Airway IL-1ß associates with IL-5 production following dust mite allergen inhalation in humans.

BACKGROUND: Preclinical studies implicate interleukin (IL)-1ß as a key mediator of asthma and have shown the efficacy of IL-1 antagonism for treatment of allergic airway inflammation; human studies in this area are lacking. OBJECTIVES: Our aim was to study the relationship of airway IL-1ß to features of acute allergen-induced asthma exacerbation in humans. METHODS: Dust mite-allergic adults with mild asthma underwent inhalation challenge with Dermatophagoides farinae. Fractional exhaled nitric oxide (FeNO), induced sputum and peripheral blood samples were obtained pre- and 24 h post-challenge. Spirometry was performed before and throughout the challenge at 10-min intervals, and allergen responsiveness was defined by a 20% fall in Forced Expiratory Volume in 1 s (FEV1). Sputum samples were analyzed for inflammatory cells, cytokines and chemokines. Multiple linear regression was employed to test the association between sputum IL-1ß concentration and biomarkers of T helper type 2 (T2)-dominant inflammation. RESULTS: Fourteen volunteers underwent inhaled allergen challenge. Allergen responsive volunteers showed a greater positive change in IL-1ß in sputum following allergen challenge compared to non-responders. Higher pre-challenge sputum IL-1ß was associated with greater increase in sputum IL-5 (p = 0.004), sputum eosinophils (p = 0.001) and blood IL-5 (p = 0.003) following allergen challenge. Allergen-induced sputum IL-1ß production was significantly associated with sputum and blood IL-5 (p < 0.001 and p = 0.007, respectively), sputum IL-4 (p = 0.001), IL-13 (p = 0.026), eosinophils (p = 0.008) and FeNO (p = 0.03). CONCLUSIONS: The positive association between production of IL-1ß and biomarkers of T2 inflammation, particularly IL-5, in humans is consistent with work in animal models that demonstrates a link between IL-1ß and the pathophysiology of allergic asthma. The role of IL-1ß in human asthma warrants further study.

Ding Chuan Tang Attenuates Airway Inflammation and Eosinophil Infiltration in Ovalbumin-Sensitized Asthmatic Mice.

Asthma is a T helper 2 (Th2) cell-associated chronic inflammatory diseases characterized with airway obstruction, increased mucus production, and eosinophil infiltration. Conventional medications for asthma treatment cannot fully control the symptoms, and potential side effects are also the concerns. Thus, complement or alternative medicine (CAM) became a new option for asthma management. Ding Chuan Tang (DCT) is a traditional Chinese herbal decoction applied mainly for patients with coughing, wheezing, chest tightness, and asthma. Previously, DCT has been proved to improve children airway hyperresponsiveness (AHR) in a randomized and double-blind clinical trial. However, the mechanisms of how DCT alleviates AHR remain unclear. Since asthmatic features such as eosinophil infiltration, IgE production, and mucus accumulation are relative with Th2 responses, we hypothesized that DCT may attenuate asthma symptoms through regulating Th2 cells. Ovalbumin (OVA) was used as a stimulant to sensitize BALB/c mice to establish an asthmatic model. AHR was detected one day before sacrifice. BALF and serum were collected for immune cell counting and antibody analysis. Splenocytes were cultured with OVA in order to determine Th2 cytokine production. Lung tissues were collected for histological and gene expression analyses. Our data reveal that DCT can attenuate AHR and eosinophil accumulation in the 30-day sensitization asthmatic model. Histological results demonstrated that DCT can reduce cell infiltration and mucus production in peribronchial and perivascular site. In OVA-stimulated splenocyte cultures, a significant reduction of IL-5 and IL-13 in DCT-treated mice suggests that DCT may alleviate Th2 responses. In conclusion, the current study demonstrates that DCT has the potential to suppress allergic responses through the reduction of mucus production, eosinophil infiltration, and Th2 activity in asthma.

An inhibitory immunoreceptor, Allergin-1, suppresses FITC-induced type 2 contact hypersensitivity.

