The Immunology of Multisystem Inflammatory Syndrome in Children with COVID-19.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is typically very mild and often asymptomatic in children. A complication is the rare multisystem inflammatory syndrome in children (MIS-C) associated with COVID-19, presenting 4-6 weeks after infection as high fever, organ dysfunction, and strongly elevated markers of inflammation. The pathogenesis is unclear but has overlapping features with Kawasaki disease suggestive of vasculitis and a likely autoimmune etiology. We apply systems-level analyses of blood immune cells, cytokines, and autoantibodies in healthy children, children with Kawasaki disease enrolled prior to COVID-19, children infected with SARS-CoV-2, and children presenting with MIS-C. We find that the inflammatory response in MIS-C differs from the cytokine storm of severe acute COVID-19, shares several features with Kawasaki disease, but also differs from this condition with respect to T cell subsets, interleukin (IL)-17A, and biomarkers associated with arterial damage. Finally, autoantibody profiling suggests multiple autoantibodies that could be involved in the pathogenesis of MIS-C.

Obesity-induced dysregulation of skin-resident PPARγ+ Treg cells promotes IL-17A-mediated psoriatic inflammation.

Obesity is a major risk factor for psoriasis, but how obesity disrupts the regulatory mechanisms that keep skin inflammation in check is unclear. Here, we found that skin was enriched with a unique population of CD4+Foxp3+ regulatory T (Treg) cells expressing the nuclear receptor peroxisome proliferation-activated receptor gamma (PPARγ). PPARγ drove a distinctive transcriptional program and functional suppression of IL-17A+ γδ T cell-mediated psoriatic inflammation. Diet-induced obesity, however, resulted in a reduction of PPARγ+ skin Treg cells and a corresponding loss of control over IL-17A+ γδ T cell-mediated inflammation. Mechanistically, PPARγ+ skin Treg cells preferentially took up elevated levels of long-chain free fatty acids in obese mice, which led to cellular lipotoxicity, oxidative stress, and mitochondrial dysfunction. Harnessing the anti-inflammatory properties of these PPARγ+ skin Treg cells could have therapeutic potential for obesity-associated inflammatory skin diseases.

IL-17RA-signaling in Lgr5+ intestinal stem cells induces expression of transcription factor ATOH1 to promote secretory cell lineage commitment.

The Th17 cell-lineage-defining cytokine IL-17A contributes to host defense and inflammatory disease by coordinating multicellular immune responses. The IL-17 receptor (IL-17RA) is expressed by diverse intestinal cell types, and therapies targeting IL-17A induce adverse intestinal events, suggesting additional tissue-specific functions. Here, we used multiple conditional deletion models to identify a role for IL-17A in secretory epithelial cell differentiation in the gut. Paneth, tuft, goblet, and enteroendocrine cell numbers were dependent on IL-17A-mediated induction of the transcription factor ATOH1 in Lgr5+ intestinal epithelial stem cells. Although dispensable at steady state, IL-17RA signaling in ATOH1+ cells was required to regenerate secretory cells following injury. Finally, IL-17A stimulation of human-derived intestinal organoids that were locked into a cystic immature state induced ATOH1 expression and rescued secretory cell differentiation. Our data suggest that the cross talk between immune cells and stem cells regulates secretory cell lineage commitment and the integrity of the mucosa.

The Gut Microbiome Regulates Psychological-Stress-Induced Inflammation.

Psychological stress has adverse effects on various human diseases, including those of the cardiovascular system. However, the mechanisms by which stress influences disease activity remain unclear. Here, using vaso-occlusive episodes (VOEs) of sickle cell disease as a vascular disease model, we show that stress promotes VOEs by eliciting a glucocorticoid hormonal response that augments gut permeability, leading to microbiota-dependent interleukin-17A (IL-17A) secretion from T helper 17 (Th17) cells of the lamina propria, followed by the expansion of the circulating pool of aged neutrophils that trigger VOEs. We identify segmented filamentous bacteria as the commensal essential for the stress-induced expansion of aged neutrophils that enhance VOEs in mice. Importantly, the inhibition of glucocorticoids synthesis, blockade of IL-17A, or depletion of the Th17 cell-inducing gut microbiota markedly reduces stress-induced VOEs. These results offer potential therapeutic targets to limit the impact of psychological stress on acute vascular occlusion.

