Development and function of TH17 cells in health and disease

Lipopolysaccharides promote a shift from Th2-derived airway eosinophilic inflammation to Th17-derived neutrophilic inflammation in an ovalbumin-sensitized murine asthma model

INTRODUCTION

The currently available treatments for severe asthma are insufficient. Infiltration of neutrophils rather than eosinophils into the airways is an important inflammatory characteristic of severe asthma. However, the mechanism of the phenotypic change from eosinophilic to neutrophilic inflammation has not yet been fully elucidated.

METHODS

In the current study, we examined the effect of lipopolysaccharides (LPS) on eosinophilic asthmatic mice sensitized with ovalbumin (OVA), as well as the roles of interleukin (IL)-17A/T helper (Th) 17 cells on the change in the airway inflammatory phenotype from eosinophilic to neutrophilic inflammation in asthmatic lungs of IL-17A-deficient mice.

RESULTS

Following exposure of OVA-induced asthmatic mice to LPS, neutrophil-predominant airway inflammation rather than eosinophil-predominant inflammation was observed, with increases in airway hyperresponsiveness (AHR), the IL-17A level in bronchoalveolar lavage fluid (BALF) and Th17 cells in the spleen and in the pulmonary hilar lymph nodes. Moreover, the neutrophilic asthmatic mice showed decreased mucus production and Th2 cytokine levels (IL-4 and IL-5). In contrast, IL-17A knockout (KO) mice exhibited eosinophil-predominant lung inflammation, decreased AHR, mucus overproduction and increased Th2 cytokine levels and Th2 cells.

CONCLUSION

These findings suggest that the eosinophilic inflammatory phenotype of asthmatic lungs switches to the neutrophilic phenotype following exposure to LPS. The change in the inflammatory phenotype is strongly correlated with the increases in IL-17A and Th17 cells.

Immunomodulation of TH2 biased immunity with mucosal administration of nanoemulsion adjuvant

TH2-biased immune responses are associated with inadequate protection against some pathogens and with cancer, colitis, asthma and allergy. Since most currently used vaccine adjuvants induce a TH2-biased response, this has led to interest in developing adjuvants capable of activating TH1 immunity and modulating existing TH2 responses. Immunotherapies to shift immune responses from TH2 to TH1 have generally required prolonged immunization protocols and have not induced effective TH1 responses. We have demonstrated that nanoscale emulsions (NE), a novel mucosal adjuvant, induce robust IgA and IgG antibody responses and TH1/TH17 cellular immunity resulting in protection against a variety of respiratory and mucosal infections. Because intranasal (i.n.) delivery of NE adjuvant consistently induces TH1/TH17 biased responses, we hypothesized that NE could be used as a therapeutic vaccine to redirect existing TH2 polarized immunity towards a more balanced TH1/TH2 profile. To test this, a TH2 immune response was established by intramuscular immunization of mice with alum-adjuvanted hepatitis B surface antigen (HBs), followed by a single subsequent i.n. immunization with NE-HBs. These animals exhibited increased TH1 associated immune responses and IL-17, and decreased TH2 cytokines (IL-4 and IL-5) and IgG1. NE immunization induced regulatory T cells and IL-10, and IL-10 was required for the suppression of TH2 immunity. These data demonstrate that NE-based vaccines can modulate existing TH2 immune responses to promote TH1/TH17 immunity and suggest the potential therapeutic use of NE vaccines for diseases associated with TH2 immunity.

Distinctive downmodulation of plasmacytoid dendritic cell functions by vitamin D3 analogue calcipotriol

BACKGROUND

In relation to Th17 cell actions, interferon (IFN)-α production by plasmacytoid dendritic cells (pDCs) are involved in the pathogenesis of psoriasis. Vitamin D3 analogues are widely used in the treatment of psoriasis, however, their actions on pDCs are not well understood.

OBJECTIVE

To investigate the effects of Vitamin D3 analogue calcipotriol (CAL) on pDCs, focusing on the cytokine production and chemotactic activity.

METHODS

We compared in mice the effects of CAL, cyclosporine A (CyA), and triamcinolone acetonide (TA) on the cytokine production by pDCs (IFN-α), conventional DCs (TNF-α), and γd T cells (IL-17A). pDCs isolated from mouse spleen cells were stimulated with CpG-ODN in the presence or absence of each drug for 48h. Purified splenic conventional DCs (cDCs) and lymph node γδ T cells were stimulated with CpG-ODN or with anti-CD3/CD28 antibody, respectively. IFN-α, TNF-α and IL-17A in the 48-h culture supernatants were quantified by ELISA. We also studied the ability of CAL to inhibit the chemotaxis of freshly isolated pDCs toward chemerin and VEGF-A, representative chemoattractants of pDCs, by a real-time monitoring method, EZ-Taxiscan. To assess the effect of CAL on pDC accumulation in vivo, we painted CAL ointment to the mouse skin inflamed by topical application of imiquimod cream (IMQ) for 4 consecutive days. In the skin samples, we enumerated 440c⁺ pDCs by immunohistochemistry and evaluated the mRNA expression of cytokines by real-time PCR.

RESULTS

CAL significantly inhibited CpG-enhanced pDC IFN-α production at a comparable level to T cell IL-17A production, whereas its effect on cDC TNF-α production was minimal. Accordingly, CAL suppressed the CpG-augmented expression of TLR9 and MyD88. On the contrary, CyA strongly suppressed the production of TNF-α and IL-17A, but not IFN-α. TA inhibited the production of all the cytokines tested. The effect of CAL on the chemotactic activity of pDCs was also evaluated, demonstrating a significant downmodulation by exposure to the reagent. CAL depressed chemerin receptor CMKLR1 expression in pDCs. The in vivo mouse study showed that simultaneous application of CAL to the imiquimod-applied skin reduce both the recruitment of pDCs and the expression of IFN-α2 in the skin.

CONCLUSIONS

Our findings suggest that CAL uniquely downmodulates the cytokine production and chemotactic activity of pDCs. The CAL suppression of the in vivo pDC accumulation to the skin suggests that these actions are therapeutically relevant.

Thymic and Postthymic Regulation of Naïve CD4(+) T-Cell Lineage Fates in Humans and Mice Models

Our understanding of how thymocytes differentiate into many subtypes has been increased progressively in its complexity. At early life, the thymus provides a suitable microenvironment with specific combination of stromal cells, growth factors, cytokines, and chemokines to induce the bone marrow lymphoid progenitor T-cell precursors into single-positive CD4⁺ and CD8⁺ T effectors and CD4⁺CD25⁺ T-regulatory cells (Tregs). At postthymic compartments, the CD4⁺ T-cells acquire distinct phenotypes which include the classical T-helper 1 (Th1), T-helper 2 (Th2), T-helper 9 (Th9), T-helper 17 (Th17), follicular helper T-cell (Tfh), and induced T-regulatory cells (iTregs), such as the regulatory type 1 cells (Tr1) and transforming growth factor-β- (TGF-β-) producing CD4⁺ T-cells (Th3). Tregs represent only a small fraction, 5–10% in mice and 1-2% in humans, of the overall CD4⁺ T-cells in lymphoid tissues but are essential for immunoregulatory circuits mediating the inhibition and expansion of all lineages of T-cells. In this paper, we first provide an overview of the major cell-intrinsic developmental programs that regulate T-cell lineage fates in thymus and periphery. Next, we introduce the SV40 immortomouse as a relevant mice model for implementation of new approaches to investigate thymus organogenesis, CD4 and CD8 development, and thymus cells tumorogenesis.

