How to help countries improve resilience during a pandemic: an example of a Rapid Exchange Forum.

BACKGROUND: The COVID-19 pandemic demanded quick exchanges between experts and institutions supporting governments to provide evidence-based information in response to the crisis. Initially, there was no regular cross-country forum in the field of population health. This paper describes the set-up and benefits of implementing such a forum. METHODS: A group of public health practitioners from academia, national public health institutes and ministries of health decided in April 2020 to meet bi-monthly to discuss a vast array of population health topics in a structured format called a Rapid Exchange Forum (REF). An ad-hoc mailing group was established to collect responses to questions brought forward in the forum from at least five countries within 24 h. This endeavour, which evolved as network of networks was awarded an EU grant in autumn 2020 and was called PHIRI (Population Health Information Research Infrastructure). RESULTS: Responses from up to 31 countries were compiled and shared immediately via the European Health Information Portal. This exchange was complemented by special REFs that focused on the advantages and disadvantages of vaccination, for example. By July 2023, 54 REFs had taken place with topics going beyond COVID-19. CONCLUSION: The REF demonstrated its value for quick yet evidence-based cross-country exchange in times of crisis and was highly appreciated by countries and European Commission. It demonstrated its sustainability even after the acute crisis by expanding the topics covered and managing to continue exchange with the aim of capacity building and mutual learning, making it a true EU response and coordination mechanism.

Phosphomevalonate kinase deficiency expands the genetic spectrum of systemic autoinflammatory diseases.

BACKGROUND: In the isoprenoid biosynthesis pathway, mevalonate is phosphorylated in 2 subsequent enzyme steps by MVK and PMVK to generate mevalonate pyrophosphate that is further metabolized to produce sterol and nonsterol isoprenoids. Biallelic pathogenic variants in MVK result in the autoinflammatory metabolic disorder MVK deficiency. So far, however, no patients with proven PMVK deficiency due to biallelic pathogenic variants in PMVK have been reported. OBJECTIVES: This study reports the first patient with functionally confirmed PMVK deficiency, including the clinical, biochemical, and immunological consequences of a homozygous missense variant in PMVK. METHODS: The investigators performed whole-exome sequencing and functional studies in cells from a patient who, on clinical and immunological evaluation, was suspected of an autoinflammatory disease. RESULTS: The investigators identified a homozygous PMVK p.Val131Ala (NM_006556.4: c.392T>C) missense variant in the index patient. Pathogenicity was supported by genetic algorithms and modeling analysis and confirmed in patient cells that revealed markedly reduced PMVK enzyme activity due to a virtually complete absence of PMVK protein. Clinically, the patient showed various similarities as well as distinct features compared to patients with MVK deficiency and responded well to therapeutic IL-1 inhibition. CONCLUSIONS: This study reported the first patient with proven PMVK deficiency due to a homozygous missense variant in PMVK, leading to an autoinflammatory disease. PMVK deficiency expands the genetic spectrum of systemic autoinflammatory diseases, characterized by recurrent fevers, arthritis, and cytopenia and thus should be included in the differential diagnosis and genetic testing for systemic autoinflammatory diseases.

YB-1 Is a Novel Target for the Inhibition of α-Adrenergic-Induced Hypertrophy.

Cardiac hypertrophy resulting from sympathetic nervous system activation triggers the development of heart failure. The transcription factor Y-box binding protein 1 (YB-1) can interact with transcription factors involved in cardiac hypertrophy and may thereby interfere with the hypertrophy growth process. Therefore, the question arises as to whether YB-1 influences cardiomyocyte hypertrophy and might thereby influence the development of heart failure. YB-1 expression is downregulated in human heart biopsies of patients with ischemic cardiomyopathy (n = 8), leading to heart failure. To study the impact of reduced YB-1 in cardiac cells, we performed small interfering RNA (siRNA) experiments in H9C2 cells as well as in adult cardiomyocytes (CMs) of rats. The specificity of YB-1 siRNA was analyzed by a miRNA-like off-target prediction assay identifying potential genes. Testing three high-scoring genes by transfecting cardiac cells with YB-1 siRNA did not result in downregulation of these genes in contrast to YB-1, whose downregulation increased hypertrophic growth. Hypertrophic growth was mediated by PI3K under PE stimulation, as well by downregulation with YB-1 siRNA. On the other hand, overexpression of YB-1 in CMs, caused by infection with an adenovirus encoding YB-1 (AdYB-1), prevented hypertrophic growth under α-adrenergic stimulation with phenylephrine (PE), but not under stimulation with growth differentiation factor 15 (GDF15; n = 10-16). An adenovirus encoding the green fluorescent protein (AdGFP) served as the control. YB-1 overexpression enhanced the mRNA expression of the Gq inhibitor regulator of G-protein signaling 2 (RGS2) under PE stimulation (n = 6), potentially explaining its inhibitory effect on PE-induced hypertrophic growth. This study shows that YB-1 protects cardiomyocytes against PE-induced hypertrophic growth. Like in human end-stage heart failure, YB-1 downregulation may cause the heart to lose its protection against hypertrophic stimuli and progress to heart failure. Therefore, the transcription factor YB-1 is a pivotal signaling molecule, providing perspectives for therapeutic approaches.

