Is deficiency of interferon gamma production by allergen triggered cord blood cells a predictor of atopic eczema?

Maternal Nutritional Status and Development of Atopic Dermatitis in Their Offspring

Atopic dermatitis (AD) is the leading chronic skin inflammatory disease and the initial manifestation of atopic march. Available evidence supports the notion that primary prevention early in life leads to a decreased incidence of AD, thus possibly decreasing the subsequent occurrence of atopic march. Nutritional status is essential to a proper functioning immune system and is valued for its important role in AD. Essential nutrients, which include carbohydrates, proteins, lipids, vitamins, and minerals, are transferred from the mother to the fetus through the placenta during gestation. Various nutrients, such as polyunsaturated fatty acids (PUFAs) and vitamin D, were studied in relation to maternal status and offspring allergy. However, no strong evidence indicates that a single nutrient or food in mothers' diet significantly affects the risk of childhood AD. In the light of current evidence, mothers should not either increase nor avoid consuming these nutrients to prevent or ameliorate allergic diseases in their offspring. Each essential nutrient has an important role in fetal development, and current government recommendations suggest specific intake amounts for pregnant women. This review discusses evidence on how various nutrients, including lipids (monounsaturated fatty acids, PUFAs, saturated fatty acids, and short-chain fatty acids), carbohydrates (oligosaccharides and polysaccharides), proteins, vitamins (A, B, C, D, and E), and trace minerals (magnesium, iron, zinc, copper, selenium, and strontium) in maternal status are associated with the development of AD and their possible mechanisms.

Post-transplant food anaphylaxis in an adult cord blood transplant recipient (Ms. No. IJHM-D-20-01037R1)

Transplant acquired food allergy (TAFA) is a well-known complication following pediatric liver transplantation, but post-cord blood transplantation (post-CBT) TAFA has rarely been reported. Here, we describe a case of new-onset food anaphylaxis after CBT in an adult patient that demonstrates that post-CBT allergen-challenge is not a risk for long-term allergic sensitization even in adult recipients. The patient was a 39-year-old Japanese man with aggressive NK cell leukemia. He had no previous history of allergies. After receiving CBT, the patient had an unbalanced diet with high preference for bread, bananas, miso-soup, cow's milk, cheese, egg, sesame and buckwheat soba noodles, and experienced repeated diarrhea. Six months later, he developed symptoms such as vomiting, epigastric pain, diarrhea, high fever and hypotension. The condition was initially diagnosed as enterocolitis, but symptoms recurred after consumption of buckwheat. Anaphylaxis induced by buckwheat was confirmed with serum radioallergosorbent tests (RAST), showing allergen-specific IgE for buckwheat (greater than 100 U/mL, Class 6) and egg ovomucoid (Class 4). Nineteen months after a buckwheat and egg-free diet, serum RAST for buckwheat and egg significantly improved. As a result, the patient acquired a tolerance and was able to consume buckwheat and egg without allergic symptoms.

Fetal Tobacco Smoke Exposure in the Third Trimester of Pregnancy Is Associated with Atopic Eczema/Dermatitis Syndrome in Infancy

The manifestation of atopic dermatitis (AD) is initially nonatopic eczema in early infancy; the manifestations subsequently change in age-specific stages. Since allergen-specific T-helper 2 cells appear in the fetus primarily after the third trimester of pregnancy and rapidly mature during the first 6 months of life, different timings of tobacco smoke exposure may have different effects on AD. In this study, we investigated whether the timing of fetal or/and infantile tobacco smoke exposure affects the cumulative incidence of atopic eczema/dermatitis syndrome (AEDS) in infants in Japan. This cross-sectional study enrolled 1,177 parent-infant pairs, in which the infants were >6 months old. Parental allergic history, number of older siblings, physician-diagnosed AEDS and food allergy (FA), and the perinatal fetal and/or infantile tobacco smoke exposure timing after 28 weeks gestation and during the first 6 months of life were assessed using self-completed questionnaires. Fetal tobacco smoke exposure after 28 weeks gestation was significantly associated with higher cumulative incidence of AEDS in exposed infants than in unexposed infants: AEDS in all infants, 41.4% versus 34.0% (Chi-squared, P = 0.020; adjusted odds ratio, 5.21; 95% confidence interval, 1.08-25.15); AEDS in those without parental allergic history, 38.0% versus 26.6% (Chi-squared, P = 0.024). Postnatal infantile tobacco smoke exposure timing was not significantly associated with cumulative incidence of AEDS. No significant associations were observed between any tobacco smoke exposure timings and the cumulative incidence of FA. Fetal tobacco smoke exposure during the third trimester of pregnancy was positively associated with AEDS in infancy and might induce epigenetic changes in the fetal allergen-specific immune responses.

Fetal Phagocytes Take up Allergens to Initiate T-Helper Cell Type 2 Immunity and Facilitate Allergic Airway Responses

RATIONALE

Actively acquired tolerance occurs when foreign antigens come into contact with the immature fetal immune system.

OBJECTIVES

Armed with the knowledge of actively acquired tolerance, we attempted to prenatally abolish or diminish allergic responses.

METHODS

In utero injection of adjuvant-free ovalbumin (OVA) was conducted in Gestational Day 14 FVB/N mouse fetuses. Postnatally, mice were evaluated for their resistance to intraperitoneal OVA sensitization and oral or aerosolized OVA challenge, and then they were examined for humoral and cellular immunological profiles, airway hyperresponsiveness to bronchospastic stimuli, and lung histology. Fluorescent conjugates of OVA were used for further studies of mechanisms.

MEASUREMENTS AND MAIN RESULTS

This presumed tolerogenic action turned out to be a sensitization process with the development of anaphylaxis or heightened recall, T-helper cell type 2-skewed responses to postnatal encounter with OVA. Further postnatal aerosolized OVA stress triggered allergic lungs with functional and structural alterations of airways. The unintended consequence resulted from macrophage-like fetal phagocytes that took up OVA and differentiated toward dendritic cells. These fetal dendritic cell progenitors attenuated proteolysis of endocytosed OVA for delayed presentation in postnatal life. This specialty of fetal phagocytes effectively retains the memory of antigens internalized early before full development of the immune system, leading to an event of in utero sensitization.

CONCLUSIONS

Our results have mechanical implications for prenatal imprinting of atopy and shed light on the importance of fetal phagocytes in shaping the developing immune system and initiating allergic airway diseases.

A programme of research to set priorities and reduce uncertainties for the prevention and treatment of skin disease

Background

Skin diseases are very common and can have a large impact on the quality of life of patients and caregivers. This programme addressed four diseases: (1) eczema, (2) vitiligo, (3) squamous cell skin cancer (SCC) and (4) pyoderma gangrenosum (PG).

Objective

To set priorities and reduce uncertainties for the treatment and prevention of skin disease in our four chosen diseases.

Design

Mixed methods including eight systematic reviews, three prioritisation exercises, two pilot randomised controlled trials (RCTs), three feasibility studies, two core outcome initiatives, four funding proposals for national RCTs and one completed national RCT.

Setting

Secondary care, primary care and the general population.

Participants

Patients (and their caregivers) with eczema, vitiligo, SCC and PG, plus health-care professionals with an interest in skin disease.

