Expressions of IL-22 in circulating CD4+/CD8+ T cells and their correlation with disease activity in SLE patients

The role of the aryl hydrocarbon receptor (AhR) in modulating intestinal ILC3s to optimise gut pathogen resistance in lupus and benefits of nutritional AhR ligands

BACKGROUND AND AIMS

Dysbiosis is emerging as a potential trigger of systemic lupus erythematosus (SLE). Group 3 innate lymphoid cells (ILC3s) are recognised as key regulators of intestinal homeostasis. The aryl hydrocarbon receptor (AhR) is critical to intestinal ILC3 development and function. This mechanistic review aimed to investigate whether AhR activation of gut ILC3s facilitates IL-22-mediated antimicrobial peptide (AMP) production to enhance colonisation resistance and ameliorate SLE pathology associated with intestinal dysbiosis. Furthermore, nutritional AhR ligand potential to enhance pathogen resistance was explored.

METHODOLOGY

This mechanistic review involved a three-tranche systematic literature search (review, mechanism, intervention) using PubMed with critical appraisal. Data was synthesised into themes and summarised in a narrative analysis.

RESULTS

Preclinical mechanistic data indicate that AhR modulation of intestinal ILC3s optimises pathogen resistance via IL-22-derived AMPs. Pre-clinical research is required to validate this mechanism in SLE. Data on systemic immune consequences of AhR modulation in lupus suggest UVB-activated ligands induce aberrant AhR signalling while many dietary ligands exert beneficial effects. Data on xenobiotic-origin ligands is varied, although considerable evidence has demonstrated negative effects on Th17 to Treg balance. Limited human evidence supports the role of nutritional AhR ligands in modulating SLE pathology. Preclinical and clinical data support anti-inflammatory effects of dietary AhR ligands.

CONCLUSION

Current evidence is insufficient to fully validate the hypothesis that AhR modulation of intestinal ILC3s can enhance pathogen resistance to ameliorate lupus pathology driven by dysbiosis. However, anti-inflammatory effects of dietary AhR ligands suggest a promising role as a therapeutic intervention for SLE.

T helper (Th) cell profiles and cytokines/chemokines in characterization, treatment, and monitoring of autoimmune diseases

Autoimmune diseases (AD) consist of a spectrum of disease entities whose etiologies are very complex and still not well understood. Every individual has the potential for developing AD under appropriate conditions because the body contains lymphocytes that are potentially reactive with self-antigens. The aims of this study are to (1) explore the flow cytometry method to identify the frequency of various circulating CD4+ T helper (Th) cell-subsets, including Th1, Th2, Th9, Th17, Th17.1, and Th22; (2) In parallel, to examine multiplex ELISA method for pathogenic inflammatory cytokines/chemokines, and (3) To assess the correlation of expression of T cell-subsets with serum cytokines/chemokines and understand its clinical importance with available AD treatments. We analyzed Th17, Th17.1, Th22, Th2, Th1, and Th9 Th cell populations and compared the concentrations of 67 cytokines/chemokines in healthy as well as AD-diagnosed patients. We observed that patients with autoimmune markers had significantly elevated percentages of naïve (Th17, Th22, and Th9) as well as memory (Th17 and Th22) Th cell-subsets, along with increased concentrations of cytokines/chemokines (Eotaxin, TNFβ, and FABP4). The percentage of Th cell-subsets correlated positively or negatively with the production of cytokines/chemokines of patients diagnosed with AD. Our study demonstrates that the naïve and memory Th cell-subsets with positive correlations to cytokines/chemokines show new diagnostic markers to predict the patients' outcome, while the negative correlation of cytokines/chemokines shows the response to autoimmune therapies. Our findings of Th cell-subsets by flow cytometry and cytokines/chemokines by multiplex ELISA suggest that CCR6+ Th cell-subsets (Th17, Th17.1, Th22, and Th9) contribute to our understanding of the pathogenesis of AD and identify the new onset of AD from the autoimmune spectrum. Our findings highlight the importance of CCR6+ as a possible marker in the characterization, treatment, and monitoring of AD.

Vitamin D Presented In Vitro Immunomodulatory Property on T Lymphocyte-Related Cytokines in Systemic Lupus Erythematosus

Inflammatory T lymphocyte cytokines contribute to tissue damage in SLE patients. Vitamin D (Vit D) has a well-established immunomodulatory action, but few studies have addressed the effect of 1,25 dihydroxyvitamin D3 (1,25 (OH)2D3) on peripheral blood mononuclear cells (PBMCs) in SLE patients. The aim of this study was to evaluate the immnunomodulatory effect of 1,25 (OH)2D3 on T lymphocyte-related cytokines. Blood from 27 female SLE patients was collected for PBMC isolation and anti-DNA, complement, and serum 25 (OH)D3 level measurements. PBMCs were stimulated with anti-CD3/anti-CD28 in the presence or absence of dexamethasone or various concentrations of 1,25 (OH)2D3 for 48 h. We assessed IL-17A, IL-22, IL-21, IL-9, IFN-γ, IL-4, IL-10, IL-2, IL-6, and TNF by cytometric bead assay (CBA) and enzyme immune assay (ELISA) on culture supernatant. The mean age of patients was 36.2 (± 10.5 years) and the median Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) was 4 (0-6). The addition of 1,25 (OH)2D3 in PBMC culture reduced IL-17 A, IL-22, IL-9, and IFN-γ levels at 100 nM (p ≤ 0.0001). Furthermore, the addition of 1,25 (OH)2D3 at all concentrations increased IL-4 (p ≤ 0.0006), and 0.1 and 1 nM increased IL-10 (p ≤ 0.0004) and 0.1 nM increased IL-2 levels (p ≤ 0.0001). There was no difference regarding IL-21 and TNF levels. The addition of 1,25 (OH)2D3 in PBMC culture presented an inhibitory effect on proinflammatory cytokines and increased immunoregulatory cytokines in SLE patients, suggesting the beneficial effect of this vitamin.