Trajectory and determinants of agreement between parental and physicians' reports of childhood atopic dermatitis.

BACKGROUND: Parent self-administered reports are commonly used in studies on childhood atopic dermatitis (AD) but data on its validity are sparse. We aimed to examine the agreement between parent- and physician-reported measures of childhood AD throughout early life and identify the determinants. METHODS: In this prospective cohort study, we used data of 449 infants and their mothers recruited in the Ulm SPATZ Health Study in Germany. Longitudinal data of parental and children's caring physicians' reports were used to assess the point and cumulative agreement of parent- and physician-reported AD diagnoses, AD onset age, and trend of agreement at child ages between 1 and 6 years overall and by child and parent demographics and health conditions. A Generalized Estimating Equation model was fitted to identify factors associated with the sensitivity of parent reports. RESULTS: The point agreement between parent- and physician-reported AD was substantial at the age of 1 (kappa = 0.63, 95% CI: 0.51-0.75) but declined with age and became fair after the age of 3 (kappa < 0.40). The cumulative agreement remained moderate at the age of 6 (kappa = 0.51, 95% CI: 0.43-0.60). Parents had a bias towards delayed reporting of the AD onset age. The AD severity was the only strong determinant for the agreement of AD diagnoses and largely explained the variance of the sensitivity of parent reports. CONCLUSION: The disagreement between parent- and physician-reported AD increases with child age, likely due to the change of AD severity. Using parent-reported data might miss a substantial portion of mild childhood AD cases.

Osteopontin attenuates aging-associated phenotypes of hematopoietic stem cells.

Upon aging, hematopoietic stem cells (HSCs) undergo changes in function and structure, including skewing to myeloid lineages, lower reconstitution potential and loss of protein polarity. While stem cell intrinsic mechanisms are known to contribute to HSC aging, little is known on whether age-related changes in the bone marrow niche regulate HSC aging. Upon aging, the expression of osteopontin (OPN) in the murine bone marrow stroma is reduced. Exposure of young HSCs to an OPN knockout niche results in a decrease in engraftment, an increase in long-term HSC frequency and loss of stem cell polarity. Exposure of aged HSCs to thrombin-cleaved OPN attenuates aging of old HSCs, resulting in increased engraftment, decreased HSC frequency, increased stem cell polarity and a restored balance of lymphoid and myeloid cells in peripheral blood. Thus, our data suggest a critical role for reduced stroma-derived OPN for HSC aging and identify thrombin-cleaved OPN as a novel niche informed therapeutic approach for ameliorating HSC phenotypes associated with aging.

Differential uptake of three clinically relevant allergens by human plasmacytoid dendritic cells.

BACKGROUND: Human plasmacytoid dendritic cells (pDC) have a dual role as interferon-producing and antigen-presenting cells. Their relevance for allergic diseases is controversial. and the impact of pDC on allergic immune responses is poorly understood. METHODS: This in vitro study on human pDC isolated from peripheral blood was designed to compare side by side the uptake of three clinically relevant representative allergens: fluorochrome-labeled house dust mite Der p 1, Bee venom extract from Apis mellifera (Api) and the food allergen OVA analyzed flow cytometry and confocal microscopy. RESULTS: We found that the internalization and its regulation by TLR9 ligation was significantly different between allergens in terms of time course and strength of uptake. Api and OVA uptake in pDC of healthy subjects was faster and reached higher levels than Der p 1 uptake. CpG ODN 2006 suppressed OVA uptake and to a lesser extent Der p 1, while Api internalization was not affected. All allergens colocalized with LAMP1 and EEA1, with Api being internalized particularly fast and reaching highest intracellular levels in pDC. Of note, we could not determine any specific differences in antigen uptake in allergic compared with healthy subjects. CONCLUSIONS: To our knowledge this is the first study that directly compares uptake regulation of clinically relevant inhalative, injective and food allergens in pDC. Our findings may help to explain differences in the onset and severity of allergic reactions as well as in the efficiency of AIT.

