Role of IL-22- and TNF-α-producing Th22 cells in uveitis patients with Behcet's disease

Increased IL-22 in cerebrospinal fluid of neuro-behçet's disease patients

Remitting-Relapsing Multiple Sclerosis (RRMS) and Neuro-Behçet Disease (NBD) are two chronic neuro-inflammatory disorders leading to brain damage and disability in young adults. Herein, we investigated in these patients the cytokine response by beads-based multiplex assays during the early stages of these disorders. Cytokine investigations were carried out on treatment-naive patients suffering from RRMS and NBD recruited at the first episode of clinical relapse. Our findings demonstrate that Cerebrospinal Fluid (CSF) cells from NBD patients, but not RRMS, secrete significant high levels of IL-22 which is associated with elevated IL-22 mRNA expression. We also observed an increase in IL-22 levels in the definite NBD subgroup as compared to the probable NBD one, indicating a clear relationship between elevated IL-22 levels and diagnostic certainty. Interestingly, we found no correlation of IL-22 secretion between CSF and serum arguing about intrathecal release of IL-22 in the CNS of NBD patients. Moreover, we showed by correlogram analysis that this cytokine doesn't correlate with IL-17A, IL-17F and IL-21 suggesting that this cytokine is secreted by Th22 cells and not by Th17 cells in the CSF of NBD patients. Finally, we found elevated levels of IL-6 and a positive correlation between IL and 6 and IL-22 in the CSF of NBD. In conclusion, these results suggest that IL-6 contributes to the production of IL-22 by T cells leading to the exacerbation of inflammation and damage within the CNS of NBD patients.

The safety and efficacy of TNF inhibitors in patients with Behçet's disease: Retrospective study from eastern Turkey

OBJECTIVE

We aimed to evaluate the clinical features, disease course, and associated factors for outcome in severe/refractory BD patients receiving TNF-i treatment.

MATERIAL AND METHODS

This retrospective study was conducted by reviewing medical records from a tertiary referral center in Van province in Eastern Turkey. Data were obtained from patients' charts followed up between June 2019 and June 2022.

RESULTS

We included 469 BD patients (59.3% male) whose 80 patients (17%) received TNF-i treatment in the study. The mean ± standard deviation of the patient age was 36.7 ± 10.1 years and the median (IQR) disease duration was 12 (12) years. IFX and ADAwere initiated in 67.5% (n = 54) and 32.5% (n = 26) patients, respectively. Overall and first-line retention rates of TNF-i were 84.7% and 92.6% for IFX and 83.3% and 80.8% for ADA, respectively. IFX was discontinued in 9 patients which were in 2 patients due to allergic reaction and tuberculosis, 3 patients for inefficacy, one patient for heart failure, and one patient for orbital zona. Although no serious adverse event was observed with ADA, 5 patients switched to IFX due to inefficacy. Overall, 72 patients (90%) resumed TNF-i at the end of the study; TNF-i was discontinued in 3 patients (3.8%) due to severe adverse events and in 5 patients (6.2%) with prolonged remission.

CONCLUSION

In our study, no case of death was observed in TNF-i receiving patients. Most patients achieved attack-free and CS-free disease and retained TNF-i treatment. TNF inhibitors appear to be safe and effective in patients with severe/refractory Behçet's disease.

Advances in pathogenesis and treatment of ocular involvement in Behcet's disease

Behcet's disease (BD) is a chronic multi-systemic disease characterized by relapsing-remitting oral ulcers, genital ulcers, ocular inflammatory involvements, and numerous other systemic features. Ocular involvements are quite common in BD and may cause severe tissue damage and potentially blindness. Even though the pathogenesis of BD remains ambiguous, growing evidences have shown that genetic factors, environmental triggers and immunological abnormalities play significant roles in its development and progression. Novel biotherapies targeting IFN-γ, TNF-α and interleukins have been used in recent years. In this review, we mainly pay attention to the ocular involvement of BD, and discuss the current understanding of mechanisms and advances in therapeutic approaches, especially novel biologics. Finally, we discuss the management in patients with pregnancy.

Human T-cell Leukemia Virus Type 1 (HTLV-1)-induced Uveitis

Human T-cell leukemia virus type 1 (HTLV-1) is a human retrovirus that causes T-cell malignant diseases (adult T-cell leukemia/lymphoma) and HTLV-1-related non-malignant inflammatory diseases, such as HTLV-1 uveitis. Although the symptoms and signs of HTLV-1 uveitis are nonspecific, intermediate uveitis with various degrees of vitreous opacity is the most common clinical presentation. It can occur in one or both eyes and its onset is acute or subacute. Intraocular inflammation can be managed with topical and/or systemic corticosteroids; however, recurrence of uveitis is common. The visual prognosis is generally favorable, but a certain proportion of patients have a poor visual prognosis. Systemic complications of patients with HTLV-1 uveitis include Graves' disease and HTLV-1-associated myelopathy/tropical spastic paraparesis. This review describes the clinical characteristics, diagnosis, ocular manifestations, management, and immunopathogenic mechanisms of HTLV-1 uveitis.

IL-22 as a target for therapeutic intervention: Current knowledge on its role in various diseases

IL-22 has emerged as a crucial cytokine mediating protective response against pathogens and tissue regeneration. Dysregulated production of IL-22 has been shown to play a pivotal role in the pathogenesis of various diseases like malignant tumours, viral, cardiovascular, allergic and autoimmune disorders. Interleukin 22 belongs to IFN-IL-10 cytokine family. It is a major proinflammatory cytokine secreted by activated Th1 cells (Th22), though can also be secreted by many other immune cells like group 3 innate lymphocytes, γδ T cells, NK cells, NK T cells, and mucosal associated invariant T cells. Th22 cells exclusively release IL-22 but not IL-17 or IFN-γ (as Th1 cells releases IFN-γ along with IL-22 and Th17 cells releases IL-17 along with IL-22) and also express aryl hydrocarbon receptor as the key transcription factor. Th22 cells also exhibit expression of chemokine receptor CCR6 and skin-homing receptors CCR4 and CCR10 indicating the involvement of this subset in bolstering epithelial barrier immunity and promoting secretion of antimicrobial peptides (AMPs) from intestinal epithelial cells. The function of IL-22 is modulated by IL-22 binding protein (binds to IL-22 and inhibits it binding to its cell surface receptor); which serves as a competitor for IL-22R1 chain of IL-22 receptor. The pathogenic and protective nature of the Th22 cells is modulated both by the site of infected tissue and the type of disease pathology. This review aims to discuss key features of IL-22 biology, comparisons between IL and 22 and IFN-γ and its role as a potential immune therapy target in different maladies.

The blood proteomic signature of prurigo nodularis reveals distinct inflammatory and neuropathic endotypes: A cluster analysis

BACKGROUND

Prurigo nodularis (PN) is an extremely pruritic, chronic inflammatory skin disease. Little is known about systemic inflammation in PN.

OBJECTIVE

To characterize plasma inflammatory biomarkers in patients with PN and investigate the presence of disease endotypes.

METHODS

In this cross-sectional study, Olink proteomic analysis was performed on plasma samples from patients with PN (n = 29) and healthy controls (n = 18).

RESULTS

Patients with PN had increased levels of 8 circulating biomarkers compared to controls, including tumor necrosis factor, C-X-C Motif Chemokine Ligand 9, interleukin-12B, and tumor necrosis factor receptor superfamily member 9 (P < .05). Two PN clusters were identified in cluster 1 (n = 13) and cluster 2 (n = 16). Cluster 2 had higher levels of 25 inflammatory markers than cluster 1. Cluster 1 had a greater percentage of patients with a history of myelopathy and spinal disc disease compared with cluster 2 (69% vs 25%, P = .03). Patients in cluster 2 were more likely to have a history of atopy (38% in cluster 2 vs 8% in cluster 1, P = .09).