Cathepsin B inhibitor alleviates Th1, Th17, and Th22 transcription factor signaling dysregulation in experimental autoimmune encephalomyelitis

Multiple sclerosis (MS) is an autoimmune disease characterized by inflammatory infiltration in association with demyelination in the central nervous system. Among the factors involved in the immunological mechanisms of MS, Th1, Th17, and Th22 cells play a critical role. In the present study, we investigated the role of CA-074, a potent Cathepsin B inhibitor, in MS progression, using the SJL/J mouse model of experimental autoimmune encephalomyelitis (EAE). Following induction of EAE, mice were administered CA-074 (10 mg/kg) intraperitoneally each day, beginning on day 14 and continuing until day 28, and were evaluated for clinical signs. We further investigated the effect of CA-074 on Th1 (T-bet/STAT4), Th17 (IL-17A/RORγT), Th22 (TNF-α/IL-22), and regulatory T (Treg/Foxp3) cells in the spleen, using flow cytometry. We also analyzed the effect of CA-074 on T-bet, IL-17A, RORγT, IL-22, and mRNA and protein levels using RT-PCR and western blot analysis for brain tissues. Cathepsin B expression were also assessed by western blot in the brain tissues. The severity of clinical scores decreased significantly in CA-074-treated mice compared with that in EAE control mice. Moreover, the percentage of CD4⁺T-bet⁺, CXCR5⁺T-bet⁺, CD4⁺STAT4⁺, CD4⁺IL-17A⁺, CXCR5⁺IL-17A⁺, CD4⁺RORγT⁺, CCR6⁺RORγT⁺, CD4⁺TNF-α⁺, CD4⁺IL-22⁺, and CCR6⁺IL-22⁺ cells decreased while CD25⁺Foxp3⁺ increased in CA-074-treated EAE mice as compared to vehicle-treated EAE mice. Further, CA-074-treated EAE mice had downregulated Cathepsin B protein expression which was associated with decreased T-bet, IL-17A, RORγT, and IL-22 mRNA/protein expression. These results suggest that Cathepsin B could be a novel therapeutic candidate against for the treatment of MS.

Effects of combined aerobic and anaerobic exercise training on cytokine profiles in patients with systemic lupus erythematosus (SLE); a randomized controlled trial

BACKGROUND

Systemic lupus erythematosus (SLE) is an inflammatory rheumatic disease characterized by production of autoantibodies and organ damage. Elevated levels of cytokines have been reported in SLE patients. Physical activity could be considered one of the factors that affect the immune system status and function. The aim of the present study was to evaluate the effects of an 8-week supervised aerobic and anaerobic training program on the immune system of SLE patients through evaluation of serum cytokine levels.

METHODS

This cross-sectional study included 24 SLE patients selected between September 2015 and March 2016. The patients were randomly divided into two groups, including exercise (n = 14) and control (n = 10) groups. The exercise group participated in an 8-week combined supervised exercise training program consisting of three times per week in 60-min exercise sessions. After collection of whole peripheral blood, peripheral blood mononuclear cells (PBMCs) were isolated from the blood samples. Following RNA extraction and cDNA synthesis, the expression levels of IFN-γ, TNF-α, IL-6, IL-2, IL-4, IL-5, IL-9, IL-10, IL-13, IL-17A, IL-17F, IL-21, and IL-22 were determined using in-house SYBER Green-based real-time polymerase chain reaction (PCR). Lastly, the data obtained were analyzed using t-test.

RESULTS

The mean and standard deviation of age were 29.00 ± 3.19 and 21.50 ± 5.52 in the intervention and control groups, respectively. No significant differences were found among the mean serum levels of IFN-γ, IL6, IL-9, IL-17A, IL-17F and IL-21 among SLE patients in the intervention and control groups. The mean serum levels of TNF-α, IL2, IL-4, and IL-5 decreased significantly in the intervention as compared with the control group. The mean serum levels of IL-10, IL-13 and IL-22 significantly increased in the control group after eight weeks, as compared with the intervention group.

CONCLUSIONS

Our findings indicated that the 8-week supervised aerobic and anaerobic training program could result in decreased inflammatory cytokines.