Lung γδ T Cells Mediate Protective Responses during Neonatal Influenza Infection that Are Associated with Type 2 Immunity.

Compared to adults, infants suffer higher rates of hospitalization, severe clinical complications, and mortality due to influenza infection. We found that γδ T cells protected neonatal mice against mortality during influenza infection. γδ T cell deficiency did not alter viral clearance or interferon-γ production. Instead, neonatal influenza infection induced the accumulation of interleukin-17A (IL-17A)-producing γδ T cells, which was associated with IL-33 production by lung epithelial cells. Neonates lacking IL-17A-expressing γδ T cells or Il33 had higher mortality upon influenza infection. γδ T cells and IL-33 promoted lung infiltration of group 2 innate lymphoid cells and regulatory T cells, resulting in increased amphiregulin secretion and tissue repair. In influenza-infected children, IL-17A, IL-33, and amphiregulin expression were correlated, and increased IL-17A levels in nasal aspirates were associated with better clinical outcomes. Our results indicate that γδ T cells are required in influenza-infected neonates to initiate protective immunity and mediate lung homeostasis.

Blocking CTLA-4 promotes pressure overload-induced heart failure via activating Th17 cells.

Targeting cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) with specific antibody offers long-term benefits for cancer immunotherapy but can cause severe adverse effects in the heart. This study aimed to investigate the role of anti-CTLA-4 antibody in pressure overload-induced cardiac remodeling and dysfunction. Transverse aortic constriction (TAC) was used to induce cardiac hypertrophy and heart failure in mice. Two weeks after the TAC treatment, mice received anti-CTLA-4 antibody injection twice a week at a dose of 10 mg/kg body weight. The administration of anti-CTLA-4 antibody exacerbated TAC-induced decline in cardiac function, intensifying myocardial hypertrophy and fibrosis. Further investigation revealed that anti-CTLA-4 antibody significantly elevated systemic inflammatory factors levels and facilitated the differentiation of T helper 17 (Th17) cells in the peripheral blood of TAC-treated mice. Importantly, anti-CTLA-4 mediated differentiation of Th17 cells and hypertrophic phenotype in TAC mice were dramatically alleviated by the inhibition of interleukin-17A (IL-17A) by an anti-IL-17A antibody. Furthermore, the C-X-C motif chemokine receptor 4 (CXCR4) antagonist AMD3100, also reversed anti-CTLA-4-mediated cardiotoxicity in TAC mice. Overall, these results suggest that the administration of anti-CTLA-4 antibody exacerbates pressure overload-induced heart failure by activating and promoting the differentiation of Th17 cells. Targeting the CXCR4/Th17/IL-17A axis could be a potential therapeutic strategy for mitigating immune checkpoint inhibitors-induced cardiotoxicity.

The transcriptional regulator Sin3A balances IL-17A and Foxp3 expression in primary CD4 T cells.

The Sin3 transcriptional regulator homolog A (Sin3A) is the core member of a multiprotein chromatin-modifying complex. Its inactivation at the CD4/CD8 double-negative stage halts further thymocyte development. Among various functions, Sin3A regulates STAT3 transcriptional activity, central to the differentiation of Th17 cells active in inflammatory disorders and opportunistic infections. To further investigate the consequences of conditional Sin3A inactivation in more mature precursors and post-thymic T cell, we have generated CD4-Cre and CD4-CreERT2 Sin3AF/F mice. Sin3A inactivation in vivo hinders both thymocyte development and peripheral T-cell survival. In vitro, in Th17 skewing conditions, Sin3A-deficient cells proliferate and acquire memory markers and yet fail to properly upregulate Il17a, Il23r, and Il22. Instead, IL-2+ and FOXP3+ are mostly enriched for, and their inhibition partially rescues IL-17A+ T cells. Notably, Sin3A deletion also causes an enrichment of genes implicated in the mTORC1 signaling pathway, overt STAT3 activation, and aberrant cytoplasmic RORγt accumulation. Thus, together our data unveil a previously unappreciated role for Sin3A in shaping critical signaling events central to the acquisition of immunoregulatory T-cell phenotypes.

Intestinal commensal microbiota and cytokines regulate Fut2+ Paneth cells for gut defense.

