Reduced production of interleukin 12 by interferon gamma primed alveolar macrophages from atopic asthmatic subjects

Distinct roles of PI3Kδ and PI3Kγ in a toluene diisocyanate-induced murine asthma model

TDI-induced asthma is characterized by neutrophil-dominated airway inflammation and often associated with poor responsiveness to steroid treatment. Both PI3Kδ and PI3Kγ have been demonstrated to play important proinflammatory roles in ovalbumin-induced asthma. We've already reported that blocking pan PI3K effectively attenuated TDI-induced allergic airway inflammation. Yet the specific functions of PI3Kδ and PI3Kγ in TDI-induced asthma are still unclear. Male BALB/c mice were first dermally sensitized and then challenged with TDI to generate an asthma model. Sellective inhibitors of PI3Kδ (IC-87114, AMG319) and PI3Kγ (AS252424, AS605240) were respectively given to the mice after each airway challenge. Treatment with IC-87114 or AMG319 after TDI exposure led to significantly decreased airway hyperresponsiveness (AHR), less neutrophil and eosinophil accumulation, attenuated airway smooth muscle (ASM) thickening, less M1 and M2 macrophages in lung, as well as lower levels of IL-4, IL-5, IL-6 and IL-18 in bronchoalveolar lavage fluid (BALF) and recovered IL-10 production. While mice treated with AS252424 or AS605240 had increased AHR, more severe ASM thickening, larger numbers of neutrophils and eosinophils, more M1 but less M2 macrophages, and higher BALF levels of IL-4, IL-5, IL-6, IL-10, IL-12, IL-18 when compared with those treated with vehicle. These data revealed that pharmacological inhibition of PI3Kδ attenuates TDI-induced airway inflammation while PI3Kγ inhibition exacerbates TDI-induced asthma, indicating distinct biological functions of PI3Kδ and PI3Kγ in TDI-induced asthma.

Sojadodamgangki-tang attenuates allergic lung inflammation by inhibiting T helper 2 cells and Augmenting alveolar macrophages

ETHNOPHARMACOLOGICAL RELEVANCE

Sojadodamgangki-tang (SDG) is a traditional East-Asian herbal medicine mainly composed of Pinellia ternate (Thunb.) Makino, Perilla frutescens (L.) Britt and 10 kinds of medicinal herbs. It has been used to treat asthma and mucus secretion including lung and bronchi.

AIM OF THE STUDY

The aim of this study was to investigate the anti-inflammatory effects of Sojadodamgangki-tang (SDG) on allergic lung inflammation in vitro and in vivo as well as the underlying mechanisms.

MATERIALS AND METHODS

We used an ovalbumin (OVA)-induced murine allergic airway inflammation model. Five groups of 8-week-old female BALB/C mice were divided into the following groups: saline control group, the vehicle (allergic) group that received OVA only, groups that received OVA and SDG (200 mg/kg or 400 mg/kg), and a positive control group that received OVA and Dexamethasone (5 mg/kg). In vitro experiments include T helper 2 (TH2) polarization system, murine macrophage cell culture, and human bronchial epithelial cell line (BEAS-2B) culture.

RESULTS

SDG administration reduced allergic airway inflammatory cell infiltration, especially of eosinophils, mucus production, Th2 cell activation, OVA-specific immunoglobulin E (IgE), and total IgE production. Moreover, the activation of alveolar macrophages, which leads to immune tolerance in the steady state, was promoted by SDG treatment. Interestingly, SDG treatment also reduced the production of alarmin cytokines by the human bronchial epithelial cell line BEAS-2B stimulated with urban particulate matter.

CONCLUSION

Our findings indicate that SDG has potential as a therapeutic drug to inhibit Th2 cell activation and promote alveolar macrophage activation.

Addressing unmet needs in understanding asthma mechanisms: From the European Asthma Research and Innovation Partnership (EARIP) Work Package (WP)2 collaborators

Asthma is a heterogeneous, complex disease with clinical phenotypes that incorporate persistent symptoms and acute exacerbations. It affects many millions of Europeans throughout their education and working lives and puts a heavy cost on European productivity. There is a wide spectrum of disease severity and control. Therapeutic advances have been slow despite greater understanding of basic mechanisms and the lack of satisfactory preventative and disease modifying management for asthma constitutes a significant unmet clinical need. Preventing, treating and ultimately curing asthma requires co-ordinated research and innovation across Europe. The European Asthma Research and Innovation Partnership (EARIP) is an FP7-funded programme which has taken a co-ordinated and integrated approach to analysing the future of asthma research and development. This report aims to identify the mechanistic areas in which investment is required to bring about significant improvements in asthma outcomes.

