The anti-inflammatory effects of interleukin-10 in allergic disease

In utero exposures to mint-flavored JUUL aerosol impair lung development and aggravate house dust mite-induced asthma in adult offspring mice

There are few reports concerning electronic nicotine delivery system (ENDS) use during pregnancy and no studies on asthma in prenatally JUUL-exposed offspring. Here, we tested the hypothesis that in utero JUUL exposure causes unfavorable birth outcomes and lasting pulmonary health effects in adult offspring. BALB/c dams were exposed to either air or mint-flavored JUUL aerosol, 1-hr/d, 20 consecutive days during gestation. Offspring were sacrificed on post-natal day (PND) 0 or at 11-week of age, following house dust mite (HDM) challenge. Gene expression was assessed in the uterine/placental tissue of the dams and lung responses were assessed in offspring at PND0 and at 11 weeks of age. JUUL-exposed offspring exhibited decreased body weights and lengths at PND0. These birth outcomes were accompanied by dysregulation of 54 genes associated with hypoxia and oxidative stress in the uterine/placental tissues of JUUL-exposed dams, as well as 24 genes in the lungs of the offspring related to Wnt signaling, plus 9 genes related to epigenetics, and 7 genes related to inflammation. At 11 weeks of age, JUUL + HDM exposed mice exhibited pulmonary inflammation when compared to their respective air + HDM controls. Additionally, the JUUL + HDM exposure dysregulated several genes associated with allergies and asthma. Further, the JUUL + HDM females showed decreased methylation of the promoter region of the Il10ra gene. Taken together, our mouse model shows that inhalation of JUUL aerosols during pregnancy affects the intrauterine environment, impairs lung development, and heightens the effects of allergic airway responses later in life.

Anti-inflammatory and anti-remodeling effects of myrtenol in the lungs of asthmatic rats: Histopathological and biochemical findings

INTRODUCTION

Asthma is a chronic inflammatory disease of the airways. In this study, we evaluated the anti-inflammatory effects of myrtenol on the inflammatory indices in the pulmonary parenchyma and airways and on the inflammatory and oxidative indices of the bronchoalveolar lavage fluid (BALF) of asthmatic rats.

METHODS

The allergic asthma was induced by sensitization (two weeks) followed by the inhalation of ovalbumin (four weeks). Animals were divided into two main groups: (1) Histopathology, and (2) measurement of inflammatory and oxidative biomarkers in the BALF. Each main group was subdivided into four subgroups: Control, Asthma, Asthma+Dexamethasone and Asthma+Myrtenol. (-)-Myrtenol (50mg/kg) or Dexamethasone (2.5mg/kg) was administered intraperitoneally once a day for one week, at the end of the inhalation period. On day 50, lung histopathologic parameters and inflammatory indices in BALF including INF-γ, IL-10, IL-1β, and TNF-α and oxidative stress biomarkers (MDA, SOD, and GPX) were measured.

RESULT

In the Asthma group, leukocyte infiltration, the thickness of smooth muscle and epithelium of airways wall and the number of goblet cells increased. Myrtenol reduced all of the above-mentioned indices except the epithelium thickness. It also inhibited the increase in BALF IL-1β, TNF-α and MDA and increased the levels of INF-γ, IL-10 and SOD.

CONCLUSION

Our results suggest that myrtenol reduced damage caused by experimental asthma by reducing the inflammatory indices, normalizing the level of interleukins and balancing oxidative stress in the lungs. It also prevented airway remodeling. Myrtenol may be suggested as a potent herbal medicine for the treatment of allergic asthma.

Osthole treatment ameliorates Th2-mediated allergic asthma and exerts immunomodulatory effects on dendritic cell maturation and function

Osthole, an active component of Chinese herbal medicines, reportedly possesses various pharmacological properties and has potential therapeutic applications. This study explored the anti-allergic effects of osthole in asthmatic mice and investigated the immunomodulatory actions of osthole on dendritic cells (DCs) and T cells. Herein, we show that oral administration of osthole to BALB/c mice after ovalbumin (OVA) sensitization ameliorated all of the cardinal features of T helper 2 (Th2)-mediated allergic asthma; namely, the production of OVA-specific immunoglobulin E, airway hyperresponsiveness, airway inflammation and the production of Th2-type cytokines including interleukin (IL)-4, IL-5 and IL-13. Surprisingly, IL-10 production was not inhibited and was even enhanced by osthole treatment. We observed a significant increase in the percentages of IL-10-producing DCs and forkhead box P3-positive regulatory T (Treg) cells in osthole-treated asthmatic mice. Additionally, in vitro analyses revealed that osthole-treated bone-marrow-derived DCs had a partial maturation phenotype, secreting large amounts of IL-10 and low levels of proinflammatory cytokines, such as IL-12, IL-6 and tumor necrosis factor-α, and displaying reduced levels of MHC class II surface molecules. These DCs displayed immunosuppressive capacity by directly inhibiting effector T-cell responses or inducing Treg cells. In addition, osthole directly inhibited the activated CD4+ T-cell proliferation and Th1/Th2-type cytokine production in this system. Collectively, these results suggest that DCs and T cells are potential target cells responsible for the action of osthole against allergic asthma.Cellular &Molecular Immunology advance online publication, 7 August 2017; doi:10.1038/cmi.2017.71.

Correlation of cutaneous sensitivity and cytokine response in children with asthma

Background:

Food allergy occurs in a significant portion of pediatric asthma. Various cells and their mediators/cytokines play a pivotal role in orchestrating the airway inflammatory response in asthma.

Objective:

To study the cutaneous hypersensitivity, Th1, Th2, and Th17 response of pediatric population with asthma and genetic predisposition to atopy, by determining total immunoglobulin E (IgE) level in response to various food allergens.

Materials and Methods:

Fifty asthmatic children with a history of worsening symptoms by various food allergens (study group) and twenty healthy children (control group) were included. Food allergy was assessed through skin prick test (SPT) of various food allergens. Total serum IgE level was measured by sandwich ELISA, and T-cell (Th1, Th2, and Th17)-dependent cytokines were measured by flow cytometry.