Although allergic contact dermatitis (ACD) is the most common T cell-mediated inflammatory responses against an allergen in the skin, the pathogenesis of ACD remains incompletely understood. In the sensitization phase in ACD, hapten-bearing dermal dendritic cells (DCs) play a pivotal role in the transport of an antigen to the lymph nodes (LNs), where they present the antigen to naïve T cells. Here we report that Allergin-1, an inhibitory immunoreceptor containing immunoreceptor tyrosine-based inhibitory motif (ITIM) in the cytoplasmic region, is highly expressed on dermal DCs. Mice deficient in Allergin-1 exhibited exacerbated fluorescein isothiocyanate (FITC)-induced type 2 contact hypersensitivity (CHS) such as ear swelling and skin eosinophilia. Allergin-1-deficient mice also showed larger numbers of CD4+ T cells and FITC-bearing DCs and greater expressions of type 2 cytokines, including IL-5, IL-10 and IL-13, in the draining LNs than did wild type mice. In sharp contrast, Allergin-1-deficient mice showed comparable level of type 1 CHS induced by 2,4-dinitrofluorobenzene (DNFB). These results suggest that Allergin-1 on dermal DC inhibits type 2, but not type 1, immune responses in the sensitization phase of CHS.

Interplay Between the IL-33/ST2 Axis and Bone Marrow ILC2s in Protease Allergen-Induced IL-5-Dependent Eosinophilia.

Background: Eosinophils develop from CD34+ progenitor cells in the bone marrow under the influence of interleukin (IL)-5. Several cell types produce IL-5, including type 2 innate lymphoid cells (ILC2s). The alarmin cytokine IL-33 is known to activate ILC2s in mucosal tissues, but little is known about IL-33-responsive ILC2s in the bone marrow in allergen-induced airway inflammation. Methods: Wild type (WT) and Rag1 deficient (Rag1-/-) mice, which lack mature T and B cells, received intranasal doses of papain to induce acute allergic inflammation. In some experiments, mice were pre-treated with anti-IL-5 prior to the papain challenge. Furthermore, recombinant IL-33 was administered to WT mice, Rag1-/- mice, lymphocyte deficient mice (Rag2-/-Il2rg-/-) and to ex vivo whole bone marrow cultures. Bone marrow eosinophils and ILC2s were analyzed by flow cytometry. Eosinophil count was assessed by differential cell count and secreted IL-5 from bone marrow cells by ELISA. Results: Intranasal administration of papain or IL-33 increased the number of mature eosinophils in the bone marrow despite the absence of adaptive immune cells in Rag1-/- mice. In parallel, an increased number of eosinophils was observed in the airways together with elevated levels of Eotaxin-2/CCL24. Bone marrow ILC2s were increased after papain or IL-33 administration, whereas ILC2s was found to be increased at baseline in Rag1-/- mice compared to WT mice. An upregulation of the IL-33 receptor (ST2) expression on bone marrow ILC2s was observed after papain challenge in both Rag1-/- and WT mice which correlated to increased number of bone marrow eosinophilia. Furthermore, an increased number of ST2+ mature eosinophils in the bone marrow was observed after papain challenge, which was further dependent on IL-5. In addition, bone marrow-derived ILC2s from both mouse strains produced large amounts of IL-5 ex vivo after IL-33 stimulation of whole bone marrow cultures. In contrast, IL-33-induced bone marrow and airway eosinophilia were abolished in the absence of ILC2s in Rag2-/-Il2rg-/- mice and no production of IL-5 was detected in IL-33-stimulated bone marrow cultures. Conclusion: These findings establish bone marrow ILC2s and the IL-33/ST2 axis as promising targets for modulation of uncontrolled IL-5-dependent eosinophilic diseases including asthma.

Tumor-Derived Lactic Acid Contributes to the Paucity of Intratumoral ILC2s.

Group 2 innate lymphoid cells (ILC2s) are abundant in non-lymphoid tissues and increase following infectious and inflammatory insults. In solid tumors, however, ILC2s constitute a relatively small proportion of immune cells. Here, we show, using melanoma as a model, that while the IL-33/IL C2/eosinophil axis suppresses tumor growth, tumor-derived lactate attenuates the function and survival of ILC2s. Melanomas with reduced lactate production (LDHAlow) are growth delayed and typified by an increased number of ILC2s compared with control tumors. Upon IL-33 stimulation, ILC2s accompanied by eosinophils more effectively restrain the growth of LDHAlow tumors than control melanomas. Furthermore, database analysis reveals a negative correlation between the expression of LDHA and markers associated with ILC2s and the association of high expression of IL33 and an eosinophil marker SIGLEC8 with better overall survival in human cutaneous melanoma patients. This work demonstrates that the balance between the IL-33/ILC2/eosinophil axis and lactate production by tumor cells regulates melanoma growth.