T Cells in Systemic Lupus Erythematosus

T-cell dysregulation has been implicated in the loss of tolerance and overactivation of B cells in systemic lupus erythematosus (SLE). Recent studies have identified T-cell subsets and genetic, epigenetic, and environmental factors that contribute to pathogenic T-cell differentiation, as well as disease pathogenesis and clinical phenotypes in SLE. Many therapeutics targeting T-cell pathways are under development, and although many have not progressed in clinical trials, the recent approval of the calcineurin inhibitor voclosporin is encouraging. Further study of T-cell subsets and biomarkers of T-cell action may pave the way for specific targeting of pathogenic T-cell populations in SLE.

Infiltration by IL22-Producing T Cells Promotes Neutrophil Recruitment and Predicts Favorable Clinical Outcome in Human Colorectal Cancer

Immune cell infiltration in colorectal cancer effectively predicts clinical outcome. IL22, produced by immune cells, plays an important role in inflammatory bowel disease, but its relevance in colorectal cancer remains unclear. Here, we addressed the prognostic significance of IL22+ cell infiltration in colorectal cancer and its effects on the composition of tumor microenvironment. Tissue microarrays (TMA) were stained with an IL22-specific mAb, and positive immune cells were counted by expert pathologists. Results were correlated with clinicopathologic data and overall survival (OS). Phenotypes of IL22-producing cells were assessed by flow cytometry on cell suspensions from digested specimens. Chemokine production was evaluated in vitro upon colorectal cancer cell exposure to IL22, and culture supernatants were used to assess neutrophil migration in vitro Evaluation of a testing (n = 425) and a validation TMA (n = 89) revealed that high numbers of IL22 tumor-infiltrating immune cells were associated with improved OS in colorectal cancer. Ex vivo analysis indicated that IL22 was produced by CD4+ and CD8+ polyfunctional T cells, which also produced IL17 and IFNγ. Exposure of colorectal cancer cells to IL22 promoted the release of the neutrophil-recruiting chemokines CXCL1, CXCL2, and CXCL3 and enhanced neutrophil migration in vitro Combined survival analysis revealed that the favorable prognostic significance of IL22 in colorectal cancer relied on the presence of neutrophils and was enhanced by T-cell infiltration. Altogether, colorectal cancer-infiltrating IL22-producing T cells promoted a favorable clinical outcome by recruiting beneficial neutrophils capable of enhancing T-cell responses.

Endogenous IL-22 is dispensable for experimental glomerulonephritis

In recent years, the cytokine interleukin (IL)-22 attracted considerable attention due to its important immunoregulatory function in barrier tissues, such as the gut, lung, and skin. Although a regenerative role of IL-22 in renal tubular damage has been demonstrated, the role of IL-22 in the immunopathogenesis of glomerular injury is still unknown. Here, we demonstrate that the IL-22 receptor is expressed in the glomerular compartment of the kidney and that IL-22 expression increases in the renal cortex after induction of glomerular injury in a mouse model for crescentic glomerulonephritis (cGN, nephrotoxic nephritis). We identified γδ T cells and TH17 cells as major sources for IL-22 in the nephritic kidney. However, neither genetic or antibody-mediated deletion of IL-22 nor genetic deficiency in its endogenous inhibitor IL-22Rα2 (IL-22 binding protein) resulted in substantial phenotypic differences in mice with cGN with respect to crescent formation, tubulointerstitial damage, and kidney function impairment. Similarly, we did not observe significant differences between wild-type or IL-22-deficient mice in a mouse model of secondary focal and segmental glomerulosclerosis (adriamycin-induced nephropathy). As shown previously, we detected concomitant upregulation of IL-17A and IFN-γ production by T cells during the course of cGN, providing alternative cytokine pathways that mediate glomerular injury in this model. In conclusion, we show here that endogenous IL-22 expression is redundant in different forms of glomerular injury, indicating that the IL-22-directed therapies that are being tested in various human diseases might not affect the kidney in patients with glomerular disease.

Impaired TGF-β signaling in patients with active systemic lupus erythematosus is associated with an overexpression of IL-22

The mechanisms leading to the disruption of self-tolerance in systemic lupus erythematosus (SLE) remain elusive. Herein, we aimed to decipher the molecular basis of the impaired response of mononuclear cells to TGF-β1. The Smad3-pathway was explored on CD3+ lymphocytes in either active or non active SLE patients. An impaired transcription of TGF-β1 target genes was demonstrated in the CD3+ lymphocytes of active SLE patients confirming that the defect involves T cells and pointing to its extrinsic nature. We further demonstrate that the defect did not result from an impaired TGF-βRII expression or Smad2/3 phosphorylation suggesting that the mechanism lies downstream Smad2/3 translocation. Interestingly, the TGF-1 signaling defect did not correlate with an increased expression of soluble or membrane-bound IL-15. However, it was associated with an overexpression of IL-22. This suggests that an excessive activation of AhR pathway (through UV radiations, infections, etc.) could lead to the inhibition of immunosuppressive actions of TGF-β thus disrupting immune homeostasis in SLE. Collectively, our data suggest that the impaired response to TGF-β in SLE patients is associated with disease activity and provide new insights into the pathogenesis of SLE since it could establish the link between the environmental factors and the aberrancies of the immune system usually described in SLE.