LIMITATIONS

Small sample size precludes robust subgroup analyses.

CONCLUSION

This study provides evidence of neuroimmune-biased endotypes in PN and can aid clinicians in managing patients with PN that are nonresponsive to traditional therapies.

Relationship between mucosal TNF-α expression and Th1, Th17, Th22 and Treg responses in Helicobacter pylori infection

Helicobacter pylori (H. pylori)-induced gastric inflammation in the gastric mucosa and significantly increases the risk of developing gastritis and peptic ulcer disease (PUD). The objective of this research is to determine the role of tumor necrosis factor-α (TNF-α) expression in the gastric mucosa of patients with H. pylori-associated gastritis and PUD compared to uninfected patients, and we determined the relation between TNF-α expression and Th1/Th17/Th22, and Treg cells. Fifty-five patients with H. pylori-associated gastritis, 47 patients with H. pylori-associated PUD, and 48 uninfected patients were in this research. Antrum biopsy was used to detect H. pylori, virulence factors and histopathological assessments. Expression of TNF-α in the infected group was significantly higher than the uninfected group. Also, cagA/oipA-positive infected patients induce significantly more TNF-α expression than do cagA/oipA-negative infected patients. Expression of TNF-α was significantly increased in the PUD group than the gastritis group. Notably, TNF-α expression had a significant positive correlation with the frequency of Th1/Th17/Th22 lymphocytes in the PUD group. These findings indicate the importance of increasing TNF-α with Th1, Th17, Th22 responses increase as an important risk factor for PUD in context of H. pylori infection.

Expression of TNF-α was significantly increased in the PUD group than the gastritis group.

Notably, TNF-α expression had a significant positive correlation with the frequency of Th1/Th17/Th22 lymphocytes in the PUD group.

These findings indicate the importance of increasing TNF-α with Th1, Th17, Th22 responses increase as an important risk factor for PUD in context of H. pylori infection.

The key player in the pathogenesis of environmental influence of systemic lupus erythematosus: Aryl hydrocarbon receptor

The aryl hydrocarbon receptor was previously known as an environmental receptor that modulates the cellular response to external environmental changes. In essence, the aryl hydrocarbon receptor is a cytoplasmic receptor and transcription factor that is activated by binding to the corresponding ligands, and they transmit relevant information by binding to DNA, thereby activating the transcription of various genes. Therefore, we can understand the development of certain diseases and discover new therapeutic targets by studying the regulation and function of AhR. Several autoimmune diseases, including systemic lupus erythematosus (SLE), have been connected to AhR in previous studies. SLE is a classic autoimmune disease characterized by multi-organ damage and disruption of immune tolerance. We discuss here the homeostatic regulation of AhR and its ligands among various types of immune cells, pathophysiological roles, in addition to the roles of various related cytokines and signaling pathways in the occurrence and development of SLE.

Mucosal-associated invariant T cells have therapeutic potential against ocular autoimmunity

Autoimmune uveitis is a sight-threatening disease induced by pathogenic T cells that recognize retinal antigens; it is observed in disorders including Vogt-Koyanagi-Harada disease (VKH). The roles of specific T cell subsets and their therapeutic potential against autoimmune uveitis are not fully understood. Here we conducted multi-parametric single-cell protein quantification which shows that the frequency of CD161^highTRAV1-2⁺ mucosal-associated invariant T (MAIT) cells that recognize vitamin B2 metabolite-based antigens is decreased in relapsing VKH patients compared to individuals without active ocular inflammation. An experimental autoimmune uveitis (EAU) mouse model revealed that genetic depletion of MAIT cells reduced the expression of interleukin (Il) 22 and exacerbated retinal pathology. Reduced IL-22 levels were commonly observed in patients with relapsing VKH compared to individuals without active ocular inflammation. Both mouse and human MAIT cells produced IL-22 upon stimulation with their antigenic metabolite in vitro. An intravitreal administration of the antigenic metabolite into EAU mice induced retinal MAIT cell expansion and enhanced the expressions of Il22, as well as its downstream genes related to anti-inflammatory and neuroprotective effects, leading to an improvement in both retinal pathology and visual function. Taken together, we demonstrate that a metabolite-driven approach targeting MAIT cells has therapeutic potential against autoimmune uveitis.

IL-17A and IFN-γ are Up-regulated in CD4 and γδ T Cells in Active Behcet's Disease Patients

Involvement of γδ T cells is implicated in the pathogenesis of Behçet's disease (BD) as a bridge between innate and adaptive responses. IL-17 and IL-22 have also been shown to participate in the BD pathogenesis in addition to IFN-γ. Mainly CD4⁺ T cells are investigated previously for the production of these inflammatory cytokines. In this study, the role of γδ T cells in cytokine-related mechanisms was evaluated in BD in comparison to CD4⁺ T cells. Surface expression of markers for functional states of both CD4⁺ and γδ T cells were compared in ex vivo samples collected from patients with BD and healthy controls (HC). Sixteen active BD (a-BD), 9 inactive BD (i-BD) patients and 25 HC were investigated. The expression of CD161, CCR6 as markers for IL-17 producing cells were analyzed on γδ and CD4⁺ T cells. IFN-γ, IL-17A, IL-22, as well as CD107a (LAMP1) and CD16 (FcγRIII) were evaluated in both cell subtypes after in vitro stimulation. Only IFN-γ production was increased in γδ T cells of a-BD patients. There was no difference in increase of CD107a or decrease of CD16 surface expression on γδ T cells upon stimulation between the groups. Ex vivo IL-17A and both IL-17A/IFN-γ production and expression of CD161, CCR6 by CD4⁺ T cells were increased in a-BD. Along with CD4⁺ T cells, γδ T cells have complementary roles in cytokine production in BD. Higher IFN-γ production of γδ T cells suggests the role of an environmental triggers in BD pathogenesis, whereas IL-17 related activity is mainly provided by CD4⁺ T cells.

Characterization of autologous platelet rich plasma (PRP) and its biological effects in patients with Behçet's Disease

Introduction

Behçet's disease (BD) is an immune-mediated chronic systemic vasculitis, characterized by clinical manifestations that include: mucocutaneous ulcers, ocular involvement, immunological alterations, vascular and neurological implications. The available treatments present limitations such as high cost and side effects, and the search for a low-cost biological treatment with immunomodulatory potential becomes of great value. Platelet rich plasma (PRP) has some characteristics that indicate a possible use as an immunomodulator due to the wide range of secreted cytokines, especially through the participation of TGF-β1 in the differentiation of T regulatory cells (Treg). This study aimed to characterize the PRP poor in leukocytes (P-PRP) of patients with BD and active ulcers and to evaluate its effects as an immunomodulator through a subcutaneous application.

Methods

We selected patients with a diagnosis of BD, with a low dose of prednisone and with no central nervous system or ocular involvement. Platelet and leukocyte count and quantification of 17 cytokines were evaluated in P-PRP. The effects of P-PRP were evaluated by cell frequency of TCD4 +, TCD8 +, Treg, natural killer (NK), and activated NK, as well as by the cytokine profile in patient's plasma, and the clinical manifestations through score and questionnaire. Also, it was evaluated the number and timing of oral ulcer closure. PRP was used as an adjuvant, with 9 applications of 3 mL, over 6 months, with a follow-up of one year.

Results

The results using PRP showed adequate values and no significant inter-and intra-individual variations. The systemic evaluations during the use of PRP showed significant alterations, characterized by the increase in Treg cell frequency (p = 0.0416) and a decrease in activated NK cells (p = 0.0010). However, no clinical correlation was observed through score analysis. The most relevant clinical data was the decrease in the closing time of ulcers throughout the application period.

