Association of neuropeptides with Th1/Th2 balance and allergic sensitization in children

MAIT cell activation in adolescents is impacted by bile acid concentrations and body weight

Bile acids (BAs) are produced by liver hepatocytes and were recently shown to exert functions additional to their well-known role in lipid digestion. As yet it is not known whether the mucosal-associated invariant T (MAIT) cells, which represent 10-15% of the hepatic T cell population, are affected by BAs. The focus of the present investigation was on the association of BA serum concentration with MAIT cell function and inflammatory parameters as well as on the relationship of these parameters to body weight. Blood samples from 41 normal weight and 41 overweight children of the Lifestyle Immune System Allergy (LISA) study were analyzed with respect to MAIT cell surface and activation markers [CD107a, CD137, CD69, interferon (IFN)-γ, tumor necrosis factor (TNF)-α] after Escherichia coli stimulation, mRNA expression of promyelocytic leukemia zinc finger protein (PLZF) and major histocompatibility complex class I-related gene protein (MR1), the inflammatory markers C-reactive protein (CRP), interleukin (IL)-8 and macrophage inflammatory protein (MIP)-1α as well as the concentrations of 13 conjugated and unconjugated BAs. Higher body weight was associated with reduced MAIT cell activation and expression of natural killer cell marker (NKp80) and chemokine receptor (CXCR3). BA concentrations were positively associated with the inflammatory parameters CRP, IL-8 and MIP-1α, but were negatively associated with the number of activated MAIT cells and the MAIT cell transcription factor PLZF. These relationships were exclusively found with conjugated BAs. BA-mediated inhibition of MAIT cell activation was confirmed in vitro. Thus, conjugated BAs have the capacity to modulate the balance between pro- and anti-inflammatory immune responses.

Smoking and pregnancy: Epigenetics and developmental origins of the metabolic syndrome

Maternal smoking causes lower birth weight, birth defects, and other adverse pregnancy outcomes. Epidemiological evidence over the past four decades has grown stronger and the adverse outcomes attributed to maternal smoking and secondhand smoke exposure have expanded. This review presents findings of latent and persistent metabolic effects in offspring of smoking mothers like those observed in studies of maternal undernutrition during pregnancy. The phenotype of offspring of smoking mothers is like that associated with maternal undernutrition. Born smaller than offspring of nonsmokers, these children have increased risk of being overweight or obese later. Plausible mechanisms include in utero hypoxia, nicotine-induced reductions in uteroplacental blood flow, placental toxicity, or toxic growth restriction from the many toxicants in tobacco smoke. Studies have reported increased risk of insulin resistance, type 2 diabetes and hypertension although the evidence here is weaker than for overweight/obesity. Altered DNA methylation has been consistently documented in smoking mothers' offspring, and these epigenetic alterations are extensive and postnatally durable. A causal link between altered DNA methylation and the phenotypic changes observed in offspring remains to be firmly established, yet the association is strong, and mediation analyses suggest a causal link. Studies examining expression patterns of affected genes during childhood development and associated health outcomes should be instructive in this regard. The adverse effects of exposure to tobacco smoke during pregnancy now clearly include permanent metabolic derangements in offspring that can adversely affect life-long health.

Stressful life events in childhood and allergic sensitization

Stressful life events evidently have an impact on development of allergic diseases, but the mechanism linking stress to pathological changes of immune system function is still not fully understood. The aim of our study was to investigate the relationship between stressful life events, neuropeptide and cytokine concentrations in children as well as the association between early stressful life events and atopic eczema (AE). Within the LISA plus (Life style – Immune system – Allergy) study, blood samples from children of 6 years of age were analyzed for concentration of the neuropeptides vasoactive intestinal peptide (VIP), somatostatin (SOM), substance P (SP) and the Th1/Th2 cytokines IFN-γ and IL-4. Life events such as severe disease or death of a family member, unemployment or divorce of the parents were assessed with a questionnaire filled in by the parents. Furthermore, lifetime prevalence of AE and incidence after the assessment period of life events were compared. Our data suggest that separation/ divorce of parents increase childrens risk of developing AE later in life. Children with separated/divorced parents showed high VIP levels and high concentrations of the Th2 cytokine IL-4 in their blood. Severe diseases and death of a family member were neither associated with neuropeptide levels nor with cytokine concentrations. Unemployment of the parents was associated with decreased IFN-γ concentrations in childrens blood but not with neuropeptide levels. Thus, the neuropeptide VIP might be a mediator between stressful life events and immune regulation contributing to the Th2-shifted immune response in children with separated/divorced parents.

