Head circumference at birth and maternal factors related to cord blood total IgE

Microglia M2A Polarization as Potential Link between Food Allergy and Autism Spectrum Disorders

Atopic diseases are frequently co-morbid with autism spectrum disorders (ASD). Allergic responses are associated with an activation of mast cells, innate lymphoid cells, and Th2 cells. These cells produce type-2 cytokines (IL4 and IL13), which stimulate microglia and macrophages to adopt a phenotype referred to as ‘alternative activation’ or ‘M2A’. M2A-polarized macrophages and microglia play a physiological role in tissue repair by secreting growth factors such as brain-derived neurotrophic factor (BDNF) and insulin-like growth factor-1. In ASD there is evidence for increased type-2 cytokines, microglia activation, M2A polarization, and increased levels of growth factors. In neurons, these growth factors drive a signal transduction pathway that leads to activation of the enzyme mammalian Target of Rapamycin (mTOR), and thereby to the inhibition of autophagy. Activation of mTOR is an effect that is also common to several of the genetic forms of autism. In the central nervous system, redundant synapses are removed via an autophagic process. Activation of mTOR would diminish the pruning of redundant synapses, which in the context of ASD is likely to be undesired. Based on this line of reasoning, atopic diseases like food allergy, eczema or asthma would represent risk factors for autism spectrum disorders.

Prenatal determinants of cord blood total immunoglobulin E levels in Mexican newborns

Asthma and allergic diseases have increased worldwide; however, etilogic factors for this increase are still poor. Prenatal consumptions of fatty acids are hypothesized, although few clinical trials in developing countries have been performed. This study was designed to identify predictors of immunoglobulin E (IgE) levels in cord blood of Mexican newborns. Total IgE was measured in umbilical cord blood from 613 infants whose mothers participated in a double-blind randomized controlled trial of 400 mg of docosahexaenoic acid or placebo from 18 to 22 weeks gestation through delivery. During pregnancy, information on sociodemographic characteristics, environmental exposures, and perceived maternal stress were obtained; a maternal blood sample was also collected to determine atopy via specific IgE levels. Logistic regression models were used to identify the main prenatal predictors of detectable total IgE levels in cord blood. IgE was detectable in cord blood from 344 (53.7%) infants; the main predictors in multivariate analyses were maternal atopy (odds ratio [OR] = 1.69; 95% CI, 1.19-2.42; p < 0.05) and pesticide use in the home (OR = 1.49; 95% CI, 1.04-2.14; p < 0.05). When stratified by maternal atopy, season of birth was a significant predictor in the atopic group only (OR = 2.48; 95% CI, 1.00-6.16; p < 0.05), and pesticide use was a significant predictor for infants born to nonatopic mothers (OR = 1.64; 95% CI, 1.07-2.51; p < 0.05). No differences were seen in the proportion of infants with detectable IgE by treatment group. Prenatal supplementation with omega-3 polyunsaturated fatty acid did not alter the detectable cord blood IgE levels. Maternal atopy and pesticide use during pregnancy are strong predictors of cord blood IgE levels in newborns. Clinical trial NCT00646360, www.clinicaltrials.gov.

Fetal growth and risk of childhood asthma and allergic disease

Introduction

Early genetic and environmental factors have been discussed as potential causes for the high prevalence of asthma and allergic disease in the western world, and knowledge on fetal growth and its consequence on future health and disease development is emerging.

Objective

This review article is an attempt to summarize research on fetal growth and risk of asthma and allergic disease. Current knowledge and novel findings will be reviewed and open research questions identified, to give basic scientists, immunologists and clinicians an overview of an emerging research field.

Methods

PubMed-search on pre-defined terms and cross-references.