Transcription factor and cytokine regulation of eosinophil lineage commitment.

PURPOSE OF REVIEW: Lineage commitment is governed by instructive and stochastic signals, which drive both active induction of the lineage program and repression of alternative fates. Eosinophil lineage commitment is driven by the ordered interaction of transcription factors, supported by cytokine signals. This review summarizes key findings in the study of eosinophil lineage commitment and examines new data investigating the factors that regulate this process. RECENT FINDINGS: Recent and past studies highlight how intrinsic and extrinsic signals modulate transcription factor network and lineage decisions. Early action of the transcription factors C/EBPα and GATA binding protein-1 along with C/EBPε supports lineage commitment and eosinophil differentiation. This process is regulated and enforced by the pseudokinase Trib1, a regulator of C/EBPα levels. The cytokines interleukin (IL)-5 and IL-33 also support early eosinophil development. However, current studies suggest that these cytokines are not specifically required for lineage commitment. SUMMARY: Together, recent evidence suggests a model where early transcription factor activity drives expression of key eosinophil genes and cytokine receptors to prime lineage commitment. Understanding the factors and signals that control eosinophil lineage commitment may guide therapeutic development for eosinophil-mediated diseases and provide examples for fate choices in other lineages.

A stromal cell niche sustains ILC2-mediated type-2 conditioning in adipose tissue.

Group-2 innate lymphoid cells (ILC2), type-2 cytokines, and eosinophils have all been implicated in sustaining adipose tissue homeostasis. However, the interplay between the stroma and adipose-resident immune cells is less well understood. We identify that white adipose tissue-resident multipotent stromal cells (WAT-MSCs) can act as a reservoir for IL-33, especially after cell stress, but also provide additional signals for sustaining ILC2. Indeed, we demonstrate that WAT-MSCs also support ICAM-1-mediated proliferation and activation of LFA-1-expressing ILC2s. Consequently, ILC2-derived IL-4 and IL-13 feed back to induce eotaxin secretion from WAT-MSCs, supporting eosinophil recruitment. Thus, MSCs provide a niche for multifaceted dialogue with ILC2 to sustain a type-2 immune environment in WAT.

Treatment of established TH2 cells with 4µ8c, an inhibitor of IRE1α, blocks IL-5 but not IL-4 secretion.

BACKGROUND: T cell activation induces ER stress and upregulates Inositol Requiring Enzyme 1 alpha (IRE1α), an activator of the unfolded protein response (UPR) pathway. Inhibition of IRE1α RNase activity in activated CD4+ splenocytes from naïve mice, via treatment of the cells with the commercially available drug 4µ8c upon activation, results in the reduction of the secretion of proteins IL-5, IL-4, and IL-13. Prior to this work, it was unknown if 4µ8c could inhibit TH2 cytokines in established TH2 cells, cells that are crucial in promoting disease in severe asthma. RESULTS: Treatment of a mouse T helper (TH)2 cell line and differentiated human TH2 cells with 4µ8c resulted in inhibition of IL-5, but not IL-4, as measured by ELISA. The reduced cytokine expression was not due to differences in mRNA stability or mRNA levels; it appears to be due to a defect in secretion, as the cells produce cytokines IL-5 as measured by flow cytometry and western blot. CONCLUSION: These data suggest that the inhibition of IL-5 was due to post-translational processes. IL-5 promotes chronic, inflammatory asthma, and 4µ8c blocks its expression in T cells in vitro. Future studies will determine if 4µ8c treatment can ameliorate the effects of the cytokine IL-5 in a disease model.

Absence of NOD2 receptor predisposes to intestinal inflammation by a deregulation in the immune response in hosts that are unable to control gut dysbiosis.