Results:

All 50 asthmatic children in the study group showed SPT positivity against various food allergens (rice = 17; banana, fish and groundnut = 10; wheat = 9; milk and orange = 7; egg = 6; and mango = 4). The average total IgE level in the study group was 316.8 ± 189.8 IU/mL. A significant positive correlation of total IgE with interleukin 17 (IL-17) (r = 0.796; P < 0.0001), IL-13 (r = 0.383; P = 0.01), and IL-4 (r = 0.263; P = 0.043) level was noted. A significant negative correlation of total IgE was noted with interferon gamma (r = −0.5823; P < 0.0001) and IL-10 (r = −0.4474; P < 0.001) level and the duration of breastfeeding (r = −0.31, P = 0.03).

Conclusions:

The present study found a positive correlation between total serum IgE level and Th2, Th17 cytokines in a pediatric population with asthma. A significant negative correlation was found between the duration of breastfeeding and the cytokines.

Cytokine profile of rats fed a diet containing shrimp

OBJECTIVE: Studies have shown that shrimps reduced the tensile strength of scars in rat skin. The aim of the present study was to assess the cytokine profile of rats fed shrimp. METHODS: Group 1 (control) received a regular diet and Group 2 (experimental) received a diet containing 33% shrimp for nine days. The two diets contained the same amounts of proteins, fats and carbohydrates. Serum cytokine levels were determined by ELISA and a segment of the jejunum was taken to investigate its histological morphology and eosinophil infiltrate. RESULTS: The experimental group had lower serum levels of interleukin-4 (IL-4) (14.4±1.9 versus 18.11±2.6pg/mL; p<0.05) and IL-10 (5.0±0.98 versus 7.5±1.2pg/mL; p<0.05) and higher levels of IL-6 (17.8±2.3 versus 3.2±0.4pg/mL, p<0.001) than controls. Morphologically, the shrimp-based diet caused an architectural disorganization of the intestinal mucosa and a greater amount of eosinophils in the jejunal villus. CONCLUSION: Our data suggests that shrimp consumption leads to a significant increase in the cytokine IL-6, a decrease in the immunomodulatory cytokine IL-10 in the serum of rats, and high eosinophil infiltration in the jejunum. The cytokine profile typical of inflammation and the histological aspect of the jejunum are compatible with food allergy.

Association between human IL-10 gene polymorphisms and serum IL-10 level in patients with food allergy

BACKGROUND/PURPOSE

Single nucleotide polymorphisms (SNPs) of the interleukin-10 (IL-10) gene are associated with allergic diseases in different populations. This study aimed to determine the distribution of two SNPs at -1082A/G and -592A/C (rs1800896 and rs1800872, respectively) in the IL-10 gene promoter of Taiwanese food allergy (FA) patients, and also to compare the serum IL-10 levels between patients with (FA) and controls.

METHODS

Thirty-seven patients with FA and 52 controls were enrolled, and their peripheral blood was collected for IL-10 SNP genotyping and the corresponding serum IL-10 level of each genotype.

RESULTS

The thirty-seven FA patients had positive food-specific IgE (≥ 0.75kU/L) to more than one food, and the most frequent allergens wereshrimp and crab (56.8% and 35.1%, respectively). The genotype distributions in the FA patients compared to the control group were AA and AG at -1082A/G (86.5% and 13.5% vs. 86.6% and 13.4%, respectively), and AA, AC, and CC at -592A/C (45.9%, 43.3% and 10.8% vs. 38.5%, 48.1% and 13.4%, respectively). Serum IL-10 levels were significantly lower in the FA group than in the control group (p=0.0187), and the IL-10 level of -592A/C of genotype AA was significantly lower than that of the other genotypes (AC+CC) (p=0.007). Patients with AA/AA haplotype homozygotes (10 of 24) had significantly lower serum IL-10 levels than those with other haplotypes.

CONCLUSIONS

The two SNPs at -1082A/G and -592A/C of IL-10 were associated with FA in our Taiwanese population, and FA patients with the genotype AA/AA haplotype homozygotes had lower serum IL-10 levels. This suggests that IL-10 might play a critical role in the pathogenesis of FA. We suggest that it may be practicable to evaluate the serum IL-10 levels of FA patients and to predict the possibility of FA if genotypes and haplotypes are checked regularly.

In vivo disruption of TGF-beta signaling by Smad7 in airway epithelium alleviates allergic asthma but aggravates lung carcinogenesis in mouse

Background

TGF-β has been postulated to play an important role in the maintenance of epithelial homeostasis and the development of epithelium-derived cancers. However, most of previous studies are mainly focused on the function of TGF-β in immune cells to the development of allergic asthma and how TGF-β signaling in airway epithelium itself in allergic inflammation is largely unknown. Furthermore, the in vivo TGF-β function specifically in the airway epithelium during lung cancer development has been largely elusive.

Methodology/Principal Findings

To evaluate the in vivo contribution of TGF-β signaling in lung epithelium to the development of allergic disease and lung cancer, we generated a transgenic mouse model with Smad7, an intracellular inhibitor of TGF-β signaling, constitutively expressed in mouse airway Clara cells using a mouse CC10 promoter. The mice were subjected to the development of OVA-induced allergic asthma and urethane-induced lung cancer. The Smad7 transgenic animals significantly protected from OVA-induced asthma, with reduced airway inflammation, airway mucus production, extracellular matrix deposition, and production of OVA-specific IgE. Further analysis of cytokine profiles in lung homogenates revealed that the Th2 cytokines including IL-4, IL-5 and IL-13, as well as other cytokines including IL-17, IL-1, IL-6, IP10, G-CSF, and GM-CSF were significantly reduced in the transgenic mice upon OVA induction. In contrast, the Smad7 transgenic animals had an increased incidence of lung carcinogenesis when subjected to urethane treatment.

Conclusion/Significance

These studies, therefore, demonstrate for the first time the in vivo function of TGF-β signaling specifically in airway epithelium during the development of allergic asthma and lung cancer.