Paneth cells are intestinal epithelial cells that release antimicrobial peptides, such as α-defensin as part of host defense. Together with mesenchymal cells, Paneth cells provide niche factors for epithelial stem cell homeostasis. Here, we report two subtypes of murine Paneth cells, differentiated by their production and utilization of fucosyltransferase 2 (Fut2), which regulates α(1,2)fucosylation to create cohabitation niches for commensal bacteria and prevent invasion of the intestine by pathogenic bacteria. The majority of Fut2- Paneth cells were localized in the duodenum, whereas the majority of Fut2+ Paneth cells were in the ileum. Fut2+ Paneth cells showed higher granularity and structural complexity than did Fut2- Paneth cells, suggesting that Fut2+ Paneth cells are involved in host defense. Signaling by the commensal bacteria, together with interleukin 22 (IL-22), induced the development of Fut2+ Paneth cells. IL-22 was found to affect the α-defensin secretion system via modulation of Fut2 expression, and IL-17a was found to increase the production of α-defensin in the intestinal tract. Thus, these intestinal cytokines regulate the development and function of Fut2+ Paneth cells as part of gut defense.

An in vitro study of the impact of IL-17A and IL-22 on ciliogenesis in nasal polyps epithelium via the Hippo-YAP pathway.

BACKGROUND: Cilia loss and impaired motile ciliary functions are among the typical pathological features of chronic rhinosinusitis with nasal polyps (CRSwNP). IL17A and IL22 are the canonical cytokines of type 3 inflammation, exhibiting similar functional effects on epithelial cells. In this study, we sought to examine the effects of IL17A and IL22 on ciliated cells and investigate the potential involvement of Hippo-YAP signaling in their influence on ciliogenesis. METHODS: We assessed both the mRNA and protein expression levels of IL17A and IL22 in nasal tissues obtained from patients with CRSwNP and compared them to those from healthy controls. To further explore the impact of IL17A and IL22, we established a primary human nasal epithelial cell model using different concentrations (2 ng/mL, 10 ng/mL, 50 ng/mL) for a duration of 28 days in an air-liquid interface culture. Additionally, we employed the inhibitor verteporfin to investigate whether IL17A and IL22 exert their effects on ciliated cells via the Hippo-YAP pathway. RESULTS: The mRNA and protein levels of IL17A and IL22 in CRSwNP were significantly higher than those in healthy controls, revealing a robust correlation between IL17A and IL22. YAP was highly expressed in the nucleus of ciliated cells in CRSwNP and displayed a positive correlation with clinical symptoms. Both IL17A and IL22 were found to reduce the number of ciliated cells. IL17A, but not IL22, suppressed ciliogenesis by disrupting the proper development and docking of the basal body of ciliated cells, resulting in motile ciliary dysfunctions. Furthermore, the expression of YAP within the nucleus of ciliated cells gradually declined as these cells reached the final stage of differentiation. However, this process was obstructed by IL17A only. YAP inhibitors, such as verteporfin, markedly reversed the effects of IL17A by increasing the proportion of ciliated cells, suppressing nuclear YAP expression in these cells, and enhancing ciliary beating frequency. CONCLUSIONS: Both IL17A and IL22 are overexpressed in nasal epithelium of CRSwNP, which is associated with the impairment of epithelial cell differentiation. Furthermore, IL17A has been shown to exert a disruptive effect on morphogenesis of motile cilia via activation of YAP.

Unraveling CCL20's role by regulating Th17 cell chemotaxis in experimental autoimmune prostatitis.

Chronic prostatitis and chronic pelvic pain syndrome (CP/CPPS), a prevalent urological ailment, exerts a profound influence upon the well-being of the males. Autoimmunity driven by Th17 cells has been postulated as a potential factor in CP/CPPS pathogenesis. Nonetheless, elucidating the precise mechanisms governing Th17 cell recruitment to the prostate, triggering inflammation, remained an urgent inquiry. This study illuminated that CCL20 played a pivotal role in attracting Th17 cells to the prostate, thereby contributing to prostatitis development. Furthermore, it identified prostate stromal cells and immune cells as likely sources of CCL20. Additionally, this research unveiled that IL-17A, released by Th17 cells, could stimulate macrophages to produce CCL20 through the NF-κB/MAPK/PI3K pathway. The interplay between IL-17A and CCL20 establishes a positive feedback loop, which might serve as a critical mechanism underpinning the development of chronic prostatitis, thus adding complexity to its treatment challenges.

