TH17 is a subset of CD4+T cells. Comparing to common asthma patients, there are more TH17 cells in the respiratory systems of the patients with severe asthma. TH17 cells are mainly adjusted by IL23 to produce IL17A and IL17F, which act on the epithelial cells and cause severe asthma. However, the TH17 function in severe asthma as a driving mechanism of neutrophilic inflammation is not yet fully understood and deserves further study. However, it is very difficult to describe the interactions between TH17 and other cells using mathematics equations due to the high complexity of immunity system. In order to explore the TH17 function in severe asthma, we used BIS (Basic Immune Simulator) platform to simulate TH17 models, and compared DC (Dendritic Cell) models with TH17 models. We studied the interaction between innate immune and adaptive immune cells, which was resulted from TH17 cells. The simulation results for the TH17 models are consistent with clinical data, which suggests that DC-IL23-TH17 axis might be the path of causing severe asthma. Our simulation studies support a role for TH17 in severe asthma, and hence it could be taken as a new target candidate for clinical treatment of severe asthma.

Chronic widespread musculoskeletal pain (CWP), has a considerable heritable component, which remains to be explained. Epigenetic factors may contribute to and account for some of the heritability estimate. We analysed epigenome-wide methylation using MeDIPseq in whole blood DNA from 1708 monozygotic and dizygotic Caucasian twins having CWP prevalence of 19.9%. Longitudinally stable methylation bins (lsBINs), were established by testing repeated measurements conducted ≥3 years apart, n = 292. DNA methylation variation at lsBINs was tested for association with CWP in a discovery set of 50 monozygotic twin pairs discordant for CWP, and in an independent dataset (n = 1608 twins), and the results from the 2 samples were combined using Fisher method. Functional interpretation of the most associated signals was based on functional genomic annotations, gene ontology, and pathway analyses. Of 723,029 signals identified as lsBINs, 26,399 lsBINs demonstrated the same direction of association in both discovery and replication datasets at nominal significance (P ≤ 0.05). In the combined analysis across 1708 individuals, whereas no lsBINs showed genome-wide significance (P < 10-8), 24 signals reached p≤9E-5, and these included association signals mapping in or near to IL17A, ADIPOR2, and TNFRSF13B. Bioinformatics analyses of the associated methylation bins showed enrichment for neurological pathways in CWP. We estimate that the variance explained by epigenetic factors in CWP is 6%. This, the largest study to date of DNA methylation in CWP, points towards epigenetic modification of neurological pathways in CWP and provides proof of principle of this method in teasing apart the complex risk factors for CWP.

IL23/Th17 axis acts as an inflammatory pathway in gastric carcinogenesis. MicroRNA- (miRNA-) binding site single-nucleotide polymorphisms (SNPs) of inflammatory genes may alter gastric cancer (GC) susceptibility. In this study, four miRNA binding site SNPs (rs3748067 of IL17A, rs887796, rs1468488 of IL17RA, and rs10889677 of IL23R) were genotyped from 500 patients and 500 controls. Unconditional logistic regression analyses and multifactor dimensionality reduction software were used to evaluate the relationships of SNPs with GC and gene-environment interactions, respectively. Quantitative real-time PCR, Western blot analysis, and luciferase report gene assay were applied for function verification. We found that CT (ORadj = 0.59; 95% CI: 0.44-0.79), CT + TT (ORadj = 0.58; 95% CI: 0.43-0.77) genotypes, and T allele (ORadj = 0.77; 95% CI: 0.47-0.80) of rs3748067 reduced GC risk; the rs10889677 CC genotype (ORadj = 2.22; 95% CI: 1.27-3.87) and C allele (ORadj = 1.24; 95% CI: 1.02-1.52) increased GC risk. A meaningful interaction among ever smoked, family history of GC, and rs3748068 could intensify GC risk by 2.25-fold. Functional tests demonstrated the inhibitory effect of miR-10a-3p on IL17A expression in SGC-7901 cells. These results suggested that miRNA binding site SNPs within IL23/Th17 inflammatory pathway genes and their interactions with environmental factors could be associated with GC risk.

