Effect of Haemophilus influenzae, Streptococcus pneumoniae and influenza vaccinations on infections, immune response, and asthma control in preschool children with asthma

BACKGROUND

Haemophilus influenzae (H. influenzae), Streptococcus pneumoniae (pneumococcus), and influenza vaccines are administered in children to prevent infections caused by these pathogens. The benefits of vaccination for asthma control in children and the elicited immune response are not fully understood. This study aims to investigate the impact of these vaccinations on respiratory infections, asthma symptoms, asthma severity and control status, pathogen colonization, and in vitro immune responses to different stimulants mimicking infections in asthmatic children.

METHODS

Children aged 4-6 years were recruited into the multi-center prospective PreDicta study conducted across five European countries. Information about vaccination history, infections, antibiotic use, inhaled corticosteroid (ICS) use, and asthma symptoms in the last 12 months were obtained from questionnaires of the study. Nasopharyngeal samples were collected at the first visit to assess bacterial and viral colonization, and venous blood for isolation of peripheral blood mononuclear cells (PBMCs). PBMCs were stimulated with phytohemagglutinin, R848, Poly I:C and zymosan. The levels of 22 cytokines and chemokines were measured in cell culture supernatants using a luminometric multiplex assay.

RESULTS

140 asthmatic preschool children (5.3 ± 0.7 years) and 53 healthy children (5.0 ± 0.8 years) from the PreDicta cohort were included in the current study. Asthmatic children were associated with more frequent upper and lower respiratory infections, and more frequent and longer duration of antibiotic use compared to healthy children. In asthmatic children, sufficient H. influenzae vaccination was associated with a shorter duration of upper respiratory infection (URI) and overall use and average dose of ICS. The airway colonization was characterized by less pneumococcus and more rhinovirus. Pneumococcal vaccination was associated with a reduction in the use rate and average dose of ICS, improved asthma control, and less human enterovirus and more H. influenzae and rhinovirus (RV) airway colonization. Influenza vaccination in the last 12 months was associated with a longer duration of URI, but with a decrease in the occurrence of lower respiratory infection (LRI) and the duration of gastrointestinal (GI) infection and antibiotic use. Asthmatic preschoolers vaccinated with H. influenzae, pneumococcus or influenza presented higher levels of Th1-, Th2-, Th17- and regulatory T cells (Treg)-related cytokines in unstimulated PBMCs. Under stimulation, PBMCs from asthmatic preschoolers with pneumococcal vaccination displayed a predominant anti-inflammatory immune response, whereas PBMCs from asthmatic children with sufficient H. influenzae or influenza vaccination were associated with both pro- and anti-inflammatory immune responses.

CONCLUSION

In asthmatic preschoolers, the standard childhood vaccinations to common respiratory pathogens have beneficial effects on asthma control and may modulate immune responses relevant to asthma pathogenesis.

The Role of Defective Epithelial Barriers in Allergic Lung Disease and Asthma Development

The respiratory epithelium constitutes the physical barrier between the human body and the environment, thus providing functional and immunological protection. It is often exposed to allergens, microbial substances, pathogens, pollutants, and environmental toxins, which lead to dysregulation of the epithelial barrier and result in the chronic inflammation seen in allergic diseases and asthma. This epithelial barrier dysfunction results from the disturbed tight junction formation, which are multi-protein subunits that promote cell–cell adhesion and barrier integrity. The increasing interest and evidence of the role of impaired epithelial barrier function in allergy and asthma highlight the need for innovative approaches that can provide new knowledge in this area. Here, we review and discuss the current role and mechanism of epithelial barrier dysfunction in developing allergic diseases and the effect of current allergy therapies on epithelial barrier restoration.

Rivaroxaban protects from the oxysterol-induced damage and inflammatory activation of the vascular endothelium

BACKGROUND

Rivaroxaban is one of the direct factor Xa inhibitors. Its function in the inactivated coagulation cascade is unclear. The aim of the study was to assess the effect of rivaroxaban on the endothelial integrity and inflammatory properties of endothelial cells stimulated by 25-hydroxycholesterol (25-OHC).