Elevated levels of CCR6+ T helper 22 cells correlate with skin and renal impairment in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease with a variety of pathological features. Our study investigated the potential role of CCR6+ T cells in organ impairment of SLE patients. We analyzed CCR6+/- T cell subset populations and compared the concentrations of IL-22, IFN-γ, TNF-α, and IL-17A cytokines in 67 patients with newly diagnosed SLE and 26 healthy controls. We found that SLE patients had elevated percentages of CCR6+ T, CCR6+ Th22, Th17, Th17.1, and CCR6- Th2 cell subsets, along with increased concentrations of IL-22, IFN-γ, TNF-α, and IL-17 cytokines. Higher levels of CCR6+ T and CCR6+ Th22 cells, along with plasma IL-22 were observed in SLE patients with sole skin and/or renal impairment. The percentage of Th22 cells also correlated with Revised Cutaneous Lupus Erythematosus Disease Area and Severity Index (RCLASI) and IgG levels, and inversely correlated with C3 levels in SLE patients with sole skin impairment. SLE patients with sole renal impairment showed a correlation between the percentage of Th22 cells and ESR levels. Our data indicated that CCR6+ Th22 cells may contribute to the pathogenesis of new onset SLE patients with skin or renal impairment, and CCR6 may, thus, be a possible therapeutic target for SLE treatment.

IL-22 promotes Fas expression in oligodendrocytes and inhibits FOXP3 expression in T cells by activating the NF-κB pathway in multiple sclerosis

Multiple sclerosis (MS) is characterized by an increase in interleukin-22 and Fas, and a decrease in FOXP3, among other factors. In this study, we examined patients with MS and healthy control subjects and used the experimental autoimmune encephalomyelitis (EAE) animal model to identify the effects of IL-22 on oligodendrocytes and T cells in MS development. In MS, the expression of Fas in oligodendrocytes and IL-22 in CD4+CCR4+CCR6+CCR10+ T cells was enhanced. Ikaros and FOXP3 were both decreased in T cells. Depending on exogenous IL-22, Fas increased the phosphorylation of mitogen- and stress-activated protein kinase 1 and activated the nuclear factor-κB pathway in oligodendrocytes, leading to an increase in Fas and oligodendrocyte apoptosis. IL-22 decreased FOXP3 expression by activating NF-κB, and it further inhibited PTEN and Ikaros expression. Tregs reversed the functions of IL-22. Taken together, these findings help to elucidate the mechanisms of IL-22 in MS development.

AAV-IL-22 modifies liver chemokine activity and ameliorates portal inflammation in murine autoimmune cholangitis

There remain significant obstacles in developing biologics to treat primary biliary cholangitis (PBC). Although a number of agents have been studied both in murine models and human patients, the results have been relatively disappointing. IL-22 is a member of the IL-10 family and has multiple theoretical reasons for predicting successful usage in PBC. We have taken advantage of an IL-22 expressing adeno-associated virus (AAV-IL-22) to address the potential role of IL-22 in not only protecting mice from autoimmune cholangitis, but also in treating animals with established portal inflammation. Using our established mouse model of 2-OA-OVA immunization, including α-galactosylceramide (α-GalCer) stimulation, we treated mice both before and after the onset of clinical disease with AAV-IL-22. Firstly, AAV-IL-22 treatment given prior to 2-OA-OVA and α-GalCer exposure, i.e. before the onset of disease, significantly reduces the portal inflammatory response, production of Th1 cytokines and appearance of liver fibrosis. It also reduced the liver lymphotropic chemokines CCL5, CCL19, CXCL9, and CXCL10. Secondly, and more importantly, therapeutic use of AAV-IL-22, administered after the onset of disease, achieved a greater hurdle and significantly improved portal pathology. Further the improvements in inflammation were negatively correlated with levels of CCL5 and CXCL10 and positively correlated with levels of IL-22. In conclusion, we submit that the clinical use of IL-22 has a potential role in modulating the inflammatory portal process in patients with PBC.

Exploring the role of interleukin-22 in neurological and autoimmune disorders

Interleukin-22 (IL-22) is a member of the IL-10 cytokine family that has recently gained attention in regard to its recognized pathogenic role in neurological and autoimmune disorders. The pathological involvement of IL-22 has been linked to Th17 cells that are involved in its production. Its biological activity results from its ability to bind to a heterodimeric receptor consisting of IL-22 receptor 1 (IL-22R1) and IL-10R2. Emerging evidence has identified IL-22 involvement in neurological diseases and autoimmune disorders such as Guillain-Barré Syndrome (GBS), multiple sclerosis (MS), Alzheimer's disease (AD), encephalitis, inflammatory myopathies, myasthenia gravis (MG), systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), Sjogren's syndrome (SS), psoriasis and Crohn's disease (CD). However, the biological activity of IL-22 is variable resulting in protective or pathogenic effects in different disease states. As such, the development of therapeutic targeting strategies to modify the biological activity of IL-22 is being explored as a promising interventional approach to treat neurological and autoimmune diseases.