IL-17A Cytokine-Regulated Glut1 Expression in Placenta Cells.

Trophoblasts, the principal cellular component of the placenta, play an important role in nutrient and gas exchange. Previous studies have indicated that maternal immune activation (MIA) leads to an elevation in IL-17A cytokine levels in maternal serum, subsequently influencing fetal brain development during pregnancy. In this study, we aimed to elucidate the impact of the IL-17A cytokine on placental function. First, we treated JAR and JEG-3, which is a placenta cell line, with IL-17A in a concentration-dependent or time-dependent manner and observed cell morphology and viability. It was confirmed that treatment with IL-17A or a double-stranded RNA mimic (PolyI:C) had no effect on the morphology or cell viability. IL-17A treatment increased the expression of IL-17R at the mRNA and protein levels, and Poly(I:C) increased the levels of IFNγ and TNFα. Additionally, PPARγ, known as a metabolism regulator, was increased by IL-17A treatment. Also, we observed that the expression of Glut1 and Glut3 was increased by IL-17A treatment. To confirm this, we examined the expression of transporters in the placental tissue of the MIA rodent model, and we observed that mRNA expression of glut1 and glut3 was significantly increased. However, the expression of Gltu1 and Glut3 was observed to be significantly inhibited in the brains of MIA-induced offspring. This study suggests that IL-17A increases signaling through IL-17R in the placenta and fetal brain tissue; however, there is a mechanism for regulating the expression of glucose transporters by increased IL-17A in the placenta.

Association of interleukin-17A and chemokine/vascular endothelial growth factor-induced angiogenesis in newly diagnosed patients with bladder cancer.

BACKGROUND: The human interleukin-17 (IL-17) family comprises IL-17A to IL-17 F; their receptors are IL-17RA to IL-17RE. Evidence revealed that these cytokines can have a tumor-supportive or anti-tumor impact on human malignancies. The purpose of this study was to assess the expression of CXCR2, IL-17RA, and IL-17RC genes at the mRNA level as well as tissue and serum levels of IL-17A, vascular endothelial growth factor (VEGF), and transforming growth factor ß (TGF-ß) in patients with bladder cancer (BC) compared to control. RESULTS: This study showed that gene expression of IL-17RA, IL-17RC, and CXCR2 in the tumoral tissue of BC patients was significantly upregulated compared with normal tissue. The findings disclosed a significant difference in the serum and tissue concentrations of IL-17A, VEGF, and TGF-ß between the patient and the control groups, as well as tumor and normal tissues. CONCLUSION: This study reveals notable dysregulation of CXCR2, IL-17RA, and IL-17RC genes, alongside changes in IL-17A, VEGF, and TGF-ß levels in patients with BC than in controls. These findings indicate their possible involvement in BC development and their potential as diagnostic and therapeutic targets.

Interleukin-17A educated hepatic stellate cells promote hepatocellular carcinoma occurrence through fibroblast activation protein expression.

BACKGROUND: Liver cancer is typified by a complex inflammatory tumor microenvironment, where an array of cytokines and stromal cells orchestrate a milieu that significantly influences tumorigenesis. Interleukin-17A (IL-17A), a pivotal pro-inflammatory cytokine predominantly secreted by Th17 cells, is known to play a substantial role in the etiology and progression of liver cancer. However, the precise mechanism by which IL-17A engages with hepatic stellate cells (HSCs) to facilitate the development of hepatocellular carcinoma (HCC) remains to be fully elucidated. This investigation seeks to unravel the interplay between IL-17A and HSCs in the context of HCC. METHODS: An HCC model was established in male Sprague-Dawley rats using diethylnitrosamine to explore the roles of IL-17A and HSCs in HCC pathogenesis. In vivo overexpression of Il17a was achieved using adeno-associated virus. A suite of molecular techniques, including RT-qPCR, enzyme-linked immunosorbent assays, Western blotting, cell counting kit-8 assays and colony formation assays, was employed for in vitro analyses. RESULTS: The study findings indicate that IL-17A is a key mediator in HCC promotion, primarily through the activation of hepatic progenitor cells (HPCs). This pro-tumorigenic influence appears to be mediated by HSCs, rather than through a direct effect on HPCs. Notably, IL-17A-induced expression of fibroblast activation protein (FAP) in HSCs emerged as a critical factor in HCC progression. Silencing Fap in IL-17A-stimulated HSCs was observed to reverse the HCC-promoting effects of HSCs. CONCLUSIONS: The collective evidence from this study implicates the IL-17A/FAP signaling axis within HSCs as a contributor to HCC development by enhancing HPC activation. These findings bolster the potential of IL-17A as a diagnostic and preventative target for HCC, offering new avenues for therapeutic intervention.