Conclusion

In a pilot study with BD patients, P-PRP promoted an anti-inflammatory profile characterized by increased Treg cells and decreased activated NK cells and alterations in cytokines. A clinical improvement was observed with a decrease in the number and time of closure of oral ulcers.

Immunopathophysiology and clinical impact of uveitis in inflammatory rheumatic diseases: An update

BACKGROUND

Uveitis is one of the most frequent ophthalmologic manifestations in rheumatology. Uveal inflammation can underlie a systemic inflammatory rheumatic disease (SIRD) in approximately 30% of cases with a significant burden on the quality of life since it represents a cause of blindness in up to 20% of cases in Western countries.

METHODS

In this review, we provide a comprehensive overview of the pathophysiology of uveitis associated with SIRDs. According to our literature survey on the epidemiology of uveitis among SIRDs, spondyloarthritides, Behçet's disease and sarcoidosis get the major impact.

RESULTS

In Behçet's uveitis, the key players are highly polarized Th1 and Th17 lymphocytes, natural killer T cells and γδ T cells. All contribute to a great destructive inflammatory environment with the most serious visual damage resulting from the involvement of the posterior segment of the eye. In contrast, spondyloarthritides-related uveitis derives from a complex interaction between genetic background and extra-ocular inflammatory mediators originating from enthesitis, arthritis, psoriatic lesions and microbiome pro-inflammatory alterations. In such conditions, the immune infiltration of CD4+ T cells, Th17 and natural killer cells along with pro-inflammatory cytokines, TNF-α among all, leads to intraocular inflammation. Lastly, granuloma formation represents the primary hallmark lesion in sarcoid uveitis. This suggests a profound link between the innate system that mainly recruits activated macrophages and adaptive system involving by Th1, Th17 and Th17.1 cells.

CONCLUSIONS

Awareness among rheumatologists of a potential severe ocular involvement generates new insights into targeted therapeutic approaches and personalized treatments for each patient.

Dynamic alterations and durability of T helper 22 and its corresponding cytokines following treatment in pediatric visceral leishmaniasis

Considering the collaboration between immune responses and medications for the improvement of visceral leishmaniasis (VL), this study investigated the levels of T helper (Th) 22 and the corresponding cytokines in the acute phase of VL and their alterations following treatment. The study was conducted on 18 patients with confirmed VL and 20 healthy sex and age matched children as the controls. The levels of Th22 cells and the cytokines driving their differentiations and functions in the blood and peripheral blood mononuclear cells (PBMC) cultured supernatants, were assessed using flow cytometry method. The results revealed significantly higher levels of Th22, IL-21 and IL-6 in the patients' blood than those in the controls. Additionally, higher levels of IL-21 and IL-22 were observed in the cultured supernatants of VL patients' PBMCs, compared to the controls. Upon treatment, Th22 and IL-6 were down-regulated and conversely, IL-21, IL-22, IL-23 and IL-33 were significantly up-regulated in the patients' blood at different time points. Receiver operating characteristic (ROC) curve analysis indicated that for the differential diagnosis of VL, plasma IL-21 is more sensitive and specific than Th22 and the above mentioned cytokines. The higher proportions of Th22 and IL-21 in the VL patients and their alterations post treatment confer their roles in the immunopathogenesis of VL. So, Th22 and IL-21 in the patients' blood can be considered as biomarkers to be used for the differential diagnosis of VL. Nevertheless, further studies are warranted to clarify their particular mechanisms in this process.

Behçet's Disease-Do Microbiomes and Genetics Collaborate in Pathogenesis?

Behçet’s disease (BD) is a multisystem autoinflammatory condition characterized by mucosal ulceration, breakdown of immune privilege sites and vasculitis. A genetic basis for BD has been described in genome-wide and validation studies. Similarly, dysbiosis of oral and gut microbiomes have been associated with BD. This review will describe links between genetic polymorphisms in genes encoding molecules involved in gut biology and changes seen in microbiome studies. A potential decrease in bacterial species producing short chain fatty acids linked to mutations in genes involved in their production suggests a potential therapy for BD.

Parallel disease activity of Behçet's disease with renal and entero involvements: a case report

Background

Behçet’s disease (BD) is a systemic inflammatory vasculitis with both autoimmune and autoinflammatory properties. Renal involvement in BD and its spontaneous remission have been rare. We herein describe a case of parallel disease activity of BD with entero and renal involvements, followed by a spontaneous remission without corticosteroid treatment.

Case presentation

A 54-year-old woman who had a 4-year history of BD, maintained with colchicine treatment, suffered abdominal pain, hemorrhagic stool and diarrhea. Physical examination revealed strong tenderness in the entire abdomen. Laboratory test results showed increased levels of inflammation, and a computed tomography scan revealed edematous intestinal wall thickening with ascites. Blood and stool cultures showed no specific findings. Since she was suspected to have developed panperitonitis with acute enterocolitis, she started treatment with an antibacterial agent under bowel rest. Her abdominal symptoms gradually improved, while diarrhea and high levels of inflammatory reaction persisted. Colonoscopy revealed discontinuous abnormal mucosal vascular patterns and ulcerations in the whole colon except for the rectum, and histological analyses of the intestine demonstrated transmural mucosal infiltration of inflammatory cells without epithelioid granuloma or amyloid deposition. Based on these findings, she was diagnosed with entero BD. Meanwhile, pedal edema appeared during her hospitalization. Urinalysis results were consistent with nephrotic syndrome, thus a renal biopsy was performed. Light microscopy showed no obvious glomerular and interstitial abnormalities, whereas electron microscopy revealed foot process effacement without immune complex deposition or fibrillary structure, compatible with minimal change disease (MCD). Only with conservative therapy, her proteinuria decreased, followed by a complete remission in 3 weeks from the onset of edema. The coincident episode of MCD was finally diagnosed as renal BD that paralleled disease activity to entero BD. She started adalimumab administration, resulting in the further improvement of diarrhea and inflammatory levels.

Conclusions

This is the first report to demonstrate MCD as renal involvement of BD along with the disease activity of entero BD.

Preliminary Report on Interleukin-22, GM-CSF, and IL-17F in the Pathogenesis of Acute Anterior Uveitis

Purpose:Anterior uveitis is the most common anatomic subset of uveitis. We developed a novel multi-parametric flow cytometry panel to identify immune dysregulation signatures in HLA B27-associated acute anterior uveitis (AAU) and axial spondyloarthritis (AxSpA).Methods: We used fluorescence activated cell sorting to characterize T cell cytokine expression in stimulated T cell subsets from patients with AAU (n = 4) compared to healthy controls (n = 14) or subjects with AxSpA (n = 6).Results: Positive findings among subjects with AAU included a statistically significant increase in stimulated granulocyte-macrophage colony stimulating factor (GM-CSF), IL-17, and IL-22 synthesized by CD8 cells, a trend for stimulated ILC (innate lymphoid cells)-3 cells to synthesize more IL-22 (p = .07), and stimulated MAIT (mucosa associated innate lymphoid cells)-like cells that express the T cell receptor V alpha 7.2 to express IL-17A, IL-17F, and IL-22 in a greater percentage of cells relative to controls. IL-17F, GM- CSF, and IL-22 represent potentially novel targets in AAU.Conclusion: Our report is arguably the first to implicate IL-17F or ILC-3 and MAIT cells in the pathogenesis of AAU.Abbreviations AAU: acute anterior uveitis; AxSpA: axial spondyloarthritis; BASDAI: Bath ankylosing spondylitis disease activity index; CCR: chemokine receptor; DMSO: dimethylsulfoxide; EULAR:European League Against Rheumatism; FACS: fluorescence activated cell sorter; FBS: fetal bovine serum; FSC: orward light scatter; GM-CSF: granulocyte-macrophage colony stimulating factor; HC: healthy control; ILC: innate lymphoid cell; KIR: killer immunoglobulin receptor; MAIT: mucosal associated immune T cell; ND: not detected; NK: natural killer cell; OHSU-Oregon Health & Science University; PBMC: peripheral blood mononuclear cell; SSC: side light scatter; TCR: T cell receptor.