BACKGROUND

Eczema vaccinatum is a life-threatening complication of smallpox vaccination in patients with atopic dermatitis (AD) characterized by dissemination of vaccinia virus (VV) in the skin and internal organs. Mutations in the filaggrin (FLG) gene, the most common genetic risk factor for AD, confer a greater risk for eczema herpeticum in patients with AD, suggesting that it impairs the response to cutaneous viral infections.

OBJECTIVE

We sought to determine the effects of FLG deficiency on the response of mice to cutaneous VV inoculation.

METHODS

VV was inoculated by means of scarification of unsensitized skin or skin topically sensitized with ovalbumin in FLG-deficient flaky tail (ft/ft) mice or wild-type (WT) control mice. The sizes of primary and satellite skin lesions were measured, and hematoxylin and eosin staining was performed. VV genome copy numbers and cytokine mRNA levels were measured by using quantitative PCR.

RESULTS

VV inoculation in unsensitized skin of ft/ft mice, independent of the matted hair mutation, resulted in larger primary lesions, more abundant satellite lesions, heavier viral loads in internal organs, greater epidermal thickness, dermal cellular infiltration, and higher local Il17a, Il4, Il13, and Ifng mRNA levels than in WT control mice. VV inoculation at sites of topical ovalbumin application amplified all of these features in ft/ft mice but had no detectable effect in WT control mice. The number of satellite lesions and the viral loads in internal organs after cutaneous VV inoculation were significantly reduced in both unsensitized and topically sensitized ft/ftxIl17a(-/-) mice.

CONCLUSIONS

FLG deficiency predisposes to eczema vaccinatum. This is mediated primarily through production of IL-17A.

In this study we show that corticosteroid-treated Il17a(-/-) mice develop invasive candidiasis from oropharyngeal infection whereas WT mice do not. By using an established murine model of oral candidiasis we document the spatial and temporal progression of fungal infection. The histological analysis of tissues in Il17a(-/-) mice showed massive infiltration of the fungus in the stomach and alterations of the gastrointestinal tract segments. Both increased permeability and mucosal ulcerations of the intestinal barrier are seen to favor Candida albicans dissemination which was quantified both in kidney and liver where typical candidal abscesses were detected. Neutrophils from Il17a(-/-) were as capable of phagocytosing the fungus comparable to that of WT mice, however, they showed decreased candidacidal ability. Our data implies that IL-17A is crucial for preventing the passage from mucosal to disseminated candidiasis. As such, our model may be suitable to study the mechanisms favoring C. albicans translocation to internal organs.

Inflammation from airborne microbes can overwhelm compensatory mucociliary clearance mechanisms leading to mucous cell metaplasia. Toll-like receptor activation (TLR) via MyD88 signaling is central to pathogen responses. We have previously shown that agricultural organic dust extract (ODE), with abundant microbial component diversity, activates TLR-induced airway inflammation. Using an established model, C57BL/6J wild type (WT) and global MyD88 knock-out (KO) mice were treated with intranasal inhalation of ODE or saline daily for 1 week. ODE primarily increased Muc5ac levels relative to Muc5b. In comparison to ODE-challenged WT mice, ODE challenged MyD88-deficient mice demonstrated significantly increased Muc5ac immunostaining, protein levels by immunoblot, and expression by qPCR. The enhanced Muc5ac levels in MyD88-deficient mice were not explained by differences in the differentiation program of airway secretory cells in naïve mice. Increased Muc5ac levels in MyD88-deficient mice were also not explained by augmented inflammation, IL17A or neutrophil elastase levels. Furthermore, the enhanced airway mucins in the MyD88-deficient mice were not due to defective secretion as the mucin secretory capacity of MyD88 KO mice remained intact. Finally, ODE-induced Muc5ac levels were enhanced in MyD88-deficient airway epithelial cells in vitro. In conclusion, MyD88 deficiency enhances airway mucous cell metaplasia under environments with high TLR activation.