Results

Several studies have shown a correlation between low birth weight and/or gestational age and asthma and high birth weight and/or gestational age and atopy. The exact mechanism is not yet clear but both environmental and genetic factors seem to contribute to fetal growth. Some of these factors are confounders that can be adjusted for, and twin studies have been very helpful in this context. Suggested mechanisms behind fetal growth are often linked to the feto-maternal circulation, including the development of placenta and umbilical cord. However, the causal link between fetal growth restriction and subsequent asthma and allergic disease remains unexplained. New research regarding the catch-up growth following growth restriction has posited an alternative theory that diseases later on in life result from rapid catch-up growth rather than intrauterine growth restriction per se. Several studies have found a correlation between a rapid weight gain after birth and development of asthma or wheezing in childhood.

Conclusion and clinical relevance

Asthma and allergic disease are multifactorial. Several mechanisms seem to influence their development. Additional studies are needed before we fully understand the causal links between fetal growth and development of asthma and allergic diseases.

Fetal origins of asthma

There is convincing evidence that asthma has its origins in early life. We review the epidemiological and biological evidence for fetal exposures that may have a causal role in asthma development. However, those factors that provoke asthma exacerbations are not necessarily the same as those associated with disease induction. Epidemiological studies have identified many potential exposures linked to asthma but these do not confirm causality and have not been replicated by experiment. Asthma is a heterogeneous disease and there are developmental influences on at least two pathways, airway structure and airway inflammation. The fetus is not immunologically naive and intrauterine exposures can act directly to invoke immunological sensitisation leading postnatally to airway inflammation. Other potential mechanisms include indirect effects on airway and lung growth through fetal nutrition and epigenetic modifications of DNA expression by environmental exposures. Identifying the causal factors will provide the targets for interventions to prevent disease.

Different implications of paternal and maternal atopy for perinatal IgE production and asthma development

Asthma is a hereditary disease associated with IgE-mediated reaction. Whether maternal atopy and paternal atopy have different impacts on perinatal IgE production and asthma development remains unclear. This paper reviews and summarizes the effects of maternal and paternal atopy on the developmental aspects of IgE production and asthma. Maternal atopy affects both pre- and postnatal IgE production, whereas paternal atopy mainly affects the latter. Maternally transmitted genes GSTP1 and FceRI-beta are associated with lung function and allergic sensitization, respectively. In IgE production and asthma development, the maternal influence on gene-environment interaction is greater than paternal influence. Maternal, paternal, and/or postnatal environmental modulation of allergic responses have been linked to epigenetic mechanisms, which may be good targets for early prevention of asthma.

Prediction of Allergy by Total Serum IgE Measurements in Infancy: A 10-Year Follow-up

Asthma, allergic rhinitis and atopic dermatitis are multifactorial disorders influenced by various familial and environmental factors. Cord blood IgE levels may be predictive for subsequent allergy onset. Serum IgE assessment has been rarely investigated. This study is aimed at evaluating serum IgE levels during the first year of life and relating to subsequent allergies. Total serum IgE levels were assessed in 102 newborns in the first days of life (2–3) and then again at 3, 5, 6, 11 and 12 months of age. After ten years, paediatricians and general practitioners caring for these children were tracked through the Local Healthcare Agency (LHA) database and asked about possible allergy of their patients, including transient ones. F Serum IgE increased in allergic infants at 1 year of life. The predictive model was significant. In conclusion, this study demonstrates that serum IgE may be predictive of subsequent allergy onset, preferably if assessed at 1 year of age.

Association among size of thymus, anthropometric dimensions and number of lymphocytes in peripheral blood in newborns from Slovakia

AIMS

Thymus is the central lymphatic organ in humans with important endocrine function that is involved in maturation of immunocompetent T-lymphocytes. In our study we investigated the relationship among thymus size and the anthropometric dimensions as well as between thymus size and the number of lymphocytes in peripheral blood in full-term newborns.

METHODS

The examined group consisted of 212 full-term newborns from the region of Southern Slovakia. We examined birth weight, birth body length, head circumference and chest circumference. Thymus size was estimated by ultrasonography and it was expressed as Thymic Index. The number of lymphocytes in peripheral blood was determined from the number of total leukocytes and from the leukogram.