Mutations in NOD2 predisposes to Inflammatory Bowel Diseases. Therefore, we evaluated the role of this innate receptor in the modulation of immunity in face of host microbiota changes. NOD2-/- mice presented higher susceptibility to experimental colitis than WT, with increased CD4 and CD8 T lymphocytes in the spleen. NOD2 deficiency also led to reduced Th17-related cytokines in the colon, with overall augmented IFN-γ in the gut and spleen. Nonetheless, there was increased frequency of CD4+IL-4+ cells in the mesenteric lymph nodes besides elevated CTLA-4 and FoxP3 regulatory markers in the spleen of NOD2-/- mice, although it did not result in more efficient control of gut inflammation. Indeed, these animals also had augmented IL-1ß and IL-5 in the peritoneum, indicating that this receptor may be important to control bacteria translocation too. Microbiota exchanging between cohoused WT and NOD2-/- mice led to colitis worsening in the absence of the receptor, while antibiotic therapy in WT mice abrogated this effect. Then, not only the genetic mutation confers increased susceptibility to inflammation, but it is also influenced by the microbiota harbored by the host. Finally, NOD2-/- mice are more prone to intestinal inflammation due to deregulated immune response and increased susceptibility to colitogenic bacteria.

Dynamic changes in intrathymic ILC populations during murine neonatal development.

Members of the innate lymphoid cell (ILC) family have been implicated in the development of thymic microenvironments and the recovery of this architecture after damage. However, a detailed characterization of this family in the thymus is lacking. To better understand the thymic ILC compartment, we have utilized multiple in vivo models including the fate mapping of inhibitor of DNA binding-2 (Id2) expression and the use of Id2 reporter mice. Our data demonstrate that ILCs are more prominent immediately after birth, but were rapidly diluted as the T-cell development program increased. As observed in the embryonic thymus, CCR6+ NKp46- lymphoid tissue inducer (LTi) cells were the main ILC3 population present, but numbers of these cells swiftly declined in the neonate and ILC3 were barely detectable in adult thymus. This loss of ILC3 means ILC2 are the dominant ILC population in the thymus. Thymic ILC2 were able to produce IL-5 and IL-13, were located within the medulla, and did not result from ILC3 plasticity. Furthermore, in WT mice, thymic ILC2 express little RANKL (receptor activator of nuclear factor kappa-B ligand) arguing that functionally, these cells provide different signals to LTi cells in the thymus. Collectively, these data reveal a dynamic switch in the ILC populations of the thymus during neonatal development.

CARD9S12N facilitates the production of IL-5 by alveolar macrophages for the induction of type 2 immune responses.

The adaptor CARD9 functions downstream of C-type lectin receptors (CLRs) for the sensing of microbial infection, which leads to responses by the TH1 and TH17 subsets of helper T cells. The single-nucleotide polymorphism rs4077515 at CARD9 in the human genome, which results in the substitution S12N (CARD9S12N), is associated with several autoimmune diseases. However, the function of CARD9S12N has remained unknown. Here we generated CARD9S12N knock-in mice and found that CARD9S12N facilitated the induction of type 2 immune responses after engagement of CLRs. Mechanistically, CARD9S12N mediated CLR-induced activation of the non-canonical transcription factor NF-κB subunit RelB, which initiated production of the cytokine IL-5 in alveolar macrophages for the recruitment of eosinophils to drive TH2 cell-mediated allergic responses. We identified the homozygous CARD9 mutation encoding S12N in patients with allergic bronchopulmonary aspergillosis and revealed activation of RelB and production of IL-5 in peripheral blood mononuclear cells from these patients. Our study provides genetic and functional evidence demonstrating that CARD9S12N can turn alveolar macrophages into IL-5-producing cells and facilitates TH2 cell-mediated pathologic responses.

Type 2 Cysteinyl Leukotriene Receptors Drive IL-33-Dependent Type 2 Immunopathology and Aspirin Sensitivity.