Interventions

Our three intervention studies included (1) barrier enhancement using emollients from birth to prevent eczema (pilot RCT); (2) handheld narrowband ultraviolet light B therapy for treating vitiligo (pilot RCT); and (3) oral ciclosporin (Neoral®, Novartis Pharmaceuticals) compared with oral prednisolone for managing PG (pragmatic national RCT).

Results

Systematic reviews included two overarching systematic reviews of RCTs of treatments for eczema and vitiligo, an umbrella review of systematic reviews of interventions for the prevention of eczema, two reviews of treatments for SCC (one included RCTs and the second included observational studies), and three reviews of outcome measures and outcome reporting. Three prioritisation partnership exercises identified 26 priority areas for future research in eczema, vitiligo and SCC. Two international consensus initiatives identified four core domains for future eczema trials and seven core domains for vitiligo trials. Two pilot RCTs and three feasibility studies critically informed development of four trial proposals for external funding, three of which are now funded and one is pending consideration by funders. Our pragmatic RCT tested the two commonly used systemic treatments for PG (prednisolone vs. ciclosporin) and found no difference in their clinical effectiveness or cost-effectiveness. Both drugs showed limited benefit. Only half of the participants’ ulcers had healed by 6 months. For those with healed ulcers, recurrence was common (30%). Different side effect profiles were noted for each drug, which can inform clinical decisions on an individual patient basis. Three researchers were trained to PhD level and a dermatology patient panel was established to ensure patient involvement in all aspects of the programme.

Conclusions

Findings from this programme of work have already informed clinical guidelines and patient information resources. Feasibility studies have ensured that large national pragmatic trials will now be conducted on important areas of treatment uncertainty that address the needs of patients and the NHS. There is scope for considerable improvement in terms of trial design, conduct and reporting for RCTs of skin disease, which can be improved through wider collaboration, registration of trial protocols and complete reporting and international consensus over core outcome sets. Three national trials have now been funded as a result of this work. Two international initiatives to establish how best to measure the core outcome domains for eczema and vitiligo are ongoing.

Trial registration

Current Controlled Trials Barrier Enhancement for Eczema Prevention (BEEP) (ISRCTN84854178 and NCT01142999), Study of Treatments fOr Pyoderma GAngrenosum Patients (STOP GAP) (ISRCTN35898459) and Hand Held NB-UVB for Early or Focal Vitiligo at Home (HI-Light Pilot Trial) (NCT01478945).

Funding

This project was funded by the National Institute for Health Research (NIHR) Programme Grants for Applied Research programme and will be published in full inProgramme Grants for Applied Research; Vol. 4, No. 18. See the NIHR Journals Library website for further project information.

Detection of major food allergens in amniotic fluid: initial allergenic encounter during pregnancy

BACKGROUND

Ingestion of food allergens present in maternal milk during breastfeeding has been hypothesized as a gateway to sensitization to food; however, this process could develop during pregnancy, as the maternal-fetal interface develops a Th2- and Treg-mediated environment to protect the fetus. We hypothesized that in these surroundings, unborn children are exposed to food allergens contained in the mother's diet, possibly giving rise to first sensitization.

METHODS

The presence of allergens in utero was studied by analyzing amniotic fluid (AF) samples in two different stages of pregnancy: at 15-20 weeks and after delivery at term. An antibody microarray was developed to test for the most common food allergens. The array detects the presence of ten allergens from milk, fruit, egg, fish, nuts, and wheat.

RESULTS

AF from 20 pregnant women was collected: eight after delivery at term and 12 from women who underwent diagnostic amniocentesis between weeks 15 and 20 of gestation. The presence of allergens was detected in all samples. Samples from amniocentesis had a higher allergen concentration than samples after delivery at term.

CONCLUSIONS

We demonstrated the presence of intact major food allergens in AF samples. This early contact could explain subsequent sensitization to foods never eaten before.

Recent considerations in the use of recombinant interferon gamma for biological therapy of atopic dermatitis

INTRODUCTION

Atopic dermatitis (AD) is the most common inflammatory skin disease in the general population. There are different endophenotypes of AD that likely have a unique immune and molecular basis, such as those who are predisposed to eczema herpeticum, or Staphylococcus aureus infections.

AREAS COVERED

In this review, we highlight the endophenotypes of AD where reduced interferon gamma expression may be playing a role. Additionally, we review the potential role of recombinant interferon gamma therapy in the treatment of atopic dermatitis and the particular phenotypes that may benefit from this treatment.

EXPERT OPINION

Recombinant interferon gamma treatment will likely benefit the pediatric population with AD, as well as those with susceptibilities for skin infections. Future studies are needed to elucidate whether IFN-γ may reduce the prevalence of skin infection in AD.

Maternal diet and its influence on the development of allergic disease

The early presentation of childhood allergies and the rise in their prevalence suggest that changes in early-life exposures may increase the predisposition. Very early-life exposures may act upon the developing foetal immune system and include infection, environmental tobacco smoke, other pollutants and nutrients provided via the mother. Three nutrients have come under close scrutiny: vitamin D, omega 3 polyunsaturated fatty acids (PUFAs) and folate (or the synthetic form, folic acid). Much of the data on these nutrients are observational although some randomised, placebo-controlled trials have been conducted with omega 3 PUFAs and one with vitamin D. Some studies with omega 3 PUFA supplements in pregnancy have demonstrated immunomodulatory effects on the neonate and a reduction in risk of early sensitisation to allergens. A few studies with omega 3 polyunsaturated fatty acid supplements in pregnancy have shown a reduction in proportion of children affected by allergic symptoms (food allergy) or in symptom severity (atopic dermatitis). Observational studies investigating the association of maternal vitamin D intake or maternal or neonatal vitamin D status have been inconsistent. One randomised, controlled trial of vitamin D supplementation during pregnancy did not show any significant effect on allergic outcome in the offspring. Studies investigating the association between maternal folic acid or folate intake or maternal or neonatal folate status and offspring risk of allergic disease have been equivocal. Further evidence is required to clarify whether increased intake of these nutrients during pregnancy influences allergic disease in the offspring. In the light of current evidence, mothers should not either increase or avoid consuming these nutrients to prevent or ameliorate allergic disease in their offspring. However, these essential nutrients each have important roles in foetal development. This is reflected in current government recommendations for intake of these nutrients by pregnant women.

Nutrition in early life and the risk of asthma and allergic disease

The prevalence of reported cases of asthma and allergic disease has seen a marked increase throughout the world since the 1960s, particularly in more developed, westernised countries. A key focus of research in this area has been the possible adverse effects of foetal and infant exposure to food allergens. There is some evidence that foetal and infant exposure to a range of allergens via the mother and her breast milk is important in the development of normal immune tolerance. Current advice is that pregnant and breastfeeding women do not need to avoid potential food allergens unless they are allergic themselves, or are advised to modify their diet by a health professional. Delaying the introduction of common food allergies beyond 6 months is unlikely to reduce the likelihood of food allergy and allergic disease. The findings of current ongoing trials investigating the potential benefits of early introduction on allergenic foods into the diet of children-as well as the comprehensive review of complementary and young-child feeding advice currently being conducted by the Scientific Advisory Committee on Nutrition-will help inform guidance in this area.

