Background IgG4 -related disease (IgG4 -RD) is a systemic condition of unknown cause characterized by highly fibrotic lesions with dense lymphoplasmacytic infiltrates. CD4+ T cells constitute the ...major inflammatory cell population in IgG4 -RD lesions. Objective We used an unbiased approach to characterize CD4+ T-cell subsets in patients with IgG4 -RD based on their clonal expansion and ability to infiltrate affected tissue sites. Methods We used flow cytometry to identify CD4+ effector/memory T cells in a cohort of 101 patients with IgG4 -RD. These expanded cells were characterized by means of gene expression analysis and flow cytometry. Next-generation sequencing of the T-cell receptor β chain gene was performed on CD4+ SLAMF7+ cytotoxic T lymphocytes (CTLs) and CD4+ GATA3+ TH 2 cells in a subset of patients to identify their clonality. Tissue infiltration by specific T cells was examined by using quantitative multicolor imaging. Results CD4+ effector/memory T cells with a cytolytic phenotype were expanded in patients with IgG4 -RD. Next-generation sequencing revealed prominent clonal expansions of these CD4+ CTLs but not CD4+ GATA3+ memory TH 2 cells in patients with IgG4 -RD. The dominant T cells infiltrating a range of inflamed IgG4 -RD tissue sites were clonally expanded CD4+ CTLs that expressed SLAMF7, granzyme A, IL-1β, and TGF-β1. Clinical remission induced by rituximab-mediated B-cell depletion was associated with a reduction in numbers of disease-associated CD4+ CTLs. Conclusions IgG4 -RD is prominently linked to clonally expanded IL-1β– and TGF-β1–secreting CD4+ CTLs in both peripheral blood and inflammatory tissue lesions. These active, terminally differentiated, cytokine-secreting effector CD4+ T cells are now linked to a human disease characterized by chronic inflammation and fibrosis.
Abstract Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) is a chronic, systemic, inflammatory condition of unknown etiology. Histopathologic examination is the key to diagnosis of IgG4-RD. The ...histopathologic features of IgG4-RD are lymphoplasmacytic infiltration, storiform fibrosis, and obliterative phlebitis. As for fewer than 15 years, IgG4-RD has been recognized as a unified diagnostic entity. CD4+ T and B cells, which likely cause organ damage and disabling tissue fibrosis, constitute the major inflammatory cell population in patients with IgG4-RD. Afected patients with active, untreated disease have a marked expansion of IgG4-secreting plasmablasts in the blood. Important mechanistic insights regarding the pathogenesis of IgG4-RD have been gradually disclosed in recent years. Exploring the role of interactions between these CD4+ T and B cells in patients with IgG4-RD is a highly promising field of investigation. In this review, we focus on CD4+ T cell subsets and the T-cell clones that are involved in the pathogenesis of IgG4-RD.
Tumor-associated macrophages (TAMs) promote tumor progression and inhibit anti-tumor immune response by producing various mediators and preferentially express CD163, CD204, and CD206. However, the ...role of these TAM subsets in oral squamous cell carcinoma (OSCC) remains unclear. Here we investigated the expression and function of TAM subsets in OSCC, especially in cancer cell proliferation. Biopsy sample from 44 patients with OSCC were examined for the expression of TAM markers and EGF by immunohistochemistry. EGF production of TAM subsets isolated from OSCC patients was assessed by flow cytometry. We also examined the effect of conditioned medium from TAM subsets on the proliferation of OSCC cells. CD163
cells were detected diffusely all over the tumor and connective tissue area, while CD204
and CD206
cells were mainly detected in/around the tumors. Flow cytometric analysis found that CD206
TAMs strongly produced EGF compared with CD163
and CD204
TAMs. Cell proliferation and invasion of OSCC cells cultured with conditioned medium of CD206
TAMs were strongly enhanced and inhibited by anti-EGFR. The number of CD206
TAMs positively correlated with worse clinical prognosis. Our results revealed differences in localization and EGF production among these TAM subsets. CD206
TAMs might play a critical role in the proliferation of OSCC via EGF production.
Tumor-associated macrophages (TAMs) promote cancer cell proliferation, invasion, and metastasis by producing various mediators. Although preclinical studies demonstrated that TAMs preferentially ...express CD163 and CD204, the TAM subsets in oral squamous cell carcinoma (OSCC) remain unknown. In this study, we examined the expression and role of TAM subsets in OSCC. Forty-six patients with OSCC were analyzed for expression of TAMs in biopsy samples by immunohistochemistry. We examined TAM subsets and their production of immune suppressive molecules (IL-10 and PD-L1) in peripheral blood mononuclear cells from three OSCC patients by flow cytometry. CD163 was detected around the tumor or connective tissue, while CD204 was detected in/around the tumors. Flow cytometric analysis revealed that CD163
CD204
TAMs strongly produced IL-10 and PD-L1 in comparison with CD163
CD204
and CD163
CD204
TAMs. Furthermore, the number of activated CD3
T cells after co-culture with CD163
CD204
TAMs was significantly lower than that after co-culture with other TAM subsets. In clinical findings, the number of CD163
CD204
TAMs was negatively correlated with that of CD25
cells and 5-year progression-free survival. These results suggest that CD163
CD204
TAMs possibly play a key role in the invasion and metastasis of OSCC by T-cell regulation via IL-10 and PD-L1 production.