Cysteinyl leukotrienes (cysLTs) facilitate mucosal type 2 immunopathology by incompletely understood mechanisms. Aspirin-exacerbated respiratory disease, a severe asthma subtype, is characterized by exaggerated eosinophilic respiratory inflammation and reactions to aspirin, each involving the marked overproduction of cysLTs. Here we demonstrate that the type 2 cysLT receptor (CysLT2R), which is not targeted by available drugs, is required in two different models to amplify eosinophilic airway inflammation via induced expression of IL-33 by lung epithelial cells. Endogenously generated cysLTs induced eosinophilia and expanded group 2 innate lymphoid cells (ILC2s) in aspirin-exacerbated respiratory disease-like Ptges-/- mice. These responses were mitigated by deletions of either Cysltr2 or leukotriene C4 synthase (Ltc4s). Administrations of either LTC4 (the parent cysLT) or the selective CysLT2R agonist N-methyl LTC4 to allergen sensitized wild-type mice markedly boosted ILC2 expansion and IL-5/IL-13 generation in a CysLT2R-dependent manner. Expansion of ILC2s and IL-5/IL-13 generation reflected CysLT2R-dependent production of IL-33 by alveolar type 2 cells, which engaged in a bilateral feed-forward loop with ILC2s. Deletion of Cysltr1 blunted LTC4-induced ILC2 expansion and eosinophilia but did not alter IL-33 induction. Pharmacological blockade of CysLT2R prior to inhalation challenge of Ptges-/- mice with aspirin blocked IL-33-dependent mast cell activation, mediator release, and changes in lung function. Thus, CysLT2R signaling, IL-33-dependent ILC2 expansion, and IL-33-driven mast cell activation are necessary for induction of type 2 immunopathology and aspirin sensitivity. CysLT2R-targeted drugs may interrupt these processes.

Characteristics of lower airway inflammatory changes in the minimal persistent inflammation of allergic rhinitis in mice.

OBJECTIVE: This study aims to establish an experimental mouse model of minimal persistent inflammation (MPI), observe the features of inflammation and hyper-responsiveness of the upper/lower airways, and explore the relationship between inflammation and hyper-responsiveness in the upper/lower airways. METHODS: Sixty-four female BALB/c mice were randomly divided into four groups: allergic rhinitis (AR) group as positive control, MPI group, negative control group and blank control group. Mice were given high and low-concentrated ovalbumin solution after basic and intensive sensitization to establish AR model and MPI model. Nasal mucosa and lung tissues were stained to observe eosinophil infiltration, goblet cell hyperplasia, and expression of intercellular adhesion molecule 1 (ICAM-1). Airway hyper-responsiveness was assessed. Levels of specific immunoglobulin E (sIgE), interleukin (IL)-4 and IL-5 in peripheral blood, nasal lavage fluid (NLF), and bronchoalveolar lavage fluid (BALF) were detected by Enzyme-linked immunosorbent assay. RESULTS: The eosinophil infiltration and expression of ICAM-1 on nasal mucosa and in lung tissues in the AR and MPI groups were significantly elevated compared to control groups. Goblet cells count increased only in the nasal mucosa and not in lung tissues. Eosinophil and neutrophil count of NLF and BALF in the AR and MPI groups increased significantly compared to control groups. Level of IL-4 did not increase significantly, but sIgE and IL-5 did. CONCLUSIONS: Mice in the MPI status exhibits lower airway inflammation and hyper-responsiveness with increase in eosinophil count, goblet cells, ICAM-1, IL-4, and IL-5. These results provide further evidence for the importance of MPI of AR in lower airway diseases.

Hox5 Paralogous Genes Modulate Th2 Cell Function during Chronic Allergic Inflammation via Regulation of Gata3.

Allergic asthma is a significant health burden in western countries, and continues to increase in prevalence. Th2 cells contribute to the development of disease through release of the cytokines IL-4, IL-5, and IL-13, resulting in increased airway eosinophils and mucus hypersecretion. The molecular mechanisms behind the disease pathology remain largely unknown. In this study we investigated a potential regulatory role for the Hox5 gene family, Hoxa5, Hoxb5, and Hoxc5, genes known to be important in lung development within mesenchymal cell populations. We found that Hox5-mutant mice show exacerbated pathology compared with wild-type controls in a chronic allergen model, with an increased Th2 response and exacerbated lung tissue pathology. Bone marrow chimera experiments indicated that the observed enhanced pathology was mediated by immune cell function independent of mesenchymal cell Hox5 family function. Examination of T cells grown in Th2 polarizing conditions showed increased proliferation, enhanced Gata3 expression, and elevated production of IL-4, IL-5, and IL-13 in Hox5-deficient T cells compared with wild-type controls. Overexpression of FLAG-tagged HOX5 proteins in Jurkat cells demonstrated HOX5 binding to the Gata3 locus and decreased Gata3 and IL-4 expression, supporting a role for HOX5 proteins in direct transcriptional control of Th2 development. These results reveal a novel role for Hox5 genes as developmental regulators of Th2 immune cell function that demonstrates a redeployment of mesenchyme-associated developmental genes.