Neonatal protein kinase C zeta expression determines the neonatal T-Cell cytokine phenotype and predicts the development and severity of infant allergic disease

BACKGROUND

Previous studies have demonstrated that reduced T-cell protein kinase C zeta (PKCζ) expression is associated with allergy development in infants born to atopic mothers. This study examined whether this relationship extends to a general population and addressed the basis for the association.

METHODS

A flow cytometry assay was developed for the measurement of T-cell PKCζ levels in PBMC, cord blood mononuclear cell and whole blood. Cord blood T-cell PKCζ levels were measured in 135 neonates, and allergic disease was evaluated by skin prick test and clinical examination at 12 months of age.

RESULTS

Allergic children (particularly those with eczema) had significantly lower neonatal T-cell PKCζ expression than nonallergic children (P < 0.001). PKCζ levels predicted allergic disease with optimal specificity of 86% and sensitivity of 54%. The sensitivity was increased in the children of allergic mothers, who had significantly lower PKC levels than the children of nonallergic mothers. Cord blood PKCζ levels did not affect T-cell maturation in culture as assessed by CD45RA/RO expression, but low PKCζ expression was associated with reduced capacity for IFNγ production by matured T cells. Low cord blood PKC expression was further associated with increased IL-13 responses at 6 months.

CONCLUSIONS

The findings suggest a potential role for the use of PKCζ levels in cord blood T cells as a presymptomatic test to predict allergy risk in children, particularly offspring of allergic mothers, and that the basis of this relationship is related to cytokine patterns in mature T cells.

Maternal exposure to air pollution before and during pregnancy related to changes in newborn's cord blood lymphocyte subpopulations. The EDEN study cohort

Background

Toxicants can cross the placenta and expose the developing fetus to chemical contamination leading to possible adverse health effects, by potentially inducing alterations in immune competence. Our aim was to investigate the impacts of maternal exposure to air pollution before and during pregnancy on newborn's immune system.

Methods

Exposure to background particulate matter less than 10 μm in diameter (PM₁₀) and nitrogen dioxide (NO₂) was assessed in 370 women three months before and during pregnancy using monitoring stations. Personal exposure to four volatile organic compounds (VOCs) was measured in a subsample of 56 non-smoking women with a diffusive air sampler during the second trimester of pregnancy. Cord blood was analyzed at birth by multi-parameter flow cytometry to determine lymphocyte subsets.

Results

Among other immunophenotypic changes in cord blood, decreases in the CD4+CD25+ T-cell percentage of 0.82% (p = 0.01), 0.71% (p = 0.04), 0.88% (p = 0.02), and 0.59% (p = 0.04) for a 10 μg/m³ increase in PM₁₀ levels three months before and during the first, second and third trimester of pregnancy, respectively, were observed after adjusting for confounders. A similar decrease in CD4+CD25+ T-cell percentage was observed in association with personal exposure to benzene. A similar trend was observed between NO₂ exposure and CD4+CD25+ T-cell percentage; however the association was stronger between NO₂ exposure and an increased percentage of CD8+ T-cells.

Conclusions

These data suggest that maternal exposure to air pollution before and during pregnancy may alter the immune competence in offspring thus increasing the child's risk of developing health conditions later in life, including asthma and allergies.

Overview of Reviews The prevention of eczema in infants and children: an overview of Cochrane and non-Cochrane reviews

BACKGROUND: Eczema is the most common inflammatory skin disease of childhood, characterized by an itchy red rash that usually involves the face and skin folds. There is currently no curative treatment for eczema, so the reduction of eczema incidence through disease prevention is a desirable goal. Potential interventions for preventing eczema include exclusive breastfeeding, hydrolysed protein formulas and soy formulas when bottle feeding, maternal antigen avoidance, omega oil supplementation, prebiotics and probiotics. OBJECTIVES: This overview of reviews aims to present the current body of data from Cochrane and non-Cochrane reviews to provide the most up-to-date evidence on the efficacy and safety of interventions to prevent eczema in infants and children at different risk levels for developing allergic disease. METHODS: Our pool of Cochrane and non-Cochrane reviews came from the 2010 United Kingdom National Health Service (NHS) Evidence Skin Disorders Annual Evidence Updates Mapping Exercise on Atopic Eczema. This group used a comprehensive search strategy last conducted in August 2010 to identify all systematic reviews on eczema prevention. We identified all reviews that met our pre-specified inclusion criteria, and data were extracted, analysed, compiled into tables and synthesized using quantitative and qualitative methods. MAIN RESULTS: Seven systematic reviews containing 39 relevant trials with 11 897 participants were included in this overview. Overall, there was no clear evidence that any of the main interventions reviewed reduced eczema incidence. In subgroup analyses of infants at high risk of allergic disease, an observational study found that exclusive breastfeeding for at least six months compared with introduction of solids at three to six months decreased the incidence of eczema by 60% (risk ratio (RR): 0.40; 95% confidence interval (CI): 0.21, 0.78), and a randomized controlled trial found that prebiotics compared with no prebiotics decreased incidence by 58% (RR: 0.42; 95% CI: 0.21, 0.84). However, each of these findings was based on the results of a single small trial, and no intervention reduced eczema incidence beyond the first two years of life. Although we pre-specified incidence of atopic eczema (i.e. eczema associated with immunoglobulin E (IgE) sensitization) as a primary outcome, data on whether participants diagnosed with eczema were truly atopic were largely lacking from systematic reviews. Similarly, data on atopy, measured using skin prick tests or specific IgE tests to allergens, were not reported in many reviews. No interventions were found to decrease atopy when reported. Adverse events data were generally lacking, but data from a trial of probiotics versus no probiotics showed significantly more spitting up in the first one (RR: 1.88; 95% CI: 1.03, 3.45) and two (RR: 1.69; 95% CI: 1.02, 2.80) months of life, but no overall increase in risk of gastrointestinal symptoms in the first year. AUTHORS#ENTITYSTARTX02019; CONCLUSIONS: Although there is currently no clear evidence showing that any of the interventions examined in this overview prevent eczema in participants not selected for risk of allergic disease, there is some evidence that exclusive breastfeeding for at least six months and prebiotics might reduce eczema incidence in high-risk participants. However, these conclusions are based on limited evidence with methodological shortcomings. Future research on prevention of eczema is needed and should examine different types of hydrolysed formulas, prebiotics and probiotics, as well as enhancement of the skin barrier and other novel approaches in infants at different risk levels for developing allergic disease.

The role of allergic risk and other factors that affect the occurrence of atopic dermatitis in the first 6 months of life

Background

Atopic dermatitis (AD) is a chronic inflammation of the skin that often appears in early childhood. The manifestation is related to the tendency towards T helper 2 cytokine immune responses (interleukin (IL)-4, IL-5). Genetic factors are suggested to play important roles in AD, and it can be transmitted to newborns, increasing their risk of developing allergies.

Objective

To determine the association between cord-blood cytokine levels (IL-5, interferon (IFN) γ), cord-blood total immunoglobulin E (IgE) level, perinatal environmental exposure, and the risks of allergy as well as the development of AD in the first 6 months of life.

