Allergen-specific T cell reactivity in cord blood: the influence of maternal cytokine production

Probiotics and prebiotics in atopic dermatitis: Pros and cons (Review)

Atopic dermatitis (AD) represents a chronic inflammatory skin condition in which the skin barrier is impaired; thus, the permeability is increased. Hence, there is a greater risk of allergic sensitization, as well as a higher pH and lower protection against resident microbes. Since this condition is currently increasing among children, it requires further study, as little is known regarding the pathogenesis that makes the skin prone to chronic relapsing inflammation. Trying to standardize the data regarding the use of prebiotics and probiotics in AD, we encountered tremendous variability in the literature data. Literature abounds in conflicting data: studies regarding prophylactic and therapeutic applications, different types of strains and dosages, applications in young children up to 5 years of age and above, usage of probiotics alone, prebiotics alone or synbiotics combined. There are also conflicting data regarding the outcome of these studies; some confirming a positive effect of prebiotics, probiotics or synbiotics and some showing no efficacy at all. The articles were divided into those assessing probiotics or prebiotics alone and a combination of the two, with studies showing a positive effect and studies proving no efficacy at all. We tried to critically analyze those articles showing weak and strong points. In summary, the most studied probiotics were the strains of Lactobacilli and Bifidobacteria. The Severity Scoring of Atopic Dermatitis (SCORAD) index was used to measure the efficacy of the treatment. Most studies compared their results with a placebo group and the efficacy when seen in moderate to severe forms of AD in patients with other allergic diseases present. However, the results are difficult to interpret, as in many studies the authors suggest that the disease may have a tendency to improve in time in some groups of patients.

The Effects of Maternal Smoking on Pregnancy and Offspring: Possible Role for EGF?

Cigarette smoke exposure during pregnancy and lactation is associated with adverse pregnancy outcomes. Here, we investigated the effects of maternal smoke exposure on pregnancy and offspring immunity and explored whether, epidermal growth factor (EGF), an important growth-promoting factor in human colostrum and milk, might be a possible missing link in maternal smoke exposure and changes in infants’ immune responses. Pregnant BALB/c mice were exposed to either cigarette smoke or air during gestation and lactation, and effects on pulmonary inflammation in dams and immune responses in offspring were examined. Maternal smoke exposure increased airway hyperresponsiveness and accumulation of inflammatory cells in the lungs of pregnant dams compared to non-pregnant dams. The E-cadherin protein expression was reduced in mammary glands of cigarette smoke-exposed pregnant dams. EGF levels were higher in mammary glands and serum of smoke-exposed pregnant dams compared to air-exposed pregnant dams. Offspring from cigarette smoke-exposed dams exhibited elevated levels of IL-17A, MCP-1, IL-22, and IL-13 in anti-CD3 stimulated spleen cell culture supernatants. EGF levels were also increased in serum of offspring from smoke-exposed dams. A positive correlation was observed between serum EGF levels and neutrophil numbers in bronchoalveolar lavage fluid of the dams. Interestingly, IL-17A, MCP-1, IL-22, IL13, and IFN-γ levels in anti-CD3 stimulated spleen cell culture supernatants of male pups also showed a positive correlation with EGF serum levels. In summary, our results reveal that maternal smoke exposure predisposes dams to exacerbated airway inflammation and offspring to exacerbated immune responses and both phenomena are associated with elevated EGF concentrations.

Sensitisation patterns and allergy outcomes in pregnant women living in the urban area

Background

Worldwide, allergy affects more than one billion people, with particularly rising prevalence in industrialised areas. Specifically, young adults appear to be predominantly targeted for an allergy diagnosis. Allergic diseases in pregnancy are mainly pre-existing but could also occur de novo. The immunological changes while pregnant, with increased Th2 lymphocyte activity, can facilitate allergen sensitisation.

Objective

The aim of this study was to evaluate the pattern of specific IgE (sIgE) sensitisation to common inhalant and food allergens in pregnancy, and assess its relationship to self-reported allergic disease.

Methods

We assessed 200 pregnant women, aged 20–38 years (mean age = 29 years), participant of ELMA (Epigenetic Hallmark of Maternal Atopy and Diet) study, living in a metropolitan area, with no pregnancy associated metabolic complications, for total IgE and allergen specific IgE to 20 allergens.

Results

48% of pregnant women were sensitised to at least one allergen, at a cut-off point of 0.35 kU/L and they were assigned as atopic. However 42% in atopic group were not reporting any allergic disease. The most common inhalant allergens were: pollen (24.5%) and animal dander (23.5%). The most common food allergens were: cow’s milk (5.5%) and apples (4.5%). 7.5% of women reported asthma, 21.5% allergic rhinitis, 11.5% atopic dermatitis and 18.5% food allergy. 8.5% of were taking medication for asthma or allergies. Atopic dermatitis had the highest tendency to become more severe during pregnancy. Total IgE values were significantly higher in atopic women.

Conclusions

Allergic sensitisation is a common phenomenon in pregnancy. Some sensitisations could be asymptomatic. Further studies should investigate if sensitisation in mothers confers risks for immune alterations in their children.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13223-021-00547-0.

Atopy risk among school-aged children in relation to early exposures to a farm environment: A systematic review

BACKGROUND AND OBJECTIVES

Childhood atopy is a complex condition with both a genetic and an environmental component. This systematic review will explore the current understanding of the importance of early life exposures to a farm in the development of atopy measured by objective markers of skin prick testing, and specific IgE measurements in school age children.

METHODS

A systematic review was performed.

RESULTS

Among 7285 references identified, 14 studies met the inclusion criteria (13 cross-sectional studies and 1 case-control study). The results were fairly consistent in that early farm-related exposures can protect children from becoming atopic at school age. In general, there was heterogeneity in the assessment of outcomes and exposures.

CONCLUSIONS

Early-life farm exposures are associated with a protective effect on childhood atopy as assessed by objective markers. Future work should focus on understanding specific farm exposures that may important in these associations between atopy and farm exposures in children.

Maternal known drug allergy and long-term dermatological morbidity of the offspring

Drug allergy is associated with adverse short-term perinatal outcomes such as caesarian delivery and preterm delivery. The aim of the present study was to determine whether being born to a mother with known drug allergy increases the risk for long-term dermatological morbidity of the offspring. A population-based cohort study, comparing long-term dermatological morbidity of offspring to mothers with and without known drug allergy, was conducted. Dermatological morbidity was assessed up to the age of 18 years according to a predefined set of ICD-9 codes associated with hospitalization of the offspring. A Kaplan-Meier survival curve was used to compare cumulative incidence of long-term dermatological morbidity, and a Cox proportional hazards model was constructed to control of confounders. During the study period, 243,682 deliveries met the inclusion criteria, of them 4% (n = 9756) were of mothers with known drug allergy. Offspring born to mothers with known drug allergy had higher rates of long-term dermatological morbidity Likewise, the cumulative incidence of long-term dermatological morbidity was higher as compared with those without known drug allergy (Kaplan-Meier log-rank P = .021). Using a Cox proportional hazards model, controlling for confounders, being born to a mother with known drug allergy was found to be an independent risk factor for long-term dermatological morbidity of the offspring (adjusted HR 1.2, 95% CI 1.03-1.33, P = .016). Being born to a mother with known drug allergy is independently associated with higher risk for long-term dermatological morbidity of the offspring.