Neuroendocrine cells derived chemokine vasoactive intestinal polypeptide (VIP) in allergic diseases

Worldwide increase incidences of allergic diseases have heightened the interest of clinicians and researchers to understand the role of neuroendocrine cells in the recruitment and activation of inflammatory cells. Several pieces of evidence revealed the association of neuropeptides in the pathogenesis of allergic diseases. Importantly, one such peptide that is secreted by neuronal cells and immune cells exerts a wide spectrum of immunological functions as cytokine/chemokine is termed as Vasoactive Intestinal Peptide (VIP). VIP mediates immunological function through interaction with specific receptors namely VPAC-1, VPAC-2, CRTH2 and PAC1 that are expressed on several immune cells such as eosinophils, mast cells, neutrophils, and lymphocytes; therefore, provide the basis for the action of VIP on the immune system. Additionally, VIP mediated action varies according to target organ depending upon the presence of specific VIP associated receptor, involved immune cells and the microenvironment of the organ. Herein, we present an integrative review of the current understanding on the role of VIP and associated receptors in allergic diseases, the presence of VIP receptors on various immune cells with particular emphasis on the role of VIP in the pathogenesis of allergic diseases such as asthma, allergic rhinitis, and atopic dermatitis. Being crucial signal molecule of the neuroendocrine-immune network, the development of stable VIP analogue and/or antagonist may provide the future therapeutic drug alternative for the better treatment of these allergic diseases. Taken together, our current review summarizes the current understandings of VIP biology and further explore the significance of neuroendocrine cells derived VIP in the recruitment of inflammatory cells in allergic diseases that may be helpful to the investigators for planning the experiments and accordingly predicting new therapeutic strategies for combating allergic diseases. Summarized graphical abstract will help the readers to understand the significance of VIP in allergic diseases.

Pro-inflammatory immune responses in leukocytes of premature infants exposed to maternal chorioamnionitis or funisitis

BACKGROUND

Acute chorioamnionitis contributes to premature birth, and is associated with postbirth complications. How chorioamnionitis impacts neonate's developing immune system has not been well defined.

METHODS

Blood from extremely preterm infants (≤28 wk gestation) was drawn at the first, second, and fourth week of life. Blood was either left unstimulated or stimulated for 4 h with PMA/ionomycin. mRNA expression of transcription factors in unstimulated cells (RORC, TBET, GATA3, and Forkhead box protein 3 (FOXP3)) and inflammatory cytokines (IFN-γ, TNF-α, IL-2, IL-4, IL-5, and IL-6) in unstimulated and stimulated cells were analyzed. Data were analyzed based on the diagnosis of chorioamnionitis, funisitis and bronchopulmonary dysplasia (BPD).

RESULTS

At 1 wk of life, exposure to funisitis, but not maternal chorioamnionitis was associated with an increased expression of RORC and RORC/FOXP3 ratio. These increases in RORC and RORC/FOXP3 ratio were sustained over the 4 wk of follow-up. Leukocytes from infants who developed BPD had increased stimulated and unstimulated IL-4 at the first week of life, but these increases were not sustained over time. In contrast, infants with mild BPD had a sustained decrease in stimulated IL-2.

CONCLUSION

Chorioamnionitis exposure, in particular to funisitis, lead to enhanced Th17-like responses that persist for 4 wk after birth. Infants who later developed BPD did not exhibit a strikingly distinct immune profile.

Attention Deficit Disorder and Allergic Rhinitis: Are They Related?

