IL-17 and IL-22 in atopic allergic disease

DiGeorge syndrome presenting with palmoplantar pustules: Comparative analysis of serum IL-22, NETs and IL-8 with usual palmoplantar pustulosis

DiGeorge syndrome, also known as 22q11.2 deletion syndrome, shows cellular immunodeficiency due to by thymic hypoplasia and hypocalcemia caused by hypoparathyroidism. It was reported that erythrodermic psoriasis occurred in a patient with 22q11 deletion syndrome. Here, we report the first case of DiGeorge syndrome presenting with a severe palmoplantar pustulosis (PPP)-like eruption with extra-palmoplantar lesions on the distal limbs. Given that PPP is a subtype of pustular psoriasis, the pustular eruption may be associated with DiGeorge syndrome. We measured serum levels of citrullinated histone H3 (CitH3), a representative marker of neutrophil extracellular traps, interleukin (IL)-8, and IL-22 and compared them with nine cases of typical PPP. In the PPP patients, the three markers were higher than in healthy subjects with significant correlations between CitH3 and IL-8/IL-22. In our patient, CitH3, IL-8, and IL-22 were also high, and IL-22 was remarkably elevated compared with the PPP patients. Our case suggests that a certain T cell abnormality associated with DiGeorge syndrome induces IL-22 overproduction, leading to the PPP-like eruption with extra- palmoplantar lesions.

Prospective feasibility study of indigo naturalis ointment for chemotherapy-induced oral mucositis

OBJECTIVES

Indigo naturalis, a herbal medicine effective against ulcerative colitis, exhibits anti-inflammatory effects and induces interleukin-22-mediated antimicrobial peptide production. Anti-inflammatory activity and the prevention of secondary infection are essential for the management of chemotherapy-induced oral mucositis (CIOM); therefore, we developed an indigo naturalis ointment to be administered topically for CIOM and evaluated its feasibility.

METHODS

We performed a single-centre, open-label, prospective feasibility study from March 2017 to December 2018. The key eligibility criteria for the subjects were as follows: (1) receiving chemotherapy for a malignant tumour; (2) grade 1 or 2 CIOM and (3) receiving continuous oral care. The treatment protocol comprised topical indigo naturalis ointment application three times a day for 7 days. The primary endpoint assessed was feasibility. The secondary endpoints assessed were the changes in oral findings, oral cavity pain and safety.

RESULTS

Nineteen patients with CIOM were enrolled. The average feasibility (the proportion of prescribed applications that were carried out) observed in this study was 94.7%±8.9% (95% CI 90.5% to 99.0%), which was higher than the expected feasibility. The revised oral assessment guide scores of the mucous membrane domain and total scores were significantly improved. All patients reported a reduction in oral cavity pain, with a median pain resolution duration of 6 days. No serious adverse events were observed.

CONCLUSIONS

The indigo naturalis ointment was feasible, and showed the potential for efficacy and safety. Larger randomised controlled trials are needed to further assess the efficacy and safety of indigo naturalis compared with a placebo.

TRIAL REGISTRATION NUMBER

UMIN000024271.

Psoriasis associated with asthma and allergic rhinitis: a US-based cross-sectional study using the All of US Research Program

Psoriasis is a common chronic inflammatory disease with multiple known comorbidities. Increasing evidence suggests some mechanistic overlap in the immunopathogenesis of psoriasis and some cases of asthma and allergic rhinitis (AR), but the potential association between psoriasis and asthma and AR has not been thoroughly investigated. The study aimed to investigate the association between psoriasis and asthma and AR. We used data from the NIH All of US Research Program, a nationwide longitudinal cohort of US adults, collected from 2018 to present. The source population comprised a demographically and socioeconomically diverse cohort of over 300,000 Americans. We used multivariable logistic regression models to examine the association between psoriasis and asthma and AR, after adjusting for sociodemographic variables, body mass index, and smoking status. In total, 235,551 participants (mean [SD] age, 54.7 [16.6] years; 59.3% female), including 5165 individuals with psoriasis and 230,386 individuals without psoriasis, were included in our analysis. Participants with psoriasis had significantly higher prevalence of asthma (26.1% vs. 12.9%; P < 0.001) and AR (31.8% vs. 13.4%; P < 0.001) compared to participants without psoriasis. Psoriasis was significantly associated with both asthma [adjusted odds ratio (aOR) 2.22; 95% confidence interval (CI) 2.08-2.37] and AR (aOR, 2.57; 95% CI 2.42-2.73). In subgroup analyses, associations remained stable in multivariable analyses after stratification by age, sex, and income. Psoriasis is associated with both asthma and AR in our sample of US adults. Further research is needed to explore potentially unifying inflammatory pathways among psoriasis, asthma, and AR.

Healthcare Provider Experience in Diagnosing and Treating Cutaneous T-Cell Lymphoma

INTRODUCTION

Cutaneous T-cell lymphoma (CTCL) is a rare, heterogeneous group of non-Hodgkin lymphomas characterized by various clinical, molecular, and histopathologic features of the skin. Variants of CTCL share many clinical features with common inflammatory skin diseases such as atopic dermatitis and psoriasis, making accurate and early diagnosis challenging in clinical settings. Inappropriate treatment or a delay in diagnosis can lead to increased morbidity and mortality. Here, we report findings from an online survey that investigated dermatology community practice, knowledge, and education surrounding CTCL.

METHODS

An electronic survey of ten questions was developed and approved by physician experts in CTCL to assess experiences in diagnosing and treating CTCL among healthcare providers (HCPs). The survey was deployed to 10,600 US dermatology HCPs, including medical doctors (MDs), doctors of osteopathic medicine (DOs), nurse practitioners (NPs), and physician assistants (PAs) and excluding HCPs associated with CTCL centers of excellence.

RESULTS

Among 44 HCPs who responded and were eligible for inclusion, 82% had diagnosed between one and ten CTCL cases in the last 5 years. Most respondents (91%) reported that they include CTCL in their differential diagnoses after patients do not respond to treatment of more common conditions. Patients with CTCL were frequently diagnosed with other inflammatory dermatoses-most commonly dermatitis and psoriasis-before a CTCL diagnosis, and many were treated with ineffective therapies for years. The most common length of time before a CTCL diagnosis was made was between 1 and 3 years, though 16% of HCPs reported that patients were treated for other diseases or skin conditions for ≥ 5 years. Two-thirds of HCPs agreed that further education surrounding CTCL is needed.

CONCLUSIONS

Given the infrequency of CTCL and its similar presentation to other common dermatologic conditions, increased education of CTCL is needed in the dermatology community to improve patient outcomes.