Influence of different types of contact hypersensitivity on imiquimod-induced psoriasis-like inflammation in mice

It is currently believed that psoriasis and allergic contact dermatitis (ACD) are different diseases; however, they share clinical similarities. The involvement of T helper 17 (Th17) cells in these disorders provides a novel opportunity to investigate the relationship between them. The present study aimed to determine whether the same or overlapping inflammatory pathways are involved in the two diseases, and the influence of different types of ACD on psoriasis. Compound mouse models of Th1 or Th2‑type contact hypersensitivity (CHS) combined with imiquimod (IMQ)‑induced psoriasis‑like inflammation were established, in order to mimic the characteristics of ACD and psoriasis. Histopathology, immunohistochemistry and cytokine detection in blood serum and tissues were used to compare the differences between the mice treated with IMQ alone or IMQ combined with Th1 and Th2‑type CHS. As compared with the IMQ‑treated mice or IMQ-treated Th1‑type CHS mice, the mice with Th2‑type CHS treated with IMQ exhibited more serious psoriasis‑like inflammation with increased epidermal thickness and infiltrating cells in the derma. High mRNA expression levels of interleukin (IL)‑17, IL‑22, IL‑23, TNF‑α and RORγt were detected in back skin lesions. Additionally, high levels of IL‑17 and IL‑22 in blood serum were detected in IMQ‑treated mice combined with Th2‑type CHS. The mice treated with IMQ alone, and IMQ treatment combined with Th1‑type CHS had a comparable psoriasis‑like inflammatory response in the back skin. In conclusion, these data demonstrate that Th2‑type CHS exacerbated the IMQ‑treated psoriatic inflammation of mice via the IL‑23/IL‑17 axis. Th17 cells and associated pathways may link ACD and psoriasis. Therefore, patients with psoriasis should avoid contact with specific sensitizers, such as fragrance and rubber products, which may induce Th2 polarization.

Increased IL-17 and TGF-β serum levels in peripheral blood of patients with β-thalassemia major: implication for continual transfusions role in T helper17-mediated proinflammatory responses

BACKGROUND/AIM

Recent studies have shown that IL-17-producing CD4+ T helper (Th17) cells play an important role in proinflammatory processes. In this report we analyzed IL-17, IL-21, and TGF-β serum levels in the peripheral blood of Iranian beta-thalassemia major patients that clinically exhibited splenectomy and iron overload.

MATERIALS AND METHODS

Blood samples were collected from 43 beta-thalassemia patients and 43 healthy individuals with no history of malignancies or autoimmune disorders. Then serum levels of IL-17, IL-21, and TGF-β were measured by enzyme linked immunosorbent assay (ELISA).

RESULTS

The levels of IL-17 (P = 0.005) and TGF-β (P < 0.001) were significantly higher in the thalassemia patients compared to the healthy control. No significant differences in the level of serum IL-21 was observed between the patients and controls. There were no significant differences in serum levels of IL-17, IL-21, and TGF-β between patients with high or low serum levels of ferritin.

CONCLUSION

Multiple blood transfusions cause constant immune stimulation, as a result of repeated exposure to new alloantigens. This might have significant effects on the stimulation of cytokine producing cells in those patients and cytokine profile can be used as a related marker for assessing disease severity and consequently therapeutic intervention.

Th17 response and its regulation in inflammatory upper airway diseases

Allergic rhinitis (AR) and chronic rhinosinusitis (CRS) are two widely prevalent inflammatory diseases in the upper airways. T cell immunity has been suggested to play an important pathogenic role in many chronic inflammatory diseases including inflammatory upper airway diseases. Inappropriate CD4(+) T cell responses, especially the dysregulation of the Th1/Th2 balance leading to excessive Th1 or Th2 cell activation, have been associated with allergic rhinitis and chronic rhinosinusitis. Nevertheless, recent studies suggest that IL-17A and IL-17A-producing Th17 cell subset, a distinct pro-inflammatory CD4(+) T cell lineage, may also play an important role in the pathophysiology of inflammatory upper airway diseases. Th17 cells may promote both eosinophilic and neutrophilic inflammation in AR and CRS. In addition, a few, but accumulating evidence shows that the Th17 responses can be tightly regulated by endogenous and exogenous substances in the context of AR and CRS. This review discusses recent advances in our understanding of the expression and function of the Th17 response and its regulation in inflammatory upper airway diseases, and the perspective for future investigation and clinical utility.

Interleukin-23-Independent IL-17 Production Regulates Intestinal Epithelial Permeability

Whether interleukin-17A (IL-17A) has pathogenic and/or protective roles in the gut mucosa is controversial and few studies have analyzed specific cell populations for protective functions within the inflamed colonic tissue. Here we have provided evidence for IL-17A-dependent regulation of the tight junction protein occludin during epithelial injury that limits excessive permeability and maintains barrier integrity. Analysis of epithelial cells showed that in the absence of signaling via the IL-17 receptor adaptor protein Act-1, the protective effect of IL-17A was abrogated and inflammation was enhanced. We have demonstrated that after acute intestinal injury, IL-23R(+) γδ T cells in the colonic lamina propria were the primary producers of early, gut-protective IL-17A, and this production of IL-17A was IL-23 independent, leaving protective IL-17 intact in the absence of IL-23. These results suggest that IL-17-producing γδ T cells are important for the maintenance and protection of epithelial barriers in the intestinal mucosa.

Vitamin D and the development of allergic disease: how important is it?

Vitamin D has known effects on lung development and the immune system that may be important in the development, severity, and course of allergic diseases (asthma, eczema, and food allergy). Vitamin D deficiency is prevalent worldwide and may partly explain the increases in asthma and allergic diseases that have occurred over the last 50-60 years. In this review, we explore past and current knowledge on the effect of vitamin D on lung development and immunomodulation and present the evidence of its role in allergic conditions. While there is growing observational and experimental evidence for the role of vitamin D, well-designed and well-powered clinical trials are needed to determine whether supplementation of vitamin D should be recommended in these disorders.

The Paracaspase MALT1

The human paracaspase MALT1 is a caspase homolog that plays a central role in NF-κB signaling. Over the past few years it has become clear that this is due to a combination of its scaffolding and proteolytic function. Knockout mice and mice expressing a catalytically dead variant of the protease have provided valuable information. This review aims to provide an overview of recent developments regarding the enzymatic mechanism and specificity of MALT1, its substrates discovered to date, different mouse models, as well as the role of MALT1 in NF-κB signaling downstream of a variety of different receptors.

Role of CD4+ Foxp3+ Regulatory T Cells in Protection Induced by a Live Attenuated, Replicating Type I Vaccine Strain of Toxoplasma gondii

Vaccination with the live attenuated Toxoplasma gondii Mic1.3KO strain induced long-lasting immunity against challenge with Toxoplasma gondii type I and type II strains. The involvement of regulatory T cells (Tregs) in the protection mechanism was investigated. Intraperitoneal injection of Mic1.3KO induced a weak and transient influx of CD4(+) Foxp3(+) T regulatory cells followed by recruitment/expansion of CD4(+) Foxp3(-) CD25(+) effector cells and control of the parasite at the site of infection. The local and systemic cytokine responses associated with this recruitment of Tregs were of the TH1/Treg-like type. In contrast, injection of RH, the wild-type strain from which the vaccinal strain is derived, induced a low CD4(+) Foxp3(+) cell influx and uncontrolled multiplication of the parasites at this local site, followed by death of the mice. The associated local and systemic cytokine responses were of the TH1/TH17-like type. In addition, in vivo Treg induction in RH-infected mice with interleukin-2 (IL-2)/anti-IL-2 complexes induced control of the parasite and a TH1/Treg cytokine response similar to the response after Mic1.3KO vaccination. These results suggest that Tregs may contribute to the protective response after vaccination with Mic1.3KO.