The association between ADHD and allergy remains controversial. Our previous findings suggest that nerve growth factor may link the nervous and immune systems. The primary objective of this study was to determine if a combination of cetirizine + methylphenidate is effective in children with comorbid ADHD and allergic rhinitis. We also examined the role of nerve growth factor in these comorbidities. Our randomized, double-blind, placebo-controlled, crossover study enrolled 38 children diagnosed with comorbid ADHD and allergy using cetirizine (n = 12), sustained-release methylphenidate (n = 12), or cetirizine + methylphenidate (n = 14). Endpoints compared baseline to posttreatment evaluations for allergic rhinitis and ADHD scores. Serum nerve growth factor levels were measured using ELISA. For allergy endpoints, combination therapy produced results superior to individual therapy. For ADHD, similar scores were achieved for individual therapy; however, combination therapy resulted in improved scores. Nerve growth factor levels were downregulated following this trend. We conclude that ADHD and allergic rhinitis may have common mechanism and represent a comorbid condition that links the nervous system to the immune system. Further studies are needed.

Environment-induced epigenetic reprogramming in genomic regulatory elements in smoking mothers and their children

Epigenetic mechanisms have emerged as links between prenatal environmental exposure and disease risk later in life. Here, we studied epigenetic changes associated with maternal smoking at base pair resolution by mapping DNA methylation, histone modifications, and transcription in expectant mothers and their newborn children. We found extensive global differential methylation and carefully evaluated these changes to separate environment associated from genotype-related DNA methylation changes. Differential methylation is enriched in enhancer elements and targets in particular "commuting" enhancers having multiple, regulatory interactions with distal genes. Longitudinal whole-genome bisulfite sequencing revealed that DNA methylation changes associated with maternal smoking persist over years of life. Particularly in children prenatal environmental exposure leads to chromatin transitions into a hyperactive state. Combined DNA methylation, histone modification, and gene expression analyses indicate that differential methylation in enhancer regions is more often functionally translated than methylation changes in promoters or non-regulatory elements. Finally, we show that epigenetic deregulation of a commuting enhancer targeting c-Jun N-terminal kinase 2 (JNK2) is linked to impaired lung function in early childhood.

The relationship between interleukin-18 polymorphisms and allergic disease: a meta-analysis

Recent studies have suggested that IL-18 −607C/A and −137G/C polymorphisms may be associated with the risk of allergic disease; however, individually published results are inconclusive. Therefore, we performed a meta-analysis to clarify whether IL-18 −607C/A and −137G/C polymorphisms were associated with the risk of allergic disease. A total of 21 studies including 5,331 cases and 9,658 controls were involved in this meta-analysis. In the overall analysis and the subgroup analysis according to ethnicity, we did not find significant association between IL-18 −607C/A or −137G/C polymorphism and the risk of allergic disease (all P > 0.05). However, in a stratified analysis by type of allergic disease, our results indicated that IL-18 −607C/A polymorphism was associated with a significantly decreased risk of allergic asthma in heterozygous comparison and IL-18 −137G/C was associated with a significantly decreased risk of allergic dermatitis in recessive model and homozygous comparison. In the stratified analysis by source of control, IL-18−607C/A showed significantly reduced risk in population-based subgroup, and for IL-18 −137G/C only significantly decreased risk was found in the hospital-based subgroup. Our meta-analysis suggests that IL-18 −607C/A and −137G/C polymorphisms may be protective factors for the risk of allergic asthma and allergic dermatitis, respectively.

The LINA cohort: Cord blood eosinophil/basophil progenitors predict respiratory outcomes in early infancy

RATIONALE

Cord blood eosinophil/basophil progenitor cells (Eo/B) of high risk infants have been shown to predict respiratory illnesses in infancy. Here we investigated this association in a population-based cohort. Furthermore, we analysed whether newborns Th1/Th2 balance and prenatal environmental exposure impact Eo/B recruitment.

METHODS

In a sub-cohort of the LINA study cord blood mononuclear cells were used for methylcellulose assays to assess Eo/B differentiation. Questionnaires were recorded during pregnancy and annually thereafter. Volatile organic compounds were measured during pregnancy and cord blood cytokines after ex vivo stimulation.

RESULTS

Cord blood IL-4 and IL-13 positively correlated with Eo/B. Tobacco smoke related benzene was also positively associated with Eo/B. Enhanced Eo/B numbers increased the risk for wheezing within the first 24 months.

CONCLUSIONS

The association between cord blood Eo/B and respiratory illnesses is not restricted to high-risk children. Prenatal environmental exposure and a Th2 milieu at birth contribute to Eo/B recruitment.