Comprehensive miRNA Analysis Using Serum From Patients With Noninfectious Uveitis

Purpose

MicroRNAs (miRNAs) are noncoding RNAs and have attracted attention as a biomarker in a variety of diseases. However, extensive unbiased miRNAs analysis in patients with uveitis has not been completely explored. In the present study, we comprehensively analyzed the deregulated miRNAs in three major forms of uveitis (Behҫet's disease [BD], sarcoidosis and Vogt–Koyanagi–Harada disease [VKH]) to search for potential biomarkers.

Methods

This study included 10 patients with BD, 17 patients with sarcoidosis, and 13 patients with VKH. Eleven healthy subjects were used as controls. The miRNAs expression levels were studied by microarray using serum samples from patients with uveitis and healthy controls.

Results

A total of 281 upregulated miRNAs and 137 downregulated miRNAs were detected in patients with BD, 35 upregulated miRNAs and 86 downregulated miRNAs in patients with sarcoidosis, and 153 upregulated miRNAs and 35 downregulated miRNAs in patients with VKH. Some deregulated miRNAs were involved in the mitogen-activated protein kinase signaling pathway and inflammatory cytokine pathways. Furthermore, we identified miR-4708-3p, miR-4323, and let-7g-3p as the best predictor miRNAs for BD, sarcoidosis, and VKH, respectively. Panels of miRNAs with diagnostic potential for the three diseases were generated using machine learning.

Conclusions

In this study, comprehensive miRNA analysis identified deregulated miRNAs in three major forms of noninfectious uveitis. This study provides new insights into molecular pathogenetic mechanisms and useful information toward developing novel diagnostic biomarkers and therapeutic targets for BD, sarcoidosis, and VKH.

Decreased Expression of Sirt1 Contributes to Ocular Behçet's Disease Progression via Th17 and Th22 Response

BACKGROUND

Previous studies have indicated that Sirtuin 1 (Sirt1) plays an important role in suppressing inflammatory responses in many diseases. However, the Sirt1 levels and role of Sirt1 in ocular Behçet's disease (OBD) have not been fully elucidated.

OBJECTIVE

The objective of this study was to investigate the role of Sirt1 in the pathogenesis of OBD.

METHODS

Sirt1 and cytokine levels were measured using ELISA. Cell viability was determined using the Cell Counting Kit-8. The frequencies of Th17 and Th22 cells were detected using flow cytometry.

RESULTS

We found decreased expression of Sirt1 in CD4+ T cells obtained from patients with active OBD. SRT1720, an agonist of Sirt1, significantly upregulated Sirt1 expression in CD4+ T cells from patients with active OBD. Sirt1 activation by SRT1720 significantly suppressed the production of interleukin (IL)-17 and IL-22 by CD4+ T cells and inhibited the expansion of Th17 and Th22 cells.

CONCLUSION

Our results suggest that decreased Sirt1 expression might be involved in the pathogenesis of OBD and that activation of Sirt1 might be considered a potential target for OBD.

Behҫet's Disease, and the Role of TNF-α and TNF-α Blockers

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-1β 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.

Crosstalk between T Helper Cell Subsets and Their Roles in Immunopathogenesis and Outcome of Polytrauma Patients

Purpose

One of the leading causes of morbidity and early-age mortality across the globe is trauma. It disrupts immune system homeostasis and intensely affects the innate and adaptive immune responses, predisposing patients to posttrauma complications and poor outcomes. Most of the studies on posttrauma cellular immune response have been centered on the T helper-1-T helper-2 imbalances after trauma. This study was conducted to understand the role of circulating novel T helper cells in the acute posttraumatic period and clinical outcome of trauma patients.

Materials and methods

Signature cytokines and transcription factors of circulating Th (T helper)-9, Th-17, Th-22, and regulatory T helper cells were studied using flowcytometry along with serum biomarkers in 49 patients with polytraumatic injuries admitted to a tertiary care hospital. The patients were followed up until their outcome. The results were correlated with their clinical outcomes.

Results

In patients who died, higher nTreg, iTreg, Tr1 (early-phase), and higher IRF4+Th-9, IL17+ Th-17, and RORγT+ Th-17 (mid-phase) were seen. However, by the late phase, only RORγT+ Th-17 remained higher. Serum IL-6 and PCT were found to be consistently higher. In survivors, higher Th-3 (early phase), Th-22 (mid-phase), and IRF4+Th-9, IL17+ Th-17, nTreg, Th-3 (late phase) were observed to have played a protective role. Serum IL-2, IL-4, IL-17A and IL-22 were significantly higher in survivors.

Conclusion

Different T helper subsets were observed to be playing pathogenic and protective roles in different phases of trauma and could be used for early prognostication and make way for noninvasive management of critically injured trauma patients by immunomodulation.

How to cite this article

Khurana S, Bhardwaj N, Kumar S, Sagar S, Pal R, Soni KD, et al. Crosstalk between T Helper Cell Subsets and Their Roles in Immunopathogenesis and Outcome of Polytrauma Patients. Indian J Crit Care Med 2020;24(11):1037–1044.

Interleukin 22 ameliorates neuropathology and protects from central nervous system autoimmunity

IL-22 has opposing effects in different tissues, from pro-inflammatory (skin, joints) to protective (liver, intestine) but little is known about its effects on neuroinflammation. We examined the effect of IL-22 on retinal tissue by using the model of experimental autoimmune uveitis (EAU) in IL-22-/- mice, as well as by intraocular injections of recombinant IL-22 or anti-IL-22 antibodies in wild type animals. During EAU, IL-22 was produced in the eye by CD4+ eye-infiltrating T cells. EAU-challenged IL-22-/- mice, as well as WT mice treated systemically or intraocularly with anti-IL-22 antibodies during the expression phase of disease, developed exacerbated retinal damage. Furthermore, IL-22-/- mice were more susceptible than WT controls to glutamate-induced neurotoxicity, whereas local IL-22 supplementation was protective, suggesting direct or indirect neuroprotective effects. Mechanistic studies revealed that retinal glial Müller cells express IL-22rα1 in vivo, and in vitro IL-22 enhanced their ability to suppress proliferation of effector T cells. Finally, IL-22 injected into the eye concurrently with IL-1, inhibited the (IL-1-induced) expression of multiple proinflammatory and proapoptotic genes in retinal tissue. These findings suggest that IL-22 can function locally within the retina to reduce inflammatory damage and provide neuroprotection by affecting multiple molecular and cellular pathways.

Detection of Complement Activators in Immune Attack Eyes After iPS-Derived Retinal Pigment Epithelial Cell Transplantation

Purpose

To determine whether human induced pluripotent stem (iPS) cell-derived retinal pigment epithelial (RPE) cells (iPS-RPE) can express complement factors.

Methods

To confirm expression of complement factors in human iPS-RPE cells, we performed flow cytometry, immunohistochemistry, ELISA, and quantitative RT-PCR for the following: C3, C5, CFB (Factor B), C5b-9 (membrane attack complex [MAC]), CFH (Factor H), CFI (Factor I), CD46, CD55, CD59, clusterin, and vitronectin. We also prepared iPS-RPE cells in the presence of recombinant IFN-γ, recombinant TNF-α, lipopolysaccharide, supernatants of naïve T cells, and T helper 1 (Th1) cells. For the transplantation, after preparation of iPS-RPE cells from cynomolgus monkeys, the iPS-RPE cells (allografts) were transplanted into the subretinal space in monkeys. After surgery, monkeys were euthanized for IHC evaluation of the retinal section and determination of complement factors (C3, C5, CFB, MAC, and C1q), cytokines, and immunoglobulin G (IgG).