RESULTS

We have found a statistically significant positive correlation among thymus size and the body dimensions of newborns. The highest correlation with thymus size was found for birth weight (r = 0.409; P < 0.001) followed by birth body length (r = 0.368; P < 0.001), head circumference (r = 0.365; P < 0.001) and chest circumference (r = 0.340; P < 0.001). We have proven also a statistically significant positive correlation between the number of lymphocytes in peripheral blood and thymus size (r = 0.208; P = 0.039).

CONCLUSION

Our results confirmed the findings of other authors about a close relationship of Thymic Index and basic body parameters in newborns.

Interleukin-10 and transforming growth factor-beta1 in cord blood: relationship with paternal allergy and cesarean section

AIM

To measure Interleukin-10 (IL-10) and transforming growth factor-beta1 (TGF-beta1) in cord blood and assess their relationship with parental allergy and perinatal characteristics.

METHODS

In a neonatal care unit 212 consecutive full-term and appropriate for gestational age newborns were recruited. IL-10 and TGF-beta1 levels were determined in cord blood by high sensitivity ELISA. Perinatal characteristics, mode of delivery and presence of allergy in parents were recorded.

RESULTS

Out of 212 newborns, 136 were of non-allergic parents and 76 (35.8%) of one or both allergic parents. In newborns of allergic fathers median IL-10 levels tended to be lower (0.67 vs. 1.06 pg/mL, p = 0.07) and TGF-beta1 levels were significantly lower (40.9 vs. 45.3 ng/mL, p = 0.008) than in newborns of non-allergic parents. Multiple general regression analysis showed that presence of paternal allergy (beta=-0.19, p = 0.003) to be born by cesarean section (beta=-0.21, p = 0.03) and younger gestational age (beta= 0.14, p = 0.04) independently contributed to decrease TGF-beta1 levels (multiple R = 0.38, p < 0.0001).

CONCLUSION

Paternal allergy and cesarean section are associated to decreased TGF-beta1, which might be the mediator of the increased risk of atopy development. Cord blood IL-10 and TGF-beta1 levels of our newborn series could be used as reference values for further studies on these relationships.

Association of IL-5 cytokine production and in vivo IgE levels in infants and parents

BACKGROUND

Total IgE in human subjects tracks strongly from birth onward through unknown mechanisms. Regulation of IgE might occur in relation to adaptive immune cytokine production. In vitro studies have assessed the role of individual cytokines in regulating IgE production in human subjects.

OBJECTIVE

We sought to investigate the association between IgE levels in vivo and the capacity of the individuals to produce adaptive immune cytokines.

METHODS

Blood samples from participants in the Tucson Infant Immune Study (children at birth and at 3 and 12 months of age, fathers, and mothers before and after delivery) were assessed for percentage of eosinophils and plasma total IgE levels. IFN-gamma, IL-4, IL-5, IL-13, and IL-10 levels were measured in supernatants of mitogen-stimulated PBMCs and examined cross-sectionally for relation to cytokine production by using simple regression, multiple regression with cytokines only and with other known predictors of IgE levels, and longitudinally by means of random effects modeling.

RESULTS

After adjusting for eosinophils and other predictors, IL-5 production (but not that of other cytokines) was associated directly with total IgE levels in children at 3 months (P = .009) and 12 months (P = .011) of age but not at birth. The IL-5/IgE association was present also in fathers (P = .040) and in mothers, both during pregnancy (P < .001) and after delivery (P = .030).

CONCLUSIONS

This study indicates that mitogen-stimulated IL-5 production is associated with in vivo total IgE levels, independent of the production of other cytokines and circulating eosinophils.

CLINICAL IMPLICATIONS

Understanding the regulation of IgE in vivo might help elucidate the development of allergic responses in individuals.