Synergistic therapeutic effects of combined adenovirus-mediated interleukin-10 and interleukin-12 gene therapy on airway inflammation in asthmatic mice

BACKGROUND

Asthma is a chronic disease characterized by airway inflammation caused by the dysregulated production of cytokines secreted by allergen-specific type 2 T helper (Th2) cells. Although the Th1-promoting cytokine, interleukin (IL)-12, is capable of inhibiting Th2-driven allergen-induced airway changes in mice, IL-12 also aggravates the Th1-driven inflammatory pulmonary pathology. Further, IL-10 was found to exert both anti-inflammatory and immunoregulatory activities. To avoid the side-effects of IL-12, we hypothesized that the low-dose expression of IL-10 with concomitant IL-12 administration in the airway may represent a more effective therapy for allergic airway diseases. Thus, the present study explored the immunomodulatory and therapeutic effects of IL-10 combined with IL-12 in airway inflammation in allergic asthma.

METHODS

Adenovirus-expressing murine IL-10 (Ad-IL-10) and IL-12 (Ad-IL-12) were co-administrated in an established murine model of ovalbumin (OVA)-induced asthma.

RESULTS

We found that a single combined treatment of low doses of Ad-IL-10 and Ad-IL-12 efficiently inhibited the development of airway hyper-responsiveness compared to Ad-IL-10 or Ad-IL-12 treatment alone. Moreover, both Ad-IL-10 and Ad-IL-12 treatment reduced pulmonary infiltration of eosinophils and neutrophils. In addition, histological studies showed that combined treatment was able to reduce tumor necrosis factor-alpha-mediated airway inflammation induced by IL-12 treatment. Suppression of IL-4, IL-5, Keratinocyte-derived chemokine (KC) and eotaxin in bronchoalveolar lavage fluid was also noted in OVA-immunized mice with combined Ad-IL-10 and Ad-IL-12 treatment.

CONCLUSIONS

Taken together, the results obtained in the present study indicate that co-administration of IL-12 and IL-10 may have therapeutic potential for the immunomodulatory treatment of allergic asthma.

Aldose reductase inhibition suppresses the expression of Th2 cytokines and airway inflammation in ovalbumin-induced asthma in mice

Airway inflammation induced by reactive oxygen species-mediated activation of redox-sensitive transcription factors is the hallmark of asthma, a prevalent chronic respiratory disease. In various cellular and animal models, we have recently demonstrated that, in response to multiple stimuli, aldose reductase (AR) regulates the inflammatory signals mediated by NF-kappaB. Because NF-kappaB-mediated inflammation is a major characteristic of asthma pathogenesis, we have investigated the effect of AR inhibition on NF-kappaB and various inflammatory markers in cellular and animal models of asthma using primary human small airway epithelial cells and OVA-sensitized/challenged C57BL/6 mice, respectively. We observed that pharmacological inhibition or genetic ablation of AR by small interfering RNA prevented TNF-alpha- as well as LPS-induced apoptosis; reactive oxygen species generation; synthesis of inflammatory markers IL-6, IL-8, and PGE(2); and activation of NF-kappaB and AP-1 in small airway epithelial cells. In OVA-challenged mice, we observed that administration of an AR inhibitor markedly reduced airway hyperresponsiveness, IgE levels, eisonophils infiltration, and release of Th2 type cytokines in the airway. Our results indicate that AR inhibitors may offer a novel therapeutic approach to treat inflammatory airway diseases such as asthma.

Downregulation of CXCR6 and CXCR3 in lymphocytes from birch-allergic patients

Preferential expression of chemokine receptors on Th1 or Th2 T-helper cells has mostly been studied in cell lines generated in vitro or in animal models; however, results are less well characterized in humans. We determined T-cell responses through chemokine receptor expression on lymphocytes, and cytokine secretion in plasma from birch-allergic and healthy subjects. The expression of CCR2, CCR3, CCR4, CCR5, CCR7, CXCR3, CXCR4, CXCR6, IL-12 and IL-18R receptors was studied on CD4(+) and CD8(+) cells from birch-allergic (n = 14) and healthy (n = 14) subjects by flow cytometry. The concentration of IL-4, IL-5, IL-10, IL-12, IFN-gamma and TNF-alpha cytokines was measured in plasma from the same individuals using a cytometric bead array human cytokines kit. The similar expression of CCR4 in T cells from atopic and healthy individuals argues against the use of the receptor as an in vivo marker of Th2 immune responses. Reduced percentages of CD4(+) cells expressing IL-18R, CXCR6 and CXCR3 were found in the same group of samples. TNF-alpha, IFN-gamma, IL-10, IL-5, IL-4 and IL-12 cytokines were elevated in samples from allergic individuals. Reduced expression of Th1-associated chemokine receptors together with higher levels of Th1, Th2 and anti-inflammatory cytokines in samples from allergic patients indicate that immune responses in peripheral blood in atopic diseases are complex and cannot be simplified to the Th1/Th2 paradigm. Not only the clinical picture of atopic diseases but also the clinical state at different time points of the disease might influence the results of studies including immunological markers associated with Th1- or Th2-type immune responses.

Patterns of food allergen-specific cytokine production by T lymphocytes of children with multiple allergies

BACKGROUND

The contribution of different T cell subsets to the overall measured cytokine response to food allergens is largely unexplored.

METHOD

The patterns of cytokine production of peripheral blood-derived T cells after allergen stimulation were studied in 22 children with multiple food allergies and in 20 non-allergic children as controls, using flow cytometry.

RESULTS

Proportions of T cells of food-sensitized children spontaneously secreting IFN-gamma and IL-10 (without antigen stimulation) were lower than non-atopic children and adult controls (P<or=0.001). The proportions of IL-4-producing cells in vitro were significantly increased (P<or=0.04) and IFN-gamma-producing cells were significantly reduced (P<or=0.05) in sensitized children after incubation with and without dendritic cell presentation of peanut extract, beta-lactoglobulin and ovalbumin. The reverse pattern was found in non-sensitized children and adult controls. IL-4 secretion in allergic children to sensitizing allergens was mainly restricted to the CD4(+) CD45 RO(+) population while in non-atopic controls both CD4(+) and CD8(+) CD45 RO(+) cells produced mostly IFN-gamma. Food-specific IgE values did not correspond with cytokine responses but IL-4 production and IFN-gamma reduction relative to normal children were closely associated with total IgE levels.