Effects of Dupilumab on Itch-Related Events in Atopic Dermatitis: Implications for Assessing Treatment Efficacy in Clinical Practice

Dupilumab attenuates itch and skin inflammation in patients with atopic dermatitis (AD). However, itch-related events that are improved by dupilumab remain unclear. Therefore, the present study investigated changes in clinical scores, serum biomarkers, and the number of intraepidermal nerve fibers (IENFs) using skin biopsies and blood samples from 12 patients with moderate to severe AD before and after treatment with dupilumab. Clinical manifestations were assessed using eczema area and severity index (EASI) and visual analogue scale (VAS) scores at baseline and after 8 and 16 weeks of treatment. Serum levels of total immunoglobulin E (IgE), thymus and activation-regulated chemokine (TARC), interleukin (IL)-4, IL-13, IL-22, and IL-31 were examined by electrochemiluminescence, chemiluminescent enzyme immunoassays, ProQuantum immunoassays, and enzyme-linked immunosorbent assays (ELISA) at baseline and after 8 and 16 weeks of treatment. In skin biopsies from AD patients at baseline and after 16 weeks of treatment, IENFs were examined immunohistochemically with the anti-protein gene product (PGP) 9.5 antibody. The dupilumab treatment significantly improved EASI and VAS scores and decreased serum levels of TARC, IgE, and IL-22, whereas those of IL-13 and IL-31, and the number of IENFs remained unchanged and those of IL-4 increased. VAS scores were positively correlated with serum TARC, IL-22, and IgE levels and the degree of epidermal thickening. Serum IL-31 levels were positively correlated with the number of IENFs. These results suggest that serum TARC, IL-22, and IgE levels and epidermal thickness are itch-related events associated with dupilumab treatment and that serum IL-31 levels may reflect the degree of IENF density in AD patients. Therefore, dynamic changes may be used to assess the efficacy of dupilumab treatment to treat itching and inflammation in patients with AD.

Anti-inflammatory and immunomodulatory effects of polysaccharide extracted from Wuguchong (maggot) on 2,4-dinitrochlorobenzene-induced atopic dermatitis in mice

Atopic dermatitis (AD) is an inflammatory, heterogeneous, chronic skin disorder characterized by recurrent eczematous lesions and intense pruritus, and the pathophysiology mechanism of AD is known for immune dysregulation and inflammatory responses. Wuguchong (maggot) has been widely used in the wound field and found with pharmacological properties of the anti-inflammatory and immunomodulatory function. Recently, some polysaccharides were proven to have beneficial effects on AD skin lesions in mice and humans. However, the effect of the polysaccharide extracted from Wuguchong (PEW) on AD remains to be investigated. In the present study, we examined the anti-inflammatory and immunomodulatory effects of PEW on AD and explored the potential mechanisms. Balb/c mice were orally administrated with PEW to evaluate the therapeutic effect of PEW on 2,4-dinitrochlorobenzene (DNCB)-induced AD. Oral PEW administration significantly ameliorated the lesions and symptoms in AD mice, such as the ear thickness and ear swelling degree, epidermal and dermal thickness, and the infiltration of mast cells. In addition, PEW treatment decreased the levels of serum IgE and histamine, the frequencies of Th1 and Th17 cells, as well as the mRNA expression levels of Th1 and Th17 cytokines and nuclear transcript factors (IFN-γ, T-bet, IL-17A, and ROR-rt). Furthermore, the activation of the NF-κB pathway and the phosphorylation of MAPKs (p38, ERK, and JNK) were significantly suppressed by PEW treatment. Taken together, our study suggests that PEW exerts anti-inflammatory and immunomodulatory effects through inhibition of Th1 and Th17 responses and downregulation of NF-κB and MAPK pathways, PEW would be developed as a promising immune therapy for AD.

The Role of T Helper 22 Cells in Dermatological Disorders

T helper 22 (Th22) cells are a newly identified subset of CD4+ T cells that secrete the effector cytokine interleukin 22 (IL-22) upon specific antigen stimulation, barely with IFN-γ or IL-17. Increasing studies have demonstrated that Th22 cells and IL-22 play essential roles in skin barrier defense and skin disease pathogenesis since the IL-22 receptor is widely expressed in the skin, especially in keratinocytes. Herein, we reviewed the characterization, differentiation, and biological activities of Th22 cells and elucidated their roles in skin health and disease. We mainly focused on the intricate crosstalk between Th22 cells and keratinocytes and provided potential therapeutic strategies targeting the Th22/IL-22 signaling pathway.

The role of ICOS in allergic disease: Positive or Negative?

With the rapid increase in the incidence of allergic diseases, the mechanisms underlying the development of these diseases have received a great deal of attention, and this is particularly true in regard to the role of ICOS in allergic diseases. Current studies have revealed that ICOS affects the functional activity of multiple immune cells that modulate the adaptive immune system. Additionally, ICOS also plays a crucial role in mediating cellular immunity and coordinating the response of the entire immune system, and thus, it plays a role in allergic reactions. However, the ICOS/ICOS-ligand (ICOS-L) axis functions in a dual role during the development of multiple allergic diseases. In this review, we explore the role of ICOS/ICOSL in the context of different immune cells that function in allergic diseases, and we summarize recent advances in their contribution to these diseases.

Epigallocatechin gallate/L-ascorbic acid-loaded poly-γ-glutamate microneedles with antioxidant, anti-inflammatory, and immunomodulatory effects for the treatment of atopic dermatitis

Epigallocatechin gallate (EGCG) is a potential therapeutic agent for treatment of atopic dermatitis (AD) due to its antioxidant and anti-inflammatory activities. However, inherent instability of EGCG greatly limits its bioavailability and clinical efficacy. In this study, we developed a poly-γ-glutamate (γ-PGA)-based microneedle (MN) formulation capable of maintaining EGCG's stability and efficiently delivering EGCG into the skin to ameliorate AD symptoms. The γ-PGA MN can not only protect EGCG from oxidation, but also serve as an immunomodulator to downregulate T helper type 2 (Th2)-type immune responses. Encapsulation of EGCG into the γ-PGA MN and utilization of L-ascorbic acid (AA) as a stabilizer preserved 95% of its structural stability and retained 93% of its initial antioxidant activity after 4 weeks of storage. Once-weekly administration of EGCG/AA-loaded MNs to an Nc/Nga mouse model of AD for 4 weeks significantly ameliorated skin lesions and epidermal hyperplasia by reducing serum IgE (from 12156 ± 1344 to 5555 ± 1362  ng/mL) and histamine levels (from 81 ± 18 to 40 ± 5 pg/mL) and inhibiting IFN-γ (from 0.10 ± 0.01 to 0.01 pg/mg total protein) and Th2-type cytokine production, when compared to the AD (no treatment) group (p < 0.05). Notably, once-weekly MN therapy was at least as effective as the daily topical application of an EGCG + AA solution but markedly reduced the administration frequency and required dose. These results show that EGCG/AA-loaded γ-PGA MNs may be a convenient and promising therapeutic option for AD treatment. STATEMENT OF SIGNIFICANCE: This study describes epigallocatechin gallate (EGCG)/L-ascorbic acid (AA)-loaded poly-γ-glutamate (γ-PGA) microneedles (MN) capable of providing antioxidant, anti-inflammatory, and immunomodulatory effects on inflamed skin for ameliorating atopic dermatitis (AD) symptoms in Nc/Nga mice. After skin insertion, the γ-PGA MN can be quickly dissolved in the skin and remain in the dermis for sustained release of encapsulated active ingredients for 6 days. We demonstrated that once-weekly MN therapy effectively alleviated skin lesions and modulated immune response to relieve Th2-polarized allergic response in mice. Once-weekly MN dosing regimen may provide patients with a more convenient, therapeutically equivalent option to daily topical dosing, and may increase compliance and long-term persistence with AD therapy.