Aside from tumor cells, ovarian cancer-related ascites contains the immune components. The aim of this study was to evaluate whether a combination of clinical and immunological parameters can predict survival in patients with ovarian cancer. Ascites specimens and medical records from 144 ovarian cancer patients at our hospital were used as the derivation group to select target clinical and immunological factors to generate a risk-scoring system to predict patient survival. Eighty-two cases from another hospital were used as the validation group to evaluate this system. The surgical status and expression levels of interleukin 17a (IL17a) and IL21 in ascites were selected for the risk-scoring system in the derivation group. The areas under the receiver operating characteristic (AUROC) curves of the overall score for disease-free survival (DFS) of the ovarian cancer patients were 0.84 in the derivation group, 0.85 in the validation group, and 0.84 for all the patients. The AUROC curves of the overall score for overall survival (OS) of cases were 0.78 in the derivation group, 0.76 in the validation group, and 0.76 for all the studied patients. Good correlations between overall risk score and survival of the ovarian cancer patients were demonstrated by sub-grouping all participants into four groups (P for trend <0.001 for DFS and OS). Therefore, acombination of clinical and immunological parameters can provide a practical scoring system to predict the survival of patients with ovarian carcinoma. IL17a and IL21 can potentially be used as prognostic and therapeutic biomarkers.

Patients with severe, treatment-refractory asthma are at risk for death from acute exacerbations. The cytokine IL17A has been associated with airway inflammation in severe asthma, and novel therapeutic targets within this pathway are urgently needed. We recently showed that IL17A increases airway contractility by activating the procontractile GTPase RhoA. Here, we explore the therapeutic potential of targeting the RhoA pathway activated by IL17A by inhibiting RhoA guanine nucleotide exchange factors (RhoGEFs), intracellular activators of RhoA. We first used a ribosomal pulldown approach to profile mouse airway smooth muscle by qPCR and identified Arhgef12 as highly expressed among a panel of RhoGEFs. ARHGEF12 was also the most highly expressed RhoGEF in patients with asthma, as found by RNA sequencing. Tracheal rings from Arhgef12-KO mice and WT rings treated with a RhoGEF inhibitor had evidence of decreased contractility and RhoA activation in response to IL17A treatment. In a house dust mite model of allergic sensitization, Arhgef12-KO mice had decreased airway hyperresponsiveness without effects on airway inflammation. Taken together, our results show that Arhgef12 is necessary for IL17A-induced airway contractility and identify a therapeutic target for severe asthma.

BACKGROUND

Drug-mediated disruption of IL17A, IL17F and IL17RA proteins is effective in psoriasis. However, disruption of the IL17 pathway by functional mutations has so far only been shown to affect risk in IL23R and TRAF3IP2. It is unclear whether this is due to rarity of disruptive mutations.

OBJECTIVE

(a) To delineate the prevalence of mutations in key IL17 pathway genes and (b) to identify candidate regulatory sites acting on IL23R, IL17A, IL17RA and TRAF3IP2 from a distance.

METHODS

Extraction of mutation frequencies from ExAc data, evolutionary sequence alignment; mapping of long-range interacting (LRI) enhancers; and genetic association testing in a novel psoriasis cohort.

RESULTS

The prevalence of disruptive mutations in genes such as IL17RA is sufficient to have been detectable by existing data sets. Therefore, lack of their association with psoriasis indicates that genetic risk primarily resides in variants acting from a distance. We identify two LRI enhancer sites, regulating IL17RA and TRAF3IP2, respectively. The TRAF3IP2 regulator localizes to the TRAF3IP2 antisense promoter, suggesting feedback regulation. Both LRI sites are associated with psoriasis in a novel Scottish psoriasis cohort and the TRAF3IP2-LRI at rs71562294 replicates in the WTCCC cohort.

CONCLUSIONS

Genetic risk for psoriasis may be encoded at LRI sites regulating IL17 pathway genes from a distance.