CONCLUSION

Food-allergic children's IL-4 cytokine response to their relevant allergens is predominantly from a memory population of CD4(+) CD45 RO(+) cells, whereas IL-4 and IFN-gamma secretion of non-allergic controls was predominantly from mixed CD4(+) and CD8(+) CD45 RO(+) populations.

A pediatric case of anaphylaxis caused by matsutake mushroom (Tricholoma matsutake) ingestion

BACKGROUND

Anaphylaxis is one of the severest forms of allergic diseases. Some kinds of mushroom are known as causative allergens in food anaphylaxis. Matsutake mushroom (Tricholoma matsutake) is a typical edible mushroom available in autumn in Japan. We encountered an 8-year-old Japanese girl who developed anaphylaxis after ingesting matsutake mushrooms.

METHODS

We studied the case in detail, by measuring specific IgE antibodies and conducting skin tests, to confirm the diagnosis. We also detected seven cytokines and chemical mediators in the blood in order to study the pathophysiology of the anaphylaxis.

RESULTS

We diagnosed anaphylaxis caused by ingestion of matsutake mushrooms based on the following. A skin prick test showed a positive reaction to matsutake mushroom, and specific IgE antibody for matsutake mushroom extract was detected in the patient's serum by fluorometric ELISA. Blood levels of chemical mediators including histamine, ECP, tryptase and cytokines such as IL-6, IL-5 and IL-10 but not IFN-gamma also increased significantly during the allergic episode.

CONCLUSIONS

We demonstrated that chemical mediators including histamine, tryptase and ECP as well as several cytokines were involved significantly during the episode of anaphylaxis. In addition, eosinophils as well as mast cells played significant roles in the anaphylaxis. Furthermore, CD4+CD25+ T regulatory cells that released IL-10 were likely activated during the anaphylaxis. Matsutake mushroom should be considered as a causative allergen in food anaphylaxis.

Cytokine production from sputum cells in eosinophilic versus non-eosinophilic asthmatics

The inflammatory pathways involved in asthma are more complex than the sole Th2-mediated eosinophilic airway inflammation. Different phenotypes of asthma have been recently highlighted and are probably underlied by different immunological profiles. The aim of the study was to assess cytokine production from sputum cells in eosinophilic versus non-eosinophilic asthmatics. Induced sputum was obtained from 48 consecutive stable mild to moderate asthmatics (20 eosinophilic asthmatics, 28 non-eosinophilic asthmatics) and 31 healthy subjects. Cytokine released from sputum cells were measured by a home-made two-step sandwich immunoassay. Cytokines investigated were interleukin (IL)-4, IL-6, IL-10, tumour necrosis factor (TNF)-alpha and interferon (IFN)-gamma. Sputum cells from eosinophilic asthmatics produced more IL-4 than those from both healthy subjects (P < 0.05) and non-eosinophilic asthmatics (P < 0.05). Conversely, sputum cells from eosinophilic asthma were found to release lower amounts of TNF-alpha than those from healthy subjects (P < 0.05). The group of non-eosinophilic asthmatics did not distinguish from healthy subjects with respect to any cytokines measured. Sputum cells from asthmatics exhibiting eosinophilic airway inflammation release more IL-4 and less TNF-alpha than those of healthy subjects. By contrast, non-eosinophilic asthmatics did not distinguish from healthy subjects by abnormal cytokine release from their sputum cells.

Immune dysregulation in allergic respiratory disease: the role of T regulatory cells

Although earlier research focused on the role of the polarity of T helper cell signalling as the defining factor in immune responses, it is now recognised that other cells with regulatory properties have a more key role. It has been recently proposed that allergic disease may result from an inappropriate balance between regulatory cells (including but not limited to CD4+ CD25+ T regulatory cells) and T helper type 2 (Th2) effector cells. In the airways, a number of other cells also have important regulatory effects on local immune responses, including epithelial cells and airway dendritic cells (DC). Allergic respiratory disease appears to be the culmination of both local epithelial dysfunction and generalised immune dysregulation resulting in Th2 propensity (atopic predisposition). Although these processes are related they also appear to occur independently. This review examines evolving models of allergy pathogenesis, including the newly recognised role of diverse groups of regulatory cells. Increasing rates of allergic disease (and other immune diseases) suggest that environmental changes may be having fundamental effects on common regulatory pathways. Understanding these influences and their mechanism of action could lead to strategies to prevent disease.

Cytokine secretion in nasal mucus of normal subjects and patients with allergic rhinitis

Allergic rhinitis is regulated by the local production and release of several cytokines. The levels of Th2 cytokines IL-4, IL-6, IL-10 and the Th1 cytokine IFN-gamma were studied in nasal mucus from 30 subjects with allergic rhinitis and 45 non-atopic healthy controls. In this study a sampling technique for collecting nasal mucus, well tolerated by the subjects and with a minimal stimulation of the mucosa, was performed. The cytokine concentrations in nasal mucus samples were detected and quantitated by a new paramagnetic particle-based immunofluorescent assay system more sensitive than the conventional ELISA techniques. The new technique showed reliable values of the measured parameters. The nasal mucus from allergic patients contained significantly higher concentrations of IL-4 (25.5 +/- 3.6 pg/ml; P < 0.001) and IL-10 (1300 +/- 190 pg/ml; P < 0.05) compared to the nasal mucus from control subjects (15.2 +/- 2.3 and 532 +/- 28 pg/ml, respectively, for IL-4 and IL-10). No significant modification in IFN-gamma levels of allergic patients was found when compared to control group (respectively, 19.9 +/- 3.3 vs. 25.7 +/- 5.1 pg/ml; P > 0.05). Moreover, the allergic patients showed lower levels of IL-6 concentrations in the nasal mucus compared to control subjects (64.8 +/- 9.1 vs. 129.0 +/- 18.1 pg/ml; P = 0.0099). These data can be interpreted by the hypothesis that in response to environmental allergens there is a preferential Th2 polarity by activated CD4+ T cells and that the cytokines IL-6 and IL-10 have, respectively, an important anti-inflammatory and counterregulatory action in the pathogenesis of allergic rhinitis.