Generation of IL-8 and IL-9 producing CD4⁺ T cells is affected by Th17 polarizing conditions and AHR ligands

The T helper cell subsets Th1, Th2, Th17, and Treg play an important role in immune cell homeostasis, in host defense, and in immunological disorders. Recently, much attention has been paid to Th17 cells which seem to play an important role in the early phase of the adoptive immune response and autoimmune disease. When generating Th17 cells under in vitro conditions the amount of IL-17A producing cells hardly exceeds 20% while the nature of the remaining T cells is poorly characterized. As engagement of the aryl hydrocarbon receptor (AHR) has also been postulated to modulate the differentiation of T helper cells into Th17 cells with regard to the IL-17A expression we ask how far do Th17 polarizing conditions in combination with ligand induced AHR activation have an effect on the production of other T helper cell cytokines. We found that a high proportion of T helper cells cultured under Th17 polarizing conditions are IL-8 and IL-9 single producing cells and that AHR activation results in an upregulation of IL-8 and a downregulation of IL-9 production. Thus, we have identified IL-8 and IL-9 producing T helper cells which are subject to regulation by the engagement of the AHR.

Neurogenic markers of the inflammatory process in atopic dermatitis: relation to the severity and pruritus

Introduction

Atopic dermatitis (AD) is a chronic and relapsing inflammatory skin disease, characterized by eczematous skin lesions and intensive pruritus. Recent studies have shed light on the role of the nervous system in the pathogenesis of AD. It can influence the course of the disease through an altered pattern of cutaneous innervation and abnormal expression of neuropeptides in the lesional skin.

Aim

The aim of the study was to evaluate plasma concentrations of the nerve growth factor (NGF), substance P (SP) and vasoactive intestinal peptide (VIP) in AD patients in comparison to two control groups (healthy volunteers and patients suffering from psoriasis). Correlations between plasma levels of evaluated parameters, severity of the disease and selected clinical parameters (skin prick tests, total and antigen specific IgE levels) were also analysed.

Material and methods

Seventy-five patients with AD, 40 patients with psoriasis and 40 healthy volunteers were included into the study. Patients with AD included 52 persons suffering from an extrinsic and 23 from an intrinsic type of the disease. The severity of skin lesions was assessed with SCORAD index. Pruritus was evaluated on the basis of the questionnaire assessing the extent, frequency and intensity of pruritus. Commercial enzyme-linked immunosorbent assays (SP, NGF: R&D Systems; and VIP: Phoenix Pharmaceuticals) were used to assess the neuropeptide and NGF plasma levels.

Results

Nerve growth factor and VIP plasma concentrations were significantly higher in AD patients compared to psoriatic patients and healthy subjects. Substance P plasma concentrations were elevated in the extrinsic type of AD and psoriasis comparing to healthy volunteers. There were no statistically significant differences in NGF, SP and VIP plasma concentrations between the extrinsic and intrinsic type of AD. There was also no correlation between plasma levels of evaluated parameters (NGF, SP, VIP) and SCORAD index in both types of AD. However, plasma SP concentration correlated with intensity of pruritus in AD patients. Plasma VIP concentrations correlated with intensity of pruritus in the intrinsic type of AD and with IgE-mediated sensitization to moulds in the extrinsic type of disease.

Conclusions

Our findings confirm that NGF and VIP play a prominent role in atopic inflammatory reactions and may serve as good alternative biomarkers of AD. The results of this study also suggest a similar important role of neuroimmune interactions in both variants of AD. Increased SP plasma concentrations in both AD and psoriasis point to its possible role in modulating immune-mediated inflammation in different chronic inflammatory skin diseases. Moreover, SP and VIP seem to influence the course of AD by increasing pruritus, whereas an elevated plasma VIP level in AD patients may be related to a risk of developing IgE-mediated sensitization to certain airborne allergens.

Stress induced neuroendocrine-immune plasticity: A role for the spleen in peripheral inflammatory disease and inflammaging?