Results

Human iPS-RPE cells expressed complement activators and inhibitors. iPS-RPE cells highly expressed complement factors during inflammatory conditions, especially IFN-γ exposure including Th1 cell supernatants. In immune attack eyes after allogeneic iPS-RPE cell transplantation, complement activators such as C3, CFB, C5, and MAC were detected around the host RPE layer, grafted RPE cells, inflammatory retinal lesions, and transplanted subretinal space. In addition, we observed a large number of C1q and IgG double positive and IFN-γ positive inflammatory cells in the retinal sections.

Conclusions

iPS-derived RPE cells greatly expressed complement factors. Thus, RPE cells might be activated and produce complement factors after exposure to infiltrating inflammatory cells in the eye.

Immunopathogenesis of Behcet's Disease

Behcet's disease (BD) is a chronic systemic inflammatory vasculitis of unknown etiology characterized by recurrent episodes of oral aphthous ulcers, genital ulcers, skin lesions, ocular lesions, and other manifestations. Although the pathogenesis of BD is unclear, some studies have shown that immunological aberrations play an important role in the development and progression of BD. Infection-related trigger factors, including antigens and autoantigens, are believed to mediate the development of BD in patients with a genetic predisposition and subsequently activate the innate and adaptive immune systems, resulting in the production of numerous cytokines and chemokines to combat the infection-related factors. The study of the immunological mechanism of BD paves the way for the development of innovative therapies. Recently, novel biotherapy approaches, including interferon-α (IFN-α), tumor necrosis factor-α (TNF-α) antagonists, and other agents that target interleukins and their receptors, have shown promising results in the treatment of patients with refractory BD and have improved the prognosis of BD. In this review, we provide the current concepts of BD immunopathogenesis.

IL-22 promotes allergic airway inflammation in epicutaneously sensitized mice

BACKGROUND

Serum IL-22 levels are increased in patients with atopic dermatitis, which commonly precedes asthma in the atopic march. Epicutaneous sensitization in mice results in TH2-dominated skin inflammation that mimics atopic dermatitis and sensitizes the airways for antigen challenge-induced allergic inflammation characterized by the presence of both eosinophils and neutrophils. Epicutaneous sensitization results in increased serum levels of IL-22.

OBJECTIVE

We sought to determine the role of IL-22 in antigen-driven airway allergic inflammation after inhalation challenge in epicutaneously sensitized mice.

METHODS

Wild-type (WT) and Il22-/- mice were sensitized epicutaneously or immunized intraperitoneally with ovalbumin (OVA) and challenged intranasally with antigen. OVA T-cell receptor-specific T cells were TH22 polarized in vitro. Airway inflammation, mRNA levels in the lungs, and airway hyperresponsiveness (AHR) were examined.

RESULTS

Epicutaneous sensitization preferentially elicited an IL-22 response compared with intraperitoneal immunization. Intranasal challenge of mice epicutaneously sensitized with OVA elicited in the lungs Il22 mRNA expression, IL-22 production, and accumulation of CD3+CD4+IL-22+ T cells that coexpressed IL-17A and TNF-α. Epicutaneously sensitized Il22-/- mice exhibited diminished eosinophil and neutrophil airway infiltration and decreased AHR after intranasal OVA challenge. Production of IL-13, IL-17A, and TNF-α was normal, but IFN-γ production was increased in lung cells from airway-challenged and epicutaneously sensitized Il22-/- mice. Intranasal instillation of IFN-γ-neutralizing antibody partially reversed the defect in eosinophil recruitment. WT recipients of TH22-polarized WT, but not IL-22-deficient, T-cell receptor OVA-specific T cells, which secrete both IL-17A and TNF-α, had neutrophil-dominated airway inflammation and AHR on intranasal OVA challenge. Intranasal instillation of IL-22 with TNF-α, but not IL-17A, elicited neutrophil-dominated airway inflammation and AHR in WT mice, suggesting that loss of IL-22 synergy with TNF-α contributed to defective recruitment of neutrophils into the airways of Il22-/- mice. TNF-α, but not IL-22, blockade at the time of antigen inhalation challenge inhibited airway inflammation in epicutaneously sensitized mice.

CONCLUSION

Epicutaneous sensitization promotes generation of antigen-specific IL-22-producing T cells that promote airway inflammation and AHR after antigen challenge, suggesting that IL-22 plays an important role in the atopic march.

T cell subsets: an integral component in pathogenesis of rheumatic heart disease

Acute rheumatic fever (ARF) is a consequence of pharyngeal infection of group A streptococcal (GAS) infection. Carditis is the most common manifestation of ARF which occurs in 30-45% of the susceptible individuals. Overlooked ARF cases might further progress towards rheumatic heart disease (RHD) in susceptible individuals, which ultimately leads to permanent heart valve damage. Molecular mimicry between streptococcal antigens and human proteins is the most widely accepted theory to describe the pathogenesis of RHD. In the recent past, various subsets of T cells have been reported to play an imperative role in the pathogenesis of RHD. Alterations in various T cell subsets, viz. Th1, Th2, Th17, and Treg cells, and their signature cytokines influence the immune responses and are associated with pathogenesis of RHD. Association of other T cell subsets (Th3, Th9, Th22, and T_FH) is not defined in context of RHD. Several investigations have confirmed the up-regulation of adhesion molecules and thus infiltration of T cells into the heart tissues. T cells secrete both Th type 1 and type 2 cytokines and these auto-reactive T cells play a key role in progression of heart valve damage. In this review, we are going to discuss about the role of T cell subsets and their corresponding cytokines in the pathogenesis of RHD.

Th22 Cells Promote Osteoclast Differentiation via Production of IL-22 in Rheumatoid Arthritis

T helper (Th) cells can differentiate into functionally distinct subsets and play a pivotal role in inflammatory and autoimmune diseases such as rheumatoid arthritis (RA). Th22 cells have been identified as a new subset secreting interleukin (IL)-22. Although elevated levels of IL-22 in the synovial fluids of RA patients were reported, its pathological roles remain unclear. Here, we demonstrated that IL-22 was characteristically produced from CD3+CD4+CC-chemokine receptor (CCR)4+CCR6+CCR10+ cells and their ability of the production of IL-22 markedly exceeded that of other Th subsets and the subset, thereby, designated Th22 cells. Th22 cells were efficiently induced by the stimulation with tumor necrosis factor-α, IL-6, and IL-1β. Th22 cells were markedly infiltrated in synovial tissue in patients with active RA, but not in patients with osteoarthritis (OA). CCL17, CCL20, and CCL28, which are chemokine ligands of CCR4, CCR6, and CCR10, respectively, were abundantly expressed in RA synovial tissue compared to OA. By in vitro Trans-well migration assay, Th22 cells efficiently migrated toward CCL28. Co-culture of Th22 cells, which were sorted from peripheral blood, with monocytes in the presence of macrophage colony-stimulating factor and receptor activator of nuclear factor (NF)-κB ligand induced osteoclasts formation more efficiently than that of either Th1 cells or Th17 cells. Furthermore, IL-22 markedly augmented osteoclast differentiation by promoting nuclear factor of activated T cells c1 expression in CD14+ monocytes. Contrarily, the addition of IFN-γ to the culture significantly decreased osteoclasts number, whereas IL-17 had marginal effects. IL-22 neutralizing antibody inhibited osteoclast formation in the co-culture of Th22 cells with CD14+ monocytes. Collectively, the results indicated that Th22 cells, which co-express chemokine receptors CCR4, CCR6, and CCR10, possess strong potency of tissue migration and accumulate into inflamed synovial tissues where the ligands such as CCL28 are highly expressed. Thus, Th22 cells have the capacity to promote osteoclast differentiation through production of IL-22 and thus play a pivotal role in bone destruction in patients with RA.