METHODS

HUVECs were stimulated with 25-OHC, rivaroxaban and 25-OHC+ rivaroxaban. HUVEC integrity and permeability were measured using the xCELLigence system and paracellular flux assay. The mRNA expression of tissue factor, ICAM-1, VEGF, IL-33, MCP-1, TNF-α was analyzed in the real-time PCR. Apoptosis and viability were measured by flow cytometry. The VEGF protein concentration was assessed by ELISA. The confocal microscope was used to evaluate the expression of VE-cadherin in endothelial cells.

RESULTS

25-OHC decreased endothelial cell integrity and increased the mRNA expression of IL-33, tissue factor, ICAM-1, MCP-1, VEGF, TNF-α as compared to unstimulated controls. Following the stimulation with rivaroxaban, HUVEC restored integrity disrupted by 25-OHC (p < .01). In HUVECs pre-stimulated with oxysterol, rivaroxaban decreased mRNA expression of IL-33, TNF-α, chemokines MCP-1, ICAM-1, VEGF and tissue factor (p < .01). Rivaroxaban 100 mg/ml+25-OHC increased the VE-cadherin expression in endothelium as compared to 25-OHC (p < .05).

CONCLUSION

Our finding suggests that rivaroxaban may restore the endothelial barrier and inhibit the inflammatory activation caused by oxysterol in vitro.

Escherichia coli lipopolysaccharide may affect the endothelial barrier and IL-10 expression of apolipoprotein B100-pulsed dendritic cells

Atherogenesis is associated with chronic gut infections; however, the mechanisms are not clear. The aim of the study was to determine whether lipopolysaccharide of E. coli (E. coli LPS) may affect endothelial barrier and modify IL-10 expression in dendritic cells (DCs). Human umbilical vein endothelial cells (HUVECs) and monocyte-derived DCs were treated with E. coli LPS, apolipoprotein B100 (ApoB100) and 7-ketocholesterol (7-kCH) - harmful oxidized form of cholesterol. The effect of E. coli LPS, 7-kCH and ApoB100 on the barrier functions of HUVECs in real-time cell electric impedance sensing system (RTCA-DP) was assessed. Furthermore, the effect of 7-kCH and ApoB100 on barrier functions of HUVECs co-cultured with DCs previously treated with LPS was analyzed. Both E. coli LPS and 7-kCH decreased barrier functions of HUVECs and reduced tight junction protein mRNA expression, whereas ApoB100 increased endothelial barrier. In DCs, ApoB100 and E. coli LPS decreased IL-10 mRNA expression. In HUVECs co-cultured with DCs treated with LPS and subsequently pulsed with ApoB100 or 7-kCH, IL-10 mRNA expression was lower. E. coli LPS-exposed DCs diminished the protective effect of ApoB100 on endothelial integrity and led to the decrease in occludin mRNA expression. LPS potentially derived from gut microflora may destabilize endothelial barrier together with oxidized cholesterol and intensify the immunogenicity of ApoB100.

Single Triglyceride-Rich Meal Destabilizes Barrier Functions and Initiates Inflammatory Processes of Endothelial Cells

Postprandial hypertriglyceridemia is an independent risk factor for cardiovascular disease. The aim of this study was to assess the effects of a single fat-rich meal on barrier functions and inflammatory status on human umbilical vascular endothelial cells (HUVECs), furthermore we assess the effects of mixture of palmitic acid and 25-hydroxycholesterol (PA +25OHCH) on integrity of endothelial cells and their inflammatory properties. HUVECs were induced with serum of healthy volunteers taken before, and 3 h after, the consumption of a meal with a standardized daily required dose of fats. In addition, endothelial cells were induced with PA +25OHCH (800 μM/L+10 μg/mL). Total cholesterol, triglycerides (TGs), high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, high sensitivity c-reactive protein, and glucose were measured at fasting and postprandially. HUVEC integrity was measured in the RTCA-DP xCELLigence system. mRNA expression of interleukin (IL)-33, IL-32, intercellular adhesion molecule-1 (ICAM-1), monocyte chemoattractant protein-1 (MCP-1), CX3C-chemokine, vascular endothelial growth factor (VEGF) occludin, and VE-cadherin was analyzed by real-time polymerase chain reaction. Viability and apoptosis were assessed in flow cytometry. The level of VEGF and IL-33 in fasting and postprandial serum was assessed by enzyme-linked immunosorbent assay (ELISA). Three hours after consumption of a fatty meal, all patients displayed increased levels of TGs and Toll-like receptors (110 ± 37 mg/dL versus 182 ± 64 mg/dL P < 0.05) (24 ± 11 mg/dL versus 42 ± 14 mg/dL P < 0.05). Postprandial serum and PA +25OHCH caused >20% decrease of HUVEC integrity than fasting serum (P < 0.001). HUVEC disintegration was accompanied by a decrease of occludin mRNA expression as compared with fasting serum (P < 0.05). The fatty meal affected neither VE-cadherin mRNA expression nor its apoptosis (P > 0.05). Mixture of PA +25OHCH caused decrease of VE-cadherin mRNA expression as compared with fasting serum (P < 0.01). PA +25OHCH did not affect HUVEC apoptosis (P > 0.05). Postprandial serum and PA +25OHCH caused increase of IL-33, MCP-1, ICAM-1, IL-32, VEGF, and CX3C-chemokine mRNA expression as compared with fasting serum (P < 0.05). Moreover, level of VEGF in fatty serum was significantly higher (P < 0.001). Postprandial lipemia after a single fatty meal may destabilize the endothelial barrier and initiate inflammatory processes.