Osteoarthritis is mediated by various types of cytokines, growth factors, and inflammatory factors that the role of the interleukin-17 family in this disease is becoming increasingly apparent. The aim of this study is to determine the association between the common polymorphisms of IL17A (including rs2275913) and IL17F (including rs2397084 and rs763780) genes with the knee osteoarthritis risk which was followed by a bioinformatics approach. In a case-control study, 254 participants consisting of 127 healthy individuals and 127 subjects with knee osteoarthritis referring to Shahid Beheshti Hospital dependents on Kashan University of Medical Sciences (Kashan, Iran) were enrolled. After samples collection, the polymorphisms genotyping was determined by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Finally, some bioinformatics tools were used to analyze the molecular effects of the three studied polymorphisms. Data analysis showed a significant association between rs2275913-GA genotype and the decreased risk of knee osteoarthritis (OR = 0.57, 95% CI = 0.33-0.97, P = .040). However, rs763780-AG genotype (OR = 2.29, 95%CI = 1.11-4.69, P = .024) and rs763780-G allele (OR = 2.01, 95% CI = 1.09-3.72, P = .026) were associated with an increased risk of knee osteoarthritis. However, no significant associations were found between the rs2397084 polymorphism and knee osteoarthritis risk. Our structural analysis revealed that the rs2275913 polymorphism could create a new binding site for TFII-I at the promoter region of IL17A. Also, rs2397084 and rs763780 could significantly affect the function and structure of IL17A. Based on our findings, rs2275913 and rs763780 could be considered as protective and risk factors for knee osteoarthritis, respectively. Therefore, these polymorphisms can be considered as biomarkers for the screening of knee osteoarthritis susceptible persons.

Ankylosing spondylitis (AS) is a chronic autoimmune inflammatory disease that mainly affects the axial and sacroiliac joints. Single-nucleotide polymorphisms (SNPs) in genes encoding cytokines have been associated with AS, which can interfere with the production of these cytokines and contribute to the development of AS. In order to contribute to a better understanding of the pathology of AS, our objective was to investigate a possible association of the IL10 -1082 A>G SNP (rs1800896) with AS and to evaluate the serum levels of TNF-α, IL-10, IL-17A, and IL-17F in AS patients and controls comparing them with their respective genotypes (TNF rs1800629, IL10 rs1800896, IL17A rs2275913, and IL17F rs763780). Patients and controls were selected from the Maringá University Hospital and the Maringá Rheumatism Clinic, in Paraná State, Southern Brazil, and they were diagnosed by the ASAS Criteria. In total, 149 patients and 169 controls were genotyped for the IL10 -1082 A>G polymorphism using a polymerase chain reaction with sequence specific primers (PCR-SSP); the measurement of TNF-α serum levels was performed through the immunofluorimetric test and IL-10, IL-17A, and IL-17F using an ELISA test. There was a high frequency of the IL10 -1082 G allele in AS patients compared with controls with an odds ratio of 1.83 and 95% confidence interval of 1.32 to 2.54, and a significant difference in the genotype frequencies of the IL10 -1082 A/G+G/G between patients and healthy controls, with an odds ratio of 3.01 and 95% confidence interval of 1.75 to 5.17. In addition, increased serum levels of IL-10 were observed in AS patients: 2.38 (IQR, 0.91) pg/ml compared with controls 1.72 (IQR 0.93) pg/ml (P = 0.01). Our results also showed an association between IL17F rs763780 C/T+T/T genotypes and increased serum levels of IL-17F in patients with AS and also in controls. We can conclude that patients with the A/G and G/G genotypes for -1082 A>G (rs1800896) in the IL10 gene are three times more likely to develop AS, that the serum level of IL-10 was higher in AS patients and that the IL17F rs763780 polymorphism can affect the levels of IL-17F in the serum of patients and controls in the same way.

Keywords: autoimmune disease; genetic polymorphism; interleukin-10; interleukin-17; rheumatological diseases; single nucleotide polymorphisms; spondyloarthritis; tumour necrosis factor alpha.