Influences of Maternal Factors Over Offspring Allergies and the Application for Food Allergy

The prevalence of food allergy has been steadily rising worldwide with the highest incidence noted among younger children, and increasingly recognized as a growing public concern. The first known ingestion of foods often causes allergic reaction, suggesting that sensitization of offspring with food allergens may occur during pregnancy and/or through breastfeeding. This creates a milieu that shapes the neonatal immune responses to these allergens. However, the effects of maternal allergen exposure and maternal sensitization with allergens on development of allergies in offspring remain controversial. This review discusses recent advances from human data in our understanding of how maternal factors, namely, food allergens, allergen-specific immunoglobulins, cytokines, genetics, and environmental factors transferred during pregnancy or breastfeeding influence offspring allergies and how such effects may be applicable to food allergy. Based on information obtained from mouse models of asthma and food allergy, the review also dissects the mechanisms by which maternal factors, including the impact of immune complexes, transforming growth factor-β, vitamin A, and regulatory T-cell responses, contribute to the induction of neonatal tolerance vs. development of allergic responses to maternally transferred allergens.

Intestinal barrier and gut microbiota: Shaping our immune responses throughout life

The gastrointestinal (GI) tract is considered the largest immunological organ in the body having a central role in regulating immune homeostasis. Contrary to earlier belief, the intestinal epithelial barrier is not a static physical barrier but rather strongly interacts with the gut microbiome and cells of the immune system. This intense communication between epithelial cells, immune cells and microbiome will shape specific immune responses to antigens, balancing tolerance and effector immune functions. Recent studies indicate that composition of the gut microbiome affects immune system development and modulates immune mediators, which in turn affect the intestinal barrier. Moreover, dysbiosis may favor intestinal barrier disruption and could be related to increased susceptibility to certain diseases. This review will be focused on the development of the intestinal barrier and its function in host immune defense and how gut microbiome composition throughout life can affect this role.

Prenatal exposure to acid-suppressive drugs and the risk of allergic diseases in the offspring: a cohort study

BACKGROUND

Recent studies reported increased risks for the development of asthma in children after prenatal exposure to acid-suppressive drugs. As a result of common pathogenesis, associations could also be present for other allergic diseases.

METHODS

Using the prescription database IADB.nl, we conducted a cohort study amongst 33 536 children in the Netherlands, with a maximum follow-up of 8 years. Maternal exposure was defined as ≥1 dispensed prescription for proton pump inhibitors (PPIs) and/or Histamine 2-antagonists (H2As) during pregnancy. Children were considered to have a drug-treated allergic disease if they received either ≥2 prescriptions for dermal (atopic dermatitis), inhaled (asthma) or nasal (allergic rhinitis) steroids within a 12-month period. Clustered Cox proportional hazard regression was used to estimate crude and adjusted hazard ratios (aHR) with 95% confidence intervals (95% CI).

RESULTS

The aHR for the development of any allergic disease was 1.37 (95% CI: 1.14-1.66) for children exposed to PPIs or H2As. Prenatal exposure to PPIs and/or H2As was associated with atopic dermatitis, asthma and allergic rhinitis with aHRs of 1.32 (95% CI 1.06-1.64), 1.57 (95% CI 1.20-2.05) and 2.40 (95% CI 1.42-4.04), respectively. The aHR for the development of two or more (aHR 2.13 95% CI: 1.43-3.19) and three allergic diseases (aHR 5.18 95% CI: 2.16-12.42) were even more elevated after prenatal exposure to PPIs or H2As.

CONCLUSION

Prenatal exposure to PPIs and H2As appeared associated with an increased risk for the development of atopic dermatitis, asthma and allergic rhinitis in the offspring, especially with the development of multiple allergic diseases. Because our study has limitations inherent to observational studies, prospective studies are now warranted to confirm our findings.

Use of acid-suppressive drugs in pregnancy and the risk of childhood asthma: bidirectional crossover study using the general practice research database

BACKGROUND

Recent studies have reported an association between maternal use of gastric acid-suppressive drugs during pregnancy and asthma in the offspring, but the association could have been confounded by unmeasured risk factors.

OBJECTIVE

We assessed the association between the use of acid-suppressive drugs during pregnancy and the risk of developing childhood asthma using a bidirectional crossover design.

METHODS

Mother-infant matched sets in the UK General Practitioners Research Database were used to identify children with a drug-treated asthma diagnosis during the years 2006-2010 who were matched to a sibling without asthma as controls. Primary exposure was use of any anti-suppressive drug during pregnancy, and subgroup analyses were conducted according to drug class (e.g. proton pump inhibitors or histamine 2 receptor antagonists) and trimester. Conditional logistic regression was used to estimate odds ratios (OR) with their corresponding 95 % confidence intervals (CIs).

RESULTS

A total of 1,874 children with asthma and 1,874 control siblings were included in the analysis. The exposure rate among case and control pregnancies was 22 and 20 %, respectively. After adjustments for gender, birth order, mother's age and general practice visits, the exposure to any gastric-acid suppressive drug during pregnancy slightly increased the risk for developing asthma (OR 1.23, 95 % CI 1.01-1.51; p = 0.042). A trend towards increased risks was observed for those who used proton pump inhibitors and/or histamine 2 receptor antagonists (adjusted OR 1.72, 95 % CI 1.00-2.98; p = 0.048).

CONCLUSIONS

These findings lend support to the emerging evidence that exposure to acid-suppressive drugs during pregnancy is associated with childhood asthma. More basic research is now warranted to investigate the mechanisms.

Cord blood cellular proliferative response as a predictive factor for atopic dermatitis at 12 months

Since the risk of developing allergic disease increases in individuals exposed to allergens previously, even during the neonatal period, the immunologic status of a fetus may be important in the subsequent development of allergy. We evaluated the fetal factors to predict atopic dermatitis (AD) at 12 months in 412 infants of a COhort for Childhood Origin of Asthma and Allergic Diseases (COCOA) in the general Korean population. Cord blood mononuclear cells (CBMCs) were stimulated with ovalbumin and phytohemagglutinin and cellular proliferative response and concentrations of interleukin-13 and interferon-γ, were measured. The risk of developing AD was greater in boys than girls (OR 1.97, 95% CI 1.26-3.09), infants delivered by cesarean section than vaginally (OR 1.93, 95% CI 1.14-3.26) and infants with than without parental history of AD (OR 2.34, 95% CI 1.29-4.24). The CBMC proliferative response to phytohemagglutinin stimulation was higher in infants with than without AD (P = 0.048), but no difference was observed in ovalbumin-stimulated cells (P = 0.771). Risk factors for the development of AD at 12 months include male gender, delivery by cesarean section and parental history of AD. Increased CBMC proliferative response to phytohemagglutinin stimulation may predict the development of AD at 12 months.