Interleukin-17A (IL-17A) is involved in antibody specificity to conformational epitopes.

The specificity of antibodies (Ab) is essential for the precise recognition of foreign or dangerous molecules. We have shown that mice infected with non-pathogenic Lactate Dehydrogenase Elevating Virus (LDV) inoculated with human growth hormone (hGH) or Ovalbumin (OVA), exhibit modified specificity of anti-hGH or anti-OVA Ab associated with the secretion of IFN-γ, IL-13, and IL-17. Cytokines are directly or indirectly involved in the isotypes, specificity, and affinity of Ab. Accordingly, here we investigated the effect of IL-17 neutralization on Ab specificities to OVA and Diphtheria Toxoid (DTx) in a mouse model of viral infection. Thereby, we employed an anti-cytokine "auto-vaccination" with an OVA/IL-17A complex or a Monoclonal Ab (MAb) anti-IL-17A (MM17/F3). Competitive ELISA assays were used to estimate the quality of the humoral immune response and the amount of Abs to conformational versus linear antigenic determinants. Results indicated that the OVA/IL-17A complex increased Abs levels to conformational epitopes of OVA, while LDV prolonged antibodies for a longer period. Mice treated with MM17F3 MAb showed an increase in Abs to conformational epitopes of OVA. A similar effect, confirmed by a competitive Western-blot assay, was produced by LDV. Moreover, an increased level of IgM, IgG1, and IgG2a was found in infected animals. Similarly, MAb anti-IL-17A treatment increased the proportion of Ab to conformational epitopes of DTx in uninfected mice, while LDV decreased this parameter. In conclusion, our findings demonstrate a correlation between IL-17A neutralization and a change in Ab specificity to OVA or DTx, presenting a novel strategy for obtaining Abs with higher specificity.

Longitudinal plasma proteomic analysis identifies biomarkers and combinational targets for anti-PD1-resistant cancer patients.

The response rate of anti-PD1 therapy is limited, and the influence of anti-PD1 therapy on cancer patients is unclear. To address these challenges, we conducted a longitudinal analysis of plasma proteomic changes with anti-PD1 therapy in non-small cell lung cancer (NSCLC), alveolar soft part sarcoma (ASPS), and lymphoma patients. We included 339 plasma samples before and after anti-PD1 therapy from 193 patients with NSCLC, ASPS, or lymphoma. The plasma proteins were detected using data-independent acquisition-mass spectrometry and customable antibody microarrays. Differential proteomic characteristics in responders (R) and non-responders (NR) before and after anti-PD1 therapy were elucidated. A total of 1019 proteins were detected using our in-depth proteomics platform and distributed across 10-12 orders of abundance. By comparing the differential plasma proteome expression between R and NR groups, 50, 206, and 268 proteins were identified in NSCLC, ASPS, and lymphoma patients, respectively. Th17, IL-17, and JAK-STAT signal pathways were identified upregulated in NR group, while cellular senescence and transcriptional misregulation pathways were activated in R group. Longitudinal proteomics analysis revealed the IL-17 signaling pathway was downregulated after treatment. Consistently, many proteins were identified as potential combinatorial therapeutic targets (e.g., IL-17A and CD22). Five noninvasive biomarkers (FLT4, SFTPB, GNPTG, F5, and IL-17A) were further validated in an independent lymphoma cohort (n = 39), and another three noninvasive biomarkers (KIT, CCL3, and TNFSF1) were validated in NSCLC cohort (n = 76). Our results provide molecular insights into the anti-PD1 therapy in cancer patients and identify new therapeutic strategies for anti-PD1-resistant patients.

Oct4 activates IL-17A to orchestrate M2 macrophage polarization and cervical cancer metastasis.