Research over the past decade has revealed close interaction between the nervous and immune systems in regulation of peripheral inflammation linking psychosocial stress with chronic somatic disease and aging. Moreover emerging data suggests that chronic inflammations lead to a pro-inflammatory status underlying premature aging called inflammaging. In this context, the spleen can be seen as a switch board monitoring peripherally derived neuroendocrine-immune mediators in the blood and keeping up a close communication with the central stress response via its mainly sympathetic innervation. The effect aims at balanced and well-timed stress axis activation and immune adaptation in acute peripheral inflammatory events. Constant adjustment to the needs generated by environmental and endogenous challenges is provided by neuroendocrine-immune plasticity. However, maladaptive plasticity induced e.g., by chronic stress-axis activation and excessive non-neuronal derived neuroendocrine mediators may be at the heart of the observed stress sensitivity promote inflammaging under chronic inflammatory conditions. We here review the role of neurotransmitters, neuropeptides and neurotrophins as stress mediators modulating the immune response in the spleen and their potential role in inflammaging.

Immune heterogeneity in neuroinflammation: dendritic cells in the brain

Dendritic cells (DC) are critical to an integrated immune response and serve as the key link between the innate and adaptive arms of the immune system. Under steady state conditions, brain DC’s act as sentinels, continually sampling their local environment. They share this function with macrophages derived from the same basic hemopoietic (bone marrow-derived) precursor and with parenchymal microglia that arise from a unique non-hemopoietic origin. While multiple cells may serve as antigen presenting cells (APCs), dendritic cells present both foreign and self-proteins to naïve T cells that, in turn, carry out effector functions that serve to protect or destroy. The resulting activation of the adaptive response is a critical step to resolution of injury or infection and is key to survival. In this review we will explore the critical roles that DCs play in the brain’s response to neuroinflammatory disease with emphasis on how the brain’s microenvironment impacts these actions.

The LINA cohort: indoor chemical exposure, circulating eosinophil/basophil (Eo/B) progenitors and early life skin manifestations

BACKGROUND

Hematopoietic progenitor cells, especially those committed to the Eo/B lineage, are known to contribute to allergic inflammation.

OBJECTIVE

The aim of the present study was to investigate whether environmental factors are associated with changes in numbers of circulating Eo/B progenitors at 1 year of age.

METHODS

Peripheral blood from 60 1-year-old children enrolled in the LINA (Lifestyle and environmental factors and their Influence on Newborns Allergy risk) birth cohort was assessed for Eo/B progenitor cells (Eo/B CFU) using standardized and validated methylcellulose assays. Frozen peripheral blood mononuclear cells (PBMC) were cultured in the presence of IL-3, IL-5 or GM-CSF, and Eo/B CFUs enumerated. Clinical outcomes and exposure to environmental tobacco smoke (ETS) were documented by standardized questionnaires, and indoor volatile organic compound (VOC) concentrations were assessed by passive sampling.

RESULTS

Children with skin manifestations (atopic dermatitis or cradle cap) within the first year of life had higher numbers of circulating IL-3-, IL-5- or GM-CSF-stimulated Eo/B CFUs (P < 0.05) at 1 year. In children with cradle cap, a positive correlation was found between Eo/B CFUs and exposure to ETS-related VOCs during pregnancy or at 1 year of age (P < 0.05).

CONCLUSIONS AND CLINICAL RELEVANCE

This is the first demonstration that environmental exposures are positively associated with levels of circulating Eo/B progenitors. The recruitment and differentiation of Eo/B progenitors in response to environmental triggers may play a role in the development of skin manifestations during the first year of life.

Cough and dyspnoea may discriminate allergic and infectious respiratory phenotypes in infancy