Prenatal exposure to acid-suppressive drugs and the risk of childhood asthma: a population-based Danish cohort study

BACKGROUND

Proton pump inhibitors (PPIs) may activate the immune system and cause asthma.

AIM

To investigate the association of prenatal exposure to PPIs and histamine 2-receptor antagonists (H2RAs) with risk of asthma.

METHODS

In this cohort study, 197,060 singletons born between 1996 and 2008 in northern Denmark were followed until the end of 2009. Data were obtained through Danish medical registries. Asthma in offspring was defined as at least two prescriptions of both a β-agonist and an inhaled glucocorticoid and/or a hospital diagnosis of asthma during the follow-up. Cox proportional-hazard regression was used to compute incidence rate ratios, adjusting for covariates.

RESULTS

A total of 2238 (1.1%) children were prenatally exposed to PPIs and 24,506 (12.4%) children developed asthma during follow-up (median follow-up = 6.8 years). The adjusted IRR (aIRR) of asthma associated with prenatal exposure to PPIs was 1.41 (95% confidence interval (CI): 1.27-1.56), compared with those unexposed. The association did not vary by trimester of exposure, and prenatal exposure to H2RAs was associated with similar increase in risk. The aIRR for maternal PPI and H2RA use in the year after, but not during pregnancy was 1.32 (95% CI: 1.20-1.46) and 1.13 (0.93-1.36), respectively, compared with non-use during and in the year after pregnancy.

CONCLUSIONS

Prenatal exposure to both PPIs and H2RAs was associated with an increased risk of asthma in our study. Because the observed association is not drug specific and also observed for maternal postnatal use it may be explained by a 'class effect' or maternal underlying condition.

Cord blood Tregs with stable FOXP3 expression are influenced by prenatal environment and associated with atopic dermatitis at the age of one year

BACKGROUND

Regulatory T cells (Tregs) with stable FOXP3 expression are characterized by a specific demethylated region in the FOXP3 gene (Treg-specific demethylated region, TSDR). The aim of this study was to analyse the influence of prenatal factors on cord blood Treg numbers, as detected by changes in the TSDR demethylation, and the subsequent risk for allergic diseases.

METHODS

Analyses were performed within the LINA study in blood samples from pregnant women (34th gestational week) and in cord blood (n = 346 mother-child pairs). Treg numbers were detected via DNA demethylation in the FOXP3 TSDR. At age 1, total and specific IgE was measured in children's blood. In addition, maternal cytokine production (Th1/Th2/Th17) was analysed. Exposure and disease outcomes were assessed by questionnaires.

RESULTS

Boys had lower Treg numbers compared with girls (P < 0.001). Parental atopy history, particularly maternal hay fever and paternal asthma were related to lower Treg numbers in cord blood (adj. MR = 0.81, 95% CI = 0.68-0.97; adj. MR = 0.60, 95% CI = 0.45-0.81). Maternal cytokines (IL-13, IL-17E and IFN-γ) and maternal smoking/exposure to tobacco smoke during pregnancy were also associated with decreased cord blood Treg numbers (adj. MR = 0.89, 95% CI = 0.97-1.00). Children with lower Treg numbers at birth had a higher risk to develop atopic dermatitis (adj. OR = 1.55, 95% CI = 1.00-2.41) and sensitization to food allergens (adj. OR = 1.55, 95% CI = 1.06-2.25) during the first year of life.

CONCLUSIONS

These results indicate that both genetic and environmental factors presumably influence the development of foetal Tregs. Low cord blood Treg numbers may predict early atopic dermatitis.

Neonatal cytokine profile in the airway mucosal lining fluid is skewed by maternal atopy

RATIONALE

Heredity from mother or father may impact differently in complex diseases, such as atopy. Maternal atopy is a stronger risk factor than paternal atopy for the development of atopy in the offspring. We hypothesized that mother's and father's atopy would have a differential imprinting on the cytokines and chemokines in the upper airway mucosal lining fluid of healthy neonates.

OBJECTIVES

To study parental atopic imprinting on the cytokines and chemokines in the upper airway mucosal lining fluid of healthy neonates.

METHODS

Eighteen cytokines and chemokines were quantified in nasal mucosal lining fluid in 309 neonates from the novel unselected Copenhagen Prospective Study on Asthma in Childhood (COPSAC) birth cohort.

MEASUREMENTS AND MAIN RESULTS

Maternal, but not paternal, atopic status (asthma, hay fever, or eczema with or without sensitization) was associated with general down-regulation of all 18 mediators assessed by principal component analysis (overall P = 0.015).

CONCLUSIONS

Maternal atopy, but not paternal atopy, showed a strong linkage with a suppressed mucosal cytokine and chemokine signature in asymptomatic neonates, suggesting imprinting by the maternal milieu in utero or perinatal life.

Maternal immune status in pregnancy is related to offspring's immune responses and atopy risk

BACKGROUND

The influence of maternal immune responses in pregnancy on children's immune competence and the development of atopic diseases later in life are poorly understood. To determine potential maternal effects on the maturation of children's immune system and resulting disease risks, we analysed immune responses in mother-child pairs in a prospective birth cohort study.

METHODS

Within the Lifestyle and Environmental factors and their Influence on Newborns Allergy risk (LINA) study, concentrations of Th1/Th2/Th17 and inflammatory cytokines/chemokines as well as IgE were measured in phytohemagglutinin and lipopolysaccharide stimulated maternal blood in the 34th week of gestation and in corresponding children's blood at birth and 1 year after (n = 353 mother-child pairs). Information on atopic outcomes during the first year of life was obtained from questionnaires.

RESULTS

Concentrations of inflammatory markers, excepting TNF-α, were manifold higher in cord blood samples compared with maternal blood. Th1/Th2 cytokines were lower in children's blood with a Th2 bias at birth. Maternal inflammatory parameters (MCP-1, IL-10, TNF-α) in pregnancy showed an association with corresponding cytokines blood levels in children at the age of one. High maternal IgE concentrations in pregnancy were associated with increased children's IgE at birth and at the age of one, whereas children's atopic dermatitis (AD) was determined by maternal AD.

CONCLUSIONS

Maternal inflammatory cytokines during pregnancy correlate with children's corresponding cytokines at the age of one but are not related to IgE or AD. While maternal IgE predicts children's IgE, AD in children is only associated with maternal disease.

Maternal immunization to modulate the development of allergic response and pathogen infections

This article reviews recent experimental approaches of preventive strategies regarding allergy and infections by pathogens, particularly in early childhood, by targeting maternal immunomodulation. Basic research is essential to understand maternal vaccination as a strategy to control allergic disease and bacterial and viral infections; thus, providing support for future translational research. The environmental stimuli and host genetic factors, along with maternal influences in early life when immune systems are developing and during postnatal life, are essential for the decision between tolerance induction or allergen sensitization. Maternal immunomodulation strategies should serve as a challenge when attempting to halt the spread of allergy responses and viral infections, until the innate and adaptive arms of the immune system of the neonates are competent.