Soluble CD14 concentration in human breast milk and its potential role in child atopic dermatitis: Results of the Ulm Birth Cohort Studies.

BACKGROUND: Soluble CD14 (sCD14) is one of many factors in human breast milk which may influence programming of the immune response in the breastfed child. Although previous studies have mostly found little association between sCD14 concentration in breast milk and atopic outcomes, recent evidence continues to support a role of sCD14 in immune-related disease. OBJECTIVE: We aimed to clarify whether an association exists between sCD14 concentration in human breast milk (m-sCD14) and child atopic dermatitis (AD) diagnosis by age 3 years within the context of two large birth cohorts. METHODS: Data were obtained from the Ulm Birth Cohort Study (UBCS) and the Ulm SPATZ Health Study, methodologically similar birth cohort studies, each consisting of approximately 1000 newborns and their mothers recruited from the general population shortly after delivery in Ulm, Southern Germany, respectively, from 11/2000 to 11/2001 and 04/2012 to 05/2013. sCD14 concentrations were measured by different ELISAs (UBCS: IBL, SPATZ: R&D) in breast milk samples collected at 6 weeks post-delivery in both studies and additionally at 6 months and 1 year in SPATZ. Children's AD diagnosis was assessed using parent and paediatrician reports at 1, 2 and 3 years of age. RESULTS: Complete exposure and outcome data were available for 659 UBCS and 489 SPATZ children. In both cohorts, sCD14 concentration was significantly associated with breastfeeding frequency (P < 0.01). We observed no association between m-sCD14 concentration and child AD diagnosis in either study. CONCLUSIONS: Our results do not support an association between sCD14 concentration in mature breast milk and AD among breastfed children.

A 2-step fast-track elastometry service for advanced workup of nonalcoholic fatty liver disease (NAFLD) patients - single-center real-world experience of outpatient clinical practice.

INTRODUCTION AND AIMS: Nonalcoholic fatty liver disease (NAFLD) is increasing globally with an estimated prevalence of approximately 25 %. Nonalcoholic steatohepatitis as the progressive disease entity often leads to fibrosis and end-stage disease. The magnitude of NAFLD patients are not diagnosed and have no access to further clinical assessment. Diagnostic pathways for individual risk evaluation fitting with available resources are of utmost importance in real-world clinical practice. METHODS: Retrospective analysis of 1346 anonymized outpatient datasets at Würzburg University Hospital, Germany. Transient elastography (TE) with controlled attenuation parameter and laboratory-based risk scores (NFS, FIB-4) were the main diagnostic workup tools for risk stratification. RESULTS: After preselection based on questionnaire information NAFLD still accounts for one-fifth of patients in the liver outpatient service. More than 80 % of NAFLD patients receive their first-time diagnosis in our unit. Laboratory-based risk scores and TE are valuable tools for second-step risk assessment as shown in our clinical data analysis. Moreover, 65 % of NAFLD patients use inpatient services for at least 1 day. The policy to perform liver biopsy in high-risk patients above the recommended threshold of 9.6 kPa if any clinical doubt exists regarding the diagnosis of cirrhosis leads to a histological down staging in almost 80 %. CONCLUSION: Questionnaire-based referral from primary care followed by broadly available fast-track TE and eventually liver biopsy for selected patients is the standard practice in our unit. This approach represents a feasible model to handle the large gap between availability and clinical need for TE facilities.

Progression from Nonalcoholic Fatty Liver to Nonalcoholic Steatohepatitis Is Marked by a Higher Frequency of Th17 Cells in the Liver and an Increased Th17/Resting Regulatory T Cell Ratio in Peripheral Blood and in the Liver.