Coordinated action of microsomal prostaglandin E synthase-1 and prostacyclin synthase on contact hypersensitivity

Microsomal prostaglandin (PG) E synthase-1 (mPGES-1) and prostacyclin (PGI2) synthase (PGIS) are PG terminal synthases that work downstream of cyclooxygenase and synthesize PGE2 and PGI2, respectively. Although the involvement of PG receptors in acquired cutaneous immune responses was recently shown, the roles of these PG terminal synthases remain unclear. To identify the pathophysiological roles of mPGES-1 and PGIS in cutaneous immune systems, we applied contact hypersensitivity (CHS) to mPGES-1 and PGIS knockout (KO) mice as a model of acquired immune responses. Mice were treated with 1-fluoro-2,4-dinitrobenzene (DNFB) and evaluated for ear thickness and histopathological features. The results showed that the severity of ear swelling in both gene-deficient mice was much lower than that in wild-type (WT) mice. Histological examination of DNFB-treated ears showed that inflammatory cell infiltration and edema in the dermis were also less apparent in both genotypic mice. LC-MS analysis further showed that the increment in PGE2 levels in DNFB-treated ear tissue was reduced in mPGES-1 KO mice, and that 6-keto PGF1α (a stable metabolite of PGI2) was not detected in PGIS KO mice. Furthermore, we made bone marrow (BM) chimera and found that transplantation of WT mouse-derived BM cells restored the impaired CHS response in mPGES-1 KO mice but did not restore the response in PGIS KO mice. These results indicated that mPGES-1 in BM-derived cells and PGIS in non-BM-derived cells might play critical roles in DNFB-induced CHS. mPGES-1-derived PGE2 and PGIS-derived PGI2 might coordinately promote acquired cutaneous immune responses.

Generation and Characterization of Inducible Lung and Skin-Specific IL-22 Transgenic Mice

IL-22 is an IL-10 family cytokine that is increased in asthma and atopic dermatitis (AD). However, the specific role of IL-22 in the pathogenesis of allergic lung inflammation and AD in vivo has yet to be elucidated. We aimed to develop mouse models of allergic diseases in the lung and skin with inducible and tissue-specific expression of IL-22, using a tetracycline (Tet)-controlled system. In this chapter, we describe a series of protocols we have developed to generate a construct that contains the TRE-Tight promoter and mouse IL-22 cDNA based on this system. Furthermore, we describe how to generate TRE-Tight-IL-22 mice through pronuclear microinjection. In our approach, two Tet-on (CC10-rtTA or SPC-rtTA) and a Tet-off (K5-tTA) transgenic mouse lines are selected to crossbreed with TRE-Tight-IL-22 mice to generate inducible tissue-specific transgenic lines. The transgenic strains, CC10-rtTA/TRE-Tight-IL-22 (CC10-rtTA-IL-22) or SPC-rtTA/TRE-Tight-IL-22 (SPC-rtTA-IL-22) mice, do not produce detectable levels of IL-22 in their bronchoalveolar lavage (BAL) samples in the absence of doxycycline (Dox). However, oral Dox treatment of these mice induces IL-22 expression in the BAL, and the airway and lung epithelial cells. For K5-tTA/TRE-Tight-IL-22 (K5-tTA-IL-22) mice, to avoid potential IL-22 toxicity to mouse embryos, Dox is given starting at the time of breeding to suppress tTA and to keep the IL-22 transgene off until the K5-tTA-IL-22 mice are 6 weeks old. Experiments are then initiated by withdrawing Dox from the drinking water. In all cases, IL-22 protein can be detected by immunohistochemistry in the skin of Tg(+) animals, but not in the skin of Tg(-) animals. Utilizing transgenic technology based on the Tetracycline-controlled system, we have established inducible transgenic mouse models in which cytokine IL-22 can be expressed specifically in the lung or skin. These models are valuable for studies in vivo in a broad range of diseases involving IL-22 and will provide a new platform for research and for seeking novel therapeutics in the fields of inflammation, asthma, and allergic dermatitis.

The Role of Genetics, the Environment, and Epigenetics in Atopic Dermatitis

Atopic Dermatitis (AD) is a common inflammatory disease with a genetic background. The prevalence of AD has been increasing in many countries. AD patients often have manifestations of pruritus, generalized skin dryness, and eczematous lesions. The pathogenesis of AD is complicated. The impaired skin barrier and immune imbalance play significant roles in the development of AD. Environmental factors such as allergens and pollutants are associated with the increasing prevalence. Many genetic and environmental factors induce a skin barrier deficiency, and this can lead to immune imbalance, which exacerbates the impaired skin barrier to form a vicious cycle (outside-inside-outside view). Genetic studies find many gene mutations and genetic variants, such as filaggrin mutations, which may directly induce the deficiency of the skin barrier and immune system. Epigenetic studies provide a connection between the relationship of an impaired skin barrier and immune and environmental factors, such as tobacco exposure, pollutants, microbes, and diet and nutrients. AD is a multigene disease, and thus there are many targets for regulation of expression of these genes which may contribute to the pathogenesis of AD. However, the epigenetic regulation of environmental factors in AD pathogenesis still needs to be further researched.

Molecular mechanisms underlying prostaglandin E2-exacerbated inflammation and immune diseases

Prostaglandins (PGs) are the major lipid mediators in animals and which are biosynthesized from arachidonic acid by the cyclooxygenases (COX-1 or COX-2) as the rate-limiting enzymes. Prostaglandin E2 (PGE2), which is the most abundantly detected PG in various tissues, exerts versatile physiological and pathological actions via four receptor subtypes (EP1-4). Non-steroidal anti-inflammatory drugs, such as aspirin and indomethacin, exert potent anti-inflammatory actions by the inhibition of COX activity and the resulting suppression of PG production. Therefore, PGE2 has been shown to exacerbate several inflammatory responses and immune diseases. Recently, studies using mice deficient in each PG receptor subtype have clarified the detailed mechanisms underlying PGE2-associated inflammation and autoimmune diseases involving each EP receptor. Here, we review the recent advances in our understanding of the roles of PGE2 receptors in the progression of acute and chronic inflammation and autoimmune diseases. PGE2 induces acute inflammation through mast cell activation via the EP3 receptor. PGE2 also induces chronic inflammation and various autoimmune diseases through T helper 1 (Th1)-cell differentiation, Th17-cell proliferation and IL-22 production from Th22 cells via the EP2 and EP4 receptors. The possibility of EP receptor-targeted drug development for the treatment of immune diseases is also discussed.

Preparation of a novel monoclonal antibody against caprine interleukin-17A and its applications in immunofluorescence and immunohistochemistry assays

BACKGROUND

Interleukin-17 (IL-17), the characteristic cytokine secreted by T helper 17 lymphocytes (Th17 cells), plays a pivotal role in host defense and many inflammatory or autoimmune diseases. The aim of this study was to obtain purified protein caprine IL-17A (cIL-17A) as an antigen for preparing an IL-17A-specific monoclonal antibody (mAb).

RESULTS

The coding sequence (CDS) region of cIL-17A was cloned from the peripheral blood mononuclear cells (PBMCs) of dairy goats and then inserted into the expression vector PET 32a and transformed into competent TransB (DE3) cells. Recombinant fusion protein obtained under optimized conditions was used to immunize BALB/c mice for preparing monoclonal antibodies. Finally, the supernatants of two hybridoma cell lines showing positive reaction with the recombinant fusion protein and negative reaction with fusion tags of PET 32a were collected for western blot, immunofluorescence (IF) and immunohistochemistry (IHC) analysis. Our results showed that the maximum amount of soluble protein could be obtained directly in the supernatant when the recombinant expression cells were induced by isopropyl-β-d-thiogalactoside (IPTG) at a concentration of 0.3 mmol/L at 16 °C for 42 h. Western blot analysis showed that the mAb H8 could recognize the eukaryotically expressed cIL-17A in the supernatant of transfected HEK293T cells. Immunofluorescence and immunohistochemistry assays showed that mAb H8 could strongly recognize both the eukaryotically expressed and natural cIL-17A.