Increased plasma concentrations of interleukin 35 in patients with coronary artery disease

INTRODUCTION

Atherosclerosis leading to coronary artery disease (CAD) is a chronic inflammatory condition. Interleukin 35 (IL-35) released by regulatory T cells (Tregs) has been found to be associated with CAD in the Chinese population. However, nothing is known about the relation between IL-35 concentrations and cholesterol levels. The aim of the study was to assess the levels of IL-35 in CAD patients and healthy subjects from a Caucasian population, and to analyze the relationship between IL-35 and the levels of total cholesterol, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol, left ventricular ejection fraction (LVEF), sex and postmenopausal status.

MATERIAL AND METHODS

Thirty-one patients with CAD and 30 healthy controls were included in the study. Levels of plasma IL-35 were analyzed by ELISA. The LVEF was assessed by transthoracic echocardiographic examination. Plasma levels of cholesterol fractions and C-reactive protein (CRP) were assessed by immunoenzymatic methods.

RESULTS

The CAD patients had higher levels of IL-35 as compared to healthy controls (58.1 ±16.6 pg/ml vs. 5.35 ±3.35 pg/ml; p < 0.001). IL-35 levels negatively correlated with total and LDL cholesterol concentrations (R = -0.31, p < 0.01) and positively correlated with HDL cholesterol in men (R = 0.53, p < 0.01). In women, IL-35 levels negatively correlated with LVEF (R = -0.29, p < 0.05) and positively with the duration of postmenopausal status (R = 0.55, p < 0.01).

CONCLUSIONS

These results suggest a possible association between high levels of IL-35 and CAD.

Endothelial integrity may be regulated by a specific antigen via an IgE-mediated mechanism

BACKGROUND

Human vascular endothelial function and integrity may be regulated by many non-specific factors. However, the potential influence of specific antigens via an IgE-mediated mechanism remains unknown. The aim of the study was to determine the expression of the IgE receptors FcεRI and FcεRII in the human vascular endothelium and to assess their relevance in the IgE-mediated regulation of endothelial integrity.

MATERIAL/METHODS

FcεRI and FcεRII expression in human umbilical vein endothelial cells (HUVEC) was genetically assessed by PCR with respective primers and sequencing. HUVEC were cultured with IL-4, and changes in FcεRI and FcεRII mRNA expression were analyzed by real-time PCR. Changes in the integrity of endothelium pre-treated with anti-BSA-DNP IgE following exposure to the specific BSA-DNP antigen was assessed using the Real-time Cell Electric Impedance Sensing system (RTCA-DP).

RESULTS

PCR and sequencing revealed the expression of FcεRI and FcεRII receptors in the human vascular endothelium. IL-4 caused respective 2- and 3-fold increases in FcεRI and FcεRII mRNA expression. Exposure of endothelium pre-treated with anti-BSA-DNP IgE to specific BSA-DNP antigen led to a 20% increase of endothelial integrity (p<0.05) after 24 hours, but only in cells pre-incubated with IL-4.

CONCLUSIONS

The presence of FcεRI and FcεRII may allow the human vascular endothelium to respond to a specific antigen by increasing its integrity via an IgE-mediated mechanism.