Anti-inflammatory potential of PI3Kδ and JAK inhibitors in asthma patients

Background

Phosphatidylinositol 3-kinase delta (PI3Kδ) and Janus-activated kinases (JAK) are both novel anti-inflammatory targets in asthma that affect lymphocyte activation. We have investigated the anti-inflammatory effects of PI3Kδ and JAK inhibition on cytokine release from asthma bronchoalveolar lavage (BAL) cells and T-cell activation, and measured lung PI3Kδ and JAK signalling pathway expression.

Method

Cells isolated from asthma patients and healthy subjects were treated with PI3Kδ or JAK inhibitors, and/or dexamethasone, before T-cell receptor stimulation. Levels of IFNγ, IL-13 and IL-17 were measured by ELISA and flow cytometry was used to assess T-cell activation. PI3Kδ, PI3Kγ, phosphorylated protein kinase B (pAKT) and Signal Transducer and Activator of Transcription (STAT) protein expression were assessed by immunohistochemistry in bronchial biopsy tissue from asthma patients and healthy subjects. PI3Kδ expression in BAL CD3 cells was measured by flow cytometry.

Results

JAK and PI3Kδ inhibitors reduced cytokine levels from both asthma and healthy BAL cells. Combining dexamethasone with either a JAK or PI3Kδ inhibitor showed an additive anti-inflammatory effect. JAK and PI3Kδ inhibitors were shown to have direct effects on T-cell activation. Immunohistochemistry showed increased numbers of PI3Kδ expressing cells in asthma bronchial tissue compared to controls. Asthma CD3 cells in BAL expressed higher levels of PI3Kδ protein compared to healthy cells.

Conclusions

Targeting PI3Kδ or JAK may prove effective in reducing T-cell activation and the resulting cytokine production in asthma.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-016-0436-2) contains supplementary material, which is available to authorized users.

Risks for infection in patients with asthma (or other atopic conditions): is asthma more than a chronic airway disease?

Most of the research effort regarding asthma has been devoted to its causes, therapy, and prognosis. There is also evidence that the presence of asthma can influence patients' susceptibility to infections, yet research in this aspect of asthma has been limited. There is additional debate in this field, with current literature tending to view the increased risk of infection among atopic patients as caused by opportunistic infections secondary to airway inflammation, especially in patients with severe atopic diseases. However, other evidence suggests that such risk and its underlying immune dysfunction might be a phenotypic or clinical feature of atopic conditions. This review argues (1) that improved understanding of the effects of asthma or other atopic conditions on the risk of microbial infections will bring important and new perspectives to clinical practice, research, and public health concerning atopic conditions and (2) that research efforts into the causes and effects of asthma must be juxtaposed because they are likely to guide each other.

What does tympanostomy tube placement in children teach us about the association between atopic conditions and otitis media?

Otitis media is the most common infection second only to viral upper respiratory infection in the outpatient setting. Tympanostomy tube insertion (TTI) is the most common ambulatory surgical procedure in the USA. While many risk factors for otitis media have been identified, atopic conditions have been underrecognized as risk factors for recurrent and persistent otitis media. Given that asthma and other atopic conditions are the most common chronic conditions during childhood, it is worth examining the association between atopic conditions and risk of otitis media, which can provide insight into how atopic conditions influence the risk of microbial infections. This paper focuses its discussion on otitis media; however, it is important that the association between atopic conditions and risk of otitis media be interpreted in the context of the association of atopic conditions with increased risks of various microbial infections.

Asthma and risk of non-respiratory tract infection: a population-based case-control study

OBJECTIVES

Asthmatics have increased risks of airway-related infections. Little is known about whether this is true for non-airway-related serious infections such as Escherichia coli bloodstream infection (BSI). We assessed whether asthma is associated with a risk of developing community-acquired E coli BSI.

DESIGN

The study was designed as a population-based retrospective case-control study.

SETTING

This population-based study was conducted in Olmsted County, Minnesota.

PARTICIPANTS

The study included 259 all eligible community-acquired E coli BSI cases in Olmsted County, MN between 1998 and 2007 and 259 birthday-matched, gender-matched and residency-matched controls.