Prebiotic oligosaccharides: in vitro evidence for gastrointestinal epithelial transfer and immunomodulatory properties

Prebiotic oligosaccharides are present in breast milk and evidence is pointing toward immunomodulatory properties of the acidic fraction. Recently, prebiotic supplements of infant formula [short-chain galacto (scGOS)-, long-chain fructo (lcFOS)-oligosaccharides] showed preventive effects on atopic disease development. We aimed to define the direct immunologic effects of these oligosaccharides and of human (aHMOS) and cows' milk (aCMOS) acidic oligosaccharides and to investigate the systemic uptake of prebiotic supplements of infant formula and a specific pectin-derived acidic oligosaccharide hydrolysate (pAOS) in vitro. After assurance of LPS-free conditions (limulus assay, toll like receptor-2, -4 transfected human embryonic kidney-cells), in vitro-transfer through a CaCo-2 cell monolayer was measured using high-pH anion exchange chromatography with pulsed amperometric detection. Direct effects on proliferation, cytokine-induction of cord blood mononuclear cells and modulation of allergen-specific CD4+ T-cell cytokine profiles from allergic and non-allergic individuals were investigated. Transfer of scGOS/lcFOS and pAOS in-vitro was detected with a rate of transfer of 4-14%, depending on the molecular size and structure. AHMOS induced IFN-γ and IL-10 but not the Th-2 cytokine IL-13 at physiologic concentrations (10-100 μg/ml) in cord blood, whereas aCMOS did not induce any of these cytokines. AHMOS significantly suppressed Th-2 type cytokine-production by Ara h1-specific CD4+ T cells (CFSE(low) CD3(+) CD4(+) cells) from peanut allergic patients. In conclusion, human milk-derived acidic oligosaccharides may modulate postnatal allergen-specific immune responses by the suppression of Th-2-type responses in atopy-prone individuals. Moreover, there is in vitro evidence for epithelial transport of prebiotic oligosaccharides.

IgE in the human placenta: why there?

Immunoglobulin E (IgE) antibodies are key effector molecules in the allergic inflammatory response and are also involved in the protection against extracellular parasites. Allergic symptoms often develop early in life, and the intrauterine environment has been proposed to play an important role in affecting the risk of later allergy development. The placenta constitutes a selective barrier between the maternal and foetal circulation. Recently, we reported that maternal IgE antibodies are present on foetal macrophages in the villous tissue of the human placenta irrespective of maternal allergy status. This review discusses the presence of IgE antibodies in the human placenta and its possible roles in normal and pathologic pregnancy. It also deals with the relationship between placental IgE and development of allergy during childhood. A better understanding of the role of IgE in placenta could give us clues on how to prevent allergy development in the future generations.

Modulation of in vivo and in vitro cytokine production over the course of pregnancy in allergic and non-allergic mothers

Cytokines secreted during pregnancy may influence immune development of the foetus. This study aimed to determine if maternal allergy alters patterns of systemic cytokine production throughout and after pregnancy. Maternal plasma cytokines and allergen-specific production of interleukin (IL)-10, IL-13 and interferon (IFN)-gamma were measured in allergic (n = 63) and non-allergic (n = 70) pregnant women who had a full set of sequential peripheral blood samples collected at 20-, 30-, 36-wk gestation and 6-wk post-partum. Maternal allergy was strictly defined by both allergen sensitization and doctor-diagnosed asthma, eczema or rhinitis. IL-13 responses to allergen were higher for allergic mothers at all time-points (20 wk: p < 0.001; 30 wk: p = 0.001; 36 wk: p < 0.001; post-partum: p < 0.001). For the non-allergic group, IL-13 levels to house dust mite decreased from 20- to 36-wk gestation (Friedman ANOVA p = 0.012) and were significantly lower at 36 wk compared with post-partum (p = 0.002). In contrast, IL-13 production by allergic mothers did not change from 20 wk through to post-partum. For both allergic and non-allergic mothers, in vitro IFN-gamma production was lower at all pregnancy time-points compared with post-partum levels. Allergic women had an increased propensity for peripheral blood allergen-specific T helper-2 responses during pregnancy, and failed to downregulate these responses in comparison with non-allergic women. This may be a factor that contributes to the increased risk of atopy in infants born to allergic mothers.

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.

Maturation of cytokine-producing capacity from birth to 1 yr of age

Little is known about the immunologic maturation in the early stages of life. The aim of this study was to investigate maturation of immune system from birth to 1 yr of age and to compare immune functions between mothers and their children. Also the effect of atopy to the immune responses of children was examined. Cord blood samples (n = 228) and peripheral blood samples of children (n = 200) and their mothers (n = 208) 1 yr after birth were collected. Whole blood samples were stimulated for 24 and 48 h with Staphylococcal enterotoxin B (SEB), lipopolysaccharide (LPS) and the combination of phorbol ester and ionomycin (P/I). Production of TNF-alpha, IFN-gamma, IL-5, IL-8 and IL-10 was determined using ELISA. Significant mother-to-child correlation was detected in cytokine-producing capacity at the age of 1 yr. TNF-alpha (P/I, SEB and LPS stimulation), IFN-gamma (P/I and SEB), IL-5 (P/I and SEB) and IL-10 (P/I, SEB and LPS) producing capacity increased from birth to 1 yr of age. In general, stimulated cytokine responses were higher in mothers' than in children's blood samples, except in the case of P/I and LPS-stimulated IL-8, which were highest at birth. Maternal inhalation atopy was associated with increased cord blood IL-5 (24 and 48 h) and IL-10 (48 h) production following P/I stimulation. Also children of food atopic mothers expressed elevated cord blood IL-10 (48 h, P/I) responses and decreased IFN-gamma/IL-5 ratio (24 h, P/I). In addition, the production of IFN-gamma (24 and 48 h, P/I) and the IFN-gamma/IL-5 ratio (24 h and 48 h, P/I) at the age of 1 yr was lower among children with food atopic mothers. In conclusion, our results suggest that both adaptive and innate immune responses increase from birth to 1 yr of age, but are still weak in comparison to adult responses. Cytokine responses of children begin to correlate with those of their mothers during the first year of life. Although only few associations were observed between atopy and cytokine-producing capacity, our results suggest that children of atopic mothers express T(h)2-polarized cytokine pattern.

Cord blood cytokines and chemokines and development of allergic disease

Exposure to ubiquitous allergens early in life, even before birth, may influence the incidence of allergic diseases later in life. During pregnancy, the fetomaternal interface is surrounded by high levels of T-helper (Th)2-like cytokines, possibly favouring the development of Th2-like immune responses in the offspring. The aim of this study was to evaluate the relation between cord blood (CB) IgE antibodies, Th1- and Th2-like cytokines and chemokines, maternal allergy and development of allergic disease during the first 2 yr of life in the offspring. The CB cytokine and chemokine levels from children of 20 allergic and 36 non-allergic women were determined by a multiplexed Luminex assay and ELISA. Total CB and maternal IgE antibody concentrations were quantified using ImmunoCAP technology. The maternal IgE levels during and after pregnancy correlated with CB IgE and Th2-associated macrophage-derived chemokine [MDC (CCL22)] levels. Development of allergic disease and sensitization was associated with increased CB IgE and MDC (CCL22) levels, as well as high ratios of MDC (CCL22) to Th1-associated interferon-gamma inducible protein 10 [IP-10 (CXCL10)] and interferon-gamma inducible T-cell alpha-chemoattractant [I-TAC (CXCL11) (n = 7 allergic vs. n = 25 non-allergic)]. The correlations between maternal IgE and CB IgE and MDC (CCL22) levels possibly indicate that the maternal immunity can affect the Th1/Th2 profile in the neonate. Development of allergic disease is associated with a more marked Th2-like deviation already at birth, shown as increased levels of CB IgE and MDC (CCL22) and higher ratios of MDC (CCL22) to IP-10 (CXCL10) and I-TAC (CXCL11).