CONCLUSIONS

The monoclonal antibody mAb H8 prepared in this study may be a potential tool for the detection of cIL-17A and beneficial for investigating the pathogenesis of various IL-17-associated diseases.

The relationship between IL-17A and IL-22 expression and clinical severity in patients with moderate/severe persistent allergic rhinitis

PURPOSE

Several reactions leading to numerous effects are regulated by IL-22. However, the relationship between IL-22 and immunopathogensis of allergic rhinitis (AR) has been rarely investigated. The aim of the present study was to investigate the levels of IL-22 and IL-17A in AR patients and their association with clinical severity of persistent allergic rhinitis (PAR).

MATERIALS AND METHODS

Thirty mild persistent allergic rhinitis (M PAR) patients, thirty moderate/severe persistent allergic rhinitis (M/S PAR) patients, and thirty healthy controls were enrolled in this study. Local production of IL-22 and IL-17A in PAR patients and healthy controls' nasal mucosa was examined by immunohistochemistry (IHC) and real-time polymerase chain reaction (RT-PCR) techniques. Serum levels of IL-22, IL-17A, specific immunoglobulin E (sIgE), and total IgE (tIgE) in PAR patients and healthy controls were determined by ELISA. In addition, blood eosinophil, nasal eosinophils per field, and total nasal syndrome score (TNSS) were also assessed.

RESULTS

In comparison with healthy controls, production of IL-22 and IL-17A in M/S PAR patients increased significantly. Furthermore, serum levels as well as the mean number of IL-22+ and IL-17A+ cells in nasal mucosa correlated with sIgE, nasal eosinophil count, and TNSS.

CONCLUSION

The results of the present study provide the first evidence that local production of IL-22 might be expressed in PAR patients. The expression of IL-22 and IL-17A, and their correlations with clinical parameters in PAR patients suggest the role of these cytokines in the events involved in the development of PAR.

Colonization by B. infantis EVC001 modulates enteric inflammation in exclusively breastfed infants

BACKGROUND

Infant gut dysbiosis, often associated with low abundance of bifidobacteria, is linked to impaired immune development and inflammation-a risk factor for increased incidence of several childhood diseases. We investigated the impact of B. infantis EVC001 colonization on enteric inflammation in a subset of exclusively breastfed term infants from a larger clinical study.

METHODS

Stool samples (n = 120) were collected from infants randomly selected to receive either 1.8 × 10¹⁰ CFU B. infantis EVC001 daily for 21 days (EVC001) or breast milk alone (controls), starting at day 7 postnatal. The fecal microbiome was analyzed using 16S ribosomal RNA, proinflammatory cytokines using multiplexed immunoassay, and fecal calprotectin using ELISA at three time points: days 6 (Baseline), 40, and 60 postnatal.

RESULTS

Fecal calprotectin concentration negatively correlated with Bifidobacterium abundance (P < 0.0001; ρ = -0.72), and proinflammatory cytokines correlated with Clostridiaceae and Enterobacteriaceae, yet negatively correlated with Bifidobacteriaceae abundance. Proinflammatory cytokines were significantly lower in EVC001-fed infants on days 40 and 60 postnatally compared to baseline and compared to control infants.

CONCLUSION

Our findings indicate that gut dysbiosis (absence of B. infantis) is associated with increased intestinal inflammation. Early addition of EVC001 to diet represents a novel strategy to prevent enteric inflammation during a critical developmental phase.

The Role and Diagnosis of Allergic Contact Dermatitis in Patients with Atopic Dermatitis

Patients with atopic dermatitis (AD) have increased penetration of allergens, immune dysregulation (including shared cytokine pathways), and frequent use of emollients and topical medications, all of which may predispose toward developing allergic contact dermatitis (ACD). Recent systematic reviews have suggested that ACD is a significant clinical problem in both children and adults with AD. While this remains controversial, ACD remains an important comorbidity and potential exacerbant of AD in clinical practice. Common relevant allergens, include lanolin, neomycin, formaldehyde, sesquiterpene lactone mix, compositae mix, and fragrances that are commonly found in AD patients' personal care products. We herein review the clinical scenarios where patch testing is indicated in AD. In addition, we review the contraindications, preferred patch-testing series, pitfalls, and challenges determining the relevance of positive patch-test reactions in AD patients.

Regulation of T helper cell responses during antigen presentation by norepinephrine-exposed endothelial cells

Dermal blood vessels and regional lymph nodes are innervated by sympathetic nerves and, under stress, sympathetic nerves release norepinephrine (NE). Exposure of primary murine dermal microvascular endothelial cells (pDMECs) to NE followed by co-culture with Langerhans cells (LCs), responsive CD4+ T-cells and antigen resulted in modulation of CD4+ T-cell responses. NE-treatment of pDMECs induced increased production of interleukin (IL)-6 and IL-17A while down-regulating interferon (IFN)-γ and IL-22 release. This effect did not require contact between pDMECs and LCs or T-cells and depended upon pDMEC production of IL-6. The presence of NE-treated pDMECs increased the proportion of CD4+ T-cells expressing intracellular IL-17A and increased IL-17A mRNA while decreasing the proportion of IFN-γ- or IL-22-expressing CD4+ T-cells and mRNA levels for those cytokines. Retinoic acid receptor-related orphan receptor gamma (ROR-γt) mRNA was significantly increased in CD4+ T-cells while T-box transcription factor (T-bet) mRNA was decreased. Intradermal administration of NE prior to hapten immunization at the injection site produced a similar bias in draining lymph node CD4+ T-cells towards IL-17A and away from IFN-γ and IL-22 production. Under stress, release of NE may have significant regulatory effects on the outcome of antigen presentation through actions on ECs with enhancement of inflammatory skin disorders involving IL-17/T helper type 17 (Th17) cells.

Identification of biomarker sets for predicting the efficacy of sublingual immunotherapy against pollen-induced allergic rhinitis

Sublingual immunotherapy (SLIT) is effective against allergic rhinitis, although a substantial proportion of individuals is refractory. Herein, we describe a predictive modality to reliably identify SLIT non-responders (NRs). We conducted a 2-year clinical study in 193 adult patients with Japanese cedar pollinosis, with biweekly administration of 2000 Japanese allergy units of cedar pollen extract as the maintenance dose. After identifying high-responder (HR) patients with improved severity scores and NR patients with unchanged or exacerbated symptoms, differences in 33 HR and 34 NR patients were evaluated in terms of peripheral blood cellular profiles by flow cytometry and serum factors by ELISA and cytokine bead array, both pre- and post-SLIT. Improved clinical responses were seen in 72% of the treated patients. Pre-therapy IL-12p70 and post-therapy IgG1 serum levels were significantly different between HR and NR patients, although these parameters alone failed to distinguish NR from HR patients. However, the analysis of serum parameters in the pre-therapy samples with the Adaptive Boosting (AdaBoost) algorithm distinguished NR patients with high probability within the training data set. Cluster analysis revealed a positive correlation between serum Th1/Th2 cytokines and other cytokines/chemokines in HR patients after SLIT. Thus, processing of pre-therapy serum parameters with AdaBoost and cluster analysis can be reliably used to develop a prediction method for HR/NR patients.