Anti-TNF Therapy Induces CD4+ T-Cell Production of IL-22 and Promotes Epithelial Repairs in Patients With Crohn's Disease

Background

Anti-tumor necrosis factor (TNF) therapy appears to be effective in the treatment of Crohn's disease (CD), a chronic inflammatory disease of the gastrointestinal tract. However, the mechanisms involved are not completely understood.

Methods

Fifty-seven active CD patients were enrolled, and cytokine profiles in colonic biopsies of patients with active CD receiving anti-TNF monoclonal antibody (mAb) (infliximab [IFX]) treatment were determined using quantitative real-time polymerase chain reaction (qRT-PCR). Colonic biopsies of active CD patients and healthy donors were cultured with IFX in vitro, and cytokine profiles were measured by qRT-PCR. Peripheral blood (PB)-CD4+ T cells were stimulated with anti-CD3 and anti-CD28 mAbs in the presence of human immunoglobin (HIg), IFX, recombinant human TNF-α converting enzyme (rhTACE), and aryl hydrocarbon receptor (AhR) inhibitor (CH-223191), respectively, to determine interleukin (IL)-22 expression by CD4+ T cells. Caco2 cells were also utilized to study their potential role in modulating epithelial cell barrier repairs in vitro.

Results

IFX therapy markedly upregulated IL-22 mRNA expression in the gut mucosa of CD patients. In vitro treatment with IFX greatly promoted CD CD4+ T cells to express IL-22, which was inhibited by rhTACE, indicating that reverse signaling through binding to membrane-bound TNF mediates anti-TNF-induced IL-22 expression of CD CD4+ T cells. However, blockade of AhR markedly inhibited anti-TNF-induced IL-22+CD4+ T (Th22) cell differentiation in CD patients. Moreover, treatment with IL-22 induced intestinal epithelial cell expression of tight junction proteins (eg, claudin1 and ZO-1) and facilitated transepithelial resistance, indicating that IL-22 protects intestinal mucosa from inflammation via maintenance of epithelial barrier integrity.

Conclusions

Our results uncover a novel mechanism whereby anti-TNF therapy upregulates IL-22 production in CD patients through promoting Th22 cell differentiation and contributes to intestinal epithelial barrier repairs.

Immune Privilege and Eye-Derived T-Regulatory Cells

Certain cellular components of the eye, such as neural retina, are unable to regenerate and replicate after destructive inflammation. Ocular immune privilege provides the eye with immune protection against intraocular inflammation in order to minimize the risk to vision integrity. The eye and immune system use strategies to maintain the ocular immune privilege by regulating the innate and adaptive immune response, which includes immunological ignorance, peripheral tolerance to eye-derived antigens, and intraocular immunosuppressive microenvironment. In this review, we summarize current knowledge regarding the molecular mechanism responsible for the development and maintenance of ocular immune privilege via regulatory T cells (Tregs), which are generated by the anterior chamber-associated immune deviation (ACAID), and ocular resident cells including corneal endothelial (CE) cells, ocular pigment epithelial (PE) cells, and aqueous humor. Furthermore, we examined the therapeutic potential of Tregs generated by RPE cells that express transforming growth factor beta (TGF-β), cytotoxic T lymphocyte-associated antigen-2 alpha (CTLA-2α), and retinoic acid for autoimmune uveoretinitis and evaluated a new strategy using human RPE-induced Tregs for clinical application in inflammatory ocular disease. We believe that a better understanding of the ocular immune privilege associated with Tregs might offer a new approach with regard to therapeutic interventions for ocular autoimmunity.

Cytokines in uveitis

PURPOSE OF REVIEW

Increasing evidence supports Th17 cells as key mediators of ocular inflammatory disease. Cytokines that are important for the development and pathologic function of these cells are potential therapeutic targets in patients with immune mediated uveitis. This review provides an overview of these cytokines including recent insights about their roles in ocular inflammation from laboratory and clinical studies.

RECENT FINDINGS

Interleukin (IL)-6, IL-10, IL-17, IL-22, IL-23 and tumour necrosis factor-alpha (TNFα) are cytokines that have been examined for their functional role in uveitis and their relationship to pathologic Th17 cells. Studies in animal models, particularly in experimental autoimmune uveitis (EAU), have been instrumental in studying the role of these cytokines in disease pathogenesis. More recently, studies on aqueous, vitreous and serum from patients with uveitis using flow cytometry and multiplex ELISA bead-based methodologies have provided insights into the contribution of Th17 cells and the related cytokines in ocular inflammatory diseases. The central role of IL-23 in determining the pathologic Th17 fate has made it an effective therapeutic target in systemic diseases such as psoriasis and thereby an attractive potential target for patients with immune-mediated uveitis.

SUMMARY

Th17 cells, and their related cytokines, are important inflammatory mediators in autoimmune uveitis. Animal and human studies continue to provide new information to direct development of new cytokine-targeted therapies for patients with uveitis.

Frequencies of IL-15Rα+ cells in patients with Behçet's disease and the effects of overexpressing IL-15Rα+ on disease symptoms in mice

It has been suggested higher serum levels of IL-15 and lower expression levels of IL-15 receptor alpha (IL-15Rα) are correlated with pathogenesis of Behçet's disease (BD). However, whether overexpressing IL-15Rα could be used as a therapeutic candidate for BD is currently unclear. Therefore, the purpose of this study was to determine whether overexpressing IL-15Rα could affect BD symptoms in a mouse model. IL-15/IL-15Rα complex expressing vector or protein complex of IL-15/IL-15Rα-Fc was used to treat BD mice. Frequencies of IL-15Rα+ cells in peripheral blood leukocytes (PBL) and lymph node cells were determined using a flow cytometer. BD symptoms in mice improved after treatment with IL-15/15Rα expression vector or IL-15/IL-15Rα-Fc protein complex. In addition, treatment with pIL-15/15Rα significantly (p = .016) decreased disease severity score of BD mice compared to treatment with control vector. Frequencies of IL-15Rα+ cells were also significantly (p = .01) higher in peritoneal macrophages of pIL-15/15Rα treated BD mice than those of mice treated with control vector. Frequencies of IL-15Rα+ PBL were also significantly higher in BD mice treated with IL-15/IL-15Rα-Fc protein complex than those in the control group. These results suggest up-regulating IL-15Rα+ cells could be used as novel therapeutic strategies to control BD in the future.

Role of N-acetyl galactosamine-4-SO4, a ligand of CD206 in HSV-induced mouse model of Behçet's disease

CD206 is a macrophage mannose receptor involved in variety of autoimmune and inflammatory diseases. This study aimed to identify the pathogenic role of CD206 in a herpes simplex virus (HSV) induced Behçet's disease (BD) mouse model. CD206 positive cells were detected in peripheral blood mononuclear cells and quantified by flow cytometry. Levels of cytokines were measured by ELISA. CD206 was found to be down-regulated both in vitro (10^-6M) and in vivo (200μg/mouse) after treatment with N-acetylgalactosamine (GalNAc), a ligand for CD206. The down-regulation of CD206 was correlated with improvement in BD symptoms. Colchicine (2μg/mouse) or pentoxifylline (400μg/mouse) treated mice displayed improvement in BD symptoms with fewer CD206 positive cells. The prevalence of CD206-positive cells differed between ligand-responsive and non-responsive BD mice. Inhibition of CD206 was associated with down-regulated serum level of interleukin-17 in GalNAc-treated BD mice. These results suggest that the expression of CD206 is correlated with HSV-induced BD symptoms in mice, implicating that CD206 might have a pathogenic role in BD.