The parasitic worm product ES-62 targets myeloid differentiation factor 88-dependent effector mechanisms to suppress antinuclear antibody production and proteinuria in MRL/lpr mice

Objective

The hygiene hypothesis suggests that parasitic helminths (worms) protect against the development of autoimmune disease via a serendipitous side effect of worm-derived immunomodulators that concomitantly promote parasite survival and limit host pathology. The aim of this study was to investigate whether ES-62, a phosphorylcholine-containing glycoprotein secreted by the filarial nematode Acanthocheilonema viteae, protects against kidney damage in an MRL/lpr mouse model of systemic lupus erythematosus (SLE).

Methods

MRL/lpr mice progressively produce high levels of autoantibodies, and the resultant deposition of immune complexes drives kidney pathology. The effects of ES-62 on disease progression were assessed by measurement of proteinuria, assessment of kidney histology, determination of antinuclear antibody (ANA) production and cytokine levels, and flow cytometric analysis of relevant cellular populations.

Results

ES-62 restored the disrupted balance between effector and regulatory B cells in MRL/lpr mice by inhibiting plasmablast differentiation, with a consequent reduction in ANA production and deposition of immune complexes and C3a in the kidneys. Moreover, by reducing interleukin-22 production, ES-62 may desensitize downstream effector mechanisms in the pathogenesis of kidney disease. Highlighting the therapeutic importance of resetting B cell responses, adoptive transfer of purified splenic B cells from ES-62–treated MRL/lpr mice mimicked the protection afforded by the helminth product. Mechanistically, this reflects down-regulation of myeloid differentiation factor 88 expression by B cells and also kidney cells, resulting in inhibition of pathogenic cross-talk among Toll-like receptor–, C3a-, and immune complex–mediated effector mechanisms.

Conclusion

This study provides the first demonstration of protection against kidney pathology by a parasitic worm–derived immunomodulator in a model of SLE and suggests therapeutic potential for drugs based on the mechanism of action of ES-62.

T cell subsets and their signature cytokines in autoimmune and inflammatory diseases

CD4(+) T helper (Th) cells are critical for proper immune cell homeostasis and host defense, but are also major contributors to pathology of autoimmune and inflammatory diseases. Since the discovery of the Th1/Th2 dichotomy, many additional Th subsets were discovered, each with a unique cytokine profile, functional properties, and presumed role in autoimmune tissue pathology. This includes Th1, Th2, Th17, Th22, Th9, and Treg cells which are characterized by specific cytokine profiles. Cytokines produced by these Th subsets play a critical role in immune cell differentiation, effector subset commitment, and in directing the effector response. Cytokines are often categorized into proinflammatory and anti-inflammatory cytokines and linked to Th subsets expressing them. This article reviews the different Th subsets in terms of cytokine profiles, how these cytokines influence and shape the immune response, and their relative roles in promoting pathology in autoimmune and inflammatory diseases. Furthermore, we will discuss whether Th cell pathogenicity can be defined solely based on their cytokine profiles and whether rigid definition of a Th cell subset by its cytokine profile is helpful.

B7-H1-expressing antigen-presenting cells mediate polarization of protumorigenic Th22 subsets

Classical IL-22-producing T helper cells (Th22 cells) mediate inflammatory responses independently of IFN-γ and IL-17; however, nonclassical Th22 cells have been recently identified and coexpress IFN-γ and/or IL-17 along with IL-22. Little is known about how classical and nonclassical Th22 subsets in human diseases are regulated. Here, we used samples of human blood, normal and peritumoral liver, and hepatocellular carcinoma (HCC) to delineate the phenotype, distribution, generation, and functional relevance of various Th22 subsets. Three nonclassical Th22 subsets constituted the majority of all Th22 cells in human liver and HCC tissues, although the classical Th22 subset was predominant in blood. Monocytes activated by TLR2 and TLR4 agonists served as the antigen-presenting cells (APCs) that most efficiently triggered the expansion of nonclassical Th22 subsets from memory T cells and classical Th22 subsets from naive T cells. Moreover, B7-H1-expressing monocytes skewed Th22 polarization away from IFN-γ and toward IL-17 through interaction with programmed death 1 (PD-1), an effect that can create favorable conditions for in vivo aggressive cancer growth and angiogenesis. Our results provide insight into the selective modulation of Th22 subsets and suggest that strategies to influence functional activities of inflammatory cells may benefit anticancer therapy.

Th17 cells in inflammation and autoimmunity

T helper 17 (Th17), a distinct subset of CD4(+) T cells with IL-17 as their major cytokine, orchestrate the pathogenesis of inflammatory and autoimmune diseases. Dysregulated Th17 cells contribute to inflammatory and autoimmune diseases. Candidate biologics are in development for targeting IL-17, IL-17 receptors or IL-17 pathways. Several drugs that impact the IL-17 pathway are already in clinical trials for the treatment of autoimmune diseases. In this review we provide evidence for the role of Th17 cells in immune-mediated diseases. An understanding of the role of Th17 in these conditions will provide important insights and unravel novel targets for therapeutic intervention.