New concepts of cytokines in asthma: is the Th2/Th1 paradigm out the window?

Although asthma is clearly associated with a systemic propensity for allergic T helper type 2 (Th2) cell cytokine responses, independent local immune events appear to be responsible for the development of allergic airways inflammation. There is growing interest in how local immune networks interact with resident airway cell populations such as epithelial cells, which are now also recognized as key producers of cytokines, chemokines and growth factors. As well as their recognized role in airway remodelling, epithelial cells are now thought to have a role in initiating events. This review examines the role of cytokines produced by these and other cells in the development of asthma. It also highlights emerging concepts that the excessive and inappropriate immune responses seen in allergic disease may be related to dysfunction of various interleukin-10 producing regulatory cell populations.

Allergen-induced cytokine secretion in atopic and non-atopic asthmatic children

Atopic asthma is characterized by excessive T helper 2 (Th2)-like immunity to allergens in the bronchial mucosa. The Th2-cytokine interleukin (IL)-4 induces IgE production, while the Th2-cytokine IL-5 promotes eosinophilic inflammation in the airways of asthmatics. Most asthmatics are atopic, but a subgroup is non-atopic. We hypothesize that allergen-induced Th2, particularly IL-5, responses can be observed in peripheral blood in both atopic and non-atopic asthmatic children but not in healthy control children. The aim of the present study was to determine IL-4, IL-5, IL-9, IL-10, IL-13 and IFN-gamma secretion induced from peripheral blood mononuclear cells (PBMC) by a broad panel of inhalant allergens (timothy, cat, birch, dog and house dust mite) in asthmatic children with and without sensitization. The study included 13 atopic asthmatic, 5 non-atopic asthmatic, and 12 non-atopic non-asthmatic children. PBMC were stimulated with allergens and cytokine production was measured with enzyme-linked immunosorbent assay (ELISA). Higher levels of cat and dog antigen-induced IL-5 release were more commonly observed in both atopic and non-atopic asthmatics than in controls. Children with atopic, but not non-atopic, asthma produced higher levels of allergen-induced IL-4 and IL-9 than controls. Non-atopic asthmatics produced more IL-10 than atopic asthmatics after cat stimulation. High levels of eosinophilia-associated IL-5 responses are induced by cat and dog allergen in both atopic and non-atopic asthmatic children. The Th2 cytokines IL-4 and IL-9 were associated only with atopic asthma, probably due to their IgE-inducing properties.

Reduced IL-2-induced IL-12 responsiveness in atopic children

Atopy may be associated with a reduced T-cell function particularly regarding maturation of T helper 1 (Th1) responses. We hypothesized that atopic children may have a reduced capacity to up-regulate the beta2 subunit of the interleukin-12 (IL-12) receptor (IL-12Rbeta2, the signal-transducing component). The study included 38 children followed from birth to the age of 7 years. Twenty one had a cumulative history of atopic disease, whereas 17 had none. Sixteen out of 21 children also had atopic symptoms within the past year (current), out of whom 10 children had atopic airway symptoms. The expression of IL-12Rbeta2 mRNA was analyzed by quantitative real-time PCR and the secretion of interferon-gamma (IFN-gamma), IL-5 and IL-10 was assessed by enzyme-linked immunosorbent assay (ELISA). Children with current atopic airway symptoms and high levels of total IgE up-regulated IL-12Rbeta2 mRNA expression less than non-atopic children with low IgE levels after IL-2 stimulation. This was accompanied by a low IL-2- and IL-12-induced IFN-gamma production, possibly reflecting the reduced capacity of atopic children to up-regulate the IL-12 receptor. As IL-2 is needed to initiate and sustain immune responses and IL-12 promotes Th1 responses, this may contribute to the Th2-skewed pattern in atopic children.

Increased serum IL-10/IL-12 ratio in wheezing infants

To investigate the association between various serum markers and atopic symptoms in the first year of life, and to evaluate the prognostic value of these markers for the development of wheezing and skin rash in the second year of life. Data of 86 children on the development of wheezing and skin rash in the first 2 years of life were collected prospectively, making use of parental completed questionnaires, weekly symptom cards, structured interview and physical examination. Serum markers (IL-10, IL-12, IL-13, eotaxin, sE-selectin, sICAM-1, sIL-2R) and total and specific IgE were determined at age 1. Children who developed wheezing in the first year of life had lower serum levels of IL-12 than children without symptoms (median 40.3 pg/ml vs. 49.0 pg/ml, p = 0.01) and a higher serum IL-10/IL-12 ratio (0.41 vs. 0.31, p = 0.001) at age 1. The IL-10/IL-12 ratio increased with an increasing number of wheezing episodes. Levels of sE-selectin in children with wheezing and in children with itchy skin rash in the first year of life were higher than in symptom free children (6.1 ng/ml and 5.9 ng/ml vs. 4.9 ng/ml, p = 0.01 and p = 0.03, respectively). Children who developed wheezing in the second year of life already had increased sICAM-1 levels at age 1. Children who developed wheezing in the first year of life showed a serum cytokine response that is skewed towards a T-helper 2 profile, with lower IL-12 levels and an increased IL-10/IL-12 ratio. Children who developed wheezing in the second year of life had elevated sICAM-1 levels at age 1. Follow-up of the children is needed to evaluate the prognostic value of various serum markers for the development of allergic disease in later childhood.