PRIMARY AND SECONDARY OUTCOME MEASURES

Only community-acquired E coli BSI cases as the primary outcome was included. Asthma status as an exposure was ascertained by predetermined criteria. An adjusted OR and 95% CI for the association between asthma and risk of community-acquired E coli BSI was calculated using conditional logistic regression.

RESULTS

Of 259 eligible cases, 179 (69%) were women and mean age was 61±22 years. Of the 259 cases 37 (14%) and 16 (6%) of 259 controls had a prior history of asthma (adjusted OR 2.74; 95% CI 1.11 to 6.76; p=0.029). The population attributable risk of asthma for community-acquired E coli BSI was 9%. Although not statistically significant, there was a borderline association between having a history of food allergy and increased risk of community-acquired E coli BSI (6% vs 2%; adjusted OR 3.51; 95% CI 0.94 to 13.11; p=0.062).

CONCLUSIONS

Based on the findings of the current population-based, case-control investigation, a history of asthma may be associated with risk of community-acquired E coli BSI. The impact of asthma on risk of microbial infections may go beyond airways.

The role of macrophages in obstructive airways disease: chronic obstructive pulmonary disease and asthma

Macrophages are a major cellular component of the innate immune system, and play an important role in the recognition of microbes, particulates, and immunogens and to the regulation of inflammatory responses. In the lung, macrophages react with soluble proteins that bind microbial products in order to remove pathogens and particles and to maintain the sterility of the airway tract. Chronic obstructive pulmonary disease and asthma are both obstructive airway diseases that involve chronic inflammation of the respiratory tract which contributes to disease progression. In the case of COPD, there is increasing evidence that lung macrophages orchestrate inflammation through the release of chemokines that attract neutrophils, monocytes and T cells and the release of several proteases. On the other hand, in asthma, it seems that alveolar macrophages are inappropriately activated and are implicated in the development and progression of the disease. In this review we summarize the current basic and clinical research studies which highlight the role of macrophages in asthma and COPD.

The alveolar macrophages in asthma: a double-edged sword

Asthma is a complex disease of the lungs, which is characterized by airway inflammation and airway hyperresponsiveness (AHR). Alveolar macrophages (AMs), one of the prominent immune system cells found in the airways, have been implicated in the development and progression of asthma. AMs constitute a unique subset of pulmonary macrophages, which serve as a first line of defense against foreign invaders to the lung tissue. In addition, based on human and animal studies, they have also been found to regulate pro- and anti-inflammatory responses in the airways, suggesting that these cells have a critical role in asthma. In this review, our focus is to evaluate the relevance of AMs in the context of asthma, and the underlying mechanisms that regulate their functions.

Evidence of association between interferon regulatory factor 5 gene polymorphisms and asthma

Asthma is a heterogeneous disorder hallmarked by chronic inflammation in the respiratory system. Exacerbations of asthma are correlated with respiratory infections. Considering the implication of interferon regulatory factor 5 (IRF5) in innate and adaptive immunity, we investigated the preferential transmission patterns of ten IRF5 gene polymorphisms in two asthmatic family cohorts. A common IRF5 haplotype was found to be associated with asthma and the severity of asthmatic symptoms. Stratified analysis of subgroups of asthmatic individuals revealed that the associations were more pronounced in nonatopic asthmatic individuals. In addition, the risk alleles of IRF5 polymorphisms for asthma were almost completely opposite to those for autoimmune disorders. Our study provides the first evidence of association between IRF5 and asthma, and sheds light on the related but potentially distinct roles of IRF5 alleles in the pathogenesis of asthma and autoimmune disorders.

Viruses exacerbating chronic pulmonary disease: the role of immune modulation

Chronic pulmonary diseases are a major cause of morbidity and mortality and their impact is expected to increase in the future. Respiratory viruses are the most common cause of acute respiratory infections and it is increasingly recognized that respiratory viruses are a major cause of acute exacerbations of chronic pulmonary diseases such as asthma, chronic obstructive pulmonary disease and cystic fibrosis. There is now increasing evidence that the host response to virus infection is dysregulated in these diseases and a better understanding of the mechanisms of abnormal immune responses has the potential to lead to the development of new therapies for virus-induced exacerbations. The aim of this article is to review the current knowledge regarding the role of viruses and immune modulation in chronic pulmonary diseases and discuss avenues for future research and therapeutic implications.