Innate lymphoid cells type 2 - emerging immune regulators of obesity and atherosclerosis

The low-grade inflammation present in obese visceral adipose tissue impairs glucose metabolism, and contributes to the development of insulin resistance and weight gain. Immune processes occurring in response to the deposition of cholesterol within the vascular walls support atherosclerotic plaque growth and contribute to the cardiovascular complications. In both the obese adipose tissue and the atherosclerotic plaque, the Th1-type immune environment dominates over the Th2/Treg-type due to the overproduction of pro-inflammatory cytokines (IFN-γ, IL-6, TNF-α) and the deficiency of Th2-type processes and interleukins (IL-4, IL-5, IL-10, IL-13). So far, Th2 cells and eosinophils have been considered as the main providers of Th2-type mediators and the basis of Th2-type immunity in tissues. However, recently discovered innate lymphoid type 2 cells (ILC2s), which infiltrate lean visceral adipose tissue and the vascular wall, are believed to orchestrate local Th2-like immune responses. Upon activation by tissue-derived IL-33 and IL-25, ILCs2 secrete mostly IL-4, IL-5, IL-9 and IL-13: cytokines responsible for the accumulation of eosinophils and polarization of alternatively-activated macrophages, which altogether create the beneficial anti-inflammatory and metabo-regulatory environment in the adipose tissue and the vascular wall. Consequently, ILC2s-orchestrated immune environment seems to prevent obesity and atherosclerosis. Thus, ILCs2 appear to be the emerging immune regulators of immune and metabolic homeostasis in both adipose tissue and the vascular wall.

The β2-adrenoreceptor gene promoter polymorphisms may modulate β2-agonist- and glucocorticoid-induced IgE synthesis

BACKGROUND

β2-adrenoreceptor (β2-AR) agonists and glucocorticoids (GCS) were shown to induce IgE synthesis in human PBMCs. Serum total IgE levels are associated with single nucleotide polymorphisms (SNPs) of the β2-AR gene. We aimed to assess the association of the effect of fenoterol (β2-AR agonist) on IL-4-driven and budesonide-induced IgE synthesis with genetic variants of β2-AR.

METHODS

The study included 25 individuals: 13 with allergic asthma and/or allergic rhinitis and 12 healthy volunteers. PBMCs were cultured with IL-4, fenoterol and/or budesonide, and IgE concentrations in supernatants were assessed. Five SNPs in positions: -47, -20, 46, 79 and 252 of β2-AR were determined by direct DNA sequencing.

RESULTS

In -47 T/T and -20 T/T patients, incubation with fenoterol resulted in decreased IgE production, whereas in -47 C/T and -47 C/C as well as in -20 C/T and -20 C/C individuals, it was enhanced. In contrast to fenoterol, budesonide-induced IgE synthesis was significantly increased in -47 T/T and -20 T/T patients as compared to -47 C/T, -47 C/C, -20 C/T and -47 C/C individuals. Polymorphisms in positions 46, 79 and 252 were not associated with fenoterol- or budesonide-modulated IgE synthesis. No differences in the distribution of IgE synthesis was seen between atopic and non-atopic individuals carrying the same alleles.

CONCLUSIONS

The differential effect of β2-agonists and GCS on IgE synthesis may be associated with genetic variants of promoter region of the β2-AR gene.

The effect of 7-ketocholesterol and 25-hydroxycholesterol on the integrity of the human aortic endothelial and intestinal epithelial barriers

OBJECTIVE AND DESIGN

The damage of barrtier tissues, such as the vascular endothelium and intestinal epithelium, may lead to disturbances of local immune homeostasis. The aim of the study was to assess and compare the effect of oxidized cholesterols (7-ketocholesterol and 25-hydroxycholesterol) on the barrier properties of human primary aortic endothelium (HAEC) and intestinal epithelium Caco-2 cells using a realtime cell electric impedance sensing system (RTCA-DP).

MATERIALS AND METHODS

HAEC and Caco-2 cells were stimulated with 7-ketocholesterol and 25-hydroxycholesterol by the RTCA-DP system. Apoptosis was assessed by flow cytometry and cell monolayer morphology was assessed under a light microscope.