Phenotyping acute and chronic atopic dermatitis-like lesions in Stat6VT mice identifies a role for IL-33 in disease pathogenesis

The Stat6VT mouse model of atopic dermatitis (AD) is induced by T-cell-specific expression of a constitutively active form of the protein signal transducer and activator of transcription 6 (STAT6). Although AD-like lesions are known to develop in Stat6VT mice, this study was designed to determine if these mice develop acute and chronic phases of disease similar to humans. To address this, AD-like lesions from Stat6VT mice were harvested at two different timepoints relative to their onset. Lesions harvested within 1 week after development were defined as acute lesions, and those present for 1 month or more were defined as chronic lesions. Acute and chronic AD-like lesions from Stat6VT mice exhibited histologic findings and cytokine expression patterns similar to acute and chronic AD lesions in humans. Further analysis revealed increased levels of interleukin (IL)-33 transcripts in AD-like lesions compared to Stat6VT nonlesional and wild-type skin controls. Immunofluorescence also revealed increased numbers of IL-33+ keratinocytes in Stat6VT lesional skin and localized IL-33+ keratinocytes to a keratin 5+ subset. Furthermore, AD-like disease was more severe in IL-33-deficient Stat6VT mice compared to IL-33-sufficient Stat6VT mice. These studies suggest that Stat6VT mice can serve as a model of acute and chronic AD and that IL-33 may attenuate inflammation in this system.

Prostaglandin E2 stimulates adaptive IL-22 production and promotes allergic contact dermatitis

BACKGROUND

Atopic dermatitis (AD) and allergic contact dermatitis (ACD) are both forms of eczema and are common inflammatory skin diseases with a central role of T cell-derived IL-22 in their pathogenesis. Although prostaglandin (PG) E2 is known to promote inflammation, little is known about its role in processes related to AD and ACD development, including IL-22 upregulation.

OBJECTIVES

We sought to investigate whether PGE2 has a role in IL-22 induction and development of ACD, which has increased prevalence in patients with AD.

METHODS

T-cell cultures and in vivo sensitization of mice with haptens were used to assess the role of PGE2 in IL-22 production. The involvement of PGE2 receptors and their downstream signals was also examined. The effects of PGE2 were evaluated by using the oxazolone-induced ACD mouse model. The relationship of PGE2 and IL-22 signaling pathways in skin inflammation were also investigated by using genomic profiling in human lesional AD skin.

RESULTS

PGE2 induces IL-22 from T cells through its receptors, E prostanoid receptor (EP) 2 and EP4, and involves cyclic AMP signaling. Selective deletion of EP4 in T cells prevents hapten-induced IL-22 production in vivo, and limits atopic-like skin inflammation in the oxazolone-induced ACD model. Moreover, both PGE2 and IL-22 pathway genes were coordinately upregulated in human AD lesional skin but were at less than significant detection levels after corticosteroid or UVB treatments.

CONCLUSIONS

Our results define a crucial role for PGE2 in promoting ACD by facilitating IL-22 production from T cells.

Placenta‑derived mesenchymal stem cells improve airway hyperresponsiveness and inflammation in asthmatic rats by modulating the Th17/Treg balance

Mesenchymal stem cells (MSCs) possess reparative and immunoregulatory properties, representing a hope for stem cell-based treatments. However, the mechanisms by which transplanted MSCs affect T helper (Th)17/regulatory T cell (Treg) balance in asthma patients remain unclear. The aim of the present study was to assess the therapeutic effects of human placenta MSCs (hPMSCs) in asthma, and explore the underlying mechanisms; in addition, the impact of hPMSCs transplantation on Th17/Treg balance in lymph and serum samples from asthmatic animals was evaluated. Sprague-Dawley rats were sensitized and challenged with ovalbumin (OVA). Administration of hPMSCs from human placenta resulted in increased Th17 and Treg in lymph samples compared with peripheral blood specimens. Enhanced pause values in OVA-treated animals were significantly higher than those in the control and hPMSCs treatment groups. The numbers of total cells, macrophages, neutrophils, and eosinophils were markedly increased in the OVA group compared with those of control + hPMSCs and control groups. In addition, interleukin 10, forkhead box P3 (Foxp3) and Treg levels in lymph, peripheral blood and lung tissue samples from asthma rats were increased significantly following hPMSC transplantation. Furthermore, Foxp3 protein levels increased, while those of RAR-related orphan receptor γ (RORγt) decreased after hPMSCs transplantation compared with the asthma group. Reduced IL-17, RORγt and Th17 levels were accompanied by reduced inflammatory cell infiltration, sub-epithelial smooth layer attenuation and mucus production in lung tissues. These results suggest that hPMSCs may improve airway hyperresponsiveness and inflammation by regulating the Th17/Treg balance in rats with asthma.

Evidence for Involvement of IL-9 and IL-22 in Cows' Milk Allergy in Infants

Although allergic inflammation is characterized by a T helper (Th) 2-dominant immune response, the discovery of a role for new T cell subsets in inflammatory diseases has added an additional layer of complexity to the understanding of the pathogeneses of allergic diseases. We evaluated plasma cytokine profiles in infants with cows' milk allergy (CMA), who were being treated with an elimination diet. In a prospective, randomized and controlled study, infants (aged 8.4 ± 3.9 months) with CMA were treated with an elimination diet for 120 days, which replaced cows' milk with a hydrolysed soy protein formula (n = 26) or a free amino acid formula (n = 20). Blood samples were collected before treatment during active disease (T0) and after 120 days, when symptoms were absent (T1). Plasma cytokine concentrations were measured. Infants with CMA had higher plasma concentrations of interleukin (IL)-4 and IL-13 and lower concentrations of IL-9, IL-17A and interferon-γ, compared with healthy breast-fed infants. At T0, there was a positive correlation between blood eosinophil numbers and plasma concentrations of IL-4, IL-9, IL-17A and IL-22. Treatment with a cows' milk elimination diet resulted in a decrease in plasma IL-4, IL-9, IL-13 and IL-22 and an increase in plasma IL-17A. We conclude that IL-4 and IL-13 are elevated in active CMA. The association of IL-9 and IL-22 with eosinophilia, and the decrease in these two cytokines with cows' milk elimination, suggests that they both play a role in the symptoms observed in CMA and may be important targets for future interventions.

A systematic review of the role of interleukin-17 and the interleukin-20 family in inflammatory allergic skin diseases

PURPOSE OF REVIEW

Allergic skin diseases include atopic dermatitis/eczema, contact dermatitis, and drug hypersensitivity. Allergic skin diseases have a high prevalence. Atopic dermatitis is one of the most common inflammatory skin diseases and similar for allergic rhinitis and allergic asthma. Over a long period, allergic diseases have been regarded as immunoglobulin E-mediated T-helper-2 (Th2)-driven. But new cytokines and T cells have been discovered within the last years. In this systematic review, the focus is laid on interleukin-17 (IL-17) and the interleukin-20 (IL-20) family which appear to be fine-tuning the Th2-driven answer.