The immune response after allogenic transplantation is a complex phenomenon involving cytokines, chemokines, and other mediators of inflammation. The aim of this study was to evaluate the influence of the IL17A and IL17F gene polymorphisms on long-term kidney allograft function, graft function loss/return to dialysis, and mortality after kidney transplantation. This study enrolled 269 Caucasian deceased donor renal transplant recipients. The rs2275913:G>A (-197G>A) polymorphism within the IL17A gene promoter and rs2397084:T>C (Glu126Gly), rs11465553:G>A (Val155Ile), and rs763780:T>C (His167Arg) polymorphisms within the IL17F gene were genotyped. Creatinine concentrations 12, 24, 36, 48, and 60 months after transplantation were significantly higher in recipients with the rs2275913:A>G IL17A GG genotype (GG vs. GA + AA: p = 0.03, p = 0.004, p = 0.006, p = 0.03, p = 0.04, respectively). Moreover, the GG genotype was statistically significantly associated with increased risk of delayed graft function. This association remained significant in multivariate regression analysis adjusted for recipients' age and sex. In the case of the rs11465553, IL17F univariate Cox regression analysis showed statistically significant association of GA genotype with higher risk of graft loss/return to dialysis (GA vs. GG: HR = 2.795, 95%CI = 1.031-7.579, p = 0.04). The results of our study suggest that the GG genotype of the rs2275913 IL17A gene promoter polymorphism is associated with significantly impaired long-term kidney allograft function, whereas the GA genotype of the rs11465553 IL17F gene polymorphism may be associated with a significantly higher risk of graft function loss and return to dialysis after kidney transplantation.

Previous cross-sectional studies showed that some patients with haemophilia A (HA) without inhibitor presented a pro-inflammatory profile during factor VIII (FVIII) replacement therapy. Furthermore, an anti-inflammatory/regulatory state was described in HA patients after inhibitor development. However, no study investigated the levels of these biomarkers before exposure to exogenous FVIII. This study investigated the immunological profile of previously untreated patients (PUPs) with HA in comparison with non-haemophiliac boys. A panel of chemokines and cytokines was evaluated in the plasma of 40 PUPs with HA and 47 healthy controls. The presence of microparticles was assessed in the plasma of 32 PUPs with HA and 47 healthy controls. PUPs with HA presented higher levels of CXCL8 (IL8), IL6, IL4, IL10, IL2, IL17A (IL17), and lower levels of CXCL10 (IP-10) and CCL2 (MCP-1) than the age-matched healthy controls (P < 0·05). We also observed higher levels of microparticles derived from endothelium, erythrocytes, platelets, leucocytes, neutrophils, and T lymphocytes in patients in comparison with controls (P < 0·05). Compared with controls, PUPs with HA presented a distinct immunological profile, characterized by a prominent pro-inflammatory status that appears to be regulated by IL4 and IL10.

Notch ligand Delta-like ligand 4 (DLL4) has been shown to regulate CD4 T-cell differentiation, including regulatory T cells (Treg). Epigenetic alterations, which include histone modifications, are critical in cell differentiation decisions. Recent genome-wide studies demonstrated that Treg have increased trimethylation on histone H3 at lysine 4 (H3K4me3) around the Treg master transcription factor, Foxp3 loci. Here we report that DLL4 dynamically increased H3K4 methylation around the Foxp3 locus that was dependent upon upregulated SET and MYDN domain containing protein 3 (SMYD3). DLL4 promoted Smyd3 through the canonical Notch pathway in iTreg differentiation. DLL4 inhibition during pulmonary respiratory syncytial virus (RSV) infection decreased Smyd3 expression and Foxp3 expression in Treg leading to increased Il17a. On the other hand, DLL4 supported Il10 expression in vitro and in vivo, which was also partially dependent upon SMYD3. Using genome-wide unbiased mRNA sequencing, novel sets of DLL4- and Smyd3-dependent differentially expressed genes were discovered, including lymphocyte-activation gene 3 (Lag3), a checkpoint inhibitor that has been identified for modulating Th cell activation. Together, our data demonstrate a novel mechanism of DLL4/Notch-induced Smyd3 epigenetic pathways that maintain regulatory CD4 T cells in viral infections.

BACKGROUND

Biological agents such as anti-tumor necrosis factor (TNF) induce remission in ulcerative colitis. There is however no consensus regarding the discontinuation of this treatment.

OBJECTIVE

The aim of this study is to assess whether clinical parameters and mucosal cytokine mRNAs in healed colonic mucosa can predict long-term remission in ulcerative colitis following discontinuation of infliximab (IFX) therapy.