Blockage of Eosinopoiesis by IL-17A Is Prevented by Cytokine and Lipid Mediators of Allergic Inflammation

Interleukin- (IL-) 17A, a pleiotropic mediator of inflammation and autoimmunity, potently stimulates bone-marrow neutrophil production. To explore IL-17A effects on eosinopoiesis, we cultured bone-marrow from wild-type mice, or mutants lacking inducible nitric oxide synthase (iNOS−/−), CD95 (lpr), IL-17RA, or IL-4, with IL-5, alone or associated with IL-17A. Synergisms between IL-17A-activated, NO-dependent, and NO-independent mechanisms and antagonisms between IL-17A and proallergic factors were further examined. While IL-17A (0.1–10 ng/mL) had no IL-5-independent effect on eosinopoiesis, it dose-dependently suppressed IL-5-induced eosinophil differentiation, by acting during the initial 24 hours. Its effectiveness was abolished by caspase inhibitor, zVAD-fmk. The effect of IL-17A (0.1–1 ng/mL) was sensitive to the iNOS-selective inhibitor aminoguanidine and undetectable in iNOS−/− bone-marrow. By contrast, a higher IL-17A concentration (10 ng/mL) retained significant suppressive effect in both conditions, unmasking a high-end iNOS-independent mechanism. Lower IL-17A concentrations synergized with NO donor nitroprusside. Eosinopoiesis suppression by IL-17A was (a) undetectable in bone-marrow lacking IL-17RA or CD95 and (b) actively prevented by LTD4, LTC4, IL-13, and eotaxin. Sensitivity to IL-17A was increased in bone-marrow lacking IL-4; adding IL-4 to the cultures restored IL-5 responses to control levels. Therefore, effects of both IL-17A and proallergic factors are transduced by the iNOS-CD95 pathway in isolated bone-marrow.

TIR-domain-containing adapter-inducing interferon-β (TRIF) regulates Th17-mediated intestinal immunopathology in colitis

Gastrointestinal mucosa reserves abundant Th17 cells where host response to commensal bacteria maintains Th17-cell generation. Although functional heterogeneity and dynamic plasticity of Th17 cells appear to be involved in chronic inflammatory disorders, how their plasticity is regulated in intestinal mucosa is unknown. Here we show that innate TRIF signaling regulates intestinal Th17-cell generation and plasticity during colitis. Absence of TRIF in mice resulted in increased severity of experimental colitis, which was associated with aberrant generation of Th17 cells especially of interferon (IFN)-γ-expressing Th17 cells in the lamina propria. The abnormal generation and plasticity of Th17 cells involved impaired expression of interleukin (IL)-27p28 by lamina propria macrophages but not dendritic cells. Treatment of TRIF-deficient mice with IL-27p28 during colitis reduced the number and IFN-γ expression of Th17 cells in the intestine. In vitro, TRIF-deficient macrophages induced more Th17 cells than wild-type (WT) macrophages during co-culture with WT naive T cells in response to cecal bacterial antigen. Many of Th17 cells induced by TRIF-deficient macrophages expressed IFN-γ due to impaired expression of IL-27p28 by macrophages and defective activation of STAT1 in T cells. These results outline TRIF-dependent regulatory mechanism by which host response to intestinal bacteria maintains Th17-cell-mediated pathology during colitis.

CXCL13 antibody for the treatment of autoimmune disorders

BACKGROUND

Homeostatic B Cell-Attracting chemokine 1 (BCA-1) otherwise known as CXCL13 is constitutively expressed in secondary lymphoid organs by follicular dendritic cells (FDC) and macrophages. It is the only known ligand for the CXCR5 receptor, which is expressed on mature B cells, follicular helper T cells (Tfh), Th17 cells and regulatory T (Treg) cells. Aberrant expression of CXCL13 within ectopic germinal centers has been linked to the development of autoimmune disorders (e.g. Rheumatoid Arthritis, Multiple Sclerosis, Systemic Lupus Erythematosis). We, therefore, hypothesized that antibody-mediated disruption of the CXCL13 signaling pathway would interfere with the formation of ectopic lymphoid follicles in the target organs and inhibit autoimmune disease progression. This work describes pre-clinical development of human anti-CXCL13 antibody MAb 5261 and includes therapeutic efficacy data of its mouse counterpart in murine models of autoimmunity.

RESULTS

We developed a human IgG1 monoclonal antibody, MAb 5261 that specifically binds to human, rodent and primate CXCL13 with an affinity of approximately 5 nM and is capable of neutralizing the activity of CXCL13 from these various species in in vitro functional assays. For in vivo studies we have engineered a chimeric antibody to contain the same human heavy and light chain variable genes along with mouse constant regions. Treatment with this antibody led to a reduction in the number of germinal centers in mice immunized with 4-Hydroxy-3-nitrophenylacetyl hapten conjugated to Keyhole Limpet Hemocyanin (NP-KLH) and, in adoptive transfer studies, interfered with the trafficking of B cells to the B cell areas of mouse spleen. Furthermore, this mouse anti-CXCL13 antibody demonstrated efficacy in a mouse model of Rheumatoid arthritis (Collagen-Induced Arthritis (CIA)) and Th17-mediated murine model of Multiple Sclerosis (passively-induced Experimental Autoimmune Encephalomyelitis (EAE)).

CONCLUSIONS

We developed a novel therapeutic antibody targeting CXCL13-mediated signaling pathway for the treatment of autoimmune disorders.

Inflammation and hypertension: new understandings and potential therapeutic targets

Research studying the role of inflammation in hypertension and cardiovascular disease has flourished in recent years; however, the exact mechanisms by which the activated immune cells lead to the development and maintenance of hypertension remain to be elucidated. The objectives of this brief review are to summarize and discuss the most recent findings in the field, with special emphasis on potential therapeutics to treat or prevent hypertension. This review will cover novel immune cell subtypes recently associated to the disease including the novel role of cytokines, toll-like receptors, and inflammasomes in hypertension.

Role of some biomarkers in placental malaria in women living in Yaoundé, Cameroon

Despite intensive research on the immunpathology of placental malaria (PM), the role of some β-chemokines known to attract inflammatory cells is less known. This study sought to determine the role of CXCL-10, IL-10, IL-19, IL-17A and IL-23 in placental malaria in women at delivery. Between 2010 and 2011, paired peripheral and placental blood specimens were collected from 139 Cameroonian women at delivery. Differential white blood cell counts and malaria parasitaemia were determined microscopically while the accumulation of parasites in the placenta was investigated through histological studies. Plasma levels of CXCL-10, IL-10, IL-17A, IL-19 and Il-23 were determined by ELISA. The cytokines IL-10, IL-17A and IL-23 were predominant in peripheral plasma from both infected and non-infected women. While IL-10 associated negatively with parity, IL-23 showed a positive correlation (p<0.05). The production of CXCL-10 was independent of parity and higher in placental plasma. There was an association between the plasma levels of IL-10 and CXCL-10 with malaria parasitaemia in the placenta impression smears, placental and peripheral blood and the presence of malaria pigments in the placenta tissue. Leukocyte accumulation into the intervillous space correlated positively with plasma levels of placental IL-17A (p<0.001). Parity also associated with peripheral IL-17A (p=0.016). The peripheral and placental plasma levels of CXCL-10 and IL-10 also correlated positively with monocyte counts (p=0.011-0.042) while a negative correlation was found with lymphocyte counts (p=0.017 to <0.001) of the impression smear. However, the levels of IL-10 in both peripheral and placental plasma and CXCL-10 in placental plasma only, were higher in low birth weight baby. With regards to IL-17A, its placental plasma level correlated positively with lymphocyte counts of placental blood (p=0.045). During PM, CXCL-10 might attract monocytes and lymphocytes into the placenta where they produce inflammatory cytokines such as IL-10 and IL-17A to modulate the disease, which affect baby weight.