Methods

A 6-month cohort study with a nested case-control within was conducted on newborns in Jakarta from December 2008 until May 2009. After the umbilical cord blood samples were taken and stored, subjects were followed up monthly until 6 months old. The occurrence of AD and lifestyle or environmental exposures were recorded. The allergic risk was determined using a modified pediatric allergy immunology work groups scoring system based on allergic history (allergic rhinitis, asthma, AD) in the family. The levels of IL-5 and IFN-γ were measured using ELISA and total IgE by CAP system FEIA. Multivariate analysis was used to evaluate risk factors.

Results

This study was conducted on 226 subjects. The incidence of AD was 16.4%; of those, 59% had low risk allergy, 38.5% moderate, and 2% high risk. AD mostly occurred at the age of 1 month (57%). Cord blood samples were examined in 37 subjects with AD and 51 without AD; of those, 25% showed high levels of total IgE (>1.2 IU/µL), and 51% showed normally-distributed high absorbance IL-5 values (≥0.0715, absolute value was undetected). The increased level of IL-5 was directly proportional to IgE. High absorbance IFN-γ values (≥0.0795, absolute value = 18.681 pg/µL) were observed in 52% of subjects.

Conclusion

The associations between the risk of allergy in the family, cord-blood total IgE, IL-5, IFN levels, and some perinatal environmental exposure with AD in the first 6 months of life have not been established.

Relationships among environmental exposures, cord blood cytokine responses, allergy, and wheeze at 1 year of age in an inner-city birth cohort (Urban Environment and Childhood Asthma study)

BACKGROUND

The Urban Environment and Childhood Asthma study was established to investigate the immunologic and environmental causes of asthma in inner-city children.

OBJECTIVE

We sought to evaluate potential atopic outcomes in the first 12 months and their relationships to environmental exposures and immune development.

METHODS

A birth cohort of 560 children with at least 1 parent with allergy or asthma was established in Baltimore, Boston, New York, and St Louis. Wheezing is assessed every 3 months, allergen-specific IgE yearly, and mononuclear cell cytokine responses at birth and yearly; environmental assessments include dust allergen and endotoxin, maternal stress, and indoor nicotine and nitrogen dioxide levels.

RESULTS

Key outcomes in the first year include wheeze in 49%, 2 or more episodes of wheeze in 23%, eczema in 30%, and detectable IgE to milk, egg, and/or peanut in 32% and to cockroach in 4%. Household dust revealed levels of greater than 2 μg/g to cockroach in 40%, mite in 19%, cat in 25%, and mouse in 29%, and 66% of homes housed at least 1 smoker. Positive associations were detected between multiple wheeze and cotinine levels, maternal stress, and maternal depression, whereas cytokine responses to a variety of innate, adaptive, and mitogenic stimuli were inversely related to eczema.

CONCLUSIONS

This high-risk cohort of inner-city infants is exhibiting high rates of wheeze, eczema, and allergic sensitization. Low cytokine responses at birth might be a risk factor for eczema, whereas a variety of adverse environmental exposures contribute to the risk of wheezing in infancy. These findings provide evidence of specificity in the interactions between immune development, environmental exposures, and the development of early features that might predict future asthma.

Food allergy: riding the second wave of the allergy epidemic

Food allergy is a substantial and evolving public health issue, recently emerging over the last 10-15 yr as a 'second wave' of the allergy epidemic. It remains unclear why this new phenomenon has lagged decades behind the 'first wave' of asthma, allergic rhinitis and inhalant sensitization. In regions like Australia, which lead the respiratory epidemic, challenge-proven IgE-mediated food allergy now affects up to 10% of infants. Although their parents were among the first generation to experience the large-scale rise in allergic diseases, disorders of oral tolerance were previously uncommon. Of further concern, this new generation appears less likely to outgrow food allergy than their predecessors with long-term implications for disease burden. Allergic disease has been linked to the modern lifestyle including changing dietary patterns, changing intestinal commensal bacteria and vehicular pollution. It is not yet known whether the rise in food allergy is a harbinger of earlier and more severe effects of these progressive environmental changes or whether additional or unrelated lifestyle factors are implicated. New studies suggest environmental factors can produce epigenetic changes in gene expression and disease risk that may be potentially heritable across generations. The rising rates of maternal allergy, a strong direct determinant of allergic risk, could also be amplifying the effect of environmental changes. Preliminary evidence that non-Caucasian populations may be even more susceptible to the adverse effects of 'westernisation' has substantial global implications with progressive urbanization of the more populous regions in the developing world. Unravelling the environmental drivers is critical to curtail a potential tsunami of allergic disease.

Clinical aspects of pediatric food allergy and failed oral immune tolerance

Food allergy seems to represent a new spectrum of disease that has elicited significant community concern and extended waiting lists for allergists and gastroenterologists alike. The apparent rise in prevalence of IgE-mediated food allergy (and associated risk of anaphylaxis) has been postulated to result from effects of a "modern lifestyle" but as yet clear environmental risk factors have not yet emerged. Family history seems to contribute to risk suggesting that gene-environment interactions will be important for identifying a subpopulation with increased susceptibility to any identified lifestyle effects. Non-IgE-mediated food allergy (including food-induced enteropathies and colitides, eosinophilic esophagitis, and Crohn's disease) with potentially similar environmental triggers resulting in diverse immune dysregulatory mechanisms. The evidence underpinning the putative rise in food allergy is discussed and potential mechanisms of disease explored. Clinical aspects of various food allergic conditions including non-IgE-mediated food allergy are outlined.

Allergic disease: understanding how in utero events set the scene

Events and exposures in pregnancy can have critical effects on fetal development with lasting implications for subsequent health and disease susceptibility. There is growing interest in how modern environmental changes influence fetal immune development and contribute to the recent epidemic of allergy and other immune disorders. Rising rates of allergic disease in early infancy, together with pre-symptomatic differences in immune function at birth, suggest that antenatal events play a predisposing role in the development of disease. A number of environmental exposures in pregnancy can modify neonatal immune function including diet, microbial exposure and maternal smoking, and there is emerging evidence from animal models that these factors may have epigenetic effects on immune gene expression and disease susceptibility. Furthermore, functional genetic polymorphisms also alter individual vulnerability to the effects of these environmental exposures, highlighting the complexity of gene-environmental interactions in this period. All these observations underscore the need for ongoing research to understand the pathogenesis and rising incidence of disease in the hope of better strategies to reverse this.

Maternal diet during pregnancy: an emerging risk factor for childhood asthma

Evaluation of: Willers SM, Wijga AH, Brunekreef B et al. Maternal food consumption during pregnancy and the longitudinal development of childhood asthma. Am. J. Respir. Crit. Care Med. 178, 124-131 (2008). It has been hypothesized that the recent marked increase in the prevalence of asthma may, in part, be a consequence of changing diet. There is increasing interest in the possibility that childhood asthma may be influenced by maternal diet during pregnancy and an increasing number of studies have highlighted associations between childhood asthma and maternal intake of certain foods (e.g., fish, fruits and vegetables) and nutrients (e.g., vitamin E, vitamin D, zinc and polyunsaturated fatty acids) during pregnancy. Maternal diet during pregnancy has the potential to influence fetal immune and airway development during a critical period of life with long-term irreversible consequences, such as childhood asthma. Further research, particularly intervention studies, needs to be carried out to establish whether dietary intervention during pregnancy can be used as a healthy, low-cost, public-health measure to reduce the prevalence of childhood asthma.

Pathogens and immunologic memory in asthma: what have we learned?