RECENT FINDINGS

IL-17 is a proinflammatory cytokine, which is produced by T cells. Primarily, IL-17 is produced by activated CD4+ cells, called Th-17 cells. IL-17 regulates keratinocyte expression of adhesion molecules and chemokines. IL-17 is involved in the pathogenesis of inflammatory diseases as psoriasis, arthritis, and inflammatory bowel diseases. In allergic diseases, the involvement of the TH17/IL17-pathway has only been recently described. Regarding the IL-20 family, IL-22 is the most interesting and the most studied cytokine in terms of allergic inflammatory disorders. IL-22 is produced by T-helper 22 cells, a new subset of CD4+ cells.

SUMMARY

IL-17 as well as IL-22 seem to play a role in the pathogenesis of allergic skin diseases.

Molecular and cellular discoveries in inflammatory dermatoses

It was no earlier than 1986 that T helper (Th)1 and Th2 cells were described for the first time, opening the field of lymphocyte diversity and the investigation of the physiopathology of inflammatory diseases such as atopic dermatitis and psoriasis. Since that time, much research has been carried out showing a very complex communication network leading to inflammatory responses. Nowadays, understanding the cellular and molecular components of the inflammatory network and of the different crosstalks not only for groups of diseases but also for the individual patient is mandatory for developing and personalizing treatments. The aim of the present proceeding was to provide an update concerning some of the most recent molecular and cellular discoveries in inflammatory skin diseases and especially of AD.

The role of iNKT cells on the phenotypes of allergic airways in a mouse model

iNKT cells and mast cells have both been implicated in the syndrome of allergic asthma through their activation-induced release of Th2 type cytokines and secretion of histamine and other mediators, respectively, which can promote airways hyperresponsiveness (AHR) to agents such as methacholine. However, a mechanistic link between iNKT cells and mast cell recruitment or activation has never been explored. Our objective was to determine whether iNKT cells are necessary for the recruitment of mast cells and if iNKT cells can influence the acute allergen induced bronchoconstriction (AIB) caused by mast cell mediator release. To do so, we pharmacologically eliminated iNKT cells using a specific antibody (NKT-14) and examined its impact on airway inflammation and physiological phenotype. In mice treated with NKT-14, the elimination of iNKT cells was sufficient to prevent AHR and pulmonary eosinophilic inflammation elicited by administration of the iNKT cell agonist αGalCer. In mice treated with NKT-14 and then sensitized and challenged with house dust mite extract (HDM), eliminating the iNKT cells significantly reduced both AHR and AIB but did not affect pulmonary inflammation, the mast cell population, nor the release of the mast cell mediators mast cell protease-1 and prostaglandin D2. We conclude that while iNKT cells contribute to the phenotype of allergic airways disease through the manifestation of AIB and AHR, their presence is not required for mast cell recruitment and activation, or to generate the characteristic inflammatory response subsequent to allergen challenge.

Expression of IL-22 in the Skin Causes Th2-Biased Immunity, Epidermal Barrier Dysfunction, and Pruritus via Stimulating Epithelial Th2 Cytokines and the GRP Pathway

Increased expression of Th22 cytokine IL-22 is a characteristic finding in atopic dermatitis (AD). However, the specific role of IL-22 in the pathogenesis of AD in vivo has yet to be elucidated. Consistent with observations in human AD, IL-22 was significantly increased in the AD skin of mice after epicutaneous sensitization to house dust mite allergen. Utilizing a skin-specific inducible transgenic system, we show in the present study that expression of IL-22 in the skin of mice caused an AD-like phenotype characterized by chronic pruritic dermatitis associated with Th2-biased local and systemic immune responses, downregulation of epidermal differentiation complex genes, and enhanced dermatitis upon epicutaneous allergen exposure. IL-22 potently induced the expression of gastrin-releasing peptide (GRP), a neuropeptide pruritogen, in dermal immune cells and sensory afferents and in their skin-innervating sensory neurons. IL-22 also differentially upregulated the expression of GRP receptor (GRPR) on keratinocytes of AD skin. The number of GRP+ cells in the skin correlated with the AD severity and the intensity of pruritus. IL-22 directly upregulated the expression of epithelial-derived type 2 cytokines (thymic stromal lymphopoietin and IL-33) and GRP in primary keratinocytes. Furthermore, GRP not only strongly induced thymic stromal lymphopoietin but it also increased the expression of IL-33 and GRPR synergistically with IL-22. Importantly, we found that the expression of GRP was strikingly increased in the skin of patients with AD. These results indicate that IL-22 plays important pathogenic roles in the initiation and development of AD, in part through inducing keratinocyte production of type 2 cytokines and activation of the GRP/GRPR pathway.

Psoriasis and Atopic Dermatitis

Psoriasis and atopic dermatitis are common, chronic inflammatory skin diseases. We discuss several aspects of these disorders, including: risk factors; incidence and prevalence; the complex disease burden; and the comorbidities that increase the clinical significance of each disorder. We also focus on treatment management strategies and outline why individualized, patient-centered treatment regimens should be part of the care plans for patients with either psoriasis or atopic dermatitis. Finally, we conclude that, while our theoretical knowledge of the optimum care plans for these patients is increasingly sophisticated, this understanding is, unfortunately, not always reflected in daily clinical practice.

Allergies - A T cells perspective in the era beyond the TH1/TH2 paradigm

Allergic diseases have emerged as a major health care burden, especially in the western hemisphere. They are defined by overshooting reactions of an aberrant immune system to harmless exogenous stimuli. The T_H1/T_H2 paradigm assumes that a dominance of T_H2 cell activation and an inadequate T_H1 cell response are responsible for the development of allergies. However, the characterization of additional T helper cell subpopulations such as T_H9, T_H17, T_H22, T_HGM-CSF and their interplay with regulatory T cells suggest further layers of complexity. This review summarizes state-of-the-art knowledge on T cell diversity and their induction, while revisiting the T_H1/T_H2 paradigm. With respect to these numerous contributors, it offers a new perspective on the pathogenesis of asthma, allergic rhinitis (AR) and atopic dermatitis (AD) incorporating recent discoveries in the field of T cell plasticity.

Expansion of Th17 Cells by Human Mast Cells Is Driven by Inflammasome-Independent IL-1β

Mast cells (MC) are most well known for their role in innate immune responses. However, MC are increasingly recognized as important regulators of adaptive immune responses, especially in setting the outcome of T cell responses. In this study we determined the effect of MC on cytokine production by naive and memory human Th cells. CD4⁺ T cells were cultured with MC supernatant or control medium, after which cytokine production by T cells was determined. Supernatant of activated MC specifically increased the number of IL-17-producing T cells. This enhancement of Th17 cell number was specifically observed for the memory CD4⁺ T cell population and not for the naive CD4⁺ T cell population. The effect of MC was inhibited for ∼80% by blocking Abs to IL-1β and the rIL-1R antagonist anakinra. Importantly, secretion of active IL-1β by MC was independent of caspase activity, indicating that Th17 cell expansion by MC occurred through inflammasome-independent IL-1β. Together, these studies reveal a role for human MC in setting the outcome of T cell responses through release of caspase-independent IL-1β, and provide evidence for a novel contribution of MC in boosting the Th17 axis in mucosal immune responses.