Autism, asthma, inflammation, and the hygiene hypothesis

Inflammation and the genes, molecules, and biological pathways that lead to inflammatory processes influence many important and disparate biological processes and disease states that are quite often not generally considered classical inflammatory or autoimmune disorders. These include development, reproduction, aging, tumor development and tumor rejection, cardiovascular pathologies, metabolic disorders, as well as neurological and psychiatric disorders. This paper compares parallel aspects of autism and inflammatory disorders with an emphasis on asthma. These comparisons include epidemiological, morphometric, molecular, and genetic aspects of both disease types, contributing to a hypothesis of autism in the context of the immune based hygiene hypothesis. This hypothesis is meant to address the apparent rise in the prevalence of autism in the population.

Predictors of cord blood IgE levels in children at risk for asthma and atopy

BACKGROUND

Increased cord blood IgE levels, in conjunction with a family history of atopy, are associated with the development of allergic diseases in children. However, little is known about predictors of cord blood IgE levels.

OBJECTIVE

Our objective was to identify predictors of cord blood IgE levels among infants at increased risk of atopy.

METHODS

Cord blood IgE levels were measured in 874 infants who were screened for participation in a birth cohort. Questionnaires were administered after birth of the infant, and maternal and cord blood was obtained for measurement of IgE levels. Logistic and tobit regression models were used to study the association between perinatal factors and cord blood IgE levels.

RESULTS

In multivariable models infant male sex, increased maternal total IgE level, maternal allergen sensitization, Hispanic ethnicity, and residence in low-income areas were associated with detectable or increased cord blood IgE levels, whereas increasing maternal age was associated with undetectable or lower cord blood IgE levels. Although maternal smoking during pregnancy was positively associated with cord blood IgE levels in univariable models, the effect did not persist after adjusting for potential confounders.

CONCLUSION

Maternal allergen sensitization, markers of socioeconomic disadvantage and race/ethnicity, maternal age, and infant sex might influence fetal production of IgE. We found no association of maternal parity, mode of delivery, gestational age, or season of birth with cord blood IgE levels.

CLINICAL IMPLICATIONS

The identification of these definable familial and environmental factors that predict cord blood IgE levels might help in the early detection of infants at risk for atopic disorders.

Early life circumstances and atopic disorders in childhood

The prevalence of childhood atopic disorders has risen dramatically in the last decades of the past century. Risk factors for the development of these disorders have been studied extensively. This review focuses on the role of early life risk factors such as pre-natal development, perinatal circumstances, birth order and childhood vaccinations.

Exposure of the fetus and infant to hens' egg ovalbumin via the placenta and breast milk in relation to maternal intake of dietary egg

BACKGROUND

Maternally derived allergens may be transferred to the developing infant during pregnancy and lactation. However, it is not known how manipulation of environmental allergen levels might impact on this early-life exposure.

OBJECTIVE

To measure dietary egg allergen (ovalbumin (OVA)) in gestation-associated environments, in relation to maternal dietary egg intake.

METHOD

OVA was measured by allergen-specific ELISA in maternal blood collected throughout pregnancy, infant blood at birth (umbilical cord) and in breast milk at 3 months post-partum. Samples derived from pregnant women undergoing diagnostic amniocentesis at 16-18 weeks gestation who were not subject to any dietary intervention, and from pregnant women, with personal or partner atopy, randomized to complete dietary egg exclusion or an unmodified healthy diet before 20 weeks gestation as a primary allergy prevention strategy. Maternal dietary egg intake was monitored closely throughout the study period by diary record and serial measurement of OVA-specific immunoglobulin G concentration.

RESULTS

Circulating OVA was detected throughout pregnancy in 20% of women and correlated with both presence (P<0.001) and concentration (r=0.754, P<0.001) of infant OVA at birth (umbilical cord). At 3 months post-partum OVA was detected in breast milk samples of 35% women, in higher concentrations than measured in blood. Blood and breast milk OVA were not related to maternal dietary intake or atopic pre-disposition.

CONCLUSIONS

Rigorous dietary egg exclusion does not eliminate trans-placental and breast milk egg allergen passage. This early-life exposure could modulate developing immune responses.