Immunological response in Stevens-Johnson syndrome and toxic epidermal necrolysis

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are life-threatening cutaneous adverse drug reactions that induce widespread epidermal necrosis. Recent advances in pharmacogenomic studies have provided evidence of genetic predispositions to SJS/TEN. Several concepts have been proposed to explain the pathogenesis of severe cutaneous adverse drug reactions. In the hapten concept, small molecules called haptens elicit an immune response only when attached to proteins. The "p-i" concept postulates that the causative drugs can stimulate cells by binding directly and reversibly to immune receptors. In addition, there is the idea that drugs alter the antigen by binding to the human leukocyte antigen pocket. With regard to keratinocyte death, several cell death mediators, such as FasL, granulysin and annexin A1, have been proposed as playing a role in SJS/TEN pathogenesis. A subset of T lymphocytes, including regulatory T cells, also may play a role in SJS/TEN.

Immunomodulation in patients with chronic hand eczema treated with oral alitretinoin

BACKGROUND

Oral alitretinoin (9-cis-retinoic acid; 9-cis-RA) has shown clinical efficacy in patients with chronic hand eczema (CHE). Herein, we investigated the impact of oral 9-cis-RA on the local and systemic immune response in patients with CHE.

METHODS

Twenty patients with CHE were treated with oral alitretinoin (10 or 30 mg/day) for at least 24 weeks. Blood samples were taken for flow cytometry, and serum samples were assessed by ELISA to determine immunoglobulin (Ig) levels. Skin biopsies from lesional skin were evaluated immunohistochemically.

RESULTS

Upon 9-cis-RA treatment, improvement of the CHE was observed in all patients. A significant decrease in plasmablasts in the peripheral blood and a significant reduction of serum IgE levels were determined. Furthermore, we detected a significant reduction of CD4+ cells and regulatory T cells in the peripheral blood upon treatment. By contrast, these cell subsets were significantly increased in the affected skin. Cytokine analysis of activated CD154-positive T cells showed a reduction of interleukin (IL)-17 but not of IL-4 or IFN-γ production.

CONCLUSIONS

Overall, our data indicate a disease-modifying effect of 9-cis-RA, including a systemic decrease in IL-17-positive cells, but decreased serum IgE and CD23 expression. The increased frequency of FoxP3-positive cells in the skin upon treatment may suggest a mechanism by which hand eczema is therapeutically targeted by 9-cis-RA, but this will need to be proven in the future studies.

Administration of mycobacterial Ag85A and IL-17A fusion protein attenuates airway inflammation in a murine model of asthma

Interleukin (IL)-17A contributes to the development of asthma, especially in severe asthma which has characteristic neutrophil infiltration in airways. However, IL-17A-blocking antibody could escalate T helper (Th) 2 cytokines, such as IL-13, IL-4 in murine models. We aimed at determining the effect of mycobacterial Ag85A and IL-17A fusion protein—Ag85A-IL-17A on airway inflammation in a murine model of asthma. IL-17A recombinant protein fused mycobacterial immunodominant antigen Ag85A was constructed, expressed and purified. The fusion protein was then administrated into BALB/c mice and its anti-inflammatory effects in the infiltration of inflammatory cells, Th2/Th17 cytokines in BALF, histopathological changes of lung tissues as well as chemokines in lung tissues were evaluated in the murine model of asthma. We found that administration of mycobacterial Ag85A and IL-17A fusion protein induced IL-17A specific immunoglobulin (Ig)G in sera and significantly decreased IL-17A and IL-6 levels in bronchoalveolar lavage fluid (BALF). Ag85A-IL-17A vaccinated mice also showed marked reduction in the infiltration of inflammatory cells in peribronchiolar region and significant decrease in total cells, eosinophil cells and neutrophil cells in BALF. The increased levels of IL-13 and IL-4 in BALF of ovalbumin-sensitized mice were significantly reduced by the administration of Ag85A-IL-17A. Furthermore, CD3+CD4+IL-13+ splenocytes stimulated with OVA and CXCL1 mRNA, CCL2 mRNA and GATA-3 mRNA expressed in lung tissues were decreased markedly in Ag85A-IL-17A vaccinated group. Our results demonstrate remarkable antiallergic effects of Ag85A-IL-17A in a murine model of asthma and it may have protective effects on allergic asthma.

Guidelines on the use of extracorporeal photopheresis

BACKGROUND

After the first investigational study on the use of extracorporeal photopheresis for the treatment of cutaneous T-cell lymphoma was published in 1983 with its subsequent recognition by the FDA for its refractory forms, the technology has shown significant promise in the treatment of other severe and refractory conditions in a multi-disciplinary setting. Among the major studied conditions are graft versus host disease after allogeneic bone marrow transplantation, systemic sclerosis, solid organ transplant rejection and inflammatory bowel disease.

MATERIALS AND METHODS

In order to provide recognized expert practical guidelines for the use of this technology for all indications the European Dermatology Forum (EDF) proceeded to address these questions in the hands of the recognized experts within and outside the field of dermatology. This was done using the recognized and approved guidelines of EDF for this task.

RESULTS AND CONCLUSION

These guidelines provide at present the most comprehensive available expert recommendations for the use of extracorporeal photopheresis based on the available published literature and expert consensus opinion.

Interleukin-17 in human inflammatory diseases

Human Th17 pro-inflammatory cells are currently defined as cells that produce IL-17A and F, tumor necrosis factor (TNF)-α, IL-6, IL-21, IL-22 and IL-23. Recently discovered related molecules are forming a family of cytokines, the IL-17 family, IL-17A, IL-17B, IL-17C, IL-17D, IL-17E and IL-17F. The associated receptors for the IL-17 family identified are IL-17R, IL-17RH1, IL-17RL (receptor like), IL-17RD and IL-17RE. This review introduces the roles of IL-17 and Th17 cells in human autoimmune diseases. Studies have shown that T cells with inflammatory effects on epithelial, endothelial and fibroblast cells express IL-17. Th17 cells are supposed to be involved in various autoimmune diseases, such as rheumatoid arthritis, psoriasis, multiple sclerosis, and inflammatory bowel diseases. Base on the biologic functions and regulation, IL-17 has regulatory roles in host defense and chronic inflammation which result in tissue damage and autoimmunity. So the IL-17 links links innate and adaptive immunity and has both beneficial and pathological effects on the immune system. This paper will focus on the possible roles of IL-17 in autoimmune diseases, a fundamental player in immune regulation.

Atopic dermatitis, STAT3- and DOCK8-hyper-IgE syndromes differ in IgE-based sensitization pattern

BACKGROUND

Increased serum IgE levels are characteristic but not specific for allergic diseases. Particularly, severe atopic dermatitis (AD) overlaps with hyper-IgE syndromes (HIES) regarding eczema, eosinophilia, and increased serum IgE levels. HIES are primary immunodeficiencies due to monogenetic defects such as in the genes DOCK8 and STAT3. As it is not known to date why allergic manifestations are not present in all HIES entities, we assessed the specificity of serum IgE of AD and HIES patients in the context of clinical and immunological findings.

METHODS

Clinical data, skin prick tests, specific IgE to aero- and food allergens, and T helper (Th) subpopulations were compared in AD and molecularly defined HIES patients.

RESULTS

Total serum IgE levels were similarly increased in STAT3-HIES, DOCK8-HIES, and AD patients. The ratio of aeroallergen-specific IgE to total IgE was highest in AD, whereas DOCK8-HIES patients showed the highest specific serum IgE against food allergens. Overall, clinical allergy and skin prick test results complied with the specific IgE results. Th2-cell numbers were significantly increased in DOCK8-HIES and AD patients compared to STAT3-HIES patients and controls. AD patients showed significantly higher nTreg-cell counts compared to STAT3-HIES and control individuals. High Th17-cell counts were associated with asthma. Specific IgE values, skin prick test, and T-cell subsets of STAT3-HIES patients were comparable with those of healthy individuals except decreased Th17-cell counts.

CONCLUSION

Hyper-IgE syndromes and atopic dermatitis patients showed different sensitization pattern of serum IgE corresponding to the allergic disease manifestations and Th-cell subset data, suggesting a key role of DOCK8 in the development of food allergy.