Endotoxin levels in Estonian and Swedish house dust and atopy in infancy

BACKGROUND

Immune responses, including those to allergens, may be T helper (Th)2 skewed in newborns. In order to redress the fetal Th1/Th2 imbalance, Th1-stimulating factors, such as bacterial endotoxin, may be required. The increasing prevalence and severity of atopic diseases in industrialized countries, which are in marked contrast with the low prevalence of allergy among children in the formerly socialist countries of Europe, have been suggested to be caused by a reduced microbial stimulation.

AIM

To relate the endotoxin levels in house dust from two countries with a low (Estonia) and a high (Sweden) prevalence of allergy to the development of atopic disease and sensitization in the children during the first 2 years of life.

METHODS

The study included 108 children from Tartu, Estonia and 111 children from Linköping, Sweden. Skin prick tests were performed at 3, 6, 12 and 24 months of age, and questionnaires were distributed to the families. At 24 months, a paediatrician examined the children. Dust samples were collected from mattresses and carpets and the endotoxin concentration was determined by a chromogenic Limulus assay.

RESULTS

The endotoxin levels were higher in Estonian than in Swedish house dust (median levels 29 (range 0.25-280) and 14 (range 0.25-99) EU/mg dust, respectively, P < 0.001). Furthermore, the levels were inversely related to the development of atopic disease and sensitization in the Swedish, but not in the Estonian, children.

CONCLUSIONS

The low prevalence of atopic disease in Estonia may, at least in part, be related to the high endotoxin levels in this country. The findings support that high levels of endotoxin, or other bacterial products with Th1-stimulating properties, might protect children from developing atopic disease.

Immune responses to birch in young children during their first 7 years of life

BACKGROUND

The character of immune responses to allergens during the first years of life may decide whether the individual will become tolerant or develop allergy later in life.

OBJECTIVE

To study the development of immune responses to the seasonal inhalant allergen birch over the first 7 years of life.

METHODS

Blood samples were obtained from 21 children who were followed prospectively from the second to the seventh pollen season of life. Birch-induced cytokine production and IgG subclass antibodies to rBet v 1 were analysed with ELISA, mRNA expression with real time PCR, IgE antibodies to birch with Magic Lite and birch-induced mononuclear cell proliferation with 3H-thymidine incorporation.

RESULTS

Birch-induced IFN-gamma and IL-10 production increased with age, both in atopic and non-atopic children, while birch-induced IL-13 production decreased. The two children who were sensitized and developed clinical allergy to birch showed persistent IL-4 and IL-5 production and IL-9 mRNA expression, as well as Th2-associated IgG4 responses. Transient Th2-like responses were observed among the other children. Proliferative responses and IgG1 antibodies were seen in all children.

CONCLUSIONS

Immune responses to birch can be demonstrated in all children, during the first 7 years of life, regardless of atopic status. A transient early Th2-like response is down-regulated after the fourth pollen season, except in children who develop clinical allergy to the particular allergen.

Transgenic overexpression of interleukin (IL)-10 in the lung causes mucus metaplasia, tissue inflammation, and airway remodeling via IL-13-dependent and -independent pathways

To address the complex chronic effector properties of interleukin (IL)-10, we generated transgenic mice in which IL-10 was overexpressed in the lung. In these mice, IL-10 inhibited endotoxin-induced tumor necrosis factor production and neutrophil accumulation. IL-10 also caused mucus metaplasia, B and T cell-rich inflammation, and subepithelial fibrosis and augmented the levels of mRNA encoding Gob-5, mucins, and IL-13. In mice bred to have null mutations of IL-13, IL-4R(alpha), or STAT-6, transgenic IL-10 did not induce mucus metaplasia but did induce inflammation and fibrosis. IL-10 was also a critical mucin regulator of virus-induced mucus metaplasia. Thus, IL-10, although inhibiting lipopolysaccharide-induced inflammation, also causes mucus metaplasia, tissue inflammation, and airway fibrosis. These responses are mediated by multiple mechanisms with mucus metaplasia being dependent on and the inflammation and fibrosis being independent of an IL-13/IL-4R(alpha)/STAT-6 activation pathway.

T-helper 1, T-helper 2 and immunosuppressive cytokines in canine atopic dermatitis

Atopic dermatitis is a common inflammatory skin disease of humans and dogs. Human atopic dermatitis is associated with T-helper (Th) 2 type responses, although Th1 cytokines are present in chronic lesions. This study used semi-quantitative reverse transcriptase polymerase chain reactions to determine the expression of gene transcripts for immunosuppressive cytokines (transforming growth factor beta [TGFbeta] and interleukin [IL]-10), Th2 type cytokines (IL-4 and IL-6) and Th1 type cytokines (interferon gamma [IFNgamma], tumour necrosis factor alpha [TNFalpha], IL-2 and IL-12) in lesional atopic, non-lesional atopic and healthy canine skin. Canine atopic dermatitis was associated with over-expression of IL-4 mRNA and reduced transcription of TGFbeta compared to healthy skin (ANOVA, p<0.05). Higher levels of IFNgamma, TNFalpha and IL-2 mRNA were seen in lesional compared to non-lesional and healthy skin (p<0.05). There were no significant differences in IL-10, IL-6 or IL-12 transcription. This is the first report to demonstrate that canine atopic dermatitis is associated with over-production of IL-4 and under expression of TGFbeta.

Expression of Th1, Th2 and immunosuppressive cytokine gene transcripts in canine atopic dermatitis

BACKGROUND

Atopic dermatitis is a common inflammatory skin disease of humans and dogs. Human atopic dermatitis is associated with Th2-type responses, although Th1 cytokines can be identified in chronic lesions. In contrast, tolerance to environmental allergens in healthy individuals is mediated by regulatory T cells.

OBJECTIVE

This study examined the expression of the immunosuppressive cytokines TGF-beta and IL-10, the Th2-type cytokines IL-4 and IL-6, and the Th1-type cytokines IFN-gamma, TNF-alpha, IL-2, IL-12p35 and IL-12p40, in canine atopic dermatitis.