Asthma symptoms are non-specific during infancy, making the identification of different subgroups among preschool children with early respiratory manifestations an important challenge. We previously used a clustering approach to identify bronchial obstructive phenotypes in 1-yr-old infants from the Pollution and Asthma Risk: an Infant Study (PARIS) birth cohort. In the present study, we examined whether these phenotypes were stable at 3 yr and studied their comorbidity and risk factors. Partitioning around medoids (PAM) method was applied at 1 and 3 yr of age to cluster children according to wheezing, dry night cough, dyspnoea with sleep disturbance and breathlessness. The resulting groups were used to derive phenotypes in 2084 children during their first 3 yr of life. Analysis of associated comorbidity and risk factors was conducted using multinomial logistic regression. PAM groups were similarly defined at both ages so that two respiratory phenotypes were identified between birth and 3 yr: cough phenotype (CP) and dyspnoea phenotype (DP) including 14.1% and 30.7% of children, respectively. CP infants experienced more often allergic features than DP, dominated by respiratory infections. Parental history of allergy, potential allergen exposure and psychosocial factors were associated with CP. Day care centre attendance was more frequent in DP as well as exposure to domestic chemical pollution, suggesting a greater vulnerability to pathogens. Finally, dry night cough and dyspnoea disturbing the sleep appear to be markers of two respiratory profiles potentially allergic and infectious before 3 yr old.

Diffuse endocrine system, neuroendocrine tumors and immunity: what's new?

During the last two decades, research into the modulation of immunity by the neuroendocrine system has flourished, unravelling significant effects of several neuropeptides, including somatostatin (SRIH), and especially cortistatin (CST), on immune cells. Scientists have learnt that the diffuse neuroendocrine system can regulate the immune system at all its levels: innate immunity, adaptive immunity, and maintenance of immune tolerance. Compelling studies with animal models have demonstrated that some neuropeptides may be effective in treating inflammatory disorders, such as sepsis, and T helper 1-driven autoimmune diseases, like Crohn's disease and rheumatoid arthritis. Here, the latest findings concerning the neuroendocrine control of the immune system are discussed, with emphasis on SRIH and CST. The second part of the review deals with the immune response to neuroendocrine tumors (NETs). The anti-NET immune response has been described in the last years and it is still being characterized, similarly to what is happening for several other types of cancer. In parallel with investigations addressing the mechanisms by which the immune system contrasts NET growth and spreading, ground-breaking clinical trials of dendritic cell vaccination as immunotherapy for metastatic NETs have shown in principle that the immune reaction to NETs can be exploited for treatment.

The possible link between the elevated serum levels of neurokinin A and anti-ribosomal P protein antibodies in children with autism

BACKGROUND

Neurogenic inflammation is orchestrated by a large number of neuropeptides. Tachykinins (substance P, neurokinin A and neurokinin B) are pro-inflammatory neuropeptides that may play an important role in some autoimmune neuroinflammatory diseases. Autoimmunity may have a role in the pathogenesis of autism in some patients. We are the first to measure serum neurokinin A levels in autistic children. The relationship between serum levels of neurokinin A and anti-ribosomal P protein antibodies was also studied.

METHODS

Serum neurokinin A and anti-ribosomal P protein antibodies were measured in 70 autistic children in comparison to 48 healthy-matched children.

RESULTS

Autistic children had significantly higher serum neurokinin A levels than healthy controls (P < 0.001). Children with severe autism had significantly higher serum neurokinin A levels than patients with mild to moderate autism (P < 0.001). Increased serum levels of neurokinin A and anti-ribosomal P protein antibodies were found in 57.1% and 44.3%, respectively of autistic children. There was significant positive correlations between serum levels of neurokinin A and anti-ribosomal P protein antibodies (P = 0.004).

CONCLUSIONS

Serum neurokinin A levels were elevated in some autistic children and they were significantly correlated to the severity of autism and to serum levels of anti-ribosomal P protein antibodies. However, this is an initial report that warrants further research to determine the pathogenic role of neurokinin A and its possible link to autoimmunity in autism. The therapeutic role of tachykinin receptor antagonists, a potential new class of anti-inflammatory medications, should also be studied in autism.

Reduced maternal regulatory T cell numbers and increased T helper type 2 cytokine production are associated with elevated levels of immunoglobulin E in cord blood

BACKGROUND

There is evidence that the basis of an atopic-skewed immune response is acquired early in life, perhaps at the fetal stage. Thus, we hypothesized that the development of the fetal immune system might be influenced by maternal regulatory T cells (Treg) and maternal T cell cytokine production during pregnancy. The aim of the present study was to assess the influence of maternal Treg and cytokine production during pregnancy on Treg and atopy at birth.