BACKGROUND: Cervical cancer is a common malignant tumor in the female. Interleukin (IL)-17A is a proinflammatory factor and exerts a vital function in inflammatory diseases and cancers. M2 macrophage has been confirmed to promote tumor development. Nevertheless, it is not yet known whether IL-17A facilitates cervical cancer development by inducing M2 macrophage polarization. Therefore, this study was conducted to investigate the regulatory effect of IL-17A on M2 macrophage polarization and the underlying mechanism in cervical cancer development. METHODS: RT-qPCR was utilized for testing IL-17A expression in cancer tissues and cells. Flow cytometry was applied to evaluate the M1 or M2 macrophage polarization. Cell proliferative, migratory, and invasive capabilities were measured through colony formation and transwell assays. ChIP and luciferase reporter assays were applied to determine the interaction between IL-17A and octamer-binding transcription factor 4 (OCT4). RESULTS: IL-17A expression and concentration were high in metastatic tissues and cells of cervical cancer. IL-17A was found to facilitate M2 macrophage polarization in cervical cancer. Furthermore, IL-17A facilitated the macrophage-mediated promotion of cervical cancer cell proliferative, migratory, and invasive capabilities. Mechanistic assays manifested that Oct4 binds to and transcriptionally activated IL-17A in cervical cancer cells. Furthermore, Oct4 promoted cervical cancer cell malignant phenotype and M2 macrophage polarization by activating the p38 pathway that, in turn, upregulated IL-17A. Additionally, in vivo experiments confirmed that Oct4 knockdown reduced tumor growth and metastasis. CONCLUSION: Oct4 triggers IL-17A to facilitate the polarization of M2 macrophages, which promotes cervical cancer cell metastasis.

IL-17A exacerbates corpus cavernosum fibrosis and neurogenic erectile dysfunction by inducing CSMC senescence via the mTORC2-ACACA pathway.

BACKGROUND: Neurogenic erectile dysfunction, characterized by neurological repair disorders and progressive corpus cavernosum fibrosis (CCF), is an unbearable disease with limited treatment success. IL-17A exhibits a complex role in tissue remodelling. Nevertheless, the precise role and underlying mechanisms of IL-17A in CCF under denervation remain unclear. METHODS: PCR array was employed to identified differentially expressed genes between neurogenic ED and normal rats. IL-17A expression and its main target cells were analyzed using Western blotting, immunofluorescence and immunohistochemistry. The phenotypic regulation of IL-17A on corpus cavernosum smooth muscle cells (CSMCs) was evaluated by cell cycle experiments and SA-ß-Gal staining. The mechanism of IL-17A was elucidated using non-target metabolomics and siRNA technique. Finally, IL-17A antagonist and ABT-263 (an inhibitor of B-cell lymphoma 2/w/xL) were utilized to enhance the therapeutic effect in a rat model of neurogenic ED. RESULTS: IL-17A emerged as the most significantly upregulated gene in the corpus cavernosum of model rats. It augmented the senescence transformation and fibrotic response of CSMCs, and exhibited a strong correlation with CCF. Mechanistically, IL-17A facilitated CCF by activating the mTORC2-ACACA signalling pathway, upregulating of CSMCs lipid synthesis and senescence transition, and increasing the secretion of fibro-matrix proteins. In vivo, the blockade of IL-17A-senescence signalling improved erectile function and alleviated CCF in neurogenic ED. CONCLUSIONS: IL-17A assumes a pivotal role in denervated CCF by activating the mTORC2-ACACA signalling pathway, presenting itself as a potential therapeutic target for effectively overcoming CCF and erection rehabilitation in neurogenic ED.

Double-negative T cells ameliorate psoriasis by selectively inhibiting IL-17A-producing γδlow T cells.