MATERIALS AND METHODS

RNA was isolated from lesional atopic, non-lesional atopic and healthy canine skin samples. Semi-quantitative reverse transcriptase polymerase chain reactions (RT-PCRs) were carried out using specific primers and one-way analyses of variance used to compare cytokine expression in each group.

RESULTS

Canine atopic dermatitis was associated with over-expression of IL-4 mRNA and reduced transcription of TGF-beta compared with healthy skin (P < 0.05). Higher levels of IFN-gamma, TNF-alpha and IL-2 mRNA were seen in lesional compared with non-lesional and healthy skin (P < 0.05). There were no significant differences in IL-10, IL-6, IL-12p35 or IL-12p40 transcription between the three groups.

CONCLUSIONS

This is the first report to demonstrate that canine atopic dermatitis is associated with over-production of IL-4. Clinical tolerance in healthy individuals appears to be associated with TGF-beta, although it is unclear if this reflects an active mechanism or simply non-responsiveness of the immune system. Th1 cytokines may be induced by subsequent self-trauma and secondary infections in atopic skin. We believe that these results better characterize spontaneously occurring canine atopic dermatitis. We further propose that this should be investigated as a possible animal model of human atopic dermatitis.

Detection of spontaneous and antigen-induced human interleukin-4 responses in vitro: comparison of ELISPOT, a novel ELISA and real-time RT-PCR

Interleukin-4 (IL-4) is an important T-helper cell type 2 (Th2) cytokine in man, driving Th2 polarisation and exerting the most antagonistic effects to the Th1 cytokine interferon-gamma (IFN-gamma). Nevertheless, few data on spontaneous and antigen-specific secretion of IL-4 in man are available, mainly due to difficulties in the detection of IL-4. In this study, we compared three assays that can detect antigen-induced IL-4 responses; ELISPOT, ELISA after blocking the IL-4 receptor during cell culture, and real-time reverse transcription polymerase chain reaction (RT-PCR). Spontaneous, antigen- and allergen-induced responses were analysed in peripheral blood mononuclear cells from three groups with different secretion patterns for IL-4: atopic individuals, nonatopic individuals and pregnant women. ELISPOT displayed the highest sensitivity and was the only assay that could detect spontaneous secretion of IL-4 in all analysed samples. The IL-4 receptor blocking ELISA was considered best for the detection of in vitro antigen- and allergen-induced responses, since the results obtained from the ELISPOT and real-time RT-PCR displayed lower specificity, possibly because of seemingly aberrant IL-4 responses in the group of pregnant women. The real-time RT-PCR for detection of IL-4 mRNA proved to be sensitive, but expression of IL-4 mRNA was not correlated with the secretion of IL-4.

Protection against acetaminophen-induced liver injury and lethality by interleukin 10: role of inducible nitric oxide synthase

Mechanistic study of idiosyncratic drug-induced hepatitis (DIH) continues to be a challenging problem because of the lack of animal models. The inability to produce this type of hepatotoxicity in animals, and its relative rarity in humans, may be linked to the production of anti-inflammatory factors that prevent drug-protein adducts from causing liver injury by immune and nonimmune mechanisms. We tested this hypothesis by using a model of acetaminophen (APAP)-induced liver injury in mice. After APAP treatment, a significant increase was observed in serum levels of interleukin (IL)-4, IL-10, and IL-13, cytokines that regulate inflammatory mediator production and cell-mediated autoimmunity. When IL-10 knockout (KO) mice were treated with APAP, most of these mice died within 24 to 48 hours from liver injury. This increased susceptibility to APAP-induced liver injury appeared to correlate with an elevated expression of liver proinflammatory cytokines, tumor necrosis factor (TNF)-alpha, and IL-1, as well as inducible nitric oxide synthase (iNOS). In this regard, mice lacking both IL-10 and iNOS genes were protected from APAP-induced liver injury and lethality when compared with IL-10 KO mice. All strains, including wild-type animals, generated similar amounts of liver APAP-protein adducts, indicating that the increased susceptibility of IL-10 KO mice to APAP hepatotoxicity was not caused by an enhanced formation of APAP-protein adducts. In conclusion, these findings suggest that an important feature of the normal response to drug-induced liver injury may be the increased expression of anti-inflammatory factors such as IL-10. Certain polymorphisms of these factors may have a role in determining the susceptibility of individuals to idiosyncratic DIH.

Cytokine modulators for allergic diseases

Cytokines play a critical role in orchestrating and perpetuating inflammation in allergic diseases and several specific cytokine inhibitors now in development for the treatment of asthma and other allergic diseases. The effects of inhibiting the T helper 2 cytokines interleukin-5, interleukin-13 and interleukin-9 are discussed, together with inhibition of tumor necrosis factor-alpha. Inhibitory cytokines, such as interleukin-10, interferons and interleukin-12, are also being considered in the treatment of allergic diseases.

Peripheral blood mononuclear cell responses to Dermatophagoides farinae in canine atopic dermatitis

Atopic dermatitis is a chronic inflammatory and pruritic skin disease commonly seen in dogs and humans that is characterised by the presence of allergen-specific IgE. Data from skin tests and serological analysis suggest that the house dust mite Dermatophagoides farinae is the most important allergen in dogs with atopic dermatitis. The aim of this study was to determine if D. farinae specific peripheral blood mononuclear cell (PBMC) responses could be detected in dogs with atopic dermatitis. PBMCs were isolated by the density centrifugation from dogs with atopic dermatitis that were skin test positive for D. farinae, dogs with atopic dermatitis that were skin test negative for D. farinae, and healthy dogs. Cells were cultured with increasing concentrations of the D. farinae extract, no antigen, vaccine antigens or concanavalin A (ConA). There was significantly greater responsiveness of PBMCs from the D. farinae positive dogs than from either the D. farinae negative or healthy dogs (ANOVA, P<0.05). In contrast, no significant differences were observed in the control responses between the three groups. This is the first study to demonstrate that D. farinae specific circulating memory cells are involved in the pathogenesis of canine house dust mite hypersensitivity.