Animal models and clinical studies of asthma have generated important insights into the first effector phase leading to the development of allergic airway disease and bronchial hyper-reactivity. In contrast, mechanisms related to asthma chronicity or persistence are less well understood. The CD4(+) T-helper 2 lymphocytes are known initiators of the inflammatory response associated with asthma. There is now increasing evidence that memory T-cells, sensitized against allergenic, occupational or viral antigens, are also involved in the persistence of asthma. Additionally, the role of pathogens in asthma has been linked to both the initial susceptibility to and flares of this disease. This review will discuss the potential links between infection and asthma, the role of the memory T-cells in asthma, and the potential mechanisms by which these factors interact to lead to the development and/or persistence of asthma.

Reduced IFN-gamma- and enhanced IL-4-producing CD4+ cord blood T cells are associated with a higher risk for atopic dermatitis during the first 2 yr of life

The aim of this study was to analyse whether altered cytokine production by cord blood (CB) T cells is of relevance regarding the development of allergic diseases during the first 2 yr of life independent from known or suspected risk factors for allergy. Within an ongoing birth cohort study (Life style - Immune System - Allergy; LISA) the cytokine production of PMA/ionomycin-stimulated CB cells was measured by intracellular cytokine staining. Data of 98 children from Leipzig and Munich with complete information on cytokine production at birth and allergic outcomes during the first 2 yr were analysed. Statistical analysis was performed using a regression model adjusted for gender, month of birth, parental history of atopy, parental education, exposure to environmental tobacco smoke, maternal smoking during pregnancy, renovation activities during pregnancy, pet ownership and study centre. During the first 2 yr of life, 17.3% of the children developed a physician-diagnosed atopic dermatitis. Children with reduced frequencies of interferon-gamma (IFN-gamma)-producing CD4(+) T cells in the CB (1st quartile) had a higher risk to develop atopic dermatitis (adjusted OR 5.16, 95% CI: 1.04-25.6). Furthermore, a high percentage of interleukin (IL)-4-producing T cells in CB in children from the Leipzig cohort were associated with an increased risk for atopic dermatitis (adjusted OR 8.92, 95% CI: 1.40-56.93 for the 90th percentile). CD8(+) cytokine-producing CB T cells had no relation to increased risk for atopic dermatitis. Low amounts of IFN-gamma and high amounts of IL-4-producing T cells at birth may enhance the risk of subsequent development of atopic dermatitis.

Peanut sensitisation and allergy: influence of early life exposure to peanuts

The aim of the present systematic review was to evaluate the influence of early life exposure (maternal and childhood) to peanuts and the subsequent development of sensitisation or allergy to peanuts during childhood. Studies were identified using electronic databases and bibliography searches. Studies that assessed the impact of non-avoidance compared with avoidance or reduced quantities of peanuts or peanut products on either sensitisation or allergy to peanuts, or both outcomes, were eligible. Six human studies were identified: two randomised controlled trials, two case-control studies and two cross-sectional studies. In addition, published animal and mechanistic studies, relevant to the question of whether early life exposure to peanuts affects the subsequent development of peanut sensitisation, were reviewed narratively. Overall, the evidence reviewed was heterogeneous, and was limited in quality, for example, through lack of adjustment for potentially confounding factors. The nature of the evidence has therefore hindered the development of definitive conclusions. The systematic review of human studies and narrative expert-led reviews of animal studies do not provide clear evidence to suggest that either maternal exposure, or early or delayed introduction of peanuts in the diets of children, has an impact upon subsequent development of sensitisation or allergy to peanuts. Results from some animal studies (and limited evidence from human subjects) suggest that the dose of peanuts is an important mediator of peanut sensitisation and tolerance; low doses tend to lead to sensitisation and higher doses tend to lead to tolerance.

Allergic women show reduced T helper type 1 alloresponses to fetal human leucocyte antigen mismatch during pregnancy

Low-level alloreactivity between mother and fetus may provide stimulation for fetal T helper type 1 (Th1) cell immune maturation. This study explored the effects of human leucocyte antigen (HLA) mismatch on materno-fetal interactions detected as cytokine responses and lymphoproliferation in mixed lymphocyte reactions, and whether this was altered in allergic women (n = 62) who have a Th2 propensity compared with non-allergic women (n = 65). HLA-DRbeta1 mismatch was associated with significantly increased Th1 interferon (IFN)-gamma, Th2 interleukin (IL)-13 and lymphoproliferative responses by both mothers and fetuses. Allergic women showed significantly lower IFN-gamma Th1 production in response to HLA-DRbeta1 mismatch. The infants of these women also showed significantly lower IL-10 and lower IFN-gamma production relative to IL-13. Both HLA-DRbeta1 mismatch and maternal allergy had significant independent effects on maternal IFN-gamma Th1 responses. Maternal allergy modifies HLA-mediated alloreactivity between the mother and the fetus, reducing Th1 activation. This may affect the cytokine milieu at the materno-fetal interface and could be implicated in the attenuated Th1 responses observed commonly in infants of atopic mothers.

Pregnancy IFN-gamma responses to foetal alloantigens are altered by maternal allergy and gravidity status

BACKGROUND

During pregnancy, variations in maternal-foetal cellular interactions may influence immune programming. This study was carried out to determine if maternal responses to foetal alloantigens are altered by maternal allergic disease and/or previous pregnancies.

METHODS

For this cohort study, peripheral blood was collected from allergic (n = 69) and nonallergic (n = 63) pregnant women at 20, 30, 36-week gestation and 6-week postpartum (pp). Cord blood was collected at delivery. Mixed lymphocyte reactions were used to measure maternal cytokine responses [interleukin-6 (IL-6), IL-10, IL-13 and (interferon-gamma) IFN-gamma] at each time point towards foetal mononuclear cells.

RESULTS

Maternal cytokine responses during pregnancy (20, 30 and 36 weeks) were suppressed compared to the responses at 6-week pp. The ratio of maternal IFN-gamma/IL-13 and IFN-gamma/IL-10 responses were lower during pregnancy. Allergic mothers had lower IFN-gamma responses at each time-point during pregnancy with the greatest difference in responses observed at 36-week gestation. When allergic and nonallergic women were further stratified by gravidity group, IFN-gamma responses of allergic multigravid mothers were significantly lower than nonallergic multigravid mothers during pregnancy.

CONCLUSIONS

During normal pregnancy, peripheral T-cell cytokine responses to foetal alloantigens may be altered by both allergic status of the mother and previous pregnancies. These factors could influence the cytokine milieu experienced by the foetus and will be further explored in the development of allergic disease during early life.

Early markers of allergic disease in a primary prevention study using probiotics: 2.5-year follow-up phase

BACKGROUND

We previously reported that a Lactobacillus acidophilus probiotic strain (LAFTI) L10/LAVRI-A1) given for the first 6 months of life increased the risk of allergen sensitization at 1 year of age.

METHODS

To assess the effects on subsequent allergic outcomes, 153 children from the initial prevention cohort (n = 178) were reviewed at 2.5 years of age. Clinical outcomes were assessed in relation to (i) probiotic supplementation; and (ii) immune function previously assessed at 6 months of age.