Total and allergen-specific IgE levels during and after pregnancy in relation to maternal allergy

Type 2 T-helper cell (Th2)-skewed immunity is associated with successful pregnancy and the ability to easily direct immune responses to a Th2-polarised profile may be an evolutionary benefit. The Th2-like immunity associated with allergic disease might generate favourable effects for the maintenance of pregnancy, but could also promote development of Th2-like immune responses and allergic disease in the offspring. The aim of this study was to explore, by using IgE as a stable proxy for Th2, the Th1/Th2 balance in allergic and non-allergic women by measuring allergen-specific and total IgE antibody levels in plasma during pregnancy and after delivery. Specific and total IgE antibody levels were determined by ImmunoCAP technology at five occasions during pregnancy (gestational weeks 10-12, 15-16, 25, 35 and 39), as well as at 2 and 12 months after delivery. Thirty-six women without and 20 women with allergic symptoms were included, of whom 13 were sensitised with allergic symptoms and 30 were non-sensitised without allergic symptoms. The levels of total IgE, but not allergen-specific IgE, were increased during early pregnancy when compared to 12 months after delivery in the sensitised women with allergic symptoms, but not in the non-sensitised women without allergic symptoms (p<0.01). This increase in total IgE levels during early pregnancy only in the sensitised women with allergic symptoms indicates that allergy is associated with an enhanced Th2 deviation during pregnancy.

First evidence of a possible association between gastric acid suppression during pregnancy and childhood asthma: a population-based register study

BACKGROUND

Recent data in mice suggest that acid suppression during pregnancy yields offspring with type 2 T helper-dominant immunity, suggesting a predisposition for allergy.

OBJECTIVE

To determine the association of in utero exposure to acid-suppressive medications and the subsequent development of allergic diseases in children.

METHODS

We studied a population-based observational cohort formed by linking data from three Swedish national healthcare registers: the Medical Birth Register, the Hospital Discharge Register, and the Swedish Prescribed Drug Register. Main outcome measures included a hospital discharge diagnosis of an allergic disease or prescription for asthma medications, epinephrine auto-injectors, antihistamines or steroid ointments in children. Data were analysed using the Mantel-Haenszel procedure.

RESULTS

Twenty-nine thousand four hundred and ninety (5.03%) children had a discharge diagnosis of allergy or prescriptions for allergy medications. Five thousand six hundred and forty-five (0.96%) children had been exposed to acid suppression therapy during pregnancy; of these, 405 (0.07%) were treated for allergic diseases. Exposure to acid-suppressive medications in utero was associated with an increased odds ratio (OR) for developing allergy (OR 1.43, 95% confidence interval (95% CI) 1.29-1.59). We observed this association irrespective of the type of drug, time of exposure during pregnancy, and maternal history of allergy. The use of maternal acid-suppressive medication was associated with an increased OR for the development of childhood asthma (3.7% in the population at large vs. 5.6% in exposed children, OR 1.51, 95% CI 1.35-1.69), but not for other allergic diseases.

CONCLUSION

These data provide first evidence of a significant association between in utero exposure to acid-suppressive drugs and the risk of developing childhood asthma.

Randomized, double-blind, placebo-controlled trial of probiotics for primary prevention: no clinical effects of Lactobacillus GG supplementation

BACKGROUND

The value of probiotics for primary prevention is controversial. Published trials vary considerably in study design and the applied probiotics, thereby limiting comparability of the results.

OBJECTIVE

The purpose of this trial was to study the preventive effect of the probiotic Lactobacillus GG on the development of atopic dermatitis.

METHODS

In a double-blind, placebo-controlled prospective trial, 105 pregnant women from families with > or = 1 member (mother, father, or child) with an atopic disease were randomly assigned to receive either the probiotic Lactobacillus GG (American Type Culture Collection 53103; 5 x 10(9) colony-forming units of Lactobacillus GG twice daily) or placebo. Ninety-four families (89.5%) completed the trial. The supplementation period started 4 to 6 weeks before expected delivery, followed by a postnatal period of 6 months. The primary end point was the occurrence of atopic dermatitis at the age of 2 years. Secondary outcomes were severity of atopic dermatitis, recurrent episodes of wheezing bronchitis, and allergic sensitization at the age of 2 years.

RESULTS

Atopic dermatitis was diagnosed in 14 (28%) of 50 in the Lactobacillus GG group and in 12 (27.3%) of 44 in the placebo group. The risk of atopic dermatitis in children on probiotics relative to placebo was 0.96 (confidence interval 0.38-2.33). Severity of atopic dermatitis was comparable between the 2 groups. Notably, children with recurrent (> or = 5) episodes of wheezing bronchitis were more frequent in the Lactobacillus GG group (26%; n = 13), as compared with the placebo group (9.1%; n = 4). No difference was observed between both groups in total immunoglobulin E concentrations or numbers of specific sensitization to inhalant allergens.

CONCLUSIONS

Supplementation with Lactobacillus GG during pregnancy and early infancy neither reduced the incidence of atopic dermatitis nor altered the severity of atopic dermatitis in affected children but was associated with an increased rate of recurrent episodes of wheezing bronchitis. Therefore, Lactobacillus GG cannot be generally recommended for primary prevention.

Heat- and formalin-inactivated probiotic bacteria induce comparable cytokine patterns in intestinal epithelial cell-leucocyte cocultures

The mode of inactivation of probiotic bacteria may profoundly affect their immune-modulatory properties to the point of reversal of effects in in vitro human intestinal epithelial-like cell cultures (Caco-2). To further investigate the influence of inactivation treatment on cytokine production, three probiotic strains were evaluated-live, heat-inactivated, and formalin-inactivated strains-for their impact on interleukin (IL) 6, IL-8, and IL-10 production in Caco-2-leucocyte cocultures. The tested bacteria induced strain-specific production of IL-6, IL-8, and IL-10. No suppressive effects on cytokine synthesis were observed. Live microorganisms seemed to be slightly more potent inducers of cytokine production than nonviable strains, but differences to inactivated bacteria were not statistically significant. Our results indicate that heat and formalin treatments of probiotic microorganisms are equivalent inactivation methods in terms of induction of IL-6, IL-8, and IL-10 production in Caco-2-peripheral blood mononuclear cell cocultures and do not invert immune-modulatory effects.