Persistently elevated circulating Th22 reversely correlates with prognosis in HBV-related acute-on-chronic liver failure

BACKGROUND AND AIM

Hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) is an acute deterioration of liver function on chronic liver disease with immune disorder. Th22 cells and IL-22 were correlated with inflammatory and autoimmune diseases. However, Th22 cells and IL-22 in the pathogenesis of HBV-ACLF remains to be elucidated. It was investigated the correlation between Th22 and prognosis in HBV-ACLF.

METHODS

Seventy-one HBV-ACLF and 65 chronic hepatitis B patients were recruited. The peripheral frequencies of Th22, Th17 and Th1, or IL-22 and IL-17 were determined, using flow cytometry or ELISA, respectively. It was further analyzed the correlation between Th22 mediated circulating IL-22 and survival rate of HBV-ACLF patients.

RESULTS

It was upregulated that the peripheral frequencies of Th22/Th17 cells as well as plasma IL-22 and IL-17 in HBV-ACLF patients, but the frequency of Th1 cells was decreased, compared with health controls. Elevated Th22 cells and IL-22 were correlated with HBV-ACLF disease severity. Elevated plasma IL-22 level (>29.5 pg/ml) was correlated with poor survival rate of HBV-ACLF patients at baseline, using Kaplan-Meier analysis.

CONCLUSIONS

Persistently elevated circulating Th22 reversely correlates with prognosis in HBV-ACLF. Th22 cells/IL-22 might be served as biomarkers for evaluating the prognosis of HBV-ACLF.

Cytokine Signatures in Mucocutaneous and Ocular Behçet's Disease

Behçet's disease (BD) is a multi-systemic inflammatory disorder consisting of recurrent oral aphthosis, genital ulcers, and chronic relapsing bilateral uveitis; however, many other organs may be affected. Several pro-inflammatory cytokines, mainly derived from Th1 and Th17 lymphocytes, seem to be involved in different pathogenic pathways leading to development of the clinical manifestations. On this basis, the primary aim of our study was to compare a core set of pro-inflammatory cytokines between patients with BD and healthy control (HC). The secondary goal was to evaluate potential correlations between these putative circulating biomarkers, the status of disease activity, and the specific organ involvement at the time of sample collection. Fifty-four serum samples were collected from 46 BD patients (17 males, 29 females, mean age 45.5 ± 11.3 years), and 19 HC (10 males, 9 females, mean age 43 ± 8.3 years). Twenty-five serum cytokines (APRIL/TNFS13, BAFF/TNFSF13B, sCD30/TNFRSF8, sCD163, Chitinase3-like1, gp130/sIL-6Rb, IFNb, sIL-6Ra, IL-10, IL-11, IL-19, IL-20, IL-26, IL-27 (p28), IL-28A/IFN-lambda2, IL-29/IFN-lambda1, IL-32, IL-34, IL-35, LIGHT/TNFSF-14, Pentraxin-3, sTNF-R1, sTNF-R2, TSLP, and TWEAK/TNFSF-12) were simultaneously quantified using a Bio-Rad cytokine bead arrays. Serum concentration of sTNF-R1 (p < 0.01) and sTNF-R2 (p < 0.01) resulted higher in both active and inactive BD than HC, while Chitinase3-like1 (p < 0.05) and gp130/sIL-6Rb (p < 0.01) serum levels were significantly higher in inactive BD, and IL-26 (p < 0.01) in active BD than HC. No differences were observed between inactive and active BD group. In addition, we observed that gp130/sIL-6Rb, sIL-6Ra, IL-35, and TSLP serum levels were significantly enhanced in patients with mucocutaneous manifestations plus ocular involvement (MO-BD) compared to subgroup with only mucocutaneous involvement (M-BD). Our findings may suggest a signature of IL-6, tumor necrosis factor-α as well as of Th17 response in BD patients due to increased levels of gp130/sIL-6Rb, sTNF-R1, sTNF-R2, IL-26, respectively. This evidence could contribute to improve the knowledge regarding the role of these citokines in the induction of specific BD clinical features.

The Role of Interleukin-22 and Its Receptor in the Development and Pathogenesis of Experimental Autoimmune Uveitis

IL-22 is a pro- and anti-inflammatory cytokine that is mainly produced by T cells and NK cells. Recent studies have reported the increased number of IL-22 producing T cells in patients with autoimmune noninfectious uveitis; however, the correlation between IL-22 and uveitis remains unclear. In this study, we aimed to determine the specific role of IL-22 and its receptor in the pathogenesis of uveitis. Serum concentration of IL-22 was significantly increased in uveitis patients. IL-22Rα was expressed in the retinal pigment epithelial cell line, ARPE-19. To examine the effect of IL-22, ARPE-19 was treated with recombinant IL-22. The proliferation of ARPE-19 and the production of monocyte chemoattractant protein (MCP)-1 from ARPE-19 were clearly elevated. IL-22 induced MCP-1 which facilitated the migration of inflammatory cells. Moreover, IL-22 increased the IL-22Rα expression in ARPE-19 through the activation of PI3K/Akt. Experimental animal models of uveitis induced by interphotoreceptor retinoid binding protein 1-20 (IRBP1-20) exhibited elevation of hyperplasia RPE and IL-22 production. When CD4+ T cells from the uveitis patients were stimulated with IRBP1-20, the production of IL-22 definitely increased. In addition, we examine the regulatory role of cysteamine, which has an anti-inflammatory role in the cornea, in uveitis through the down-regulation of IL-22Rα expression. Cysteamine effectively suppressed the IRBP1-20-induced IL-22Rα expression and prevented the development of IRBP1-20-induced uveitis in the experimental animal model. These finding suggest that IL-22 and its receptor have a crucial role in the development and pathogenesis of uveitis by facilitating inflammatory cell infiltration, and that cysteamine may be a useful therapeutic drug in treating uveitis by down-regulating IL-22Rα expression in RPE.

Analysis of Th Cell-related Cytokine Production in Behçet Disease Patients with Uveitis Before and After Infliximab Treatment

PURPOSE

To examine antigen-stimulated cytokine production by Behçet disease patients (BD) before and after infliximab infusion.

METHODS

PBMCs were obtained before and after infliximab infusion in BD patients with or without recurrent uveitis during at least 1 year of infliximab therapy, and from healthy subjects. PBMCs were cultured with IRBP, and Th-related cytokines in cultures were measured.

RESULTS

Levels of IL-4, IL-6, IL-10 IL-17A, IL-17F, IL-31, IFN-γ, and TNFα were higher in BD before infliximab infusion than in healthy subjects, and these levels were the highest in BD with recurrent uveitis. After infliximab infusion, these cytokine levels were reduced to a greater extent in BD without recurrent uveitis than in BD with recurrence.

CONCLUSIONS

Th-related cytokines produced by IRBP-stimulated PBMCs were elevated in BD, and infliximab infusion suppressed these cytokines to a greater extent in BD without recurrent uveitis than in those with recurrence.

New insights into CD4(+) T cell abnormalities in systemic sclerosis

Systemic sclerosis (SSc) is an autoimmune connective tissue disease that is characterized by vasculopathy and excessive deposition of extracellular matrix, which causes fibrosis of the skin and internal organs and eventually leads to multiorgan dysfunction. Studies have shown that CD4(+) T cell activation is a key factor in the pathogenesis of scleroderma because activated T cells can release various cytokines, resulting in inflammation, microvascular damage and fibrosis. T helper cell 17 (Th17) and regulatory T (Treg) cell activities are a hallmark SSc, as Th17-type cytokines can induce both inflammation and fibrosis. More recently, several studies have reported new T cell subsets, including Th9 and Th22 cells, along with their respective cytokines in the peripheral blood, serum and skin lesions of individuals with SSc. Herein, we review recent data on various CD4(+) T helper cell subsets in SSc, and discuss potential roles of these cells in promoting inflammation and fibrosis.