METHODS

Within the mother-child study LINA (Lifestyle and Environmental factors and their Influence on Newborns Allergy risk), we determined the frequency and function of Treg and the total IgE concentration in pregnant women in the 34th week of gestation and in corresponding cord bloods at birth (n=24). Furthermore, we assessed how maternal mitogen-induced T-helper type 1/T-helper type 2 and inflammatory cytokines influence the level of cord blood Treg and IgE.

RESULTS

Frequencies of CD4(+)CD25(high) T cells were higher (P=0.001), whereas percentages of FOXP3+ T cells were lower (P<0.001) in cord blood cells compared with maternal blood. Reduced maternal CD4(+)CD25(high) Treg frequencies correlated with increased total IgE concentrations at the 34th week of gestation (r=-0.32, P=0.028) and with increased IgE concentrations in cord blood (r=-0.50, P<0.001). Elevated maternal mitogen-induced Th2 cytokine production was related to increased total IgE levels in the serum of corresponding cord bloods (IL-4, r=0.53; IL-5, r=0.43; IL-13, r=0.52).

CONCLUSIONS

Because cord blood IgE has been shown to be predictive for allergic diseases in early childhood, our results indicate that reduced maternal Treg numbers and increased Th2 cytokine production during pregnancy might influence the allergy risk of the child.

Effects of somatostatin and octreotide on cytokine and chemokine production by lipopolysaccharide-activated peripheral blood mononuclear cells

BACKGROUND

Somatostatin plays an important role in the communication between the nervous, endocrine, and immune systems. Although somatostatin or its analogues have been shown to modulate a number of immune functions, their immunomodulatory effects are not uniform and are strongly dependent on the underlying cell system.

AIM

The aim of our study was to analyze the immunomodulatory effects of somatostatin and its analogue octreotide on peripheral blood mononuclear cells (PBMC) in vitro. MATERIALS/SUBJECTS:We used lipopolysaccharide-activated cells from normal glucose tolerant (NGT) subjects and from Type 2 diabetes mellitus (T2DM) patients as T2DM is associated with chronic, low-grade inflammation, and measured immune mediator release with multiplex bead-based assays.

RESULTS

Our data showed no statistically significant effects on the secretion of the cytokines interleukin (IL)-1beta, IL-6, IL-10, IL-12, interferon-gamma and tumor necrosis factor-alpha as well as the chemokines IL-8 and monocyte chemoattractant protein (MCP)-1, either on PBMC from T2DM patients or on those from NGT controls. However, a trend towards a dose-dependent biphasic effect was observed for IL- 6, IL-10 and MCP-1 with reduced immune mediator levels at low and increased/unaltered levels at higher somatostatin or octreotide concentrations. These observations could not be explained by interference with cell viability or proliferation.

CONCLUSIONS

We could not confirm immunomodulatory properties of somatostatin and octreotide on PBMC. Further analyses are necessary to explain the interaction between neuropeptides and the immune system.

Relation between stressful life events, neuropeptides and cytokines: results from the LISA birth cohort study

Stressful life events evidently have an impact on development of allergic diseases, but the mechanism linking stress to pathological changes of immune system function is still not fully understood. The aim of our study was to investigate the relationship between stressful life events, neuropeptide and cytokine concentrations in children. Within the LISAplus (Life style-Immune system-Allergy) study, blood samples from children of 6 yr of age were analysed for concentration of the neuropeptides vasoactive intestinal peptide (VIP), somatostatin (SOM), substance P (SP) and the Th1/Th2 cytokines interferon-gamma (IFN-gamma) and interleukin (IL)-4. Life events such as severe disease or death of a family member, unemployment or divorce of the parents were assessed with a questionnaire filled in by the parents. For 234 children, blood analysis and questionnaire data regarding life events were available. Children with separated/divorced parents showed high VIP levels and high concentrations of the Th2 cytokine IL-4 in their blood. Severe diseases and death of a family member were neither associated with neuropeptide levels nor with cytokine concentrations. Unemployment of the parents was associated with decreased IFN-gamma concentrations in children's blood but not with neuropeptide levels, whereas children experiencing concomitant severe disease and death of a family member had reduced SP blood levels. The neuropeptide VIP might be a mediator between stressful life events and immune regulation contributing to the Th2 shifted immune response in children with separated/divorced parents. Unemployment of the parents was associated with immune regulation in children on the basis of a still unknown mechanism whereas reduced SP levels seem to have no effect on immune regulation.