RESULTS

7-ketocholesterol decreased impedance (nCI) in both the endothelium and epithelium. However, the decrease was more profound in the endothelium. Similarly, although 25-hydroxycholesterol decreased nCI in both the endothelium and epithelium, the effect was weaker than that of 7-ketocholesterol, which caused extensive damage to the endothelial monolayer, while 25-hydroxycholesterol caused partial damage and did not affect the epithelial monolayer. 7-ketocholesterol, but not 25-hydroxycholesterol, increased endothelial cell apoptosis and decreased the viability of endothelial cells. However, 7-ketocholesterol and 25-hydroxycholesterol decreased epithelial cell apoptosis and increased viability.

CONCLUSION

Oxidized cholesterols destroy the HAEC, but not the Caco-2 epithelial barrier, via cell apoptosis dependent on the site of oxidation. Damage to the endothelium by oxidized cholesterol may disrupt local homeostasis and provide open access to inner parts of the vascular wall for lipids, other peripheral blood-derived agents, and immune cells, leading to inflammation and atherogenesis.

The effect of oxidized cholesterol on barrier functions and IL-10 mRNA expression in human intestinal epithelium co-cultured with dendritic cells in the transwell system

The intestinal epithelium is exposed to oxygenated cholesterol products present in foodstuffs. In vitro studies demonstrate the effect of oxysterols on cytokine release by intestinal cells cultured alone. However, physiologically, the response of the intestinal epithelium to external agents occurs in the presence of dendritic cells (DCs). The aim of the study was to analyze the effect of 7-ketocholesterol on the barrier functions and IL-10 mRNA expression of Caco-2 cells in the presence of DCs, and secondly, on IL-10 mRNA expression in DCs. Caco-2 cells were co-cultured with monocyte-derived dendritic cells and induced with 7-ketocholesterol in a transwell system. DCs did not affect the transepithelial electrical resistance (TER) of the Caco-2 cell monolayer, but increased IL-10 mRNA expression in Caco-2 cells. 7-ketocholesterol decreased the TER of Caco-2 cells co-cultured with DCs and diminished IL-10 mRNA expression in Caco-2 cells induced by the presence of DCs. IL-10 mRNA expression fell in DCs co-cultured with Caco-2 cells after treatment with 7-ketocholesterol. Oxidized cholesterols present in gut mucosa may contribute to the decrease of epithelial barrier functions and the inappropriate development of an inflammatory response to food compounds.

Comprehensive insight into immune regulatory mechanisms and vascular wall determinants of atherogenesis - emerging perspectives of immunomodulation

For many years atherosclerosis was believed to be the passive accumulation of cholesterol in vessel walls. Today the picture is more complex, as immune processes occur in atherogenesis. Considerable attention is focused on the particular role of adaptive immune responses orchestrated by T cell subsets. Since the role of Th1/Th2 balance and Th1 cell domination in atherogenesis is already known, the involvement of regulatory T lymphocytes and recently described Th17 cells raises new concerns. On one hand, each of these cells may specifically drive responses of vascular wall tissues and immune cells; however, they are subject to the control of a plethora of tissue- and pathogen-derived agents. Due to ineffective tissue regeneration, remodeling of the vascular wall occurs. The understanding of the immune regulatory network gives perspectives of innovative immunomodulatory therapies of atherosclerosis and the prevention of its complications, such as coronary artery disease.

Claudin-1 expression in airway smooth muscle exacerbates airway remodeling in asthmatic subjects

BACKGROUND

Increased airway smooth muscle (ASM) mass is an essential component of airway remodeling and asthma development, and there is no medication specifically against it. Tight junction (TJ) proteins, which are expressed in endothelial and epithelial cells and affect tissue integrity, might exist in other types of cells and display additional functions in the asthmatic lung.

OBJECTIVE

The aim of this study was to investigate the existence, regulation, and function of TJ proteins in ASM in asthmatic patients.

METHODS

The expression and function of TJ proteins in primary ASM cell lines, human bronchial biopsy specimens, and a murine model of asthma were analyzed by means of RT-PCR, multispectral imaging flow cytometry, immunohistochemistry, Western blotting, 5-(and-6)-carboxyfluorescein diacetate succinimidyl ester staining, tritiated thymidine incorporation, wound-healing assay, and luminometric bead array.