Could T cells be involved in lung deterioration and hyperglycemia in cystic fibrosis?

Cystic fibrosis-related diabetes (CFRD) is the most frequent complication of cystic fibrosis (CF) and associated with increased mortality. Why patients have an accelerated loss of lung function before the diagnosis of CFRD remains poorly understood. We reported that patients with or without CFRD had increased glucose excursions when compared to healthy peers. Studies have demonstrated that patients with CF have increased glucose fluctuations and hyperglycemia and that this may affect the clinical course of CF and lead to lymphocyte dysfunction. T-helper 17 (Th17) lymphocytes produce and secrete the pro-inflammatory cytokine IL-17. The Th17 pathway is involved in CF lung inflammation, β-cell destruction in type 1 diabetes (T1D) and Th17 cells of patients with type 2 diabetes have increased production of IL-17 when compared to healthy peers. Also, regulatory T-cells (Tregs) have been shown to be dysfunctional and produce IL-17 in T1D. Furthermore, vitamin D can affect inflammation in CF, diabetes and the differentiation of lymphocytes. In this review, we discuss the potential roles of hyperglycemia on Th17 cells, Tregs and IL-17 as a potential cause for accelerated lung function decline before CFRD and how this could be modulated by vitamin D or by directly intervening in the IL-17A pathway.

Insulin resistance and serum levels of interleukin-17 and interleukin-18 in normal pregnancy

We performed this study to evaluate the role of Interleukin-17 (IL-17) and Interleukin-18 (IL-18) in insulin resistance during normal pregnancy. This descriptive cross sectional study was carried out on 97 healthy pregnant women including 32, 25, and 40 individuals in the first, second, and third trimesters, respectively, and on 28 healthy non pregnant women between the autumn of 2012 and the spring of 2013. We analyzed the serum concentrations of IL-17 and IL-18 by using the enzyme linked immunosorbent assay (ELISA). Insulin resistance was measured by homeostasis model assessment of insulin resistance equation. No significant differences between the demographic data of the pregnant and non pregnant groups were observed. Insulin resistant in pregnant women was significantly higher than the controls (p=0.006). Serum IL-17 concentration was significantly different in non pregnant women and pregnant women in all gestational ages (p<0.05). Serum IL-18 level was significantly lower in subjects with first, second, and third trimesters of pregnancy in compared to non pregnant women (p<0.05). No significant correlations were found between serum IL-17 and IL-18 levels with insulin resistance (r=0.08, p=0.34 vs. r=0.01, p=0.91, respectively). Our data suggested that IL-17 and IL-18 do not appear to attribute greatly to pregnancy deduced insulin resistance during normal pregnancy.

IL-17A mediates a selective gene expression profile in asthmatic human airway smooth muscle cells

Airway smooth muscle (ASM) cells are thought to contribute to the pathogenesis of allergic asthma by orchestrating and perpetuating airway inflammation and remodeling responses. In this study, we evaluated the IL-17RA signal transduction and gene expression profile in ASM cells from subjects with mild asthma and healthy individuals. Human primary ASM cells were treated with IL-17A and probed by the Affymetrix GeneChip array, and gene targets were validated by real-time quantitative RT-PCR. Genomic analysis underlined the proinflammatory nature of IL-17A, as multiple NF-κB regulatory factors and chemokines were induced in ASM cells. Transcriptional regulators consisting of primary response genes were overrepresented and displayed dynamic expression profiles. IL-17A poorly enhanced IL-1β or IL-22 gene responses in ASM cells from both subjects with mild asthma and healthy donors. Interestingly, protein modifications to the NF-κB regulatory network were not observed after IL-17A stimulation, although oscillations in IκBε expression were detected. ASM cells from subjects with mild asthma up-regulated more genes with greater overall variability in response to IL-17A than from healthy donors. Finally, in response to IL-17A, ASM cells displayed rapid activation of the extracellular signal-regulated kinase/ribosomal S6 kinase signaling pathway and increased nuclear levels of phosphorylated extracellular signal-regulated kinase. Taken together, our results suggest that IL-17A mediated modest gene expression response, which, in cooperation with the NF-κB signaling network, may regulate the gene expression profile in ASM cells.

Activation of memory Th17 cells by domain 4 pneumolysin in human nasopharynx-associated lymphoid tissue and its association with pneumococcal carriage

Pneumococcal carriage is common in children that may account for the high incidence of disease in this age group. Recent studies in animals suggest an important role for CD4+ T cells, T helper type 17 (Th17) cells in particular, in pneumococcal clearance. Whether this Th17-mediated mechanism operates in humans and what pneumococcal components activate Th17 are unknown. We investigated the ability of domain 4 pneumolysin (D4Ply) to activate CD4+ T cells including Th17 in human nasopharynx-associated lymphoid tissue (NALT) and peripheral blood. We show that D4Ply elicited a prominent CD4+ T-cell proliferative response. More importantly, D4Ply elicited a significant memory Th17 response in NALT, and a moderate response in peripheral blood mononuclear cells (PBMCs). This D4Ply-elicited memory Th17 response was more marked in carriage- than in carriage+ children in both NALT and PBMCs. In contrast, no difference was shown in D4Ply-induced Th1 response between the two groups. We also show D4Ply activated human monocytes and murine macrophages that was in part dependent on Toll-like receptor 4 (TLR-4). Our results support a protective role of Th17 against pneumococcal carriage in human nasopharynx, and identify a novel property of D4Ply to activate Th17 in NALT that may offer an attractive vaccine candidate in intranasal immunization against pneumococcal infection.

Local expression of interleukin-17a is correlated with nasal eosinophilia and clinical severity in allergic rhinitis

Interleukin (IL)-17A is a major cytokine produced by Th17 cells, which are associated with chronic inflammations. The local expression of IL-17A in allergic rhinitis (AR) remains to be characterized. We sought to determine the role of IL-17A expression in human inferior turbinate mucosa in the pathophysiology of AR. Inferior turbinate mucosa was sampled from medical treatment–resistant, surgery-required patients with perennial AR (PAR, n = 21), nonallergic rhinitis with eosinophilia syndrome (NARES, n = 7), and nonallergic hypertrophic rhinitis (HR, n = 13). IL-17A expression was determined with immunohistochemical staining. The mean number of IL-17A⁺ cells and eosinophils per field were counted. Total serum immunoglobulin E (IgE) levels, blood eosinophil count, and forced expiratory volume in 1 second (FEV₁)/forced vital capacity (FVC) ratio were also examined in each patient. IL-17A was primarily expressed in infiltrating inflammatory cells. The number of IL-17A⁺ cells in nasal mucosa was significantly higher in the PAR group compared with HR (p = 0.002) and NARES (p = 0.021) groups. There was a significant and positive correlation between the number of IL-17A⁺ cells and total nasal symptom score (rho = 0.403; p = 0.011), especially sneezing score (rho = 0.471; p = 0.003). The number of IL-17A⁺ cells was significantly and positively correlated with the degree of eosinophil infiltration (rho = 0.623; p < 0.001), but not with total serum IgE levels (rho = 0.284; p = 0.098), blood eosinophil counts (rho = 0.302; p = 0.056), or FEV₁/FVC ratio (rho = 0.092; p = 0.569). The present study provides evidence that IL-17A expression in the nasal mucosa is associated with the pathophysiology of AR, including disease severity and nasal eosinophilia.