Maternal influence in the transmission of asthma susceptibility

Asthma is one of the most common chronic diseases in children, with increasing morbidity and mortality. A genetic predisposition and exposure to allergens have been implicated as major risk factors for the development of asthma. However, increasing evidence indicates that the mother plays a crucial role in mediating the development of fetal-infant immune responses to inhaled allergens. The exact nature and mechanism of this maternal influence and how it might be associated with the development of allergic sensitization and asthma are not clear. Under normal conditions, the maternal environment during pregnancy promotes an initial Th2 skewed immune response in the offspring which transitions to a nonallergic Th1 type response after birth. However, the allergic mother's influence may delay the normal transition to a nonallergic immune response to inhaled allergens in her children, thus increasing the risk for the development of allergic sensitization and/or asthma. Understanding the underlying mechanisms by which the maternal immune environment can influence the development of the fetal-infant immune response to inhaled allergens may lead to identifying new targets for the prevention of allergic sensitization and asthma.

Absence of systemic immunologic changes during dose build-up phase and early maintenance period in effective specific sublingual immunotherapy in children

BACKGROUND

Sublingual immunotherapy (SLIT) has been reported to be a safe treatment for inhalant allergies in children. Yet the immunologic mechanisms resulting in clinical improvement are poorly understood.

OBJECTIVE

To identify early systemic immunologic changes during the first 8 weeks of clinically effective SLIT to grass pollen, tree pollen or house dust mite in paediatric patients with allergic rhinoconjunctivitis and/or asthma.

METHODS

Peripheral blood mononuclear cells and plasma samples of 13 children with reduced symptoms after 1 year of SLIT were obtained before therapy and at 2 and 8 weeks after the initiation of SLIT. Allergen-specific lymphocyte proliferation assays were performed, and allergen-induced cytokine production (IL-2, IL-4, IL-10, IFN-gamma, and TGF-beta(1)) was measured by ELISA and flow cytometry. Allergen-specific IgE, IgG1, IgG4, and IgA levels in plasma samples were determined in ELISA.

RESULTS

During the first 8 weeks of successful SLIT, allergen-specific lymphoproliferation (n=13) as well as levels of allergen-specific intracellular (n=8) and secreted cytokines (n=9) did not change significantly. In addition, no alterations in levels of allergen-specific Igs (n=7) were observed.

CONCLUSION

We could not find any early systemic immunologic changes during the first 8 weeks of clinically effective SLIT to inhalant allergens in paediatric patients with allergic rhinoconjunctivitis and/or asthma.

Prenatal, perinatal, and heritable influences on cord blood immune responses

BACKGROUND

Maternal and perinatal environmental exposures, as well as inherited factors, may influence neonatal immune responses.

OBJECTIVE

To determine relations of maternal and perinatal exposures to antigen-specific cord blood lymphoproliferative responses.

METHODS

In 427 newborns from a Boston pregnancy/birth cohort, lymphoproliferative responses in cord blood mononuclear cells to stimulation with cockroach (Bla g 2), house dust mite (Der f 1), ovalbumin, and mitogen phytohemagglutinin were measured as stimulation index (SI). We used the Wilcoxon rank sum and chi2 tests to evaluate predictors of ovalbumin SI as a continuous ranked or dichotomous outcome. We used t test and Spearman correlation for univariate testing and linear regression to evaluate predictors of natural log-transformed Bla g 2, Der f 1, and phytohemagglutinin SI. Logistic multivariate regression was applied to evaluate predictors of Bla g 2, Der f 1, and phytohemagglutinin SI dichotomized at 2 or at the median for phytohemagglutinin.

RESULTS

Maternal smoking during pregnancy, inadequate or excessive maternal weight gain during pregnancy, neonate black race/ethnicity (compared with white), and Apgar score less than 8 were each independently associated with increased cord blood mononuclear cell proliferative responses to stimulation with Bla g 2 and/or Der f 1. Maternal history of asthma was associated only with increased lymphoproliferative response to ovalbumin stimulation.

CONCLUSIONS

Distinct fetal and perinatal exposures and black race/ethnicity may be associated with increased cord blood lymphoproliferative responses. The implications of these findings for future development of allergy or asthma are, as yet, unknown.

Prenatal lipopolysaccharide-exposure prevents allergic sensitization and airway inflammation, but not airway responsiveness in a murine model of experimental asthma

BACKGROUND

Epidemiological evidence underlines the impact of prenatal environmental factors on the development of postnatal allergies. In this regard an inverse correlation between lipopolysaccharide (LPS) exposure and development of childhood allergy has been found.

OBJECTIVE

To assess the impact of prenatal LPS exposure on the development of postnatal respiratory allergies in a mouse model of experimental asthma.

METHODS

Female BALB/c mice were exposed to LPS before conception and during pregnancy. Several weeks after birth offspring were sensitized to ovalbumin (OVA) followed by aerosol allergen challenges.

RESULTS

Prenatal, maternal LPS-exposure enhanced neonatal IFN-gamma, but not IL-4 and IL-2 production. OVA sensitization of prenatally LPS-exposed mice was accompanied by a marked suppression in anti-OVA IgG1 and IgE as well as unchanged IgG2a antibody responses, paralleled by a significant reduction in IL-5 and IL-13 levels following mitogenic stimulation of splenic leucocytes. Assessment of bronchoalveolar lavage fluids following allergen challenges revealed a marked reduction in eosinophils and macrophages in these mice. Surprisingly, development of airway hyper-responsiveness, a hallmark of bronchial asthma, was not affected.

CONCLUSION

This study provides first experimental evidence that LPS may already operate in prenatal life in order to modulate the development of allergies in the offspring.

Prenatal factors associated with the development of eczema in the first year of life

Prenatal factors have been implicated in childhood eczema, but the relationship between maternal cytokine production during pregnancy and infant eczema is unknown. Non-selected women in their third trimester were enrolled in the Tucson Infant Immune Study. Data from three sources were used to define MD-eczema: parent-completed illness questionnaires at age 2, 3, 4, 6 and 9 months regarding physician-seen eczema, parent-completed questionnaires at 12 months regarding physician-diagnosed eczema, and medical record reviews. Blood samples were taken from mothers during their third trimester and from the umbilical cord at birth. Maternal peripheral blood mononuclear cells and cord blood mononuclear cells were stimulated with ConA/PMA, and supernatants were assayed for IFN-gamma and IL-4, -5, -10, and -13. Of 364 children, 28% were seen by a physician for eczema by 1 yr of age. After adjustment for potential confounders using logistic regression, the odds for development of eczema in infancy were significantly higher when mothers had active eczema in pregnancy (OR, 2.46, CI 1.0-5.8, p <0.042) and when mothers were in the highest tertile of serum IgE production (OR 2.28, CI 1.2-4.4, p <0.013). Colds in the third trimester were associated with lower odds of eczema (OR 0.32, CI 0.16-0.63, p <0.001). Our findings from this cohort study suggest that in utero factors, including maternal IgE, colds, and eczema, may influence the risk of infant eczema.