Genetic Basis of Irritant Susceptibility in Health Care Workers

OBJECTIVE

The aim of this study was to investigate the association of single nucleotide polymorphisms (SNPs) within genes involved in inflammation, skin barrier integrity, signaling/pattern recognition, and antioxidant defense with irritant susceptibility in a group of health care workers.

METHODS

The 536 volunteer subjects were genotyped for selected SNPs and patch tested with three model irritants: sodium lauryl sulfate (SLS), sodium hydroxide (NaOH), and benzalkonium chloride (BKC). Genotyping was performed on genomic DNA using Illumina Goldengate custom panels.

RESULTS

The ACACB (rs2268387, rs16934132, rs2284685), NTRK2 (rs10868231), NTRK3 (rs1347424), IL22 (rs1179251), PLAU (rs2227564), EGFR (rs6593202), and FGF2 (rs308439) SNPs showed an association with skin response to tested irritants in different genetic models (all at P < 0.001). Functional annotations identified two SNPs in PLAU (rs2227564) and ACACB (rs2284685) genes with a potential impact on gene regulation. In addition, EGF (rs10029654), EGFR (rs12718939), CXCL12 (rs197452), and VCAM1 (rs3917018) genes showed an association with hand dermatitis (P < 0.005).

CONCLUSIONS

The results demonstrate that genetic variations in genes related to inflammation and skin homeostasis can influence responses to irritants and may explain inter-individual variation in the development of subsequent contact dermatitis.

Thiol redox chemistry: role of protein cysteine oxidation and altered redox homeostasis in allergic inflammation and asthma

Asthma is a pulmonary disorder, with an estimated 300 million people affected worldwide. While it is thought that endogenous reactive oxygen species (ROS) and reactive nitrogen species (RNS) such as hydrogen peroxide and nitric oxide, are important mediators of natural physiological processes, inflammatory cells recruited to the asthmatic airways have an exceptional capacity for producing a variety of highly reactive ROS and RNS believed to contribute to tissue damage and chronic airways inflammation. Antioxidant defense systems form a tightly regulated network that maintains the redox environment of the intra- as well as extracellular environment. Evidence for an oxidant-antioxidant imbalance in asthmatic airways is demonstrated in a number of studies, revealing decreased total antioxidant capacity as well as lower levels of individual antioxidants. Thiols in the form of GSH and sulfhydryl groups of proteins are among the most susceptible oxidant-sensitive targets, and hence, studies investigating protein thiol redox modifications in biology and disease have emerged. This perspective offers an overview of the combined efforts aimed at the elucidation of mechanisms whereby cysteine oxidations contribute to chronic inflammation and asthma, as well as insights into potential cysteine thiol-based therapeutic strategies.

Food allergy in mice is modulated through the thymic stromal lymphopoietin pathway

Background

Thymic stromal lymphopoietin (TSLP) is involved in the pathogenesis of allergic reactions in the skin and the lung. Nevertheless, data on the role of TSLP in food allergy are scarce. We explored the role of TSLP in a mouse model with oral sensitization and oral challenge eliciting food allergy.

Methods

TSLP receptor (TSLPR)−/− mice and wild type mice were orally sensitized to β-lactoglobulin in presence of cholera toxin (CT) or CT alone. The elicited immune response was characterized in vitro and the mice were subsequently challenged with the antigen. Lymphocytes from various locations in the gut were activated either by the antigen or by CT and assayed for cytokine secretion.

Results

Here we report that TSLPR−/− are less prone to generate food-induced reactions in conjunction with a decreased antigen-specific IgG1, but not IgE response. In addition, mesenteric lymphnode lymphocytes of TSLPR−/− mice were secreting lower quantities of IL-4, IL-5 and IL-10 after in vivo Ag activation, whereas higher numbers of IL-17 secreting cells were observed. Similarly, activation by the Th2-type adjuvant cholera toxin resulted in an increased frequency of IL-12 and IL-17 secreting lamina propria and mesenteric lymphocytes, together with increased production of IL-12 by activated dendritic cells in TSLPR−/− mice.

Conclusions

TSLP can be considered as an essential, but not exclusive, mediator for elicitation of food allergy in mice, as well as a potential target for future therapeutic interventions.

Th-17 regulatory cytokines inhibit corticosteroid induced airway structural cells apoptosis

Background

Although corticosteroid is a powerful anti-inflammatory drug that is used widely to control asthma, still severe asthmatics can develop steroid resistance. Airway fibroblasts are quite resistant to steroids during Idiopathic pulmonary fibrosis (IPF) and fibrosis in asthmatic lungs is not always controlled. Th-17 regulatory cytokine which are elevated in lung tissues of asthmatics were shown to enhance the survival of various types of cells. STAT factors are central to this anti-apoptotic function. However, it is not yet clear whether these cytokines contribute to steroid hypo-responsiveness in asthma. Therefore, in this study, we investigated the ability of Th-17 regulatory cytokines, specifically IL-21, IL22 and IL23, to protect structural airway cells against dexamethasone-induced apoptosis.

Methods

Primary human fibroblasts, ASM cells, and lung endothelial cells line were treated with IL-21, IL-22, and IL-23 cytokines before incubation with dexamethasone and the level of apoptosis was determined by measuring cellular Annexin-V using Flow cytometry.

Results

Our data indicated that treatment with Th-17 regulatory cytokines was effective in inhibiting induced apoptosis for both fibroblasts and endothelial cells but not ASM cells. STAT3 phosphorylation levels were also upregulated in fibroblasts and endothelial upon treatment with these cytokines. Interestingly, inhibiting STAT3 phosphorylation abrogated IL-21, IL-22, and IL-23 anti-apoptotic effect on fibroblasts and endothelial cells.

Conclusions

This data suggest that Th-17 regulatory cytokines may play a critical role in regulating the survival of fibroblasts during asthma, IPF as well as other chronic lung inflammatory diseases leading to enhanced fibrosis. Accordingly, findings of this paper may pave the way for more extensive research on the role of these regulatory cytokines in fibrosis development in various chronic inflammatory diseases.

Molecular Mechanisms of Airway Hyperresponsiveness in a Murine Model of Steroid-Resistant Airway Inflammation

IL-13 and IL-17A, produced mainly by Th2 and Th17 cells, respectively, have an influential role in asthma pathogenesis. We examined the role of IL-13 and IL-17A in mediating airway hyperresponsiveness (AHR), lung inflammation, and mucus metaplasia in a dual Th2/Th17 model of asthma. IL-13 and/or IL-17A were neutralized using mAbs. Th2/Th17 adoptive transfer induced a mixed asthma phenotype characterized by elevated eosinophilia and neutrophilia, tissue inflammation, mucus metaplasia, and AHR that were partially reversible with steroid treatment. Pulmonary inflammation and quasi-static lung compliance were largely unaffected by neutralization of IL-13 and/or IL-17A. However, neutralization of IL-13 alone or in combination with IL-17A significantly attenuated AHR and mucus metaplasia. Further, STAT6 activation was attenuated following IL-13 and IL-13/IL-17A Ab treatment. We next assessed the role of STAT6 in Th2/Th17-mediated allergic airway disease using STAT6(-/-) mice. STAT6(-/-) mice adoptively transferred with Th2/Th17 cells had decreased AHR compared with controls. These data suggest that IL-13 drives AHR and mucus metaplasia in a STAT6-dependent manner, without directly contributing to airway or tissue inflammation. IL-17A independently contributes to AHR, but it only partially mediates inflammation and mucus metaplasia in a mixed Th2/Th17 model of steroid-resistant asthma.