Macrophages in allergic asthma: fine-tuning their pro- and anti-inflammatory actions for disease resolution

Macrophages exert prominent effects in the defense of the respiratory tract from airborne pathogens. These cells are specialized to recognize, phagocytose, and destroy these infectious agents and then promote appropriate tissue repair after successful pathogen clearance. For reasons that are not presently clear, macrophages appear to be inappropriately activated during asthma responses. Evidence stems from the appearance of either classically (or M1) and alternatively activated (or M2) cells in the alveolar compartment of asthmatic lung. Macrophages localized in the interstitial area of the lung appear to be less prone to polarization toward either the M1 or M2 phenotype as these cells predominately express interleukin-10 and exhibit immunoregulatory properties. Effective treatment of clinical asthma, regardless of severity, might depend on restoring an appropriate balance between M1, M2, and immunoregulatory macrophages in the lung.

Interleukin-12 peripheral blood levels in asthmatic children

Interleukin-12 (IL-12) was measured in 45 asthmatic children aged 3 to 16 years. The assessments were performed on 20 children during an episode of acute exacerbation and on 25 children during remission. There was no significant difference between the mean IL-12 level during exacerbation (1.63 ± 2.08 pg/mL) and during remission (0.88 ± 0.56 pg/mL) (p = .83). A positive, but insignificant, correlation was found between forced expiratory volume in 1 second and IL-12 (p = .634). IL-12 levels were significantly lower in children with a positive family history of asthma (1.13 ± 1.78 pg/mL) compared with those without (1.31 ± 1.06 pg/mL) (p < .012), supporting the theory that the gene-environment interactions affect the immune responses. IL-12 peripheral blood levels had no detectable impact on the course of established asthma in the study population.

Secreted phospholipase A2 group X overexpression in asthma and bronchial hyperresponsiveness

RATIONALE

Secreted phospholipase A(2) enzymes (sPLA(2)s) play key regulatory roles in the biosynthesis of eicosanoids, such as the cysteinyl leukotrienes, but the role of these enzymes in the pathogenesis of asthma is not known.

OBJECTIVES

To establish if sPLA(2)s are overexpressed in the airways of patients with asthma, and to determine if these enzymes may play a role in the generation of eicosanoids in exercise-induced bronchoconstriction.

METHODS

Induced sputum samples were obtained from subjects with asthma with exercise-induced bronchoconstriction and nonasthmatic control subjects at baseline, and on a separate day 30 minutes after exercise challenge. The expression of the PLA(2)s in induced sputum cells and supernatant was determined by quantitative polymerase chain reaction, immunocytochemistry, and Western blot.

MEASUREMENTS AND MAIN RESULTS

The sPLA(2)s expressed at the highest levels in airway cells of subjects with asthma were groups X and XIIA. Group X sPLA(2) (sPLA(2)-X) was differentially overexpressed in asthma and localized to airway epithelial cells and bronchial macrophages. The gene expression, immunostaining in airway epithelial cells and bronchial macrophages, and the level of the extracellular sPLA(2)-X protein in the airways increased in response to exercise challenge in the asthma group, whereas the levels were lower and unchanged after challenge in nonasthmatic control subjects.

CONCLUSIONS

Increased expression of sPLA(2)-X may play a key role in the dysregulated eicosanoid synthesis in asthma.

Physiological concentrations of transforming growth factor beta1 selectively inhibit human dendritic cell function

In this study the effects of different in vitro conditioning with transforming growth factor (TGF) beta1 on human monocyte-derived DC maturation (hMo-DC) were investigated. hMo-DC differentiated in the presence of physiologically relevant concentrations of TGFbeta1 (2 ng/ml) failed to undergo complete maturation despite adequate stimulation with LPS or LPS+IFNgamma. These hMo-DC did not produce IL-12p70 or PGE2, and showed decreased IL-10 and IL-18 production and HLA-DR expression. However, the expression of these molecules, except for IL-12p70, was not significantly affected in hMo-DC differentiated in the presence of lower concentrations of TGFbeta1 (0.2 and 0.02 ng/ml). Exposure of hMo-DC to TGFbeta1 (2 ng/ml) after they had completed differentiation had minimal effects. Thus, the functional response of hMo-DC to LPS or LPS+IFNgamma depended on the stage of hMo-DC differentiation at which cells were first exposed to TGFbeta1 and on the concentration of TGFbeta1. These results suggest that in the in vivo micro-environment, the concentrations and the timing of monocyte exposure to TGFbeta1 may be crucial in the differentiation of DC toward more or less mature phenotypes, and this may have important implications for DC functions. The decrease in T-cell proliferation and a small increase in IL-5 production by T cells co-cultured with hMo-DC that had been treated with TGFbeta1, suggest the possibility that in vivo such DC may provide chronic, but incomplete signals to T cells, and this could be a potential mechanism underlying polarisation of T cells towards anergy.