Decreased plasma IL-22 levels and correlations with IL-22-producing T helper cells in patients with new-onset systemic lupus erythematosus

Interleukin-22 (IL-22) and IL-22-producing T helper (Th) cells are involved in the pathogenesis of autoimmune diseases. However, the roles of IL-22 and IL-22-producing T helper cells in systemic lupus erythematosus (SLE) remain unclear. Plasma levels of IL-22 were measured in 41 patients with SLE (19 new-onset and 22 relapsing patients) and 20 healthy controls by enzyme-linked immunosorbent assay (ELISA). Meanwhile, the percentages of CD4(+) IFN-γ(+) (Th1), CD4(+) IL-17(+) (Th17) and CD4(+) IFN-γ(-) IL-17(-) IL-22(+) (Th22) cells in peripheral lymphocytes were determined by flow cytometry, and plasma IL-22 autoantibodies were detected by ELISA in 19 new-onset SLE patients and 20 healthy controls. Plasma IL-22 levels in new-onset SLE patients were significantly decreased compared with relapsing SLE patients and healthy controls. After treatment with prednisone and hydroxychloroquine, the levels of plasma IL-22 in new-onset SLE patients were obviously increased but still lower than healthy controls. There was a positive correlation between plasma IL-22 levels and the percentages of Th22 cells, but not Th1 and Th17 cells. Moreover, plasma IL-22 levels as well as peripheral Th17 and Th22 cells correlated with SLE disease activity index (SLEDAI) scores and erythrocyte sedimentation rate (ESR). High frequencies of plasma IL-22 autoantibodies were detected in new-onset SLE patients. However, IL-22 levels did not correlate with IL-22 autoantibody. Decreased plasma IL-22 levels and correlation with Th22 cells may be distinct features in new-onset SLE. Moreover, IL-22 and Th22 cell correlated with SLE disease activity.

Targeting interleukin-22 in psoriasis

Interleukin-22 (IL-22) is an IL-10 family cytokine that was recently discovered to be released by T helper 17 (Th17) cells, Th22 cells, etc. Recently, there is emerging evidence that IL-22 is involved in the development and pathogenesis of psoriasis. For instance, IL-22 can inhibit keratinocyte terminal differentiation and can induce psoriasis-like epidermis alterations; serum IL-22 levels were correlated with the disease severity of psoriasis patients, and IL-22 mRNA was positively expressed in the psoriatic skin lesions, but negatively expressed in the normal controls. All these findings suggest that IL-22 may be implicated in psoriasis; therapeutics targeting IL-22 may have promise as a potential therapeutic target for treating psoriasis. In the present review, we summarize recent advances on the role of IL-22 in the pathogenesis and treatment of psoriasis.

A higher frequency of circulating IL-22(+)CD4(+) T cells in Chinese patients with newly diagnosed Hashimoto's thyroiditis

BACKGROUND

IL-22 and IL-17A are implicated in the pathogenesis of autoimmune diseases. However, the role of IL-22(+) and IL-17A(+) CD4(+) T cells in the pathogenesis of Hashimoto's thyroiditis (HT) is not fully understood. This study investigates serum IL-22 and IL-17A levels and determines the frequency of circulating IL-22(+) CD4(+) T cells in HT patients to understand their roles in the pathogenesis of HT.

METHODS

The levels of serum IL-22, IL-17A and IFN-γ and the frequency of circulating IL-22(+)CD4(+) and IL-17A(+)CD4(+) T cells in 17 HT patients and 17 healthy controls (HC) were determined by enzyme-linked immunosorbent assay (ELISA) and flow cytometry. The levels of serum free triiodothyronine (FT4), free thyroxine (FT3), thyroid stimulating hormone (TSH), anti-thyroid peroxidase (TPO) and anti-thyroglobulin antibodies (TgAb) by chemiluminescent enzyme immunoassay and radioimmunoassay.

RESULTS

The percentages of circulating IL-22(+)CD4(+) and IL-17(+)CD4(+) T cells (p<0.0001, p<0.0001) and the levels of serum IL-22, IL-17A and IFN-γ (p<0.0001, p<0.0001, p = 0.0210) in the HT patients were significantly higher than that in the HC. The percentages of IL-22(+)CD4(+) T cells were positively correlated with Th17 cells (r = 0.8815, p<0.0001) and IL-17A(+)IL-22(+)CD4(+) T cells (r = 0.8914, p<0.0001), but were negatively correlated with Th1 cells (r = -0.6110, p<0.0092) in the HT patients. The percentages of Th22 cells, Th17 cells and IL-17A(+)IL-22(+)CD4(+) T cells were negatively correlated with the levels of serum TSH in the HT patients (r = -0.8402, p<0.0001; r = -0.8589, p<0.0001; r = -0.8289 p<0.0001, respectively).

CONCLUSIONS

A higher frequency of circulating IL-22(+)CD4(+) and IL-17A(+)CD4(+) T cells may be associated with the development of HT in Chinese patients.

IL-22 secreting CD4+ T cells in the patients with neuromyelitis optica and multiple sclerosis

Interleukin (IL)-22 secreting CD4(+) T (Th22) cells and IL-22 are involved in the pathogenesis of autoimmune disease, but their role in neuromyelitis optica (NMO) and multiple sclerosis (MS) is unclear. We measured the proportion of Th22, Th17, CD4(+)IL-22(+)IL-17A(+) T cells and serum IL-22 in NMO and MS patients. The proportion of Th22 cells, Th17 cells and serum IL-22 were increased in patients with NMO and MS. Our findings suggest that increased Th22 cells may play an important role in the pathogenesis of NMO and MS.