Functional Maturation of CD4+CD25+CTLA4+CD45RA+T Regulatory Cells in Human Neonatal T Cell Responses to Environmental Antigens/Allergens

A number of laboratories have reported cord blood T cell responses to ubiquitous environmental Ags, including allergens, by proliferation and cytokine secretion. Moreover, the magnitude of these responses has been linked with risk for subsequent expression of allergy. These findings have been widely interpreted as evidence for transplacental priming and the development of fetal T memory cells against Ags present in the maternal environment. However, we present findings below that suggest that neonatal T cell responses to allergens (and other Ags) differ markedly from those occurring in later life. Notably, in contrast to allergen-responsive adult CD4(+) T cell cultures, responding neonatal T cell cultures display high levels of apoptosis. Comparable responses were observed against a range of microbial Ags and against a parasite Ag absent from the local environment, but not against autoantigen. A notable finding was the appearance in these cultures of CD4(+)CD25(+)CTLA4(+) T cells that de novo develop MLR-suppressive activity. These cells moreover expressed CD45RA and CD38, hallmarks of recent thymic emigrants. CFSE-labeling studies indicate that the CD4(+)CD25(+) cells observed at the end of the culture period were present in the day 0 starting populations, but they were not suppressive in MLR responses. Collectively, these findings suggest that a significant component of the reactivity of human neonatal CD4(+) T cells toward nominal Ag (allergen) represents a default response by recent thymic emigrants, providing an initial burst of short-lived cellular immunity in the absence of conventional T cell memory, which is limited in intensity and duration via the parallel activation of regulatory T cells.

Interleukin-18 enhances the production of interferon-gamma (IFN-γ) by allergen-specific and unspecific stimulated cord blood mononuclear cells

BACKGROUND

IL-18 is a pleiotropic cytokine involved in the polarisation of T-cell response. This study was performed to determine whether or not IL-18 is detectable in phytohemagglutinin (PHA) or betalactoglobulin (BLG) stimulated supernatants of cord blood mononuclear cells (CBMC) and to study the in vitro effect of IL-18 on the interferon (IFN)-gaamma and IL-13 release of CBMC of healthy neonates.

METHODS

CBMC of neonates were isolated by Ficoll density centrifugation. The cytokines IFN-gamma, IL-13 and IL-18 in the cell culture supernatants were measured using the ELISA technique following stimulation with a unspecific (PHA 20 microg/ml) and an allergen-specific stimulus (BLG 25 microg/ml). In order to study the in vitro effect of IL-18, CBMC were stimulated either with medium alone or with IL-18, IL-18 + PHA and IL-18 + BLG.

RESULTS

IL-18 levels in supernatants of CBMC were low and did not vary significantly between unstimulated and PHA or BLG stimulated cell cultures (median 21.4; 23.5 and 15.5 pg/ml, respectively). IFN-gamma and IL-13 levels were significantly higher in response to PHA and BLG (PHA: IFN-gamma, 6154; IL-13, 4357; BLG: IFN-gamma, 801; IL-13, 249 pg/ml) compared to unstimulated cell cultures. The addition of IL-18 to PHA or BLG stimulated CBMC significantly enhanced the IFN-gamma release (PHA: 6154; PHA + IL-18: 13474, p = 0.0001; BLG: 801; BLG + IL-18: 1077, p = 0.008). In comparison to incubation without IL-18, the release of IL-13 was invariable or even reduced, when CBMC were stimulated with PHA + IL-18 (4026, p = 0.16) or BLG + IL-18 (124, p = 0.0001) compared to stimulation of CBMC with PHA (4357 pg/ml) or BLG (249 pg/ml) alone.

CONCLUSIONS

IL-18 is detectable in supernatants of CBMC. We observed a significant effect of IL-18 + PHA as well as IL-18 + BLG on IFN-gamma release in vitro. Based on our findings we conclude that IL-18 could act as a strong TH1-inducing factor on stimulated CBMC also in vivo.

Immunostimulatory potential of beta-lactoglobulin preparations: effects caused by endotoxin contamination

BACKGROUND

The immunomodulating potential residing in cow's milk proteins is currently receiving increasing attention because of growing interest in functional foods and the complex problem of cow's milk allergy. One of the major cow's milk allergens, whey protein beta-lactoglobulin, has previously been shown to mediate cellular activation in both human and murine immune cells.

OBJECTIVE

We examined the response to different beta-lactoglobulin preparations in naive immune cells.

METHODS

Splenocytes and cells from mesenteric lymph nodes derived from BALB/c mice bred and maintained on a milk-free diet were cultured in vitro with different beta-lactoglobulin preparations. Cell proliferation, cytokine production, and increases in intracellular glutathione were used as cellular activation markers. Moreover, the effect of beta-lactoglobulin on cytokine production in murine bone-marrow-derived dendritic cells was examined.

RESULTS

We observed that some commercial beta-lactoglobulin preparations induced pronounced proliferation of both spleen cells and cells from mesenteric lymph nodes; production of TNF-alpha, IL-6, IL-1beta, and IL-10; and an increased level of intracellular glutathione in spleen cell cultures. Furthermore, TNF-alpha, IL-6, IL-1beta, and IL-10 production was induced in murine bone-marrow-derived dendritic cells. Purification of beta-lactoglobulin from raw milk using nondenaturating conditions, however, revealed that the beta-lactoglobulin per se did not possess the immunomodulatory activity. Eventually, the immunostimulatory effect was found to be caused by endotoxin contamination.

CONCLUSION

These results identify endotoxin as the main immunostimulatory component present in some commercial beta-lactoglobulin preparations. Moreover, the present study makes it evident that immunomodulatory effects attributed to beta-lactoglobulin need to be reassessed.

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

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

Maternal smoking in pregnancy alters neonatal cytokine responses

BACKGROUND

Maternal cigarette smoking in pregnancy is an important, common and avoidable exposure that has been linked with elevated cord blood (CB) immunoglobulin E levels and subsequent asthma and allergic disease in childhood. Despite this, there is still very little information about the immunological effects of maternal smoking on the fetus.

METHODS

This aim of this study was to compare cord blood mononuclear cell (CBMC) cytokine responses to allergens [ovalbumin (OVA) or house dust mite (HDM)] and mitogens [concanavalin A (ConA) or phytohemaglutinen (PHA)] in neonates whose mothers smoked throughout pregnancy (n = 17) with responses of neonates whose mothers never smoked (n = 40). Cell cultures were stimulated for 24 h and supernatants collected for cytokine detection by enzyme-linked immunosorbent assay [interleukin (IL)-13, IL-6, interferon (IFN)gamma and IL-10]. Cell pellets were also collected for cytokine mRNA detection (IL-5, IL-9, IFNgamma).

RESULTS

Maternal smoking in pregnancy was associated with significantly higher neonatal T helper type 2 (IL-13 protein) responses to both HDM (P = 0.01) and OVA (P = 0.035). These effects remained statistically significant after allowing for confounding factors, including the effects of maternal atopy. Similar trends were also seen for IL-9mRNA, IL-5mRNA and IL-6 responses, although these were not statistically significant. Although IFNgamma mRNA responses to PHA (P = 0.015) and ConA (P = 0.025) were lower if mothers smoked in pregnancy, there were no differences in neonatal (Th1) IFNgamma protein responses to allergens or mitogens.