Associations of Genetic Polymorphisms Relevant to Metabolic Pathway of Vitamin D3 with Development and Prognosis of Childhood Bronchial Asthma.

This study was aimed at investigating the correlation between genetic polymorphisms relevant to metabolic pathway of vitamin D3 (VD3) and susceptibility to childhood bronchial asthma. Altogether 143 childhood patients with bronchial asthma and 143 healthy children of Chinese Han ethnicity were enrolled in this study. The key single-nucleotide polymorphisms (SNPs) were identified by HaploView 4.2 software and selected from previous investigations. Genomic DNAs were isolated from peripheral blood samples by using TaqMan Blood DNA kits. The genotyping of SNPs was performed by TaqMan SNPs genotyping assay. Odds ratios and corresponding 95% confidence intervals were calculated to evaluate the association between SNPs and susceptibility to bronchial asthma. Statistical analyses were conducted by using SPSS 13.0 software. Rs10766197 of CYP2R1, rs7041 and rs4588 of CG, rs4646536 of CYP27B1, rs2228570, rs7975232, and rs1544410 of VDR, as well as rs1805192 and rs10865710 of PPAR were shown to be significantly associated with increased risk of bronchial asthma. Besides, prognosis of childhood bronchial asthma, which was represented as Saint George Respiratory Questionnaire (SGRQ) scoring, was closely linked with CYP2R1 rs10766197, CYP27B1 rs4646536, VDR rs7975232, VDR rs1544410, PPAR rs1805192, and PPAR rs10865710. The haplotype analysis suggested that TA and CG of CG rs7041/rs4588, CA and AG of VDR rs7975232/rs1544410, and CC of PPAR rs1805192/rs10865710 were, respectively, correlated with levels of VD, IL-4, and IL-5. And only haplotypes of VDR showed associations with risk of bronchial asthma during childhood, whereas hardly any significance could be observed between the haplotypes and behavior of quality-of-life (SGRQ) scoring. Significant associations were found between rs10766197 of CYP2R1, rs7041 and rs4588 of CG, rs4646536 of CYP27B1, rs2228570, rs7975232, and rs1544410 of VDR, as well as rs1805192 and rs10865710 of PPAR and susceptibility to and prognosis of childhood bronchial asthma, providing novel targets for treating the disorder.

T Cell-Restricted Notch Signaling Contributes to Pulmonary Th1 and Th2 Immunity during Cryptococcus neoformans Infection.

Cryptococcus neoformans is a ubiquitous, opportunistic fungal pathogen but the cell signaling pathways that drive T cell responses regulating antifungal immunity are incompletely understood. Notch is a key signaling pathway regulating T cell development, and differentiation and functional responses of mature T cells in the periphery. The targeting of Notch signaling within T cells has been proposed as a potential treatment for alloimmune and autoimmune disorders, but it is unknown whether disturbances to T cell immunity may render these patients vulnerable to fungal infections. To elucidate the role of Notch signaling during fungal infections, we infected mice expressing the pan-Notch inhibitor dominant negative mastermind-like within mature T cells with C. neoformans Inhibition of T cell-restricted Notch signaling increased fungal burdens in the lungs and CNS, diminished pulmonary leukocyte recruitment, and simultaneously impaired Th1 and Th2 responses. Pulmonary leukocyte cultures from T cell Notch-deprived mice produced less IFN-γ, IL-5, and IL-13 than wild-type cells. This correlated with lower frequencies of IFN-γ-, IL-5-, and IL-13-producing CD4+ T cells, reduced expression of Th1 and Th2 associated transcription factors, Tbet and GATA3, and reduced production of IFN-γ by CD8+ T cells. In contrast, Th17 responses were largely unaffected by Notch signaling. The changes in T cell responses corresponded with impaired macrophage activation and reduced leukocyte accumulation, leading to diminished fungal control. These results identify Notch signaling as a previously unappreciated regulator of Th1 and Th2 immunity and an important element of antifungal defenses against cryptococcal infection and CNS dissemination.