A high frequency of circulating th22 and th17 cells in patients with new onset graves' disease

T-helper (Th) 22 and Th17 cells are involved in the pathogenesis of autoimmune diseases. However, their roles in the pathogenesis of Graves'disease (GD) are unclear. This study is aimed at examining the frequency of peripheral blood Th22, Th17, and Th1 cells and the levels of plasma IL-22, IL-17, and IFN-γ in patients with GD. A total of 27 patients with new onset GD and 27 gender- and age-matched healthy controls (HC) were examined for the frequency of peripheral blood Th22, Th17, and IFN-γ cells by flow cytometry. The concentrations of plasma IL-22, IL-17, and IFN-γ were examined by enzyme-linked immunosorbent assay. The levels of serum TSHR antibodies (A-TSHR), free triiodothyronine (FT3), free thyroxine (FT4), and thyroid stimulating hormone (TSH) were examined by radioimmunoassay and chemiluminescent assay, respectively. The levels of serum TSAb were examined by enzyme-linked immunosorbent assay. In comparison with those in the HC, significantly elevated percentages of Th22 and Th17 cells, but not Th1 cells, and increased levels of plasma IL-22 and IL-17, but not IFN-γ, were detected in GD patients (P<0.0001, for both). The percentages of both Th22 and Th17 cells and the levels of plasma IL-22 and IL-17 were correlated positively with the levels of serum TSAb in GD patients (r = 0.7944, P<0.0001; r = 0.8110, P<0.0001; r = 0.7101, p<0.0001; r = 0.7407, p<0.0001, respectively). Th22 and Th17 cells may contribute to the pathogenesis of GD.

Expression of interleukin-22 in myasthenia gravis

IL-17 and IL-22 are implicated in the pathogenesis of autoimmune diseases. The roles of IL-22 in the pathophysiology of myasthenia gravis (MG) remain unsettled. The aim of this study was to investigate the possible relationship between serum IL-22, IL-17 levels, anti-acetylcholine receptor antibody (anti-AChR Ab) titres and clinical parameters in patients with MG. The serum IL-22, IL-17 levels and anti-AChR Ab titres were tested by enzyme-linked immunosorbent assay (ELISA), while the expression of IL-22 and IL-17 mRNAs in peripheral blood mononuclear cells (PBMC) from healthy and MG subjects were detected by quantitative real-time PCR (qRT-PCR). Furthermore, PBMC from 12 patients with generalized MG were purified and treated with recombinant human IL-22 (rhIL-22), the IL-17 levels of supernatant were detected by ELISA. We found that the IL-17 levels were significantly increased, but IL-22 levels were significantly decreased in the serum of patients with MG compared with healthy controls. Consistantly, a significant decrease in IL-22 mRNA levels and an increase in IL-17 mRNA levels were detected in PBMC collected from patients with MG, compared with healthy controls. A negative correlation between IL-22 mRNA in PBMC, serum IL-22 and serum anti-AChR Ab levels was found in patients with MG. Moreover, in cultured MG PBMC treated with recombinant human IL-22 (rhIL-22), the IL-17 levels were decreased in a dose-dependent manner. Our findings indicated a possible role of IL-22 as a protective factor in MG.

Th17-relevant cytokines vary with sera of different ANA staining patterns

Antinuclear antibodies (ANA) react with components located in the cell nucleus and cytoplasm. Differing ANA staining patterns may reflect the specificity of autoantibodies in sera and indicate some autoimmune diseases specifically, to some extent. Th17-relevant cytokines have been shown to be involved in a variety of autoimmune diseases, but not consistently. In this study, we investigated whether differences in Th17-relevant cytokines exist between different ANA pattern sera. Sera of 64 ANA-positive patients (12 homogeneous, 13 speckled particle, 11 nucleolar, 15 centromere, 6 peripheral nuclear) and 16 healthy donors were analyzed for IL-17, IL-6, IL-21, IL-22, IL-23 (p19), and TGF-β, and subsequently correlations between IL-17 and IL-6, IL-21, IL-22, IL-23, and TGF-β were analyzed. Results showed that these Th17-relevant cytokines varied with different ANA-positive sera compared with healthy donors, except TGF-β. Among them, IL-21 and IL-22 were higher with all ANA-positive sera and IL-17, IL-6, and IL-23 were higher with three or more ANA staining sera. No significant difference in these cytokines was seen between the different ANA staining sera except IL-17 levels in sera of peripheral nuclear staining positive subjects were higher than nucleolar. Additionally, in ANA-positive sera, IL-17 correlated with IL-6, IL-21, IL-22, and IL-23, but not with TGF-β. Thus, we demonstrated that Th17-relevant cytokines varied with different ANA staining pattern sera, suggesting that Th17-relevant cytokines play differing roles in autoimmune diseases.