CONCLUSIONS

These findings indicate that maternal cigarette smoking can modify aspects of fetal immune function and highlight the need for further studies in this area.

Exposure to high doses of birch pollen during pregnancy, and risk of sensitization and atopic disease in the child

BACKGROUND

The role of maternal allergen exposure during pregnancy in sensitization and development of atopic disease in the child remains controversial. In the spring of 1993, extremely high levels of birch pollen were recorded in Stockholm, Sweden. In 1994, the corresponding pollen levels were low. The aim of this study was to assess the influence of exposure during pregnancy to high/low doses of birch pollen on the risk of sensitization and development of atopic disease in children. In addition, a comparison was made with children exposed to birch pollen in early infancy.

METHODS

Three hundred and eighty-seven children with atopic heredity, born in Stockholm in July-October 1993 or 1994 (mothers exposed during pregnancy), were investigated at age 4.5 years. The children were clinically examined and were skin prick tested (SPT) with inhalant and food allergens. IgE antibodies (RAST) against birch pollen and recombinant birch pollen allergen (rBet v 1) were analysed in serum. A comparison was made with a similar group of children exposed during the same incident, but in the first 3 months of life, in 1993.

RESULTS

The children of mothers high-dose exposed during pregnancy in 1993 tended to be more sensitized (SPT > or = 3 mm) to birch pollen than the children with low-dose exposure during the corresponding period in 1994 (7.6 and 4.6%, respectively, OR: 1.7; 95% CI: 0.7-4.1). A similar but weak tendency was seen for positive RAST analyses (> or =0.35 kU/l) against birch pollen and rBet v 1. Children of mothers high-dose exposed during pregnancy were significantly less sensitized to birch pollen than the children high-dose exposed in early infancy (17.9%, OR: 0.4; 95% CI: 0.2-0.7). There was an overall trend towards a slightly increased prevalence of bronchial asthma, allergic rhinoconjunctivitis and atopic dermatitis in the group with mothers high-dose exposed during pregnancy, compared to those with low exposure.

CONCLUSION

Exposure of the mother during pregnancy to high levels of birch pollen resulted in a tendency towards increased risk of sensitization to the same allergen and symptoms of atopic disease in children with atopic heredity. Furthermore, our data indicate that exposure of the mother during pregnancy to inhalant allergens is less likely to result in sensitization in the child than exposure of the child in early infancy.

Cytokine production by cord blood mononuclear cells stimulated with cows milk proteins in vitro: interleukin-4 and transforming growth factor beta-secreting cells detected in the CD45RO T cell population in children of atopic mothers

BACKGROUND

Food antigens from the maternal circulation may sensitize fetal T cells in utero and be an important determinant in the development of food allergy.

METHODS

Here we have examined the spontaneous and recall response to cow's milk proteins of cord blood mononuclear cells (CBMC) of newborn children, using single cell ELISPOT assays.

RESULTS

In term newborns, confirming previous studies, the spontaneous cytokine response of CBMC is dominated by IL-4, IL-5, IL-10, and as shown here for the first time, TGF-beta. For TGF-beta only, the response of samples from infants of atopic mothers was significantly lower than samples from infants of non-atopic mothers. In vitro stimulation of CBMC with bovine serum albumin, casein and beta-lactoglobulin resulted in a significant increase of all cytokine-secreting cells, again dominated by T helper type 2 (Th2) cytokines. There was a clear tendency for samples from infants of atopic mothers to have lower Th2 responses than samples from infants of non-atopic mothers, which was particularly significant for both IL-4 and TGF-beta. Spontaneous cytokine secreting cells were virtually absent in cord blood from infants < 34 weeks gestation, as were cows milk protein-induced responses, although they were readily detectable in samples from infants aged > 34 weeks. To explore whether the cytokine secreting cells were in the naive CD4+ CD45RA population or memory CD4+ CD45RO T cells, these subsets were purified by positive and negative selection and tested for spontaneous and cows milk protein-induced cytokine responses. Strikingly, although the responses were small, the CD45RO+ cells from children of atopic mothers showed significant spontaneous and antigen-specific IL-4 and TGF-beta responses, whereas the same population from infants of non-atopic mothers showed virtually no response. In addition CD45RA+ cells from infants of mothers with maternal atopy showed decreased IL-4 and TGF-beta responses, especially the latter.

CONCLUSIONS

The cows milk antigen-specific IL-4 and TGF-beta responses preferentially seen in the memory cell subset of infants with a maternal history of atopy strongly suggests Th2 skewing to dietary antigens in utero.

Early origins of allergic disease: a review of processes and influences during early immune development

PURPOSE OF REVIEW

With the disturbing increase in allergic disease, there is a pressing need to determine the causes, pathogenesis and safe avenues for disease prevention. Although events in early life appear important, no causal pathways have been identified. This review examines new developments in the area of foetal and early postnatal immune maturation. It secondly addresses early predisposing influences and protective factors that may have a future role in allergy prevention.

RECENT FINDINGS

New developments in the understanding of the ontogeny of allergen-specific immune responses in atopic infants are discussed, including the role of early type 1 and 2 immune responses, and how these are influenced by perinatal antigen presenting cell and T-cell immaturity. The controversial role of early dietary exposures including breastfeeding, food allergens, hydrolyzed formulae and other dietary factors including omega-3 fatty acids are discussed in the context of the most recent literature. Equally contentious, the role of early house dust and pet allergen exposure is discussed in light of new epidemiological studies and disappointing early results of multicentre allergen avoidance studies. Finally, a number of studies in animals and humans suggest that bacterial products can influence early immune development, providing a new potential therapeutic avenue for disease treatment and prevention.

SUMMARY

Complex multifactorial genetic and environmental interactions make research in this area difficult and apparent associations with allergic disease may not be causal in nature. Many current targets for prevention, such as early allergen exposure and infant feeding practices, are proving to be ineffective and may not be directly implicated in rising rates of disease.

Peripheral blood mononuclear cell proliferation to heat shock protein-70 derived from autologous lung carcinoma

In animals, tumor-derived heat shock proteins (HSP) induce immune-mediated protection against autologous cancer. We investigated whether HSP-70 derived from human lung carcinoma are also complexed to tumor-specific antigens. Peripheral blood mononuclear cells collected 10 days after surgery from patients with lung cancer were stimulated with HSP-70 purified from autologous and heterologous tumors. The stimulation index (SI) obtained when stimulating cells with autologous tumor-derived HSP-70 averaged 3.07 +/- 0.75 in patients with lung cancer and 1.57 +/- 0.33 in control subjects (p < 0.001 by analysis of variance). No significant stimulation was observed with HSP-70 derived either from the majority of heterologous tumors or from autologous tumor-free lung tissue. SI decreased from 3.59 +/- 0.65 to 1.65 +/- 0.38 in six patients tested again 3 months after surgery (p = 0.02 by Wilcoxon test for paired data). HSP-70 derived from lung carcinoma are shown to be associated with T cell antigens. The T cell reactivity appears transient and restricted to antigens complexed to HSP-70 derived from autologous tumors only. This suggests that the antigenicity of human lung tumors is unique, which may be crucial for the design of new vaccines.