Perinatal characteristics and obstetric complications as risk factors for asthma, allergy and eczema at the age of 6 years

BACKGROUND

Considerable effort has been put into identifying early determinants for atopic disorders. Many studies have evaluated the role of fetal development and obstetric complications. However, the results are not unequivocal.

STUDY OBJECTIVE

To assess the relationship between perinatal characteristics and obstetric complications, and the presence of reported current asthma, allergy and eczema at the age of 6 years in the framework of a previously conducted study.

METHOD

Seven hundred families in the Netherlands with index children born in 1988-1990 were retrospectively selected. Data were extracted from the Municipal Health Service's records of health examinations of these children and their siblings. These examinations were carried out at the age of 6 years. The records contained data on reported atopic disorders and perinatal characteristics.

RESULTS

Gestational age was inversely related to the risk of asthma (P for trend: 0.03). Children with low birth weight tended to have a lower risk of any allergy, albeit not significant (P=0.07). However, no link was found between neonatal head circumference and atopic disorders. The ratio of neonatal head circumference to birth weight was positively associated with the risk of atopic disorders, especially with the risk of asthma (odds ratio (OR)=1.87; 95% confidence interval (CI(95%))=[1.11, 3.15]). Vacuum extraction was a risk factor for allergy (OR=1.84, CI(95%)=[1.03, 3.28]), but not for asthma. Induced labour was positively associated with the risk of inhalant allergy (OR=2.22, CI(95%)=[1.09, 4.51]) and, to a lesser extent, asthma (OR=1.72, CI(95%)=[0.95, 3.10]). For caesarean section and forcipal extraction there were no such relationships.

CONCLUSIONS

Prematurity is a risk factor for asthma reported at 6 years. A high ratio of head circumference to birth weight is a risk factor for any atopic disorder. Vacuum extraction was associated with a higher risk of allergy, and induced labour is a risk factor for inhalant allergy. All results should be viewed with the possibility of residual confounding.

Intervention during pregnancy and allergic disease in the offspring

The etiology of allergy is multifactorial, with many variables contributing to the final expression of atopic disease. Three breeding grounds are needed to develop allergic disease: the appropriate genetic background, contact with the allergen(s) and environmental factors. Timing and dosing of allergen(s) are of major importance. Contact with (dietary) allergens and various agents such as tobacco smoke and infections occur not only during post-natal life, but also perinatally and even pre-natally. A critical review of published evidence regarding the impact of maternal exposure to antigens during pregnancy on later development of allergy in the offspring can only conclude that more research is urgently needed. Contact with multiple dietary allergens should be in general of benefit to the fetus to develop tolerance. Current knowledge suggests that pregnant women should have a normal diversified diet, avoiding toxic agents such as tobacco and alcohol. The role of maternal intake of poly-unsaturated fatty acids on the development of atopy in the infants needs to be further evaluated. If parental history would be insufficient to determine the fetal risk, preventive measurements would be advisable for all fetuses.

Association of active and passive smoking with allergic disorders in pregnant Japanese women: baseline data from the Osaka Maternal and Child Health Study

BACKGROUND

Evidence remains inconclusive as to whether smoking is a risk factor for allergic disorders in adults.

OBJECTIVE

To investigate the relationship between active and passive smoking exposure and allergic disorders in pregnant Japanese women.

METHODS

This cross-sectional study included 1,002 pregnant women. Participants were classified as having asthma after the age of 18 years if they had used an asthma medication at any time after reaching the age of 18 years. Current atopic eczema and allergic rhinitis (including cedar pollinosis) were defined as being present if participants had received any drug treatment during the previous 12 months. Adjustment was made for age; gestation; parity; family history of asthma, atopic eczema, and allergic rhinitis; indoor domestic pets; family income; education; and the mite antigen level in house dust.