Evaluation of Th1-like, Th2-like and immunomodulatory cytokine mRNA expression in the skin of dogs with immunomodulatory-responsive lymphocytic-plasmacytic pododermatitis

The term immunomodulatory-responsive lymphocytic-plasmacytic pododermatitis (ImR-LPP) has previously been proposed to denote a subpopulation of dogs with idiopathic pododermatitis. The objective of this study was to quantify the expression of mRNA encoding Th(1)-like [interferon (IFN)-gamma, interleukin (IL)-2 and IL-12], Th(2)-like [IL-4 and IL-6] and immunomodulatory cytokines [IL-10 and transforming growth factor (TGF)-beta] in lesional ImR-LPP, nonlesional ImR-LPP and healthy control pedal skin. Gene transcripts were quantified using TaqMan real-time reverse transcriptase-polymerase chain reaction assays. The skin of dogs with ImR-LPP had significant overexpression of IL-6 mRNA (P < 0.05) and significant underexpression of IL-12 mRNA (P < 0.01) compared to healthy controls. In addition, lesional ImR-LPP skin had significantly higher levels of IL-10 transcripts compared to healthy control pedal skin (P < 0.05). Although not attaining significance (P = 0.07), a trend towards reduced TGF-beta mRNA expression in lesional ImR-LPP skin was also evident. There were no significant differences in the levels of IFN-gamma or IL-2 mRNA transcripts among the three skin sample sources. IL-4 mRNA was detected in only one lesional sample. These results suggest that the pathogenesis of ImR-LPP may be associated with a T-cell-mediated inflammatory response characterized by impaired Th(1)-like, but enhanced Th(2)-like cytokine expression.

Activated human dendritic cells express inducible cyclo-oxygenase and synthesize prostaglandin E2 but not prostaglandin D2

Prostaglandins (PG) are well known lipid mediators with important immunoregulatory properties. While exogenous PGE2 has the ability to modulate the function and maturation of antigen presenting cells, such as dendritic cells (DC), it is not clear whether human DC have the capacity to synthesize PGE2 and other prostaglandins themselves. We therefore examined the expression of inducible cyclo-oxygenase (COX-2) by monocyte derived DC and the production of PGE2 and PGD2. Both monocyte derived DC and freshly isolated blood myeloid DC expressed little COX-2 constitutively, though COX-2 expression was rapidly but transiently upregulated in response to lipopolysaccharide stimulation. COX-2 mRNA was detectable within 1 h of LPS exposure, peaked at 4-6 h, and rapidly declined thereafter. COX-2 expression was accompanied by DC synthesis of PGE2, with peak levels present at 6-18 h post-stimulation. In contrast, PGD2 synthesis was not detected at any time point. When DC were activated with LPS in the presence of nimesulide, a COX-2 selective inhibitor, IL-10 synthesis was inhibited, indicating that endogenous prostaglandins regulate DC cytokine production. PGE2 production by DC may therefore modulate DC and T-cell function, thereby shaping the character of the immune response.

Why are dendritic cells important in allergic diseases of the respiratory tract?

Increasing evidence points to the role of antigen-presenting dendritic cells (DC) in regulating adaptive immune responses. DC are especially sensitive to signals derived from microbes, allergens, and the airway tissue microenvironment, can polarize naïve T-cells into either Th1 or Th2 effector cells, and are increasingly recognized as having a central role in the establishment of T-cell memory and tolerance to inhaled antigens. DC form a closely meshed network within the respiratory mucosa and are rapidly recruited from the circulation in response to a variety of proinflammatory stimuli. Studies using animal models have highlighted the role of DC in both initiation and maintenance of allergic airway inflammation. Increased numbers of airway mucosal DC are found in both allergic rhinitis and asthma, and an increasing number of investigators have highlighted important functional differences between DC from atopic and normal individuals. This article reviews recent information on the involvement of DC in the pathogenesis of allergic airway disease and the means by which DC could be exploited as targets for therapy in asthma and allergic rhinitis.