How T follicular (Tfh) cells contribute to many different B-cell class-switching events during T-cell–dependent immune responses has been unclear. Diseases with polarized isotype switching offer a ...unique opportunity for the exploration of Tfh subsets. Secondary and tertiary lymphoid organs in patients with elevated tissue expression levels of IgE (Kimura disease, KD) and those of IgG4 (IgG4-related disease, IgG4-RD) can provide important insights regarding cytokine expression by Tfh cells.
We sought to identify disease-specific Tfh cell subsets in secondary and tertiary lymphoid organs expressing IL-10 or IL-13 and thus identify different cellular drivers of class switching in 2 distinct types of fibrotic disorders: allergic fibrosis (driven by type 2 immune cells) and inflammatory fibrosis (driven by cytotoxic T lymphocytes).
Single-cell RNA sequencing, in situ sequencing, and multicolor immunofluorescence analysis were used to investigate B cells, Tfh cells, and infiltrating type 2 cells in lesion tissues from patients with KD or IgG4-RD.
Infiltrating Tfh cells in tertiary lymphoid organs from IgG4-RD were divided into 6 main clusters. We encountered abundant infiltrating IL-10–expressing LAG3+ Tfh cells in patients with IgG4-RD. Furthermore, we found that infiltrating AICDA+CD19+ B cells expressing IL-4, IL-10, and IL-21 receptors correlated with IgG4 expression. In contrast, we found that infiltrating IL-13–expressing Tfh cells were abundant in affected tissues from patients with KD. Moreover, we observed few infiltrating IL-13–expressing Tfh cells in tissues from patients with IgG4-RD, despite high serum levels of IgE (but low IgE in the disease lesions). Cytotoxic T cells were abundant in IgG4-RD; in contrast, type 2 immune cells were abundant in KD.
Our analysis revealed a novel subset of IL-10+LAG3+ Tfh cells infiltrating the affected organs of IgG4-RD patients. In contrast, IL-13+ Tfh cells and type 2 immune cells infiltrated those of KD patients.
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Objective
IgG4‐related disease (IgG4‐RD) is a unique inflammatory disorder in which Th2 cytokines promote IgG4 production. In addition, recent studies have implicated the Toll‐like receptor (TLR) ...pathway. This study was undertaken to examine the expression of TLRs in salivary glands (SGs) from patients with IgG4‐RD.
Methods
SGs from 15 patients with IgG4‐RD, 15 patients with Sjögren's syndrome (SS), 10 patients with chronic sialadenitis, and 10 healthy controls were examined histologically. TLR family gene expression (TLR‐1 through TLR‐10) was analyzed by DNA microarray in the submandibular glands (SMGs). Up‐regulation of TLRs was confirmed in SGs from patients with IgG4‐RD. Finally, the phenotype of human TLR‐7 (huTLR‐7)–transgenic C57BL/6 mice was assessed before and after stimulation with TLR agonist.
Results
In patients with IgG4‐RD, TLR‐4, TLR‐7, TLR‐8, and TLR‐9 were overexpressed. Polymerase chain reaction validated the up‐regulation of TLR‐7 in IgG4‐RD compared with the other groups. Immunohistochemical analysis confirmed strong infiltration of TLR‐7–positive cells in the SGs of patients with IgG4‐RD. Double immunohistochemical staining showed that TLR‐7 expression colocalized with CD163+ M2 macrophages. After in vitro stimulation with a TLR‐7 agonist, CD163+ M2 macrophages produced higher levels of interleukin‐33 (IL‐33), which is a Th2‐activating cytokine. In huTLR‐7–transgenic mice, the focus and fibrosis scores in SMGs, pancreas, and lungs were significantly higher than those in wild‐type mice (P < 0.05). Moreover, the concentration of serum IgG, IgG1, and IL‐33 in huTLR‐7–transgenic mice was distinctly increased upon stimulation with a TLR‐7 agonist (P < 0.05).
Conclusion
TLR‐7–expressing M2 macrophages may promote the activation of Th2 immune responses via IL‐33 secretion in IgG4‐RD.
Abstract IgG4-related dacryoadenitis and sialoadenitis (IgG4-DS) is characterized by bilateral swelling of glandular tissues with extensive fibrosis, and is immunologically considered a ...Th2-predominant disease. Recent studies reported that alternatively activated (M2) macrophages enhanced Th2 immune responses and fibrosis by production of pro-fibrotic factors (IL-10, IL-13 and CCL18). Therefore, we examined the association between M2 macrophages and fibrosis in submandibular glands from 7 patients with IgG4-DS, 10 patients with chronic sialoadenitis, 10 patients with Sjögren's syndrome, and 10 healthy subjects. The number of M2 macrophages in SMGs from patients with IgG4-DS was also significantly higher than in the other groups. Double immunofluorescence staining showed that IL-10 and CCL18 expression co-localized with M2 macrophage-marker (CD163). Furthermore, the SMG fibrosis score was positively correlated with the frequency of M2 macrophages in only IgG4-DS. These results indicate that IL-10 and CCL18 secreted by preferential M2 macrophages possibly play a key role in the development of severe fibrosis in IgG4-DS.