RESULTS

Current smoking, but not environmental tobacco smoke exposure, was independently related to an increased prevalence of asthma after the age of 18 years (adjusted odds ratio [OR], 2.66; 95% confidence interval [CI], 1.30-5.38). A significant positive association of current passive smoking exposure at home (adjusted OR, 1.89; 95% CI, 1.10-3.30) and at work (adjusted OR, 2.50; 95% CI, 1.29-4.76) with the prevalence of current allergic rhinitis was observed, whereas no measurable association with active smoking exposure was found. Neither active nor passive smoking was statistically significantly related to the prevalence of current atopic eczema.

CONCLUSIONS

These findings suggest that active smoking and environmental tobacco smoke exposure may increase the likelihood of asthma and allergic rhinitis, respectively, in pregnant Japanese women.

The effect of prenatal exposure on total IgE at birth and sensitization at twelve months and four years of age: The PIAMA study

There is increasing evidence that the development of the fetal immune system can be influenced by environmental exposure in utero. We investigated whether prenatal exposure is associated with a high neonatal total IgE level and sensitization at the age of 1 and 4 yr. Data from 1027 infants were collected in a Dutch birth cohort study (PIAMA study). Total IgE was measured in heel prick blood collected in the first week of life. Sensitization was defined as a specific IgE level in serum of > or =0.35 IU/ml against house dust mite, cat, dog, milk or egg. Logistic regression analysis was performed to study independent relationships between risk factors and a high neonatal total IgE (> or =0.50 IU/ml) or sensitization. A high neonatal total IgE was found in 12.2% of boys and 6.2% of girls. A dog at home during pregnancy was negatively associated with a high neonatal total IgE [odds ratio (95% CI) 0.5 (0.2-1.0)]. A cat at home [OR 0.6 (0.4-1.0) and maternal smoking (OR 0.4 (0.2-1.0)] were negatively associated with sensitization at 12 months, but not at 4 yr. The presence of older siblings, season of birth, birth weight, mode of delivery, gestational age and maternal age were not associated with a high neonatal total IgE or sensitization. The higher total IgE level and prevalence of sensitization at 4 yr in boys compared with girls was only present in children from allergic mothers. Our results suggest a short-lasting protective effect of prenatal exposure to pets on total IgE at birth and early sensitization.

Relationship between active and passive smoking and total serum IgE levels in Japanese women: baseline data from the Osaka Maternal and Child Health Study

BACKGROUND

Many studies have shown that cigarette smoking is associated with elevated concentrations of total serum IgE. Few studies, however, have examined total IgE in relation to passive smoking exposure, especially in adults. This cross-sectional study investigated the association of active and passive smoking exposure with levels of total serum IgE in Japan.

METHODS

Study subjects were 981 pregnant women in Osaka. Total IgE levels were measured using UniCAP 1000 and were defined as elevated if they exceeded 170 ml/UI. Age, gestation, parity, family history of asthma, atopic eczema and allergic rhinitis, indoor domestic pets, family income, education and the mite allergen level in house dust were selected as potential confounding factors.

RESULTS

Current smoking of at least 15 cigarettes a day and 8.0 or more pack-years of smoking were independently related to an increased prevalence of elevated total serum IgE (adjusted odds ratios 3.40 and 2.51, 95% confidence intervals 2.12-5.47 and 1.55-4.06, respectively), and both cigarette smoking status and pack-years of smoking were significantly positively associated with total serum IgE levels, especially in subjects with a positive familial allergic history. There was no measurable association of exposure to environmental tobacco smoke (ETS) at home or at work with total serum IgE concentrations among those who had never smoked.

CONCLUSIONS

Our results corroborate a positive relationship between active smoking and total serum IgE levels; however, this study failed to substantiate a positive association of ETS exposure with total IgE. Investigations with more precise and detailed exposure measurements are warranted.

Are maternal psychosocial factors associated with cord immunoglobulin E in addition to family atopic history and mother immunoglobulin E?

BACKGROUND

Atopy in maternal and family histories is known to be a risk factor for elevated umbilical cord immunoglobulin E (cIgE). However, the association between cIgE and psychosocial factors remains under investigation.