(Xeno)estrogen regulation of food allergy

Food allergy and other types of allergies are becoming epidemic in both the developed and developing countries. A large amount of information is available in literature that (xeno)estrogens can regulate the immune response in general, and the development of allergy in particular; however, the effect of (xeno)estrogens on food allergy is basically unknown. With increasing use of xenobiotics worldwide, chemicals with estrogenic activity have been accumulating in our environment. This review has summarized the current literature relating to the topic (xeno)estrogen regulation of food allergy. The effect of (xeno)estrogens on enterocytes, proteases for protein hydrolysis, dendritic cells and T-regulatory cells in the gastrointestinal tract has been discussed. Finally, considering the current confusion in literature regarding the effect of phytoestrogen genistein on the immune system, a brief discussion has been included for its effect on T(H)1-T(H)2 polarization, and possibly food allergy in its relation to windows of exposure. Sufficient evidences exist to support the notion that (xeno)estrogens can regulate food allergy, with the developmental periods more sensitive. Further clinical and animal studies are needed to determine the causal relationship between the exposure of (xeno)estrogens and incidence of food allergy, and the underlying mechanisms.

Association between suppressors of cytokine signalling, T-helper type 1/T-helper type 2 balance and allergic sensitization in children

BACKGROUND

Suppressors of cytokine signalling (SOCS) family members have been shown to play an important role in the balance of cytokines that determine the onset of T-helper type 1 (Th1)- and Th2-mediated immune responses. In particular, for cytokine-induced Src-homology 2 protein (CIS), SOCS1, SOCS3 and SOCS5, a role in the regulation of T cell differentiation has been discussed. However, only few data exist so far in the human system.

OBJECTIVES

The aim of the present study was to analyse the relationship between these suppressors and Th1/Th2 regulation as well as allergic sensitizations within a population-based study.

METHODS

Within the Lifestyle-Immune system-Allergy plus cohort study, mRNA was prepared from blood samples of 6-year-old children for the analysis of cytokines, transcription factors for T cell regulation and SOCS molecule expression by quantitative real-time polymerase chain reaction. In addition, total and specific IgE concentrations have been measured by the Pharmacia CAP System. A complete data set from 248 children was available. Results Among the SOCS molecules investigated, only SOCS1 showed a strong positive correlation to allergic sensitizations. In addition, an up-regulated SOCS1 expression correlated with down-regulated T-box expressed in T cells (Tbet) and higher expression levels of GATA-binding protein 3 (GATA-3) and IL-4. No association between SOCS1 and forkhead box P3 (FOXP3) was observed. For SOCS3, SOCS5 and CIS, a contradictory picture was found. The expression of these SOCS molecules was positively correlated with Tbet and FOXP3 and (with the exception of CIS) negatively with IL-4.

CONCLUSIONS

Our data suggest that SOCS3, SOCS5 and CIS, which correlate with an up-regulated Th1 and regulatory T cell activity, are without relevance for the allergic status. In contrast, SOCS1 might be involved in the development of a Th2-skewed immune response and subsequent allergic sensitizations.

A novel VIP signaling pathway in T cells cAMP-->protein tyrosine phosphatase (SHP-2?)-->JAK2/STAT4-->Th1 differentiation

Vasoactive intestinal peptide (VIP) is a potent anti-inflammatory agent. In addition to the deactivation of macrophages, dendritic cells, and microglia, VIP shifts the Th1/Th2 balance, promoting the preferential differentiation and survival of Th2 cells, to the detriment of the proinflammatory Th1 effectors. Several mechanisms operate in the Th1/Th2 shift induced by VIP. Here we report on a novel mechanism for the effect of VIP on T cell differentiation, and show that VIP inhibits Th1 differentiation by interfering directly with the IL-12Jak2/STAT4 signaling pathway in T cells. The effect of VIP is cAMP-dependent, and appears to be mediated through the activation of protein tyrosine phosphatases (PTP), with SHP-2 as a potential target. The activation of PTPs represents a novel cAMP-downstream target for the immunomodulatory effects of VIP.