Nonalcoholic fatty liver disease is increasing in prevalence. It can be subdivided into nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH). Five to twenty percent of cases progress from NAFL to NASH. Increased hepatic Th17 cells and IL-17 expression were observed in NASH mice and patients, respectively. We analyzed CD4(+) effector T cells and regulatory T cells (Tregs) from peripheral blood and livers of NAFL and NASH patients. A total of 51 NAFL patients, 30 NASH patients, 31 nonalcoholic fatty liver disease patients (without histology), and 43 healthy controls were included. FACS analysis was performed on PBMCs and intrahepatic lymphocytes. Compared with healthy controls, a lower frequency of resting Tregs (rTregs; CD4(+)CD45RA(+)CD25(++)) and higher frequencies of IFN-γ(+) and/or IL-4(+) cells were detected among CD4(+) T cells of peripheral blood in NASH, and to a lesser degree in NAFL. In hepatic tissue, NAFL to NASH progression was marked by an increase in IL-17(+) cells among intrahepatic CD4(+) T cells. To define immunological parameters in peripheral blood to distinguish NAFL from NASH, we calculated different ratios. Th17/rTreg and Th2/rTreg ratios were significantly increased in NASH versus NAFL. The relevance of our findings for NASH pathogenesis was highlighted by the normalization of all of the changes 1 y after bariatric surgery. In conclusion, our data indicate that NAFL patients show changes in their immune cell profile compared with healthy controls. NAFL to NASH progression is marked by an increased frequency of IL-17(+) cells among intrahepatic CD4(+) T cells and higher Th17/rTreg and Th2/rTreg ratios in peripheral blood.

9-cis-Retinoic acid induces a distinct regulatory dendritic cell phenotype that modulates murine delayed-type allergy.

BACKGROUND: Hand eczema, which is frequently caused by delayed-type allergy, is treated with 9-cis-retinoic acid (9cisRA). However, knowledge on how 9cisRA modulates skin immunity is sparse. OBJECTIVE: As dendritic cells (DCs) are central in the pathogenesis of contact allergy, we investigated 9cisRA modulation of DC function in murine contact hypersensitivity (CHS). METHODS: 9cisRA-differentiated DCs (9cisRA-DCs) were analysed for phenotype and function. In vivo 9cisRA-DCs were tested in the CHS model. RESULTS: 9cisRA induces the differentiation of a distinct CD103- CD207- regulatory DC phenotype. CD11c+ DCs differentiated with 9cisRA have lower expression of major histocompatibility complex-II and costimulatory molecules, but conversely have higher expression of the inhibitory coreceptor PD1-L. 9cisRA-DC culture does not induce the expression of proinflammatory cytokines, but strongly enhances osteopontin (OPN) secretion. 9cisRA-DCs are compromised in the induction of T cell proliferation in vitro, but efficiently convert naive T cells into regulatory T cells (Tregs). Notably, OPN-deficient 9cisRA-DCs show a loss of Treg-inducing function, which is re-established by substituting OPN. In vivo, in allergic mice, allergen-primed 9cisRA-DCs suppress allergic inflammation and induce Treg accumulation in skin draining lymph nodes. CONCLUSIONS: This study describes 9cisRA-mediated differentiation of a distinct DC phenotype that relies on OPN for Treg transformation and suppresses established CHS through Treg induction.

Farnesoid X receptor-dependent and -independent pathways mediate the transcriptional control of human fibroblast growth factor 19 by vitamin A.

Fibroblast growth factor 19 (FGF19) is a gut-derived hormone that controls bile acid (BA), carbohydrate and lipid metabolism. Whereas strong evidence supports a key role of BAs and farnesoid X receptor (FXR) for the control of FGF19 expression, information on other regulators is limited. In mice, FGF15 expression (ortholog of human FGF19) is induced by vitamin A (VitA) in an FXR-dependent manner. However, the significance of this finding for human FGF19 is currently unclear. Here, we demonstrate that VitA derivatives induce FGF19 in human intestinal cell lines by a direct transcriptional mechanism. In contrast to mouse FGF15, however, this direct regulation is not dependent on FXR but mediated by retinoic acid receptors (RARs) and their interaction with a novel DR-5 element in the human FGF19 gene. In addition to this direct effect, VitA derivatives impacted on the BA-mediated control of FGF19 by regulation of FXR protein levels. In conclusion, VitA regulates human FGF19 expression through FXR-dependent and -independent pathways. Moreover, we suggest that considerable mechanistic differences exist between humans and mice with regard to the nuclear receptors controlling the VitA-FGF15/19 axis. These findings may implicate a clinical relevance of RAR-activating VitA derivatives for the regulation of FGF19 levels in humans.