METHODS

The prospective Tromsø Inflammatory Bowel Disease (IBD) Study is based on an intensified induction treatment algorithm with IFX to achieve disease remission. Following clinical and endoscopic remission, IFX treatment was discontinued, and follow-up until relapse was performed. Patients who achieved clinical and endoscopic remission following an induction course of IFX were included. Expression levels of TNF alpha (TNF), interferon gamma (IFNG), interleukin (IL) 6 (IL6), IL17A, IL23, and transforming growth factor beta (TGFB) were quantified by real-time PCR in mucosal biopsies obtained at colonoscopy. Remission was defined as Ulcerative Colitis Disease Activity Index (UCDAI) below 3, and an endoscopic sub-score of 0-1. Relapse was defined as UCDAI score >3 and endoscopic sub-score >1. Mucosal cytokine transcript levels from 20 non-IBD patients with a normal colonoscopy served as control group.

RESULTS

Of the 45 patients included, twenty patients (44%) had normalized levels of mucosal TNF expression at the time of mucosal healing, whereas 35 of 42 (83%) had normalized IL17A expression levels, and 31 of 36 (86%) had normalized IFNG expression levels. The median time to relapse was 8months (range 4-12). Normalization of TNF gene expression predicted 20months (1-39) relapse-free survival after withdrawal of IFX compared to 5months (3-7) in the group with elevated TNF expression. Mucosal expression levels of IL17A, IL23, IFNG, TGFB, IL6 did not predict long-term remission (>12months)

CONCLUSIONS

Normalization of mucosal TNF predicts long-term remission after discontinuation of IFX.

Pro-inflammatory and anti-inflammatory cytokines have been shown to play an important role in dengue disease pathogenesis. In the present study, to find out whether single nucleotide polymorphisms (SNPs) in the pro-inflammatory and anti-inflammatory cytokine genes are associated with dengue disease severity, SNPs in TNF, IFNG, IL1B, IL8, IL0, IL17A and IL17F genes were investigated using polymerase chain reaction based methods in 132 dengue (DEN) cases [87 dengue fever (DF), 45 dengue hemorrhagic fever (DHF) cases] and 108 apparently healthy controls (HC) from Pune, Maharashtra, western India. Under recessive genetic model (C/C vs. T/T+T/C), the TNF rs1799964 C/C genotype was significantly associated with DEN [P=0.014, OR with 95% CI 3.07 (1.18-7.98)]. Frequency of T/C genotype of IL17F rs763780 was significantly lower in DEN group as compared to HC [P=0.033, OR with 95% CI 0.43 (0.19-0.95)]. Under overdominant genetic model (A/T vs. A/A+T/T), IL8 rs4973 A/T genotype was negatively associated with DHF compared to HCs [p=0.029, OR with 95% CI 0.43 (0.20-0.93)]. Under overdominant genetic model, A/G genotype of IL10 rs1800871 was significantly negatively associated with DHF compared to DF cases [p=0.014, OR with 95% CI 0.35 (0.15-0.84)]. Significantly higher frequency of the combined genotype IL10 A/A-IFNG A/T and lower frequency of the combined genotypes IL10 A/G-IL1B A/A, IL10 A/G-IL8 A/T and IL10 A/G-IL17F T/T were observed in DHF cases compared to DF. The results suggest that heterozygous genotypes of IL8 rs4973 and IL10 rs1800871 are associated with reduced risk of DHF. Combinations of IL10 rs1800871 and pro-inflammatory cytokine genotypes influence the risk of DHF.