Neurotrophins in inflammatory lung diseases: modulators of cell differentiation and neuroimmune interactions

Chronic inflammatory lung diseases represent a group of severe diseases with increasing prevalence as well as epidemiological importance. Inflammatory lung diseases could result from allergic or infectious genesis. There is growing evidence that the immune and nervous system are closely related not only in physiological but also in pathological reactions in the lung. Extensive communications between neurons and immune cells are responsible for the magnitude of airway inflammation and the development of airway hyperreactivity, a consequence of neuronal dysregulation. Neurotrophins are molecules regulating and controlling this crosstalk between the immune and peripheral nervous system (PNS) during inflammatory lung diseases. They are constitutively expressed by resident lung cells and produced in increasing quantities by immune cells invading the airways under inflammatory conditions. They act as activation, differentiation and survival factors for cells of both the immune and nervous system. This article will review the most recent data of neurotrophin signaling in the normal and inflamed lung and as yet unexplored, roles of neurotrophins in the complex communication within the neuroimmune network.

Airway dendritic cells: co-ordinators of immunological homeostasis and immunity in the respiratory tract

The large quantities and complex mixtures of antigens encountered daily at airway mucosal and alveolar surfaces pose a major challenge to maintenance of immunological homeostasis in the respiratory tract. Amongst this myriad of antigens, the immune system must discriminate between innocuous components that can be tolerated by the host and potentially life-threatening pathogens that require a rapid immune response. Dendritic cells (DC) represent the principal cell type at these sites capable of processing antigens and delivering signals that initiate tolerogenic or immunogenic immune responses. This review will discuss the role of DC at the "front-line" of immune surveillance and homeostasis within the respiratory tract and their role in the pathogenesis of respiratory disease.

The role of dendritic cells in immune regulation and allergic airway inflammation

Dendritic cells (DC) are potent antigen presenting cells that display an extraordinary capacity to present antigen to naïve T-cells and initiate primary immune responses. In the context of the lung and upper airway it is clear that DC play a key role in the regulation of adaptive immune responses to inhaled antigen. DC are particularly sensitive to signals derived from microbes, allergens and the airway tissue microenvironment. By the nature of the signals they provide at the time of antigen presentation, DC can polarize naïve T-cells into either T-helper type 1 (Th1) or Th2 effector cells, and are increasingly recognized as having a central role in the establishment of T-cell memory and peripheral immune tolerance. DC form a network within the upper airway and lung, and are rapidly recruited from the circulation in response to a variety of proinflammatory stimuli. Studies using animal models have highlighted the role of DC in both the initiation and maintenance of allergic airway inflammation. In early childhood, human DC are functionally immature, and this is thought to contribute to the development of allergic sensitization in those children who are genetically at risk for the development of atopy. Increased numbers of airway mucosal DC are found in both allergic rhinitis and asthma, while studies of blood-derived DC have emphasized important differences between the function of DC from atopic and normal individuals. This article reviews recent information on the involvement of DC in allergic airway disease, and the mechanisms by which DC could be exploited as targets for therapy in asthma and allergic rhinitis.

Developmental changes in interleukin-12-producing ability by monocytes and their relevance to allergic diseases

BACKGROUND

The T helper type-2 (Th2)-dominated situation can be observed in allergic diseases such as asthma or atopic dermatitis. A reduced ability to produce IL-12, which is a key cytokine for the induction of Th1 responses, has been proposed to lead to aberrant Th2 development in these disease conditions.

OBJECTIVE

This study was intended to examine how IL-12-producing ability might associate with allergic diseases as a function of age.

METHODS

IL-12 production by monocytes at various ages was assessed in patients with bronchial asthma and/or atopic dermatitis (n = 100) in comparison with non-allergic control subjects (n = 144). Whole blood cells were stimulated with lipopolysaccharide (LPS) after priming with IFN-gamma, then intracellular cytokine expression of IL-12 and IL-8 as a control cytokine of CD14-positive cells was assessed by flow cytometric analysis.