RESULTS

Supplementation with this probiotic did not reduce the risk of dermatitis at 2.5 years (31/74, 42%) compared with that in placebo group (25/76, 34%). There was no significant reduction in any other allergic disease or allergen sensitization. Inhalant sensitization at 2.5 years (n = 29) was associated with higher proportions of circulating CD4+ CD25+ regulatory T-cell populations (P = 0.005) and higher allergen-induced FOXP3 levels (P = 0.003) at 6 months. This was also seen in children with dermatitis. Children with dermatitis at 2.5 years also had significantly lower toll-like receptor 4 lipopolysaccharide responses at 6 months of age (IL-12 P = 0.04, IL-6 P = 0.039) and lower polyclonal (PHA) responses (IFN-gamma P = 0.005, IL-10 P = 0.001, and IL-6 P = 0.001). Children who had previously received the probiotic had fewer gastrointestinal infections in the preceding 18 months (P = 0.023).

CONCLUSION

The LAFTI L10 probiotic strain did not have any significant effect on allergy outcomes. Allergic children showed a number of early differences in immune function including altered regulatory T-cell markers and innate immune function.

Supplementation with Lactobacillus rhamnosus or Bifidobacterium lactis probiotics in pregnancy increases cord blood interferon-gamma and breast milk transforming growth factor-beta and immunoglobin A detection

BACKGROUND

This study explored the effects of maternal probiotic supplementation on immune markers in cord blood (CB) and breast milk.

METHODS

CB plasma and breast milk samples were collected from a cohort of women who had received daily supplements of either 6 x 10(9) CFU/day Lactobacillus rhamnosus HN001 (n=34), 9 x 10(9) CFU/day Bifidobacterium lactis HN019 (n=35) or a placebo (n=36) beginning 2-5 weeks before delivery and continuing for 6 months in lactating women. CB plasma and breast milk (collected at 3-7 days, 3 months and 6 months postpartum) were assayed for cytokines (IL-13, IFN-gamma, IL-6, TNF-alpha, IL-10, TGF-beta1) and sCD14. Breast milk samples were also assayed for total IgA.

RESULTS

Neonates of mothers who received a probiotic had higher CB IFN-gamma levels (P=0.026), and a higher proportion had detectable blood IFN-gamma levels, compared with the placebo group (P=0.034), although levels were undetectable in many infants. While this pattern was evident for both probiotics, when examined separately only the L. rhamnosus HN001 group showed statistically significant higher IFN-gamma levels (P=0.030) compared with the placebo group. TGF-beta1 levels were higher in early breast milk (week 1) from the probiotic groups (P=0.028). This was evident for the B. lactis HN019 group (P=0.041) with a parallel trend in the L. rhamnosus HN001 group (P=0.075). Similar patterns were seen for breast milk IgA, which was more readily detected in breast milk from both the B. lactis HN019 (P=0.008) and the L. rhamnosus HN001 group (P=0.011). Neonatal plasma sCD14 levels were lower in the B. lactis HN019 group compared with the placebo group (P=0.041).

CONCLUSION

The findings suggest that supplementation with probiotics in pregnancy has the potential to influence fetal immune parameters as well as immunomodulatory factors in breast milk.

Impact of PUFA on early immune and fetal development

It has recently been reported that the increased prevalence in childhood allergy may be linked to deviations in fetal immune development. One reason may be impaired nutrient supply. Hence, a well-differentiated placenta together with an optimal fetal nutrition via the mother are important prerequisites for the establishment of a functional immune system with normal immune responses. Fatty acids and their derivatives can influence both the early immune development and immune maturation by regulating numerous metabolic processes and the gene expression of important proteins such as enzymes and cytokines. The present review summarises the impact of nutritional fatty acids on the development of the immune system as well as the fetal development. It describes the mechanisms of action of PUFA, trans fatty acids and conjugated linoleic acids in programming the fetus with regard to its risk of acquiring atopic diseases in childhood.

Presymptomatic differences in Toll-like receptor function in infants who have allergy

BACKGROUND

Microbial exposure might play a key role in allergy development, but little is known about the role of Toll-like receptors (TLRs).

OBJECTIVE

This study explored the association between neonatal TLR microbial recognition/function, allergy risk (maternal allergy), and prospective allergy development.

METHODS

Cord blood mononuclear cells (n = 111) were cultured either alone or with optimal concentrations of TLR ligands: lipoteichoic acid (TLR2), polyinosinicpolycytidylic acid (TLR3), LPS with IFN-gamma (TLR4), flagellin (TLR5), imiquimod R837 (TLR7), or CpG (TLR9). Cytokine responses were assessed in relation to allergy risk (maternal allergy) and allergy outcomes (sensitization, food allergy, and atopic dermatitis) at 12 months of age.

RESULTS

Maternal allergy (n = 59) was associated with significantly higher neonatal IL-12 and IFN-gamma responses to TLR2, TLR3, and TLR4 activation, whereas TNF-alpha and IL-6 responses to TLR2, TLR4, and TLR5 activation were significantly higher in newborns who subsequently had allergic disease (n = 32). Notably, consistent with previous reports, newborns who had disease had lower T(H)1 IFN-gamma response to mitogens (PHA).

CONCLUSION

Allergic disease was associated with increased (rather than decreased) perinatal TLR responses. Further studies are needed to determine how these responses track in the postnatal period and whether this relative hyperresponsiveness is a product of intrauterine influences, including maternal atopy, functional genetic polymorphisms, or both.

Children with egg allergy have evidence of reduced neonatal CD4(+)CD25(+)CD127(lo/-) regulatory T cell function

BACKGROUND

The role of regulatory T (Treg) cells in allergic predisposition is not known.

OBJECTIVE

This study compared the frequency and function of cord blood Treg cells from nonallergic children (n = 18) with those from children who have egg allergy (n = 15) in the first year of life.

METHODS

CD4(+) effector T cells and autologous antigen-presenting cells isolated from cord blood mononuclear cells were cocultured with or without CD4(+)CD25(+)CD127(lo/-) Treg cells, and cytokine responses to staphylococcal endotoxin B were assessed after 48 hours.

RESULTS

The addition of Treg cell populations to cord blood mononuclear cell cultures resulted in significant reduction in IL-10 (P = .002), IL-13 (P = .012), and IFN-gamma (P < .001) production. Consistent with other reports, effector CD4(+) T-cell responses (IFN-gamma and IL-13) tended to be lower in the allergic group. These neonates showed less significant Treg cell-associated suppression of IFN-gamma (P = .015) compared with that seen in the nonallergic group (P = .001). The allergic group was also less likely (44%) to show Treg cell-associated suppression of IFN-gamma effector responses compared with that seen in the nonallergic group (78%, P = .015). The magnitude of suppression (change in IFN-gamma level when CD4(+)CD25(+)CD127(lo/-) Treg cells were added to responding effector T-cell cultures) was significantly lower in the allergic group (P = .004). There were no between-group differences in the circulating CD4(+)CD25(+)CD127(lo/-) Treg cells (as a percentage of cord blood T cells) or in the FOXP3 expression of these cells.

CONCLUSION

This study confirms the presence and activity of Treg cells in cord blood and provides preliminary evidence of differences in neonates who progress to allergic disease in the first year of life.