Dysregulation of interleukin 5 expression in familial eosinophilia.

BACKGROUND: Familial eosinophilia (FE) is a rare autosomal dominant inherited disorder characterized by the presence of lifelong peripheral eosinophilia (>1500/µL). Mapped to chromosome 5q31-q33, the genetic cause of FE is unknown, and prior studies have failed to demonstrate a primary abnormality in the eosinophil lineage. OBJECTIVE: The aim of this study was to identify the cells driving the eosinophilia in FE. METHODS: Microarray analysis and real-time PCR were used to examine transcriptional differences in peripheral blood mononuclear cells (PBMC), and in purified cell subsets from affected and unaffected family members belonging to a single large kindred. Cytokine levels in serum and PBMC culture supernatants were assessed by suspension array multiplexed immunoassays. RESULTS: Whereas IL-5 mRNA expression was significantly increased in freshly isolated PBMC from affected family members, this was not accompanied by increased mRNA expression of other Th2 cytokines (IL-4 or IL-13). Serum levels of IL-5 and IL-5 receptor α, but not IgE, were similarly increased in affected family members. Of note, IL-5 mRNA expression was significantly increased in purified CD3+ CD4+, CD14+, CD19+, and ILC2 cells from affected family members, as were IL-5 protein levels in supernatants from both stimulated PBMC and ILC2 cultures. CONCLUSIONS: These data are consistent with the hypothesis that the eosinophilia in FE is secondary to dysregulation of IL-5 production in PBMC (and their component subsets).

Chromones: A Promising Ring System for New Anti-inflammatory Drugs.

The quest for safer anti-inflammatory drugs is still the focus of several medicinal chemistry programs. Chromones (4H-chromen-4-ones) are a group of naturally occurring compounds ubiquitous in plants, and the chromone core has proven to be a privileged scaffold in medicinal chemistry. Herein we provide an overview of the relevance of chromones as anti-inflammatory agents, specifically as inhibitors of cyclooxygenase (COX), 5-lipoxygenase (5-LOX), interleukin-5 (IL-5), and nitric oxide (. NO) production. Numerous structure-activity relationships and mechanisms of action are discussed. This review is therefore intended to provide a foundation for the design and synthesis of novel chromone-based compound libraries for further development into safer and more efficient anti-inflammatory agents.

Human eosinophils modulate peripheral blood mononuclear cell response to Schistosoma mansoni adult worm antigen in vitro.

High numbers of eosinophils are observed in parasitic infections and allergic diseases, where they are proposed to be terminally differentiated effector cells that play beneficial role in host defence, or cause harmful inflammatory response. Eosinophils have been associated with killing of schistosomulae in vitro, but there is growing evidence that eosinophils can play additional immuno-regulatory role. Here, we report results of a study that examines peripheral blood mononuclear cell (PBMC) cytokine responses to Schistosoma mansoni adult worm antigen (SWA) when stimulated alone or enriched with autologous eosinophils. Production of the Th-2 type cytokines interleukin (IL)-4, IL-5 and IL-13 was lower (P = 0·017, 0·018 and <0·001, respectively) in PBMC + eosinophil cultures than in PBMC-only cultures stimulated with SWA. Substantial levels of IL-13, IL-10, interferon gamma and tumour necrosis factor alpha were recorded in cultures of eosinophils, but none of these cytokines showed significant association with the observed eosinophil-induced drop in cytokine responses of PBMC. Transwell experiments suggested that the observed effect is due to soluble mediators that downmodulate production of Th-2 type cytokines. This study shows that eosinophils may down-modulate schistosome-specific Th-2 type cytokine responses in S. mansoni-infected individuals. The mechanism of this immune modulation remains to be elucidated.