RESULTS

Increased claudin-1 expression was observed in ASM of asthmatic patients, as well as in a murine model of asthma-like airway inflammation. Whereas IL-1β and TNF-α upregulated claudin-1 expression, it was downregulated by the T(H)2 cytokines IL-4 and IL-13 in primary human ASM cells. Claudin-1 was localized to the nucleus and cytoplasm but not to the cell surface in ASM cells. Claudin-1 played a central role in ASM cell proliferation, as demonstrated by increased ASM cell proliferation seen with overexpression and decreased proliferation seen with small interfering RNA knockdown of claudin-1. Overexpression of claudin-1 induced vascular endothelial growth factor and downregulated IL-6, IL-8, and IFN-γ-induced protein 10 production by ASM cells. Claudin-1 upregulation by IL-1β or TNF-α was suppressed by dexamethasone but not by rapamycin, FK506, or salbutamol.

CONCLUSION

These results demonstrate that claudin-1 might play a role in airway remodeling in asthmatic patients by means of regulation of ASM cell proliferation, angiogenesis, and inflammation.

Glucocorticoid-induced immunoglobulin E synthesis by peripheral blood mononuclear cells from allergic and nonallergic subjects

BACKGROUND

Glucocorticoids (GCS) have been shown to induce IgE synthesis in human peripheral blood mononuclear cells (PBMCs) and purified B cells in vitro. However, the differences in immunoglobulin E (IgE) response to GCS between allergic and non-allergic individuals and the mechanism this interaction have not been elucidated.

OBJECTIVE

We aimed to compare the effect of GCS (budesonide) on interleukin (IL)-4-driven IgE production in vitro in allergic and non allergic subjects and assess the engagement of intracellular mechanisms.

METHODS

The study included 22 patients with allergic asthma and/or allergic rhinitis and 24 healthy volunteers. PBMCs were cultured for 11 days with IL-4 and budesonide and IgE concentrations in supernatants were assessed by immunoassays. T and B cell markers were assessed by flow cytometry.

RESULTS

Budesonide enhanced IgE synthesis to higher extent in healthy donors than in allergic patients (mean increase of 16.5 vs 6.3 kU/L, P< .05 respectively) acting through glucocorticoid receptor. Budesonide significantly increased lymhoplasmocytoid cells percentage in both media-controlled (2.5-fold increase) and IL-4-stimulated PBMCs (2-fold increase). Added to IL-4 budesonide decreased the percentage of both T cells and CD40L(+) T cells, but strongly increased the percentage of B cells. Protein tyrosine kinase (PTK) inhibitor decreased, but NF-κB and protein kinase A (PKA) inhibitors expressed modulatory effects on budesonide-induced IgE synthesis.

CONCLUSIONS

Budesonide-induced IgE generation in PBMCs differs in magnitude and seems to involve different mechanisms in atopic and non-atopic subjects.

Influence of statins on effector and regulatory immune mechanisms and their potential clinical relevance in treating autoimmune disorders

Studies have shown that HMG-CoA reductase inhibitors possess anti-inflammatory properties, for example, decreasing serum levels of proinflammatory cytokines (e.g., TNF-α, IL-1β, and IL-6) or decreasing the activity of numerous effector mechanisms. However, they also may influence the immune system by affecting a wide range of regulatory actions, for example, Treg- and Th2-type response activation as well as Th1 and Th17 response diminishing. These features provide the rationale for potential application of statins in treating chronic inflammatory diseases and other disorders with the involvement of the immune system. This article seeks to review the immunomodulatory actions of statins and their possible implementation in treating rheumatoid arthritis, multiple sclerosis, and other autoimmune disorders in humans.

Endocrine disrupters--potential modulators of the immune system and allergic response

Endocrine disrupters (EDs) are environmental pollutants of industrial or agricultural origin (e.g. herbicides, fungicides, insecticides, industrial chemicals) that may influence health of wildlife and human. Endocrine-disrupting effect is obtained by mimicking the action of the steroid hormones and has been associated with several reproductive disorders as well as cancerogenesis both in animals and humans. EDs can also influence synthesis of cytokines, immunoglobulins, and cell mediators as well as immune cell activation and survival. Modulation by EDs of interleukin-4 production, Th1/Th2 balance and IgE production suggest their potential effect on allergic immune responses. The aim of this review was to summarize data indicating a potential effect of EDs exposure on the immune system and allergic responses.