IL-17A is an important cytokine in intestinal inflammation. However, anti-IL-17A therapy does not improve clinical outcomes in patients with Crohn's disease. We aimed to evaluate the role of RORγt⁺ innate lymphoid cells (ILCs) in murine colitis models in the absence of IL-17A. An acute colitis model was induced with either dextran sulfate sodium (DSS) or trinitrobenzenesulfonic acid (TNBS) and a chronic colitis model was induced by CD4⁺CD45RB^hi T cell transfer from either wild-type C57BL/6 or Il17a^-/- mice. An anti-IL-17A antibody, secukinumab, was also used to inhibit IL-17A function in the colitis model. Flow cytometry was performed to analyze the population of RORγt⁺ ILCs in the colonic lamina propria of mice with chronic colitis. Acute intestinal inflammation due to DSS and TNBS was attenuated in IL-17A knockout mice, whereas chronic colitis was not relieved by T cell transfer from Il17a^-/- mice (% of original body weight: wild-type mice vs. Il17a^-/- mice, 81.9% vs. 82.2%; P = 0.922). However, the mean proportion of Lin^-RORγt⁺ lymphocytes was higher after T cell transfer from Il17a^-/- mice than that after T cell transfer from wild-type mice (28.8% vs. 18.5%). The proportion of Lin^-RORγt⁺ was also increased in Rag2^-/- mice that received T cell transfer from wild-type mice when anti-IL-17A antibody was administered (31.7%). Additionally, Il6 and Il22 tended to be highly expressed after T cell transfer from Il17a^-/- mice. In conclusion, RORγt⁺ ILCs may have an important role in the pathogenesis of chronic colitis in the absence of IL-17A. Blocking the function of IL-17A may upregulate Il6 and recruit RORγt⁺ ILCs in chronic colitis, thereby upregulating IL-22 and worsening the clinical outcomes of patients with Crohn's disease.

BACKGROUND

Chronic infections with HCV (CHC) induce a chronic inflammation which can lead to liver fibrosis and subsequently cirrhosis. A recent study suggests a role of IL-17 polymorphism and serum IL17 in hepatitis B related HCC. These data indicate that the IL-17 G-197A polymorphism may be a good indicator for susceptibility to cancer development.

OBJECTIVE

To investigate the role of the IL17A gene polymorphism, serum IL17 and total IgE in Egyptian population with chronic infections with HCV and HCC.

METHODS

This study was carried out on 40 patients with chronic HCV, 35 patients with hepatocellular carcinoma and 20 healthy persons as control. All subjects were submitted to History taking, clinical examination, abdominal ultrasound, laboratory tests including CBC, liver function tests, alpha fetoprotien, determination of IL17gene polymorphisms by PCR-RFLP, IL17 by ELISA and IgE by immunonephelometric assay.

RESULTS

In reference to AA genotype, the frequencies of GG, GA+GG genotypes in the cases with HCC were significantly different from that of the controls (p=0.012, 0.011) and carry 6.12,4.9 respectively fold increase for HCC risk and that of chronic HCV without HCC (p=0.005, 0.004) respectively. However, there was no significant difference in allele frequency in the studied groups (p=0.095). Cases with HCC significantly have higher levels of serum IL17 and IgE than both healthy control and chronic HCV. In conclusion, the present study showed the GG, GG+GA genotypes of IL17A gene is a risk factor for HCC development may be through increased IL17 and IgE and further studies with larger sample size and different populations are recommended.

Previous studies have suggested a role for Tet1 in the pathogenesis of childhood asthma. However, how Tet1 contributes to asthma remains unknown. Here we used mice deficient for Tet1 in a well-established model of allergic airway inflammation and demonstrated that loss of Tet1 increased disease severity including airway hyperresponsiveness and lung eosinophilia. Increased expression of Muc5ac, Il13, Il33, Il17a, Egfr, and Tff2 were observed in HDM-challenged Tet1-deficient mice compared to Tet1^+/+ littermates. Further, transcriptomic analysis of lung RNA followed by pathway and protein network analysis showed that the IFN signaling pathway was significantly upregulated and the aryl hydrocarbon receptor (AhR) pathway was significantly downregulated in HDM-challenged Tet1^-/- mice. This transcriptional regulation of the IFN and AhR pathways by Tet1 was also present in human bronchial epithelial cells at base line and following HDM challenges. Genes in these pathways were further associated with changes in DNA methylation, predicted binding of transcriptional factors with relevant functions in their promoters, and the presence of histone marks generated by histone enzymes that are known to interact with Tet1. Collectively, our data suggest that Tet1 inhibits HDM-induced allergic airway inflammation by direct regulation of the IFN and AhR pathways.