Allergen-induced Th1 and Th2 cytokine secretion in relation to specific allergen sensitization and atopic symptoms in children

BACKGROUND

Allergic diseases are believed to be due to T helper (Th)2-like immunity to allergens in affected tissues, and immune responses to allergens are characterized by a cross-regulation between Th1 and Th2 cells. Atopic individuals may develop IgE antibodies to only one or more allergens. However, the mechanisms behind sensitization to a specific allergen, e.g. why an individual develops IgE to cat but not birch, are not known. Our aim was to study birch- and cat-induced Th1 and Th2 cytokine secretion in children who were sensitized to birch but not to cat, and vice versa.

MATERIALS AND METHODS

The subjects in the study were 60 12-year-old children. Seventeen of the children were sensitized (skin prick test and circulating IgE positive) to birch but not cat, 13 were sensitized to cat but not birch, 11 were sensitized both to birch and cat, and 19 children were skin prick test and circulating IgE negative. Forty-six children had a history of atopic symptoms, and 42 of them had current symptoms. Peripheral blood mononuclear cells were separated from venous blood and stimulated with cat or birch allergen. The levels of IL-4, IL-5, IL-9, IL-10, IL-13 and IFN-gamma in the cell supernatants were analysed by ELISA.

RESULTS

Sensitized children produced more of the Th2 cytokines IL-4, IL-5, IL-9 and IL-13 than non-sensitized atopic and non-atopic children in response to stimulation with the allergen they were sensitized to. High levels of the Th2 cytokines IL-4 and IL-5 and low levels of the anti-inflammatory cytokine IL-10 were associated with atopic symptoms, and high cat-induced IL-9 levels with asthma.

CONCLUSIONS

The Th2 cytokines IL-4, IL-5, IL-9 and IL-13 were all commonly detected in sensitized children after stimulation with the specific, in contrast to an unrelated, allergen. Atopic symptoms were associated with increased levels of IL-4 and IL-5 and tended to be associated with low levels of IL-10, and asthma with high cat-induced IL-9 levels.

Proinflammatory cytokines (IL-17, IL-6, IL-18 and IL-12) and Th cytokines (IFN-gamma, IL-4, IL-10 and IL-13) in patients with allergic asthma

Allergen-reactive T helper type-2 (Th2) cells and proinflammatory cytokines have been suggested to play an important role in the induction and maintenance of the inflammatory cascade in allergic asthma. We compared the plasma concentrations of novel proinflammatory cytokines IL-17 and IL-18, other proinflammatory cytokines IL-6 and IL-12, Th2 cytokines IL-10 and IL-13, and intracellular interferon-gamma (IFN-gamma) and IL-4 in Th cells of 41 allergic asthmatics and 30 sex- and age-matched health control subjects. Plasma cytokines were measured by enzyme-linked immunosorbent assay. Intracellular cytokines were quantified by flow cytometry. Plasma IL-18, IL-12, IL-10, IL-13 concentrations were significantly higher in allergic asthmatic patients than normal control subjects (IL-18: median 228.35 versus 138.72 pg/ml, P < 0.001; IL-12: 0.00 versus 0.00 pg/ml, P = 0.001; IL-10: 2.51 versus 0.05 pg/ml, P < 0.034; IL-13: 119.38 versus 17.89 pg/ml, P < 0.001). Allergic asthmatic patients showed higher plasma IL-17 and IL-6 concentrations than normal controls (22.40 versus 11.86 pg/ml and 3.42 versus 0.61 pg/ml, respectively), although the differences were not statistically significant (P = 0.077 and 0.053, respectively). The percentage of IFN-gamma-producing Th cells was significantly higher in normal control subjects than asthmatic patients (23.46 versus 5.72%, P < 0.001) but the percentage of IL-4 producing Th cells did not differ (0.72 versus 0.79%, P > 0.05). Consequently, the Th1/Th2 cell ratio was significantly higher in normal subjects than asthmatic patients (29.6 versus 8.38%, P < 0.001). We propose that allergic asthma is characterized by an elevation of both proinflammatory and Th2 cytokines. The significantly lower ratio of Th1/Th2 cells confirms a predominance of Th2 cells response in allergic asthma.

Counterbalancing of TH2-driven allergic airway inflammation by IL-12 does not require IL-10

BACKGROUND

Asthma is characterized by allergen-induced airway inflammation orchestrated by TH2 cells. The TH1-promoting cytokine IL-12 is capable of inhibiting the TH2-driven allergen-induced airway changes in mice and is therefore regarded as an interesting strategy for treating asthma.

OBJECTIVE

The antiallergic effects of IL-12 are only partially dependent of IFN-gamma. Because IL-12 is a potent inducer of the anti-inflammatory cytokine IL-10, the aim of the present study was to investigate in vivo whether the antiallergic effects of IL-12 are mediated through IL-10.

METHODS

C57BL/6J-IL-10 knock-out (IL-10(-/-)) mice were sensitized intraperitoneally to ovalbumin (OVA) and subsequently exposed from day 14 to day 21 to aerosolized OVA (1%). IL-12 was administered intraperitoneally during sensitization, subsequent OVA exposure, or both.

RESULTS

IL-12 inhibited the OVA-induced airway eosinophilia, despite the absence of IL-10. Moreover, a shift from a TH2 inflammatory pattern toward a TH1 reaction was observed, with concomitant pronounced mononuclear peribronchial inflammation after IL-12 treatment. Allergen-specific IgE synthesis was completely suppressed only when IL-12 was administered along with the allergen sensitization. Furthermore, treating the animals with IL-12 at the time of the secondary allergen challenge resulted not only in a significant suppression of the airway responsiveness but also in an important IFN-gamma-associated toxicity.

CONCLUSIONS

These results indicate that IL-12 is able to inhibit allergen-induced airway changes, even in the absence of IL-10. In addition, our results raise concerns regarding the redirection of TH2 inflammation by TH1-inducing therapies because treatment with IL-12 resulted not only in a disappearance of the TH2 inflammation but also in a TH1-driven inflammatory pulmonary pathology.