In vivo and in vitro studies of Th17 response to specific immunotherapy in house dust mite-induced allergic rhinitis patients

T helper (Th)17 cells have been implicated in the development of allergic rhinitis (AR), but their response to specific immunotherapy (SIT) remains unclear. We investigated the impact of SIT on Th17 response and Th1/Th2 changes in AR patients. Blood samples from AR patients (n = 20) who were monosensitized to house dust mite (HDM) were collected before the initiation of SIT (SIT-untreated) and after the end of 2-year SIT (SIT-treated) treatment. Twenty healthy volunteers were recruited as controls. In vitro HDM stimulation in peripheral blood mononuclear cells (PBMCs) was also performed. Expression levels of Th17 associated genes were determined in both PBMCs and plasma by PCR and ELISA, while Th17/Th1/Th2/IL10 producing cell proportions were evaluated in PBMCs by flow cytometry. The SIT effect was evaluated by assessing clinical symptoms. mRNA levels of Th17 specific genes (IL17 and RORC) were increased in SIT-untreated AR versus controls, and decreased following SIT treatment. SIT can change the production of Th17 associated genes (reduction of IL17, IL6, and IL23, but increase of IL27) in plasma from AR patients. Th2/Th1 ratio and proportions of Th17 cells were suppressed while IL10 producing CD4⁺ T cells were elevated after SIT. In vitro HDM challenge presents concordant patterns with in vivo findings: 1) increase of Th2 and Th17 response in AR patients; 2) suppression of IL10 producing CD4⁺ T cells in SIT-untreated AR but elevation in SIT-treated AR patients. Most importantly, a positive correlation between IL17 mRNA/protein levels and clinical symptom scores was observed. SIT significantly inhibits Th17 mediated inflammation in AR and IL17 may be a useful biomarker for both AR severity and SIT therapeutic effect.

Trial Registration

Australian New Zealand Clinical Trials Registry (ANZCTR) ACTRN12613000445774

Th17 Cells in Immunopathogenesis and treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by the sequestration of various leukocyte subpopulations within both the developing pannus and synovial space. The chronic nature of this disease results in inflammation of multiple joints, with subsequent destruction of the joint cartilage and erosion of bone. Identification of T helper (Th)17 cells led to breaking the dichotomy of the Th1/Th2 axis in immunopathogenesis of autoimmune diseases such as RA, and its experimental model, collagen-induced arthritis (CIA). Th17 cells produce cytokines, including interleukin (IL)-17, IL-6, IL-21, IL-22 and tumor necrosis factor (TNF)-α, with pro-inflammatory effects, which appear to have a role in immunopathogenesis of RA. Regarding the wide ranging production of pro-inflammatory cytokines and chemokines by Th17 cells, it is expected that Th17 cell could be a potent pathogenic factor in disease immunopathophysiology. Thus the identification of effector mechanisms used by Th17 cells in induction of disease lesions may open new prospects for designing a new therapeutic strategy for treatment of RA.

Importins and exportins regulating allergic immune responses

Nucleocytoplasmic shuttling of macromolecules is a well-controlled process involving importins and exportins. These karyopherins recognize and bind to receptor-mediated intracellular signals through specific signal sequences that are present on cargo proteins and transport into and out of the nucleus through nuclear pore complexes. Nuclear localization signals (NLS) present on cargo molecules to be imported while nuclear export signals (NES) on the molecules to be exported are recognized by importins and exportins, respectively. The classical NLS are found on many transcription factors and molecules that are involved in the pathogenesis of allergic diseases. In addition, several immune modulators, including corticosteroids and vitamin D, elicit their cellular responses by regulating the expression and activity of importin molecules. In this review article, we provide a comprehensive list of importin and exportin molecules and their specific cargo that shuttled between cytoplasm and the nucleus. We also critically review the role and regulation of specific importin and exportin involved in the transport of activated transcription factors in allergic diseases, the underlying molecular mechanisms, and the potential target sites for developing better therapeutic approaches.

Vitamin D, the immune system and asthma

The effects of vitamin D on bone metabolism and calcium homeostasis have long been recognized. Emerging evidence has implicated vitamin D as a critical regulator of immunity, playing a role in both the innate and cell-mediated immune systems. Vitamin D deficiency has been found to be associated with several immune-mediated diseases, susceptibility to infection and cancer. Recently, there has been increasing interest in the possible link between vitamin D and asthma. Further elucidation of the role of vitamin D in lung development and immune system function may hold profound implications for the prevention and treatment of asthma.

Increased frequency of Th17 cells in systemic sclerosis is related to disease activity and collagen overproduction

Introduction

Although immune dysfunction plays a role in the pathogenesis of systemic sclerosis (SSc), involvement of T helper 17 (Th17) and T regulatory (Treg) cells remains unclear. We aimed to investigate the presence of Th17 and Treg cells in SSc patients and the role of Th17 cells in collagen production in SSc fibroblasts.

Methods

We analyzed inflammatory cell profiles in the skin of 13 SSc patients by immunohistochemistry, the percentage of Th17 and Treg cells in peripheral blood mononuclear cells (PBMCs) of 45 SSc patients and 24 healthy controls by flow cytometry, gene expression in PBMCs by real-time reverse transcription-polymerase chain reaction and interleukin-17 (IL-17) in sera and culture supernatants by enzyme-linked immunosorbent assay. We also investigated the effect of Th17 cell-derived IL-17 on fibroblast growth and collagen production.

Results

Infiltration of inflammatory cells including IL-17⁺ and Foxp3⁺ lymphocytes was detected in the skin of patients with early SSc. The percentages of circulating Th17 cells and IL-17 production were elevated in samples from patients with active SSc, whereas the percentage of circulating Treg cells was not affected. The number of Th17 cells was closely related to disease activity. IL-17 from SSc patients promoted fibroblast growth and collagen production, whereas IL-17 neutralizing antibody effectively blocked collagen production.

Conclusion

SSc progression might be linked to expansion of circulating Th17 cells and increased infiltration of IL-17⁺ cells in skin. Th17-derived IL-17 is involved in fibroblast growth and collagen production. IL-17 blocking antibody may be a useful tool for intervention in the fibrotic course of SSc.

Immunopathogenesis of 2009 pandemic influenza

Three years after the pandemic, major advances have been made in our understanding of the innate and adaptive immune responses to the influenza A(H1N1)pdm09 virus and those responses' contribution to the immunopathology associated with this infection. Severe disease is characterized by early secretion of proinflammatory and immunomodulatory cytokines. This cytokine secretion persisted in patients with severe viral pneumonia and was directly associated with the degree of viral replication in the respiratory tract. Cytokines play important roles in the antiviral defense, but persistent hypercytokinemia may cause inflammatory tissue damage and participate in the genesis of the respiratory failure observed in these patients. An absence of pre-existing protective antibodies was the rule for both mild and severe cases. A role for pathogenic immunocomplexes has been proposed for this disease. Defective T cell responses characterize severe cases of infection caused by the influenza A(H1N1)pdm09 virus. Immune alterations associated with accompanying conditions such as obesity, pregnancy or chronic obstructive pulmonary disease may interfere with the normal development of the specific response to the virus. The role of host immunogenetic factors associated with disease severity is also discussed in this review. In conclusion, currently available information suggests a complex immunological dysfunction/alteration that characterizes the severe cases of 2009 pandemic influenza. The potential benefits of prophylactic/therapeutic interventions aimed at preventing/correcting such dysfunction warrant investigation.

Cytokine correlation between sinus tissue and nasal secretions among chronic rhinosinusitis and controls

OBJECTIVES/HYPOTHESIS

Compare cytokine levels in sinus tissue to sinus secretions from controls and chronic rhinosinusitis patients.

STUDY DESIGN

In vitro.

METHODS

Polyurethane foam sponges were placed into middle meati of patients with chronic rhinosinusitis without nasal polyps (CRSsNP), with polyps (CRSwNP), and controls. Sinus biopsies were then taken from the same location. Protein levels of tumor necrosis factor-alpha (TNF-α), interferon-γ (IFN-γ), and interleukins (IL) 2, 4, 6, 8, 10, and 17A were measured via cytometric bead assay for each sample. Protein values from sinus tissue and secretions were compared with Pearson's correlation between samples as well as one-way ANOVA with posthoc t test between groups.