Maternal prenatal stress and child atopic dermatitis up to age 2 years: The Ulm SPATZ health study.

BACKGROUND: Evidence linking maternal psychosocial stress during pregnancy to subsequent child atopic dermatitis (AD) is growing, but the definition of AD is diverse and results are inconsistent. We aimed to analyze the relationship between stress and AD using alternative measurements of stress and AD. METHODS: In the Ulm SPATZ Health Study, chronic stress and symptoms of anxiety and depression were assessed by standardized self-reported questionnaires in 934 mothers of singletons following delivery in Ulm, Germany, from 04/2012-05/2013. Maternal hair cortisol concentrations (HCCs, n = 626) at childbirth and the cumulative incidences of parent-reported child AD symptoms, parent-, and pediatrician-reported AD diagnoses were assessed until age 2 years (n = 787). Overall, 205 dermatologic examinations were performed in 167 children showing AD symptoms. Crude and adjusted risk ratios (RR, aRR) with 95% confidence intervals were estimated. RESULTS: Maternal stress and anxiety were associated with child AD symptoms by trend (RR and aRR: 1.5 (1.0,2.3) for the highest vs. the lowest quarter of chronic stress; aRR: 1.4 (1.0,2.0) for possible anxiety symptoms vs. no symptoms). No relationship was found between stress or related constructs and AD diagnoses nor could we show consistent associations between maternal HCC and child AD. However, a higher RR of child AD was evident in families not yet affected by AD in siblings given maternal depressive symptoms, examined in the crude model. CONCLUSIONS: Stress measurements or related constructs are linked to AD symptoms, but association with AD diagnoses is limited. The reason for this divergence still needs further research.

Transabdominal laparoscopic retroperitoneal neurectomy for chronic pain after inguinal hernia repair and appendicectomy -a matched-pair study.

BACKGROUND: Chronic debilitating pain is a rare but significant cause of postoperative morbidity after inguinal surgery. Such pain is usually of neuropathic origin and frequently caused by intraoperative nerve damage. In this retrospective matched-pair study we analysed results of a minimal-invasive approach to neurectomy on quality of life and pain relief. METHODS: From March 2010 to January 2012, 9 patients developing chronic neuropathic pain after inguinal hernia repair (8 patients) or open appendicectomy (one patient) were operated using a laparoscopic transabdominal approach in our department. Clinical examinations and specific questionnaires on pain and quality of life (PainDetect, SF-36) were completed 6 months to 3 years after neurectomy. Every patient was matched with one patient without chronic pain. RESULTS: Seven of nine patients had severe or very severe pain before neurectomy, two had mild pain but refused a conservative treatment. Four patients were free of pain after neurectomy, three described an improved pain status, whereas two did not observe any change in pain. Within a follow-up period of 14,3 months, no deterioration of pain or other complications were observed. Patients who underwent neurectomy had significantly lower quality of life compared to the control group. No postoperative complications were observed. CONCLUSIONS: Laparoscopic transabdominal neurectomy represents a possible surgical approach in treating patients with chronic disabling postoperative groin pain requiring surgery. This technique was feasible, safe, and effective in our series to relieve chronic debilitating pain in the majority of our patients with comparable results to other published approaches.

Feasibility of liver stiffness measurement in morbidly obese patients undergoing bariatric surgery using XL probe.

