anti-adalimumab antibodies, even after long follow up.
Subject(s)
Adalimumab/therapeutic use , Behcet Syndrome , Immunosuppressive Agents/therapeutic use , Behcet Syndrome/drug therapy , Drug Resistance , Humans , Tumor Necrosis Factor-alpha/antagonists & inhibitorsABSTRACT
PURPOSE: To relate erythrocyte sedimentation rates (ESR) and C-reactive protein (CRP) values to different uveitis entisties. METHODS: A retrospective study of patients with a first episode of active uveitis visiting the Erasmus University Medical Center, uveitis clinic, Rotterdam, the Netherlands, was performed. Levels of ESR and CRP were determined within 2 weeks and 1 week after onset of uveitis, respectively. Uveitis had to be of unknown origin at that moment. The specific etiologic groups were related to ESR and CRP values. RESULTS: The majority of patients with uveitis had ESR and/or CRP values within the normal limits and no association of ESR and/or CRP with the specific cause of uveitis was observed. However, elevation of ESR ≥ 60 mm/h and/or CRP ≥ 60 mg/L was mostly seen in patients with systemic immune-mediated diseases (8/59, 14% of all with immune-mediated diseases) or systemic infectious causes (7/38, 18% of all infectious uveitis). Patients with ocular toxoplasmosis typically exhibited normal ESR and CRP (9/11, 82%) while patients with endogenous endophthalmitis had elevated ESR and/or CRP in 6/7, 86%. Sarcoidosis-associated uveitis showed predominantly elevated ESR (13/24, 54%; range 20-59 mm/h in 11/13, 85%). Human immunodeficiency virus-positive patients had more often elevated ESR values when compared to the remainder of patients (9/11, 82% vs. 64/163, 39%, 18%, P = 0.009). The cause of uveitis was established in 19/20 (95%) of patients with ESR ≥ 60 mm/h and/or CRP ≥ 60 mg/L. CONCLUSIONS: The majority of patients with first attack of uveitis had ESR and CRP within the normal limits. Elevated levels of ESR and CRP reflected systemic involvement and high levels of both values were associated with established uveitis cause.
Subject(s)
Blood Sedimentation , C-Reactive Protein/metabolism , Uveitis/blood , Adult , Biomarkers/blood , Cross-Sectional Studies , Female , Humans , Male , Middle Aged , Predictive Value of Tests , Retrospective Studies , Severity of Illness Index , Uveitis/diagnosisABSTRACT
BACKGROUND: IgG4-related disease (IgG4-RD) is a systemic fibroinflammatory condition affecting various organs and has a diverse clinical presentation. Fibrosis and accumulation of IgG4+ plasma cells in tissue are hallmarks of the disease, and IgG4-RD is associated with increased IgG4 serum levels. However, disease pathogenesis is still unclear, and these cellular and molecular parameters are neither sensitive nor specific for the diagnosis of IgG4-RD. OBJECTIVE: Here we sought to develop a flow cytometric gating strategy to reliably identify blood IgG4+ B cells to study their cellular and molecular characteristics and investigate their contribution in disease pathogenesis. METHODS: Sixteen patients with histologically confirmed IgG4-RD, 11 patients with sarcoidosis, and 30 healthy subjects were included for 11-color flow cytometric analysis of peripheral blood for IgG4-expressing B cells and TH subsets. In addition, detailed analysis of activation markers and chemokine receptors was performed on IgG4-expressing B cells, and IgG4 transcripts were analyzed for somatic hypermutations. RESULTS: Cellular and molecular analyses revealed increased numbers of blood IgG4+ memory B cells in patients with IgG4-RD. These cells showed reduced expression of CD27 and CXCR5 and increased signs of antibody maturation. Furthermore, patients with IgG4-RD, but not patients with sarcoidosis, had increased numbers of circulating plasmablasts and CD21low B cells, as well as TH2 and regulatory T cells, indicating a common disease pathogenesis in patients with IgG4-RD. CONCLUSION: These results provide new insights into the dysregulated IgG4 response in patients with IgG4-RD. A specific "peripheral lymphocyte signature" observed in patients with IgG4-RD, could support diagnosis and treatment monitoring.
Subject(s)
B-Lymphocytes/immunology , Immunoglobulin G/immunology , Sarcoidosis/immunology , T-Lymphocytes, Regulatory/immunology , Th2 Cells/immunology , Adolescent , Adult , Aged , Biomarkers/blood , Chemokines/immunology , Female , Humans , Immunologic Memory , Male , Middle Aged , Plasma Cells/immunology , Receptors, CXCR5/immunology , Sarcoidosis/blood , Tumor Necrosis Factor Receptor Superfamily, Member 7 , Young AdultABSTRACT
OBJECTIVES: Behçet's disease (BD), an auto-inflammatory vasculitis with oro-genital ulcerations, skin lesions and uveitis, is regarded as T cell mediated. A successful trial with rituximab suggests an additive role for B cells in the pathogenesis. Therefore, we studied B cell abnormalities in BD patients and the effect of TNF-blocking therapy. METHODS: B cells in blood (n = 36) and tissue (n = 6) of BD patients were analysed with flow cytometry and/or immunohistochemistry and compared with healthy controls (n = 22). BD current activity form (BDCAF) in relation to B cell somatic hypermutations (SHMs) and immunoglobulin class-switching were studied. RESULTS: Thirty-six patients (17 males) were included, mean age 44 years, average disease duration 10 years and mean BDCAF 2.7. Blood B cell numbers were significantly lower in patients than in controls (P = 0.0061), mostly due to decreased CD27+ memory B cells expressing IgM (P = 0.0001), IgG (P = 0.0002) and IgA (P = 0.0038) B cell subsets. CD27+ IgA+ B cells showed the highest magnitude of decrease in active disease, measured with BDCAF (P = 0.02). CD27+ IgM+ IgD+ B cells were impaired in replication history (P = 0.0133) and selection of SHM, whereas IgA+ B cells carried elevated SHM levels (P = 0.04) and lower IgA2 subclass usage (P = 0.0004) than controls. Immunohistochemistry revealed B cells in tissue of active mucosal ulcers. In adalimumab-treated patients, blood B cells were similar to controls. CONCLUSION: We show significant deviations in the memory B cell compartment, related to disease activity and therapeutic efficacy. Pronounced molecular impairments were seen in the fast-responding IgM+-memory and the mucosal IgA+-memory B cells. Because of the demonstrated abundance of B cells in affected tissue, we hypothesize relocation of memory B cells to the site of inflammation could account for the deviations found in blood of BD patients. These peripheral B cells are easily accessible as a marker to monitor therapeutic efficacy.