Down-regulation of the Th1, Th17, and Th22 pathways due to anti-TNF-α treatment in psoriasis

BACKGROUND

Psoriasis is a T-cell-mediated chronic inflammatory dermatosis. Th1, Th17 and Th22 cells are suggested to contribute to the pathogenesis of psoriasis.

OBJECTIVE

To determine whether treatment with the anti-tumor-necrosis-factor antagonist, adalimumab, induces significant modulation of the Th1, Th17 and Th22 pathways, and correlates cellular activity with clinical response.

METHODS

This study included 21 patients with moderate-to-severe psoriasis who were treated with adalimumab, and 10 healthy control subjects. Blood samples were collected at baseline and at week 12. Flow cytometry was used to analyze the frequency of circulating Th1, Th17 and Th22 cells. Real-time polymerase chain reaction was used to analyze the expression of T-bet (Th1-related), retinoid-acid receptor-related orphan receptor gamma t (RORγt, Th17-related) and aryl hydrocarbon receptor (AHR, Th22-related). An enzyme-linked immunosorbent assay was used to analyze the serum levels of IFN-γ, IL-17, IL-22, IL-6 and tumor necrosis factor-α (TNF-α).

RESULTS

At baseline, the frequencies of Th1, Th17 and Th22 cells were higher in psoriasis patients compared to the healthy controls. The expression of transcription factors T-bet, RORγt and AHR, and the serum levels of IFN-γ, IL-17, IL-22, IL-6 and TNF-α were higher in psoriasis patients compared to the healthy controls. After adalimumab therapy, there was a significant decline in the frequencies of Th1, Th17 and Th22 cells, and a concomitant decrease in the levels of their associated transcription factors and cytokines.

CONCLUSION

The results suggest that the anti-tumor-necrosis-factor antagonist, adalimumab, disrupts the Th1, Th17 and Th22 pathways, resulting in clinical improvement of psoriasis.

Inflammation-related cytokine gene polymorphisms in Behçet's disease

Behçet's disease (BD) is a complex, multisystemic inflammatory disorder of unclear etiology. Single nucleotide polymorphisms in tumor necrosis factor (TNF) and interleukin (IL)-10 genes have been implicated in susceptibility to BD with inconsistent results in several ethnic populations. The aim of this case-control study was to evaluate the association of TNF-α (-308G/A), TNF-β (+252A/G), and IL-10 (-1082G/A, -819C/T, and -592 C/A) polymorphisms with susceptibility of BD in Saudi patients. Molecular genotyping of TNF-α, TNF-β, and IL-10 gene polymorphisms was performed to analyze the alleles and genotypes distribution in 272 Saudi subjects, including BD patients (61) and healthy controls (211). The frequencies of allele A and genotype GA of TNF-α (-308G/A) were significantly higher, whereas those of allele G and genotypes GG were significantly lower in BD patients than controls, indicating that A allele and GA genotype are susceptible, while G allele and GG genotype may be refractory to BD. The distribution of frequencies of alleles and genotype of TNF-β (+252A/G) promoter polymorphism was not significantly different between BD patients and healthy controls. Genotypes 1082GG, -819TT, and 592AA of IL-10 polymorphisms are significantly associated with susceptibility risk of BD, while genotypes 1082AA, 1082GA, 819CC, 819CT, 592CC, and 592CA are resistant to BD. This study indicates that TNF-α (-308G/A) and IL-10 (-1082G/A, -819C/T, and -592C/A) polymorphisms are associated with risk of BD susceptibility in Saudi patients. However, larger scale studies in Saudi population as well as in other ethnicities are needed to confirm this association.

T-helper 22 cells as a new player in chronic inflammatory skin disorders

T-helper 22 (Th22) cell is a new subset of CD4+ T cells that secrets interleukin (IL)-22 but not IL-17 or interferon-γ. Th22 is distinct from Th17 and other known CD4+ T-cell subsets with distinguished gene expression and function. Th22 subsets have chemokine receptors CCR6+ CCR4+ CCR10+ phenotype and aryl hydrocarbon receptor as the key transcription factor. This T-helper subset, by producing cytokines such as IL-22, IL-13, and tumor necrosis factor-α, is implicated in the pathogenesis of inflammatory skin disorder. This review discusses the role of Th22 and its cytokine IL-22 in the immunopathogenesis of inflammatory skin disorders such as psoriasis and atopic dermatitis.

Murine pattern recognition receptor dectin-1 is essential in the development of experimental autoimmune uveoretinitis

Mycobacteria in complete Freund's adjuvant (CFA) are an essential component of immunization protocols in a number of autoimmune disease animal models including experimental autoimmune encephalomyelitis and uveoretinitis (EAE and EAU, respectively). We determined the role in EAU of two C-type lectin receptors on myeloid cells that recognize and respond to mycobacteria. Using receptor-specific antibodies and knockout mice, we demonstrated for the first time that the macrophage mannose receptor delays disease development but does not affect severity. In contrast, dectin-1 is critically involved in the development of CFA-mediated EAU. Disease severity is reduced in dectin-1 knockout mice and antibody blockade of dectin-1 during the induction, but not the effector phase, prevents EAU development. Significantly, similar blockade of dectin-1 in vivo has no effect in non-CFA-mediated, spontaneously induced or adoptive transfer models of EAU. Thus dectin-1 plays a critical role in the ability of complete Freund's adjuvant to induce EAU in mice.

Anti-tumor necrosis factor-α therapy in uveitis

Since the first reported use in 2001 of an anti-tumor necrosis factor-alpha (TNF-α) agent, infliximab, for the treatment of uveitis, several new anti-TNF-α agents have emerged for the treatment of refractory noninfectious uveitides, although their use remains off-label in the US. These agents have demonstrated remarkable clinical antiinflammatory efficacy and a potential immunoregulatory role in selected uveitis patients, but it is currently unclear whether they can modify the natural history of disease. We review the rationale and clinical indications for this therapy, the differences between agents, how to manage dosing and intervals, and how to screen for and identify potential side effects. We also present a summary of the science behind the use of anti-TNF-α agents in ocular inflammation and the evidence for their efficacy.

The potential protective role of the combination of IL-22 and TNF-α against genital tract Chlamydia trachomatis infection

Th22 cells are a novel class of lymphocytes characterized by the secretion of both IL-22 and TNF-α. In summary, Th22 cells have little or no direct impact on other immune cells, but exert selective effects on epithelia. It is not known, however, whether Th22 cells play a role in genital mucosal immunity. Here, we demonstrate that IL-22 and TNF-α synergistically induce several immunomodulatory molecules, such as the antimicrobial peptide mBD-2 (murine β-defensin 2) and the antimicrobial chemokines CXCL-9, -10, and -11 in primary murine oviduct epithelial cells (MOECs). The induction of innate immunity is relevant in an in vitro infection model, in which MOECs stimulated with Th22 cell supernatants or recombinant IL-22 and TNF-α effectively inhibit the growth of Chlamydia trachomatis and maintain the survival of the epithelia compared with IL-22 or TNF-α alone. In summary, we demonstrate that the Th22 cell cytokines IL-22 and TNF-α play important roles in genital tract infection. The potential for Th22 cell cytokines to modulate innate immune mediators may lead to the development of new topical agents to treat and/or prevent immune-mediated sexually transmitted diseases (STDs). In summary, we demonstrate that IL-22 and TNF-α represent a potent, synergistic cytokine combination for inducing genital mucosal immunity.