BACKGROUND: Psoriasis is a chronic immune-mediated skin condition. Although biologic treatments are effective in controlling psoriasis, some patients do not respond or lose response to these therapies. Thus, new strategies for psoriasis treatment are still urgently needed. Double-negative T cells (DNT) play a significant immunoregulatory role in autoimmune diseases. In this study, we aimed to evaluate the protective effect of DNT in psoriasis and explore the underlying mechanism. METHODS: We conducted a single adoptive transfer of DNT into an imiquimod (IMQ)-induced psoriasis mouse model through tail vein injection. The skin inflammation and IL-17A producing γδ T cells were evaluated. RESULTS: DNT administration significantly reduced the inflammatory response in mouse skin, characterized by decreased skin folds, scales, and red patches. After DNT treatment, the secretion of IL-17A by RORc+ γδlow T cells in the skin was selectively suppressed, resulting in an amelioration of skin inflammation. Transcriptomic data suggested heightened expression of NKG2D ligands in γδlow T cells within the mouse model of psoriasis induced by IMQ. When blocking the NKG2D ligand and NKG2D (expressed by DNT) interaction, the cytotoxic efficacy of DNT against RORc+IL17A+ γδlow T cells was attenuated. Using Ccr5-/- DNT for treatment yielded evidence that DNT migrates into inflamed skin tissue and fails to protect IMQ-induced skin lesions. CONCLUSIONS: DNT could migrate to inflamed skin tissue through CCR5, selectively inhibit IL-17-producing γδlow T cells and finally ameliorate mouse psoriasis. Our study provides feasibility for using immune cell therapy for the prevention and treatment of psoriasis in the clinic.

Repeated immunization with ATRA-containing liposomal adjuvant transdifferentiates Th17 cells to a Tr1-like phenotype.

In many autoimmune diseases, autoantigen-specific Th17 cells play a pivotal role in disease pathogenesis. Th17 cells can transdifferentiate into other T cell subsets in inflammatory conditions, however, there have been no attempts to target Th17 cell plasticity using vaccines. We investigated if autoantigen-specific Th17 cells could be specifically targeted using a therapeutic vaccine approach, where antigen was formulated in all-trans retinoic acid (ATRA)-containing liposomes, permitting co-delivery of antigen and ATRA to the same target cell. Whilst ATRA was previously found to broadly reduce Th17 responses, we found that antigen formulated in ATRA-containing cationic liposomes only inhibited Th17 cells in an antigen-specific manner and not when combined with an irrelevant antigen. Furthermore, this approach shifted existing Th17 cells away from IL-17A expression and transcriptomic analysis of sorted Th17 lineage cells from IL-17 fate reporter mice revealed a shift of antigen-specific Th17 cells to exTh17 cells, expressing functional markers associated with T cell regulation and tolerance. In the experimental autoimmune encephalomyelitis (EAE) mouse model of MS, vaccination with myelin-specific (MOG) antigen in ATRA-containing liposomes reduced Th17 responses and alleviated disease. This highlights the potential of therapeutic vaccination for changing the phenotype of existing Th17 cells in the context of immune mediated diseases.

Establishment of reference intervals for plasma IL-2, IL-4, IL-5, and IL-17A in healthy adults from the Jiangsu region of eastern China using flow cytometry: A single-center study.

BACKGROUND: Cytokines are of utmost importance in both the physiological and pathological immune responses of the human body. This study utilized flow cytometry to measure the levels of plasma interleukin-2 (IL-2), interleukin-4 (IL-4), interleukin-5 (IL-5) and interleukin-17A (IL-17A) and established their reference intervals, aiming to provide data support for the diagnosis and treatment of clinical diseases. METHODS: According to the inclusion and exclusion criteria, a total of 728 reference individuals were included in this study from January 2023 to June 2023. The Kolmogorov-Smirnov test was used to analyse the distributions of plasma IL-2, IL-4, IL-5 and IL-17A. The reference intervals of plasma IL-2, IL-4, IL-5 and IL-17A were established by the unilateral percentile method (95th percentile) based on the guidelines of C28-A 3 and WS/T 402-2012. RESULTS: In this study, the levels of plasma IL-2, IL-4, IL-5 and IL-17A were nonnormally distributed. The concentrations of plasma IL-2, IL-4, IL-5 and IL-17A in healthy adults were not significantly different by sex or age (all P > 0.05). Therefore, all the reference individuals were combined into one group, and the reference intervals of plasma IL-2, IL-4, IL-5 and IL-17 were established by flow cytometry (IL-2 ≤ 10.25 pg/mL, IL-4 ≤ 9.87 pg/mL, IL-5 ≤ 3.36 pg/mL and IL-17A ≤ 9.46 pg/mL). CONCLUSIONS: We first established the reference intervals of plasma IL-2, IL-4, IL-5 and IL-17A in healthy adults based on a single-center population in the Jiangsu region in eastern China, which will provide an important reference value for evaluating human immune status and the diagnosis and treatment of clinical diseases.