OBJECTIVE: Prevalence of non-alcoholic fatty liver disease is rising in the Western world and reaches up to 90% in patients undergoing bariatric surgery. Fibroscan(®) as a non-invasive tool for liver stiffness measurement (LSM) has several limitations in morbidly obese patients. Only few data exist about the technical feasibility and accuracy of LSM in these patients. We aimed to analyse the feasibility of LSM by Fibroscan(®) in bariatric patients. MATERIALS AND METHODS: In morbidly obese patients, LSM was performed using XL probe. Measurements were termed reliable if 10 successful measurements with a success rate ≥60% and an interquartile range/median (IQR/M) <0.3 were obtained, unreliable if 10 successful measurements were obtained but the IQR/M was >0.3, and they were termed failed if they were neither reliable nor unreliable. RESULTS: A total of 149 patients were included (87 with liver biopsies); mean BMI was 51.6 ± 8.5 kg/m(2). In 41% LSM using XL-probe was reliable, in 22% unreliable and in 37% failed. Failed LSM was significantly more frequent in patients with higher BMI compared to reliable and unreliable measurements (p < 0.05). In patients with failed measurement, sonographic paramedian and intercostal distances were significantly higher compared to reliable measurements. All three patients with F4 fibrosis could successfully be differentiated by LSM from patients without fibrosis. CONCLUSIONS: LSM with XL probe is feasible in almost two-thirds of morbidly obese patients with a BMI ≥50 kg/m(2). Reliable prediction of advanced fibrosis appears to be possible even if formal criteria of successful measurements are not met.

Wells syndrome.

A rare eosinophilic dermatosis, Wells syndrome, also referred to as eosinophilic cellulitis, is characterized by great clinical variability. Typical findings include infiltrated erythematous plaques arising on the extremities. Lesions initially resemble erysipelas/cellulitis, however, they do not improve with antibiotic treatment. Eosinophilic cellulitis is a diagnosis of exclusion that may only be made over the course of the disease, taking into account clinical and characteristic histological findings (flame figures). Although multiple potential triggers have been proposed, the exact etiology remains unresolved. Involvement of abnormal Th2 cells, IL-5, and activated eosinophilic granulocytes suggest a nonspecific hypersensitivity response to exogenous or endogenous stimuli. Corticosteroids may have a beneficial effect on the chronic, recurrent course frequently observed. The disease is often self-limiting, healing without sequelae. Given that transitions to hematological and oncological disorders have been observed, patients should be closely followed up.

Wells-Syndrom.

Das Wells-Syndrom, auch als eosinophile Zellulitis bezeichnet, ist eine seltene, sporadisch auftretende eosinophile Dermatose mit polymorphem klinischem Bild. Als typisch gelten entzündliche Erytheme oder Plaques an den Extremitäten, die initial als Erysipel imponieren können, unter antimikrobieller Behandlung aber persistieren. Die eosinophile Zellulitis ist eine Ausschlussdiagnose, die in Zusammenschau von klinischem Befund und charakteristischem histologischem Bild (Flammenfiguren) nur im Verlauf gestellt werden kann. Mit einer Vielzahl möglicher Triggerfaktoren ist die Ätiologie nicht geklärt. Die Beteiligung abnormer Th2-Zellen, des Zytokins IL-5 und aktivierter eosinophiler Granulozyten lässt eine unspezifische Hypersensitivitätsreaktion auf exo- und endogene Stimuli vermuten. Die häufiger vorkommenden chronisch- rezidivierenden Formen lassen sich durch Glukokortikoide günstig beeinflussen. Der Verlauf ist meist selbstlimitierend, ohne Residuen. Aufgrund von Übergängen in hämatoonkologische Erkrankungen sind Verlaufskontrollen angezeigt.

Osteopontin deficiency affects imiquimod-induced psoriasis-like murine skin inflammation and lymphocyte distribution in skin, draining lymph nodes and spleen.

Osteopontin (OPN) that enhances autoimmunity is expressed in psoriasis lesions; however, its functions in psoriatic inflammation are unknown. We investigated the role of OPN in OPN deficient mice (OPN-/-) by inducing psoriasis-like inflammation through skin application of imiquimod (IMQ). OPN-/- mice treated with IMQ showed delayed onset ear swelling and attracted less inflammatory cells to the skin. IMQ-induced lymph node swelling was reduced in the absence of OPN, and IMQ-mediated expansion of B cells was inhibited. Further, reduction of CD4(+) T-cell numbers by IMQ in lymph nodes was suppressed in OPN-/- mice, with an increase in the CD4/CD8 ratio. A comparable pattern was found in spleen. Importantly, IMQ-induced IL-17 and IL-4 expression by CD4(+) lymph node T cells was reduced in OPN-/- mice. In conclusion, OPN may modulate psoriasis-like inflammation through altering lymphocyte distribution in skin and draining lymph nodes and by inducing IL-17 expression of inflammatory T cells.