Prenatal exposures to persistent and non-persistent organic compounds and effects on immune system development

Immune system development, particularly in the prenatal period, has far-reaching consequences for health during early childhood, as well as throughout life. Environmental disturbance of the complex balances of Th1 and Th2 response mechanisms can alter that normal development. Dysregulation of this process or an aberrant trajectory or timing of events can result in atopy, asthma, a compromised ability to ward off infection, or other auto-immune disease. A wide range of chemical, physical and biological agents appear to be capable of disrupting immune development. This MiniReview briefly reviews developmental milestones of the immune system in the prenatal period and early life, and then presents examples of environmentally induced alterations in immune markers. The first example involves a birth cohort study linked to an extensive programme of air pollution monitoring; the analysis shows prenatal ambient polycyclic aromatic hydrocarbons (PAH) and fine particle (PM2.5) exposures to be associated with altered lymphocyte immunophenotypic distributions in cord blood and possible changes in cord serum immunoglobulin E levels. The second example is a study of prenatal-polychlorinated biphenyl (PCB) exposures and the foetal development of the thymus, the organ responsible for lymphocyte maturation. Mothers with higher serum concentrations of PCBs gave birth to neonates having smaller indices of thymus size. Finally, this report underscores the tight connection between development of the immune system and that of the central nervous system, and the plausibility that disruption of critical events in immune development may play a role in neurobehavioural disorders.

Sulphidoleukotriene release of cord blood basophils in response to allergen stimulation correlates with neither a family history of atopy nor a subsequent development of atopic eczema

OBJECTIVE

We tested a possible relationship between sulphidoleukotriene (SLT) release of cord blood (CB) basophils, a family history of atopy (HA) and subsequent development of atopic eczema. Population and methods A cohort of 86 neonates were involved (48.8% males; 46.5% with a positive HA(+)). CB samples were analysed for in vitro SLT release quantified by ELISA, and in a subgroup for basophilic activation (CD 63 expression) by flow cytometry in response to a positive control (anti-IgE-receptor antibody), an allergen-mix (TOP and PTOP), egg white (EW), egg yolk (EY), and the purified allergens beta-lactoglobulin (BLG) and alpha-lactalbumin (ALA).

RESULTS

Median concentrations of SLT were 124.2 (negative), 3871.5 (positive), 123.9 (TOP), 128.5 (PTOP), 113.1 (EW), 108.4 (EY), 125.2 (BLG) and 122.3 (ALA) pg/mL. Groups of HA(+) and HA(-) show no difference in all analysed allergens. An allergen-specific SLT release (defined as SLT>125 pg/mL above individual baseline and a stimulation index >2) was detected in 98% (positive control), 5% (TOP), 7% (BLG), 3% (ALA) and 2% (EW and EY), respectively. After a median observation period of 18 months, n=7 out of 70 children developed an atopic eczema, but we observed no association between CB SLT release (positive response to at least one tested allergen).

CONCLUSION

Allergen-specific SLT release is detectable in 15.5% of healthy neonates, irrespective of their family history of atopy. However, early allergen-specific SLT release is not predictive for the development of atopy.

Developmental mismatch: consequences for later cardiorespiratory health

Clinical and epidemiological studies have established that people who were small at birth and had poor infant growth have an increased risk of adult cardiovascular and respiratory disease, particularly if their restricted early growth is followed by accelerated childhood weight gain. This relationship extends across the normal range of infant size in a graded manner. The 'mismatch hypothesis' proposes that ill health in later life originates through developmental plastic responses made by the fetus and infant; these responses increase the risk of adult disease if the environment in childhood and adult life differs from that predicted during early development.

Elevated allergen-induced IL-13 secretion predicts IgE elevation in children ages 2-5 years

It is unclear if early immune responses to allergens, specifically Th1 and Th2 cytokine production, predict later immune responses, including increased IgE levels. In a group of children (n = 151) with a parental history of allergy or asthma followed from ages 2 through 5 years, we examined IL-13, IL-4, and IFN-gamma secretion by peripheral blood mononuclear cells in response to phytohemagglutinin (PHA), and to dust mite (Der f 1), cockroach (Bla g 2), and cat (Fel d 1) allergens in relation to elevated IgE. Elevated IgE was defined either as a positive IgE-specific response to at least one allergen (dust mite, cockroach, cat, and ovalbumin) or as an elevated total IgE level above a specified cut-off value. In multivariate logistic regression models including 181 observations made between the age of 2 through 5 years and accounting for repeated measures, we found an association between increased IL-13 secretion in response to Der f 1 and elevated IgE (odds ratio [OR] = 1.21, 95% confidence interval [CI] = 1.09-1.34). Age did not modify this relationship. No association was found between allergen-induced IFN-gamma secretion and IgE production. Among the group of children with measurements made at age 4-5 (n = 70), IL-13 in response to Der f 1 (p = 0.046), and IL-4 in response to PHA (p = 0.04) were increased among children with elevated IgE. In a smaller subset of children with measurements made at both age 2-3 and age 4-5 (n = 36), IL-13 levels at age 2-3 were also significantly increased in response to Der f 1 (p = 0.01) and Fel d 1 (p = 0.002) among those with elevated IgE at age 4-5. In a group of children ages 2-5 years, there is an association between IL-13 and elevated IgE.

Protein kinase Cζ: A novel protective neonatal T-cell marker that can be upregulated by allergy prevention strategies

BACKGROUND

Variations in neonatal T-cell function have been associated with allergic disease.

OBJECTIVES

To examine the relationship between neonatal T-cell protein kinase (PKC) expression and subsequent allergic disease.

METHODS

T cells were purified from cord blood samples (n = 74) obtained from a cohort of mothers who received either 4 g/d fish oil or a placebo from 20 weeks of gestation. PKC expression was examined in relationship to supplementation, fatty acid levels, cytokine production, and allergic outcomes at 1 year and 2.5 years of age.

RESULTS

Neonatal T-cell PKCzeta expression was lower in children who had evidence of allergic disease at 1 year (P = .001) and 2.5 years (P = .052) of age. It was also lower in children with sensitization (positive skin prick test) at each age (P = .02 and P = .072, respectively). PKCzeta expression was inversely correlated to PKCalpha (r = -0.28; P = .025), which was strongly related to IL-5 responses to allergens (ovalbumin, r = 0.59; P = .003; dust mite, r = 0.52; P = .011) at 1 year of age. Fish oil supplementation was associated with significantly higher PKCzeta expression (P = .014), whereas most other isozymes were reduced by fish oil supplementation.

CONCLUSION

This is the first study to show that allergic disease is associated with altered expression of T-cell PKC isozymes in the neonatal period. It has also demonstrated that fish oil can modulate expression of PKC isozymes in a potentially favorable direction.

CLINICAL IMPLICATIONS

Protein kinase Czeta should be explored further as an early marker and potential target for disease prevention.

Maternal allergy influences the proliferation of neonatal T cells expressing CCR4, CXCR5 or CD103

BACKGROUND

Elevated proliferative response to allergen in cord blood mononuclear cells (CBMCs) is related to subsequent allergy development of the neonate and has been suggested as a screening marker for high allergy risk.

OBJECTIVE

To characterize the proliferating cells in CBMCs from a neonatal group influenced by maternal allergy compared with a control group without known allergic heredity.