The commensal gut microbiota critically regulates immunomodulatory processes that influence normal skeletal growth and maturation. However, the influence of specific microbes on commensal gut microbiota osteoimmunoregulatory actions is unknown. We have shown previously that the commensal gut microbiota enhances T_HIL17A immune response effects in marrow and liver that have procatabolic/antianabolic actions in the skeleton. Segmented filamentous bacteria (SFB), a specific commensal gut bacterium within phylum Firmicutes, potently induces T_HIL17A-mediated immunity. The study purpose was to delineate the influence of SFB on commensal gut microbiota immunomodulatory actions regulating normal postpubertal skeletal development. Two murine models were utilized: SFB-monoassociated mice versus germ-free (GF) mice and specific-pathogen-free (SPF) mice +/- SFB. SFB colonization was validated by 16S rDNA analysis, and SFB-induced T_HIL17A immunity was confirmed by upregulation of Il17a in ileum and IL17A in serum. SFB-colonized mice had an osteopenic trabecular bone phenotype, which was attributed to SFB actions suppressing osteoblastogenesis and enhancing osteoclastogenesis. Intriguingly, SFB-colonized mice had increased expression of proinflammatory chemokines and acute-phase reactants in the liver. Lipocalin-2 (LCN2), an acute-phase reactant and antimicrobial peptide, was substantially elevated in the liver and serum of SFB-colonized mice, which supports the notion that SFB regulation of commensal gut microbiota osteoimmunomodulatory actions are mediated in part through a gut-liver-bone axis. Proinflammatory T_HHIl17a in the gut and Lcn2 in the liver resulted in increased circulating levels of IL17A and LCN2. Recognizing that IL17A and LCN2 support osteoclastogenesis/suppress osteoblastogenesis, SFB actions impairing postpubertal skeletal development appear to be mediated through immunomodulatory effects in both the gut and liver. This research reveals that specific microbes critically impact commensal gut microbiota immunomodulatory actions regulating normal postpubertal skeletal growth and maturation. © 2020 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Background: Multiple types of immune cells producing IL-17 are found in the tumor microenvironment. However, their roles in tumor progression and exhaustion of CD8⁺ tumor-infiltrating lymphocytes (TILs) remain unclear.

Methods: To determine the role of type 17 immunity in tumor, we investigated the growth of B16F10 melanoma and the exhaustion of CD8⁺ TILs in Il17a ^-/- mice, Il17a ^Cre R26 ^DTA mice, RORγt inhibitor-treated mice, or their respective control mice. Adoptive transfer of tumor-specific IL-17-producing T cells was performed in B16F10-bearing congenic mice. Anti-CD4 or anti-Ly6G antibodies were used to deplete CD4⁺ T cells or CD11b⁺Gr-1^hi myeloid cells in vivo, respectively. Correlation between type 17 immunity and T cell exhaustion in human cancer was evaluated by interrogating TCGA dataset.

Results: Depletion of CD4⁺ T cells promotes the exhaustion of CD8⁺ T cells with a concomitant increase in IL-17-producing CD8⁺ T (Tc17) cells in the tumor. Unlike IFN-γ-producing CD8⁺ T (Tc1) cells, tumor-infiltrating Tc17 cells exhibit CD103⁺KLRG1^-IL-7Rα^hi tissue resident memory-like phenotypes and are poorly cytolytic. Adoptive transfer of IL-17-producing tumor-specific T cells increases, while depletion of IL-17-producing cells decreases, the frequency of PD-1^hiTim3⁺TOX⁺ terminally exhausted CD8⁺ T cells in the tumor. Blockade of IL-17 or RORγt pathway inhibits exhaustion of CD8⁺ T cells and also delays tumor growth in vivo. Consistent with these results, human TCGA analyses reveal a strong positive correlation between type 17 and CD8⁺ T cell exhaustion signature gene sets in multiple cancers.

Conclusion: IL-17-producing cells promote terminal exhaustion of CD8⁺ T cells and tumor progression in vivo, which can be reversed by blockade of IL-17 or RORγt pathway. These findings unveil a novel role for IL-17-producing cells as tumor-promoting cells facilitating CD8⁺ T cell exhaustion, and propose type 17 immunity as a promising target for cancer immunotherapy.

Keywords: CD8-positive T-lymphocytes; cytokines; cytotoxicity; immunologic; lymphocytes; tumor microenvironment; tumor-infiltrating.