RESULTS

In the control subjects, the ability of monocytes to produce IL-12 was negligible at birth and gradually increased with advancing age, whereas IL-8 production was intense throughout the human life. At more than 7 years of age, IL-12 production of patients with allergic diseases was significantly lower compared with that of control subjects. The unexpected finding was that infants and children below 6 years of age with allergic diseases tended to produce more IL-12 compared with age-matched controls. In this young group, it was noted that enhanced IL-12 production by monocytes was especially observed in allergic patients with specific IgE antibodies against some food allergens. Significant inverse relationships between serum IgE levels and IL-12-producing ability were found in the teenage and adult groups, but not in the younger children.

CONCLUSION

IL-12 appeared to play different roles in the pathogenesis of allergic diseases between younger and older ages.

Investigating the TNP-OVA and direct popliteal lymph node assays for the detection of immunostimulation by drugs associated with anaphylaxis in humans

Using current animal models, it is not possible to identify low-molecular-weight compounds (LMWCs) that are likely to be associated with anaphylaxis. It is generally accepted that the ultimate effector mechanism involves drug-induced IgE antibody. The objective of the present study was to determine if diclofenac, zomepirac and glafenine, which are associated with anaphylaxis in humans, have immunostimulating potential in the murine TNP-OVA (trinitrophenyl-ovalbumin) popliteal lymph node assay (PLNA), and more specifically to determine if the immunostimulation caused by these LMWCs results in IgE antibody production. These LMWCs were chosen because both zomepirac and glafenine were removed from the market due to high association with anaphylaxis, and diclofenac, which remains on the market, is frequently associated with anaphylaxis. In addition to conducting a TNP-OVA PLNA, the immunostimulating potential of these compounds was examined in the direct PLNA. When co-administered with TNP-OVA, all three LMWCs caused dose-dependent (0.25, 0.50, 1.00 and 1.25 mg) increases in popliteal lymph node (PLN) weight and cellularity that were observed beginning with the 0.25-mg dose. In addition, beginning with the 0.25-mg dose, all three compounds caused dose-dependent increases in TNP-OVA specific IgM and IgG(1) antibody-forming cells (AFCs). Diclofenac induced an isotype switch and caused a dose-dependent increase in the number of IgE AFCs with no detectable IgG(2a) AFCs and minimal high-dose-only IgG(2b) AFCs. Zomepirac induced IgE, IgG(2a) and IgG(2b) AFCs following the injection of 0.50 mg only, and glafenine induced IgE, IgG(2a) and IgG(2b) AFCs following the injection of 0.50-1.00 mg. In the direct PLNA, diclofenac caused dose-dependent increases in PLN weight and cellularity that were observed beginning with dose of 0.50 mg, whereas zomepirac failed to increase any PLN parameter and glafenine only increased the PLN weight. These results suggest that diclofenac, zomepirac and glafenine are immunostimulating LMWCs in the TNP-OVA PLNA with the potential to induce IgE antibody against a co-administered hapten-conjugate. Furthermore, these results suggest that the TNP-OVA PLNA offered significant advantages over the direct PLNA. Although it is not realistic to suggest that a single assay, based on a low number of test compounds, can identify all LMWCs with the potential to cause anaphylaxis in humans, these observations do demonstrate the potential utility of the PLNAs in examining LMWC-induced immunomodulation and support further development and investigation of the assays.

Immunotherapy in atopic dermatitis

Atopic dermatitis (AD) is a common inflammatory disease involving the skin and often other organs and systems, mainly respiratory. A definitive general consensus on the AD pathogenesis has not yet been established, however several lines of evidence suggest that T-cells play a crucial role in priming AD early-stage lesions. Main topics involved in the disease pathogenesis have been reviewed, which considered the concept of local and systemic haemopoietic events as important contributors to allergic inflammation, a concept now achieving great acceptance. The recently recognised atopic nature of the skin inflammation in AD has raised increasing interest for treatment with allergen-specific immunotherapy. However, we only found eight studies using specific immunotherapy (SIT) in AD, two double-blind, placebo-controlled (DBPC) and six observational. One controlled and five observational reported favourable outcomes. The one unique study providing negative results was flawed by the ineffective oral route of extract administration. Despite being encouraging, the reported results do not allow definitive conclusions based on meta-analytic techniques because the amount and quality of information in the literature is not sufficient. The highly promising sub-lingual immunotherapy (SLIT) is discussed with its potential capability of controlling not only the skin lesion severity but also its capability of preventing the development of atopic dermatitis into asthma.