RESULTS

Samples from 43 patients in total were examined. Mucus was measured from 10 controls, 11 CRSsNP and 10 CRSwNP, and sinus tissue was measured from 10 controls, 15 CRSsNP and 10 CRSwNP. IL-8 and IFN-γ levels were outside of the detectable range of the assay. Levels of secreted IL-2, 4, 6, 10, and 17A correlated with tissue levels (P < 0.05 for all, r > 0.49) while TNF-α did not (P = 0.71). CRSsNP had elevated mucus levels of IL-2, 4, 6, 10, and 17A compared to controls. CRSwNP had elevated mucus levels of IL-4, 6, 10, 17A, and TNF-α compared to controls.

CONCLUSIONS

Cytokine levels in sinus secretions correlate with levels in sinus tissue and are elevated in CRS versus control based on Th1/Th2 skewing.

Immunopathogenesis of allergic disorders: current concepts

Allergic disorders are a group of immune-mediated disorders that are associated with considerable morbidity and ill health. There has been significant rise in the prevalence of allergy in the last few years. This has heightened interest in uncovering the novel mechanisms involved in etiopathogenesis of allergic disorders. Understanding the pathways underlying allergy will help in developing effective modalities for its prevention and treatment. This review focuses primarily on common IgE-mediated allergic conditions and recent developments in their immunopathogenesis, especially those involving respiratory mucosa.

Role of Fat-Soluble Vitamins A and D in the Pathogenesis of Influenza: A New Perspective

Reduced exposure to solar radiation, leading to a deficiency of vitamin D and hence impaired innate immunity, has been suggested as a trigger for influenza viral replication and as an explanation of seasonal influenza. Although this hypothesis accounts for many unexplained facts about the epidemiology of influenza, gaps remain in understanding the pathogenesis and manifestations of the disease. Several observations suggest a role for vitamin A compounds (retinoids) in the disease. This paper presents a new model of the etiopathogenesis of influenza, suggesting that host resistance and susceptibility depend importantly on the ratio of vitamin D to vitamin A activity. Retinoid concentrations within normal physiological limits appear to inhibit influenza pathogenesis whereas higher background concentrations (i.e., very low vitamin D : A ratios) increase the risk of severe complications of the disease. There is also evidence that influenza-induced or preexisting liver disease, diabetes, and obesity worsen the severity of infection, possibly via liver dysfunction and alterations in retinoid metabolism. The model could be tested by determining the presence of retinoids in the secretions of patients with influenza and by studies of retinoid profiles in patients and controls. Potential strategies for prevention and treatment are discussed.

Hepatitis B virus induces IL-23 production in antigen presenting cells and causes liver damage via the IL-23/IL-17 axis

IL-23 regulates myriad processes in the innate and adaptive immune systems, and is a critical mediator of the proinflammatory effects exerted by Th17 cells in many diseases. In this study, we investigated whether and how hepatitis B virus (HBV) causes liver damage directly through the IL-23 signaling pathway. In biopsied liver tissues from HBV-infected patients, expression of both IL-23 and IL-23R was remarkably elevated. In vivo observations also indicated that the main sources of IL-23 were myeloid dendritic cells (mDCs) and macrophages. Analysis of in vitro differentiated immature DCs and macrophages isolated from healthy donors revealed that the HBV surface antigen (HBsAg) efficiently induces IL-23 secretion in a mannose receptor (MR)-dependent manner. Culture with an endosomal acidification inhibitor and the dynamin inhibitor showed that, upon binding to the MR, the HBsAg is taken up by mDCs and macrophages through an endocytosis mechanism. In contrast, although the HBV core antigen (HBcAg) can also stimulate IL-23 secretion from mDCs, the process was MR- and endocytosis-independent. In addition, IL-23 was shown to be indispensible for HBsAg-stimulated differentiation of naïve CD4(+) T cells into Th17 cells, which were determined to be the primary source of IL-17 in HBV-infected livers. The cognate receptor, IL-17R, was found to exist on the hepatic stellate cells and mDCs, both of which might represent the potential target cells of IL-17 in hepatitis B disease. These data provide novel insights into a yet unrecognized mechanism of HBV-induced hepatitis, by which increases in IL-23 expression, through an MR/endocytosis-dependent or -independent manner, produce liver damage through the IL-23/IL-17 axis.

Lead optimization of a 4-aminopyridine benzamide scaffold to identify potent, selective, and orally bioavailable TYK2 inhibitors

Herein we report our lead optimization effort to identify potent, selective, and orally bioavailable TYK2 inhibitors, starting with lead molecule 3. We used structure-based design to discover 2,6-dichloro-4-cyanophenyl and (1R,2R)-2-fluorocyclopropylamide modifications, each of which exhibited improved TYK2 potency and JAK1 and JAK2 selectivity relative to 3. Further optimization eventually led to compound 37 that showed good TYK2 enzyme and interleukin-12 (IL-12) cell potency, as well as acceptable cellular JAK1 and JAK2 selectivity and excellent oral exposure in mice. When tested in a mouse IL-12 PK/PD model, compound 37 showed statistically significant knockdown of cytokine interferon-γ (IFNγ), suggesting that selective inhibition of TYK2 kinase activity might be sufficient to block the IL-12 pathway in vivo.

Extracorporeal photochemotherapy as systemic monotherapy of severe, refractory atopic dermatitis: results from a prospective trial

BACKGROUND

Previous work has indicated that extracorporeal photochemotherapy (ECP) may be a safe and effective treatment in patients with severe atopic dermatitis.

METHODS

We performed a prospective study to investigate the effect of a defined 20-week ECP protocol in patients with severe, refractory atopic dermatitis. The patient inclusion criteria included (i) disease duration of at least 1 year, (ii) SCORAD > 45, and (iii) resistance to first-line therapy, including topical steroids, topical calcineurin inhibitors, and one form of phototherapy (UVA, UVB, or PUVA) or one second-line therapy, including systemic steroids or cyclosporine. Ten patients (4 women and 6 men; age range 29 to 61 years) were enrolled and treated with two sessions of standard ECP in 2-week intervals for 12 weeks and 4-week intervals thereafter until week 20. The patients' clinical status and response was determined by SCORAD at baseline and every 2 weeks, and quality of life was assessed every 4 weeks using SKINDEX, SF-36, and FACT scores.

RESULTS

There was a statistically significant (p = 0.015) reduction of the mean SCORAD by 10.3 (95% CI, 2.5 to 18.0) from 64.8 at baseline to 54.5 (i.e., 15.9% reduction) at week 20. In a subset of patients (all of female sex), the relative reduction in SCORAD after ECP was more than 25% at week 20. Improvement in quality of life measured by SKINDEX, SF-36, and FACT did not reach statistical significance.

CONCLUSIONS

We detected a small but significant therapeutic effect of ECP in patients with severe, refractory atopic dermatitis.

Lead identification of novel and selective TYK2 inhibitors

A therapeutic rationale is proposed for the treatment of inflammatory diseases, such as psoriasis and inflammatory bowel diseases (IBD), by selective targeting of TYK2. Hit triage, following a high-throughput screen for TYK2 inhibitors, revealed pyridine 1 as a promising starting point for lead identification. Initial expansion of 3 separate regions of the molecule led to eventual identification of cyclopropyl amide 46, a potent lead analog with good kinase selectivity, physicochemical properties, and pharmacokinetic profile. Analysis of the binding modes of the series in TYK2 and JAK2 crystal structures revealed key interactions leading to good TYK2 potency and design options for future optimization of selectivity.