Non-redundant roles for Th17 and Th22 cells in multiple myeloma clinical correlates

We recently reported that in multiple myeloma increased Th22 cell frequencies correlate with poor prognosis. Here we show that within the same patients' cohort Th17 cells associate with bone disease and not with prognosis. Thus, we propose that Th22 and Th17 cells play non-redundant roles in multiple myeloma and constitute independent therapeutic targets.

Dynamic control of Th2 cell responses by STAT3 during allergic lung inflammation in mice

Signal transducer and activator of transcription (STAT) family molecules play essential roles during the differentiation of helper T cells from naïve precursors. Although the role of STAT3 in driving Th17 cell polarization has been well established, its role on Th2 responses to allergens remains incompletely understood. By employing T cell-specific STAT3 deficient mice, we demonstrate that STAT3 in T cells plays diverse role on Th2 cells depending on their locations in an animal model of allergic asthma. In the bronchial lymph nodes, STAT3-deficient T cells produced significantly reduced levels of Th2 cytokines. The frequencies of Th2 cells among CD4(+) T cells in the lung were comparable between STAT3-sufficient and STAT3-deficient T cells. By contrast, STAT3-deficient T cells in the airway exhibited significantly enhanced production of Th2 cell cytokines compared to STAT3-sufficient T cells. Interestingly, a major population of IL-4/5 producers among STAT3-deficient T cells in the airway co-produced IFNγ. The frequency of Th17 cells was significantly diminished whereas that of Th1 cells was increased in all the lung-associated tissues. Our results demonstrate the dynamic and opposing roles of STAT3 during the development of Th2 cells from bronchial lymph nodes to the airway and propose the need of careful consideration on STAT3-targeting approaches for the treatment of lung diseases.

Parasites-allergy paradox: Disease mediators or therapeutic modulators

The noticeable phenomenon of an increased frequency of immune-inflammatory disorders, in the industrialized world, has led to the implication of parasitic infections in the pathophysiology of these diseases. Most of the studies investigated the infection connection to allergy have centered on helminthes. Parasitic helminthes are a group of metazoans that are evolutionary diverse, yet converge to evolve common modes of immunomodulation. Helminth immunoregulation is mainly mediated by a regulatory response including Treg and Breg cells with alternatively-activated macrophages. There is increasing evidence for a causal relationship between helminth infection and allergic hyporesponsiveness, however, conflicting data are still generating. The helminth immunoregulation seems to be species-specific and phase-specific. It depends on the stage of the clinical disease which correlates with a corresponding parasitic stage (egg, larva or mature adult). Here, we review the cellular and molecular mechanisms utilized by helminthes to manipulate the immune system and the consequent bystander immunomodulatory responses toward environmental allergens. We especially focus on parasitic species and molecules involved in the modulation of allergic disorders and summarize the experimental and clinical trials using them as therapeutic agents. We also discuss the potentials and obstacles, for helminthes and/or their derived molecules, to emerge as novel therapeutic modalities.

Therapeutic effects of resveratrol in a mouse model of HDM-induced allergic asthma

Asthma is an inflammatory disease of the lungs characterized by airway remolding. In this study, we examined whether resveratrol exerts protective effects on allergic asthma in a murine model. To investigate the effects of resveratrol on allergic airway inflammation in house dust mite (HDM)-induced mouse asthma and explore its mechanism, a chronic asthma mouse model was established by intranasally administering extracts of HDM (25μg of protein in 10μl of saline) for 5days/week for up to 7 consecutive weeks. Resveratrol (50mg/kg body weight), dexamethasone (1mg/kg body weight) or a vehicle was administered orally 1h before antigen challenges for up to 2weeks. Compared with the HDM-induced mice, the level of TNF-α of the BALF in the resveratrol+HDM-treated mice had obviously decreased. Histological examination of the lung tissue revealed that the resveratrol treatments attenuated the fibrotic response and airway inflammation. In addition, resveratrol inhibited the expression of the Syk protein and degranulation in mast cells. The presented findings collectively suggest that resveratrol has a therapeutic effect on mouse allergic asthma, and its mechanism of action might be related to reducing the production of the Syk protein.

Filaggrin silencing by shRNA directly impairs the skin barrier function of normal human epidermal keratinocytes and then induces an immune response

The objective of this study was to investigate whether a single defect in skin barrier function simulated by filaggrin silencing could induce Th2-predominant inflammation. Filaggrin gene expression was silenced in cultured normal human epidermal keratinocytes (NHEKs) using small hairpin RNA (shRNA, GTTGGCTCAAGCATATTATTT). The efficacy of silencing was confirmed by polymerase chain reaction (PCR) and Western blotting. Filaggrin-silenced cells (LV group), shRNA control cells (NC group), and noninfected cells (Blank group) were evaluated. The expression of cornified cell envelope-related proteins, including cytokeratin (CK)-5, -10, -14, loricrin, involucrin, and transglutaminase (TGM)-1, was detected by Western blotting. Interleukins (IL)-2, IL-4, IL-5, IL-12p70, IL-13, and interferon-gamma (IFN-γ) were detected by enzyme-linked immunosorbent assay (ELISA). After filaggrin was successfully silenced by shRNA, the expressions of CK-5, -10, -14, involucrin, and TGM-1 in NHEKs were significantly downregulated compared to the Blank and NC groups (P<0.05 or P<0.01); only loricrin expression was markedly upregulated (P<0.01). Filaggrin silencing also resulted in significant increases of IL-2, IL-4, IL-5, and IL-13 (P<0.05 or P<0.01), and significant decreases of IL-12p70 and IFN-γ (P<0.01) compared with cells in the Blank and NC groups. Filaggrin silencing impaired normal skin barrier function mainly by targeting the cornified cell envelope. The immune response after filaggrin silencing was characterized by Th2 cells, mainly because of the inhibition of IFN-γ expression. Lack of filaggrin may directly impair skin barrier function and then further induce the immune response.

Molecular biology of atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease with specific genetic and immunological mechanisms. The rapid development of new techniques in molecular biology had ushered in new discoveries on the role of cytokines, chemokines, and immune cells in the pathogenesis of AD. New polymorphisms of AD are continually being reported in different populations. The physical and immunological barrier of normal intact skin is an important part of the innate immune system that protects the host against microbials and allergens that are associated with AD. Defects in the filaggrin gene FLG may play a role in facilitating exposure to allergens and microbial pathogens, which may induce Th2 polarization. Meanwhile, Th22 cells also play roles in skin barrier impairment through IL-22, and AD is often considered to be a Th2/Th22-dominant allergic disease. Mast cells and eosinophils are also involved in the inflammation via Th2 cytokines. Release of pruritogenic substances by mast cells induces scratching that further disrupts the skin barrier. Th1 and Th17 cells are mainly involved in chronic phase of AD. Keratinocytes also produce proinflammatory cytokines such as thymic stromal lymphopoietin (TSLP), which can further affect Th cells balance. The immunological characteristics of AD may differ for various endotypes and phenotypes. Due to the heterogeneity of the disease, and the redundancies of these mechanisms, our knowledge of the pathophysiology of the disease is still incomplete, which is reflected by the absence of a cure for the disease.