(IgG4-RD) is an immune-mediated fibrotic disorder characterized by severe resolution of inflammation and dysregulation of wound healing. IgG4-RD has been considered a unique disease since 2003, and ...significant progress has been achieved in the understanding of its essential features. The central role of B cells in IgG4-RD has been demonstrated by the robust clinical responsiveness of IgG4-RD to B cell depletion and the identification of multiple self-antigens that promote B cell expansion. Studies have increasingly revealed critical roles of these B cells and T cells in the pathogenesis of IgG4-RD, and we and other authors further identified CD4+ cytotoxic T lymphocytes as the main tissue-infiltrating CD4+ T cell subset in IgG4-RD tissues. Additionally, T follicular helper cell subsets that play a role in IgG4 isotype switching have been identified. In this review, we discuss research on IgG4-RD and the roles of B cell and T cell subsets, as well as the functions of CD4+ cytotoxic T cells in IgG4-RD pathogenesis. We highlight our findings from ongoing research using single-cell analysis of infiltrating CD4+ cytotoxic T cells, CD4+ follicular helper T cells, and infiltrating B cells in IgG4-RD and propose a model for the pathogenesis of IgG4-RD.
IgG4-related disease (IgG4-RD) is a fibroinflammatory condition involving loss of B-cell tolerance and production of autoantibodies. However, the relevant targets and role of these aberrant humoral ...immune responses are not defined.
Our aim was to identify novel autoantibodies and autoantigen targets that promote pathogenic responses in IgG4-RD.
We sequenced plasmablast antibody repertoires in patients with IgG4-RD. Representative mAbs were expressed and their specificities characterized by using cytokine microarrays. The role of anti–IL-1 receptor antagonist (IL-1RA) autoantibodies was investigated by using in vitro assays.
We identified strong reactivity against human IL-1RA by using a clonally expanded plasmablast-derived mAb from a patient with IgG4-RD. Plasma from patients with IgG4-RD exhibited elevated levels of reactivity against IL-1RA compared with plasma from the controls and neutralized IL-1RA activity, resulting in inflammatory and fibrotic mediator production in vitro. IL-1RA was detected in lesional tissues from patients with IgG4-RD. Patients with anti–IL-1RA autoantibodies of the IgG4 subclass had greater numbers of organs affected than did those without anti–IL-1RA autoantibodies. Peptide analyses identified IL-1RA epitopes targeted by anti–IL-1RA antibodies at sites near the IL-1RA/IL-1R interface. Serum from patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) also had elevated levels of anti–IL-1RA autoantibodies compared with those of the controls.
A subset of patients with IgG4-RD have anti–IL-1RA autoantibodies, which promote proinflammatory and profibrotic meditator production via IL-1RA neutralization. These findings support a novel immunologic mechanism underlying the pathogenesis of IgG4-RD. Anti–IL-1RA autoantibodies are also present in a subset of patients with SLE and RA, suggesting a potential common pathway in multiple autoimmune diseases.
Abstract
Objectives
IgG4-related disease (IgG4-RD) is a systemic fibro-inflammatory disorder characterized by a dysregulated resolution of inflammation and wound healing response that might develop ...after an apoptotic insult induced by cytotoxic T lymphocytes (CTLs). Mer receptor tyrosine kinase (MerTK) and its ligand, protein S (ProS1), have a pivotal role in the resolution of inflammation, being implicated in the clearance of apoptotic cells, quenching of the immune response and development of tissue fibrosis. In the present work we aimed to investigate a possible involvement of the MerTK signalling pathway in the pathogenesis of IgG4-RD and development of tissue fibrosis.
Methods
MerTK and ProS1 expression patterns in IgG4-RD lesions were evaluated by immunohistochemistry and immunofluorescence studies. Circulating MerTK+ monocytes, soluble Mer and MerTK ligands were measured in the peripheral blood of IgG4-RD patients and healthy controls by flow cytometry and ELISA, respectively.
Results
MerTK was highly expressed by macrophages infiltrating IgG4-RD lesions. MerTK+ macrophages were more abundant in IgG4-RD than in Sjögren’s syndrome and interacted with apoptotic cells and ProS1-expressing T and B lymphocytes. Moreover, they expressed the pro-fibrotic cytokine TGF-β and their numbers declined following rituximab-induced disease remission. Circulating MerTK+ monocytes, soluble Mer and MerTK ligands were not increased in the peripheral blood of patients with IgG4-RD.
Conclusions
The MerTK–ProS1 axis is activated in IgG4-RD lesions, possibly leading to persistent stimulation of processes involved in the resolution of inflammation and tissue fibrosis.
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