Tim-3 alters the balance of IL-12/IL-23 and drives TH17 cells: role in hepatitis B vaccine failure during hepatitis C infection

Hepatitis B virus (HBV) vaccination is recommended for individuals with hepatitis C virus (HCV) infection given their shared risk factors and increased liver-related morbidity and mortality upon super-infection. Vaccine responses in this setting are often blunted, with poor response rates to HBV vaccinations in chronically HCV-infected individuals compared to healthy subjects. In this study, we investigated the role of T cell immunoglobulin mucin domain-3 (Tim-3)-mediated immune regulation in HBV vaccine responses during HCV infection. We found that Tim-3, a marker for T cell exhaustion, was over-expressed on monocytes, leading to a differential regulation of IL-12/IL-23 production which in turn TH17 cell accumulation, in HCV-infected HBV vaccine non-responders compared to HCV-infected HBV vaccine responders or healthy subjects (HS). Importantly, ex vivo blockade of Tim-3 signaling corrected the imbalance of IL-12/IL-23 as well as the IL-17 bias observed in HBV vaccine non-responders during HCV infection. These results suggest that Tim-3-mediated dysregulation of innate to adaptive immune responses is involved in HBV vaccine failure in individuals with chronic HCV infection, raising the possibility that blocking this negative signaling pathway might improve the success rate of HBV immunization in the setting of chronic viral infection.

Emerging targets in lipid-based therapy

The use of prostaglandins and NSAIDS in the clinic has proven that lipid mediators and their associated pathways make attractive therapeutic targets. When contemplating therapies involving lipid pathways, several basic agents come to mind. There are the enzymes and accessory proteins that lead to the metabolism of lipid substrates, provided through diet or through actions of lipases, the subsequent lipid products, and finally the lipid sensors or receptors. There is abundant evidence that molecules along this lipid continuum can serve as prognostic and diagnostic indicators and are in fact viable therapeutic targets. Furthermore, lipids themselves can be used as therapeutics. Despite this, the vernacular dialog pertaining to "biomarkers" does not routinely include mention of lipids, though this is rapidly changing. Collectively these agents are becoming more appreciated for their respective roles in diverse disease processes from cancer to preterm labor and are receiving their due appreciation after decades of ground work in the lipid field. By relating examples of disease processes that result from dysfunction along the lipid continuum, as well as examples of lipid therapies and emerging technologies, this review is meant to inspire further reading and discovery.

Differential regulation of interleukin-12 (IL-12)/IL-23 by Tim-3 drives T(H)17 cell development during hepatitis C virus infection

Cytokine production by innate immunity is critical for shaping the adaptive immunity through regulation of T cell differentiation. In this report, we studied T cell immunoglobulin mucin domain protein 3 (Tim-3) expression on monocytes and its regulatory effect on interleukin-12 (IL-12)/IL-23 production by CD14(+) monocytes, as well as IL-17 production by CD4(+) T cells in individuals with chronic hepatitis C virus (HCV) infection. We found that Tim-3 and IL-23p19 are highly expressed and that IL-12p35 is inhibited in human CD14(+) monocytes, while IL-17 expression is upregulated in CD4(+) T cells, in chronically HCV-infected individuals compared to healthy subjects. Interestingly, Tim-3 expression is closely associated with the differential regulation of IL-12/IL-23 expression in CD14(+) monocytes and correlated to IL-17 production by CD4(+) T cells. These Tim-3-associated IL-12/IL-23/IL-17 dysregulations in HCV-infected individuals are also recapitulated in vitro by incubating healthy monocytes or peripheral blood mononuclear cells with Huh-7 hepatoma cells transfected with HCV RNA. Importantly, blocking Tim-3 signaling on monocytes restores the balance of IL-12/IL-23 through the intracellular STAT3 signaling, which in turn reverses the upregulated IL-17 expression both ex vivo and in vitro. Our findings suggest that Tim-3-mediated differential regulation of IL-12/IL-23 drives T(H)17 cell development, a milieu favoring viral persistence and autoimmune phenomenon during HCV infection.

Serum levels of the chemokine CXCL13, genetic variation in CXCL13 and its receptor CXCR5, and HIV-associated non-hodgkin B-cell lymphoma risk

BACKGROUND

CXCL13 and CXCR5 are a chemokine and receptor pair whose interaction is critical for naïve B-cell trafficking and activation within germinal centers. We sought to determine whether CXCL13 levels are elevated before HIV-associated non-Hodgkin B-cell lymphoma (AIDS-NHL), and whether polymorphisms in CXCL13 or CXCR5 are associated with AIDS-NHL risk and CXCL13 levels in a large cohort of HIV-infected men.

METHODS

CXCL13 levels were measured in sera from 179 AIDS-NHL cases and 179 controls at three time-points. TagSNPs in CXCL13 (n = 16) and CXCR5 (n = 11) were genotyped in 183 AIDS-NHL cases and 533 controls. OR and 95% confidence intervals (CI) for the associations between one unit increase in log CXCL13 levels and AIDS-NHL, as well as tagSNP genotypes and AIDS-NHL, were computed using logistic regression. Mixed linear regression was used to estimate mean ratios (MR) for the association between tagSNPs and CXCL13 levels.

RESULTS

CXCL13 levels were elevated for more than 3 years (OR = 3.24; 95% CI = 1.90-5.54), 1 to 3 years (OR = 3.39; 95% CI = 1.94-5.94), and 0 to 1 year (OR = 3.94; 95% CI = 1.98-7.81) before an AIDS-NHL diagnosis. The minor allele of CXCL13 rs355689 was associated with reduced AIDS-NHL risk (OR(TCvsTT) = 0.65; 95% CI = 0.45-0.96) and reduced CXCL13 levels (MR(CCvsTT) = 0.82; 95% CI = 0.68-0.99). The minor allele of CXCR5 rs630923 was associated with increased CXCL13 levels (MR(AAvsTT) = 2.40; 95% CI = 1.43-4.50).

CONCLUSIONS

CXCL13 levels were elevated preceding an AIDS-NHL diagnosis, genetic variation in CXCL13 may contribute to AIDS-NHL risk, and CXCL13 levels may be associated with genetic variation in CXCL13 and CXCR5.

IMPACT

CXCL13 may serve as a biomarker for early AIDS-NHL detection.

Analysis of IL28B alleles with virologic response patterns and plasma cytokine levels in HIV/HCV-coinfected patients

OBJECTIVES

To estimate the impact of interleukin 28B (IL28B) polymorphisms (rs12980275, rs8099917, rs7248668, and rs11881222) and their haplotypes on hepatitis C virus (HCV) treatment (peg-interferon-α and ribavirin) success in 324 HIV/HCV-coinfected patients. We also explore the behavior of plasma cytokine levels.

DESIGN

Retrospective follow-up study.

METHODS

Virologic response to HCV treatment was measured by plasma HCV viral load at different endpoints: rapid virologic response (RVR), early virologic response (EVR), end-of-treatment virologic response (ETVR) and sustained virologic response (SVR). IL28B polymorphisms were genotyped using GoldenGate assay. Finally, 13 cytokines were measured at baseline in 57 plasma samples using a multiplex immunoassay kit.

RESULTS

IL28B polymorphisms were strongly associated to virologic responses (RVR, EVR, ETVR, and SVR), although only for HCV genotypes 1 and 4 (P < 0.05). Strong linkage disequilibrium was detected for rs12980275/rs11881222 (r = 0.94) and rs8099917/rs7248668 (r = 0.99). IL28B haplotypes showed association but no improvement on treatment outcome prediction. Thus, the genotyping of only one single-nucleotide polymorphism was enough for predicting treatment response in GT1/4 patients with favorable rs12980275 (AA) genotype, while for subjects harboring unfavorable genotypes, the inclusion of rs8099917 was useful (SVR increased from 31 to 45%). Moreover, patients with rs12980275 (AA) that achieved SVR showed reduced plasma levels of Th1 (IFN-γ), Th2 (IL-6 and IL-9), and proinflammatory (TNF-α) cytokines.

CONCLUSION

The presence of IL28B polymorphisms was significantly associated with HCV clearance during and after HCV therapy. The evaluated cytokine profile was much more favorable in patients with rs12980275 (AA) who achieved SVR.