METHODS

CBMCs were stimulated with bovine beta-lactoglobulin (beta-LG) and proliferation was analysed by radioactive thymidine incorporation and expressed both as the traditional stimulation index (SI) and SI corrected by eliminating non-specific proliferation. After beta-LG combined with endotoxin stimulation, cellular expression of IL-4 and IFN-gamma mRNA was determined by quantitative RT-PCR and adhesion as well as chemokine receptors were analysed by three-colour flow cytometry in proliferating T cells (CD3+ Ki-67+).

RESULTS

The percentage of CCR4+ cells correlated weakly with concurrent IL-4 expression (r(S)=0.5, P<0.05), while CXCR3 correlated strongly with IFN-gamma expression (r(S)=0.83, P<0.001). In the allergy risk group, the percentage of proliferating T cells expressing CCR4 or integrin alphaE (CD103) was significantly reduced compared with the control group, while CXCR5 and the corrected SI were relatively increased (CCR4: P=0.01; integrin alphaE: P=0.03; CXCR5: P=0.04; SI: P=0.04).

CONCLUSION

Our results implied delayed maturation of immune functions involved in cellular migration, cell-cell interaction and immunoregulatory functions in neonates with hereditary allergy risk. The alterations observed in this subject group suggested that the corrected SI as well as proliferation of CCR4+, CXCR5+ or CD103+ T cells in allergen-stimulated CBMCs might serve as early screening markers for allergy risk.

Antenatal risk factors, cytokines and the development of atopic disease in early childhood

Atopic diseases are complex entities influenced by an array of risk factors, including genetic predisposition, environmental allergens, antenatal exposures, infections and psychosocial factors. One proposed mechanism by which these risk factors contribute to the development of atopic disease is through changes in the production of T helper cell type 1 (Th1) and T helper cell type 2 (Th2) cytokines. The objectives of this review are to discuss antenatal exposures that are associated with paediatric atopic diseases, to discuss the influence of the intrauterine environment on neonatal immune responses, to provide an overview of the Th1 and Th2 pathways and how they relate to atopic disease, and to summarise our current understanding of the association between cytokine responses in cord blood and the development of atopic disease in early childhood.

Can allergic diseases be prevented prenatally?

Allergic diseases continue to increase in prevalence, and now affect over a third of the population in many countries. There is evidence that the increase in such diseases has its origins in early life exposures. Pregnancy or early childhood may therefore be critical periods for preventing the onset of allergic disease, and prenatal interventions are an attractive possibility for a population-based preventive approach. Here we review the data suggesting that prenatal exposures are important in the development of allergic disease, and that interventions during this time might be effective in prevention. We find evidence from both animal and human studies that prenatal interventions can influence the future development of allergic disease. There are a number of mechanisms through which such interventions may act to prevent allergic sensitization. We conclude that prenatal interventions have the potential to reduce the burden of allergic disease, and merit continued investigation. Further research in this area may lead to significant public health initiatives.

Childhood asthma and measles vaccine response

BACKGROUND

Asthmatic patients have a TH2-predominant milieu that is associated with humoral immunity. However, little is known about whether humoral immune responses to viral antigens differ between asthmatic and nonasthmatic children.

OBJECTIVE

To determine whether humoral immune response differs in asthmatic patients vs nonasthmatic patients.

METHODS

Measles virus specific IgG antibody levels were determined for the Rochester Family Measles Study cohort (n = 876), a convenience sample of healthy children 5 to 12 years of age in Rochester, MN. We conducted comprehensive medical record reviews of 838 children who were eligible for this study. We determined the child's asthma status at the time of determination of antibody levels by applying predetermined criteria for asthma. Comparisons were made using the 2-sample t test or chi2 test.

RESULTS

Of the 838 children, 156 (18.6%) had asthma at the time of the determination of antibody levels and were not taking systemic steroids within 14 days of specimen collection. Among those with a nonequivocal antibody reading, the seropositive response rates were similar in asthmatic patients and nonasthmatic patients (89.7% vs 90.3%, respectively; P = .83). However, the equivocal response rates were slightly higher among asthmatic patients than nonasthmatic patients (6.4% vs 4.7%, respectively).

CONCLUSION

Asthmatic children seem to have similar humoral immune responses to measles vaccine as those without asthma. Although the findings reassure health care practitioners, whether this finding is generalizable to other vaccines and whether asthmatic patients with low antibody levels have normal cell-mediated immunity need to be elucidated in future studies.

Acute infections, infection pressure, and atopy

BACKGROUND

During the recent years, a new theory postulating that lack of early childhood infections would increase the prevalence rate of allergies has rapidly gained momentum. This hygiene hypothesis has been widely disseminated to the general public and it has been suggested that vaccinations would accordingly indirectly increase rates of atopy. We thus investigated associations between acute infections, infection pressure (i.e. number of daily child contacts) and atopy in one of the largest population-based medical surveys ever published in the medical literature.

METHODS

Almost all Finns born between 1976 and 1984 and a sample of older teenagers aged up to 19 years (n=5 47 190) were vaccinated and questioned to establish clinical history of mumps and rubella and manifestations of atopy (rhinoconjunctivitis, eczema, and asthma) in 1982-1986. A subsample (n=37 733) including all those subjects who were vaccinated during the first 2 months of the measles, mumps, and rubella (MMR) programme were also queried information about upper respiratory infections (URIs) and infection pressure. Crude and adjusted prevalence ratios of atopy among those with infectious disease history compared with those without it were calculated.

RESULTS

The risk of URI and a history of mumps and rubella increased with the number of daily contacts. This association was apparent especially among the youngest subjects with regard to URIs whereas the proportion with histories of mumps and rubella increased with increasing infection pressure more clearly among the 6-year-olds. Atopy was not associated with daily child contacts among pre-schoolers. Children with histories of repeated URIs and MMR diseases had substantially more atopy than those with lower URI or MMR disease rates.

CONCLUSIONS

Atopic subjects seem to be especially prone to clinically apparent acute respiratory tract infections, and might be in particular need of protection by immunizations. This study does not support the idea that the prevalence of atopy in affluent countries would be affected from disappearing respiratory tract infections.

Anti-TNF-alpha and Th1 cytokine-directed therapies for the treatment of asthma

PURPOSE OF REVIEW

This article examines recent work about the role of TNF-alpha and of selected Th1-related cytokines in asthma with particular emphasis on the therapeutic potential of blocking the biological activity of these mediators.

RECENT FINDINGS

Current research endeavours suggest that asthma pathogenesis is driven by a mixed Th1/Th2 immune response. The contribution of individual Th1-associated and Th2-associated effector mechanisms to this mixed response profile is highly heterogeneous and variations in response patterns seem to be associated with heterogeneity in clinical phenotypes. In particular, it is now acknowledged that allergen-specific Th1 responses appear to be responsible for the pathogenetic effects seen in patients suffering from the more severe chronic forms of the disease. This is important because usual treatments for asthma appear to have limited effects on the more chronic severe forms of the disease and there is a pressing need for the development of new treatment strategies. The failure of topical corticosteroids to reduce TNF-alpha and Th1-derived cytokines to a significant level in asthmatic airways may explain to a certain extent why these drugs appear to have limited effects in the more severe forms of asthma.

SUMMARY

It is likely that therapies blocking TNF-alpha and interfering with Th1-derived cytokines may be a considerable advance in the management of those asthma patients who are particularly resistant to typical treatment modalities.