Increased expression of IL-22 is associated with disease activity in Behcet's disease

OBJECTIVE

Interleukin (IL)-22 has been reported to be involved in the development of autoimmune diseases. This study aimed to analyze the expression and potential role of IL-22 in the pathogenesis of Behcet's disease (BD).

METHODS

The levels of IL-22 in patient sera or supernatants of cultured peripheral blood mononuclear cells (PBMCs) and CD4(+)T cells were detected by enzyme-linked immunosorbent assay (ELISA). Flow cytometry was used to evaluate the frequency of IL-22-producing CD4(+) T cells. IL-22 mRNA from erythema nodosum skin lesions was examined using real time quantitative RT-PCR.

RESULTS

BD patients with active uveitis showed a significantly higher expression of IL-22 in the supernatants of stimulated PBMCs and CD4(+)T cells compared with BD patients without active uveitis and normal controls. An increased frequency of IL-22-producing CD4(+)T cells was also found in BD patients with active uveitis. IL-22 mRNA expression was elevated in erythema nodosum skin lesions. In BD patients, a high IL-22 level in the supernatant of stimulated PBMCs correlated with the presence of retinal vasculitis and erythema nodosum.

CONCLUSIONS

IL-22 was associated with disease activity in BD and correlated with the presence of small vessel inflammation, suggesting that it may be involved in its pathogenesis.

IL-22+CD4+ T-cells in patients with active systemic lupus erythematosus

Interleukin-22 (IL-22) is a regulator of autoimmune diseases. However, the role of IL-22(+)CD4(+) T-cells in the pathogenesis of systemic lupus erythematosus (SLE) remains unclear. This study is aimed at elucidating the potential role of IL-22 and IL-22(+)CD4(+) T-cells in patients with SLE. A total of 22 patients with freshly diagnosed SLE and 18 age-/gender-matched healthy controls (n = 18) were evaluated for the frequency of different types of IL-22-producing CD4(+) T-cells by flow cytometry analysis following in vitro stimulation. The concentrations of plasma IL-22, IL-17A, IFNγ, serum complement factors (C3, C4), C-reactive protein (CRP), antidouble-stranded (ds) DNA and anti-Smith (Sm) antibodies were measured. The potential association among these measures was analyzed. The percentages of IL-22(+)IL-17(-)IFNγ(-), IL-22(+)IL-17A(-)IFN-γ(+), IL-22(-)IL-17(+)IFN-γ(-) and IL-22(+)IL-17(+)IFN-γ(-) CD4(+) T-cells and the levels of plasma IL-22 and IL-17A in the patients were significantly higher than that in the healthy controls (P < 0.01). The frequency of Th22 cells was correlated positively with that of Th17 and IL-22(+)IL-17(+) CD4(+) T-cells, and the frequency of Th17 and IL-22(+)CD4(+) T-cells was correlated positively with the values of SLE disease activity index (SLEDAI), but not with the values of CRP, ERS and C3 in SLE patients. Our data suggest that both Th17 and IL-22(+)CD4(+) T-cells may participate in the pathogenesis of SLE.

Emerging role of interleukin-22 in autoimmune diseases

Interleukin-22 (IL-22) is an IL-10 family cytokine member that was recently discovered to be mainly produced by Th17 cells. Previous studies have indicated the importance of IL-22 in host defense against Gram-negative bacterial organisms (in gut and lung). Recently, there is emerging evidence that IL-22 is involved in the development and pathogenesis of several autoimmune diseases, such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), multiple sclerosis (MS), Sjögren's syndrome (SS) and psoriasis. Therapeutics targeting IL-22 therefore may have promise for treating various autoimmune diseases. In this review, we discuss the recent progression of the involvement of IL-22 in the development and pathogenesis of autoimmune diseases, as well as its clinical implications and therapeutic potential.

Increased circulating Th22 and Th17 cells are associated with tumor progression and patient survival in human gastric cancer

Although Th22 and Th17 cells have been reported to play critical roles during autoimmunity and inflammation, information on their role in cancer-immunity is limited. In this study, we investigated clinical relevance of circulating Th22 and Th17 cells in patients with gastric cancer (GC). Using multi-color flow cytometry and PMA stimulation, we determined the levels of Th22, Th17 and Th1 cells in the peripheral blood of 32 GC patients and 19 healthy donors, and evaluated their correlations with tumor stage and overall survival. Compared with healthy donors, the frequencies of circulating CD4(+)IL-22(+) T cells, CD4(+)IL-17(+) T cells, Th22 (CD4(+)IL-22(+)IL-17(-)INF-γ(-)) cells, Th17 (CD4(+)IL-17(+)INF-γ(-)) cells were increased in patients with GC, but there was no significant differences in the frequencies of CD4(+)IFN-γ(+) T cells and Th1 (CD4(+)IL-17(-)INF-γ(+)) cells. Th22 cells showed positive correlation with Th17 cells and CD4(+)IL-17(+) T cells in patients with GC. Furthermore, the frequencies of Th22 and Th17 cells were significantly higher in stage III-IV GC patients versus stage I-II and correlated with patients' overall survival. These data suggest that circulating Th22 cells as well as Th17 cells are increased in the peripheral blood of GC patients with tumor progression, and that these cells may be promising novel clinical markers for GC.