OBJECTIVE

To explore whether psychosocial factors in addition to atopy contribute to elevated cIgE.

METHODS

Four private maternity hospitals fitting the quantile levels of SO(2) in 2000 cooperated with us by recruiting participants for this study: pairs of mothers and neonates living within 3-km catchment areas of air-monitoring stations. We used a questionnaire to collect exposure data, and the Pharmacia UniCap IgE assay test system to determine the levels of IgE in gravidas and cord blood.

RESULTS

Between July 2001 and March 2003, 334 mother and neonate pairs participated in this study. The frequencies of sensitization, serum IgE (sIgE)>100 IU/mL, or cIgE> or =0.35 IU/mL were not different between the four different hospitals. By multi-variate logistic regression analysis adjusted for environmental factors, genetic factors, and psychosocial factors, the risk factors for elevated cIgE were being a male neonate (odds ratio (OR)=3.5, 95% confidence interval (CI)=[1.5, 8.5]), carpets at home (OR=3.0, 95% CI=[1.02, 8.4]), maternal allergy to dog dander (OR=9.7, 95% CI=[1.2, 98.8], maternal total serum IgE>100 IU/mL (OR=5.1, 95% CI=[2.2, 12.8]), maternal regularly/mostly/often self-reported nervousness (OR=4.0, 95% CI=[1.3, 12.8]), family income 11,574-17 361 US dollars/year (OR=3.7, 95% CI=[1.3, 11.5]), incense burning (OR=4.0, 95% CI=[1.4, 13.3]), and atopy in maternal grandparents (OR=4.8, 95% CI=[1.7, 14.0]). By principle component analysis and logistic regression, psychosocial stress (beta +/- standard error=0.26+/-0.13, P=0.04) was associated with increased cIgE.

CONCLUSION

Psychosocial factors are potentially important risk factors for elevated cIgE.

In utero exposure to lead and cord blood total IgE. Is there a connection?

BACKGROUND

Lead exposure and total immunoglobulin E (IgE) have been shown to be positively related in animals and humans even at lead levels below those recognized as toxic. In the last decades, exposure to lead has become more frequent in urban areas of industrialized as well as of developing countries where IgE-mediated allergy prevalence has also increased.

METHODS

We examined for the first time the relationship between in utero exposure to lead and cord blood total IgE in two samples of 137 and 237 mother-newborn pairs, respectively, recruited in Paris.

RESULTS

Cord blood IgE was positively related to hair lead level at birth, providing an integrated measure of long-term exposure in utero, in each cohort (Spearman's coefficient r = 0.32, P < 0.001 and r = 0.19, P < 0.01, respectively) and in the combined cohort (r = 0.21; P < 0.01). The relationship appeared to be more pronounced in newborns of nonallergic mothers (r = 0.24; P < 0.01) than in those of allergic mothers (r = 0.12). This could be due to the fact that familial history of allergy, the strongest determinant of IgE development, may overshadow the influence of lead on IgE in the offspring.

CONCLUSIONS

Our findings suggest a possible intervention of environmental exposure besides genetic factors in early life development of IgE production. Further studies are needed to confirm the finding.

Early life factors related to clinical manifestations of atopic disease but not to skin-prick test positivity in young children

The relative influence of early life events in the development of IgE-mediated allergy is still undetermined. We investigated early life factors in relation to skin-prick test positivity (SPT) and clinical manifestations of atopic disease in a population-based sample of 201 Italian children (3 months-5 years), after considering their interactions with known determinants of allergy. Among them, 143 children had SPT performed to common allergens. Threatened abortions, general anesthesia at delivery, prematurity, birthweight < 2500 g, maternal smoking, dampness and gas heating exposure were all significantly related to an increased risk of frequent rhinitis in the absence of cold (18%). In utero smoking, threatened abortions, fetal health complications, infantile colic, maternal smoking in childhood (satisfactorily correlated with maternal expired CO during the survey) and respiratory infections were all independent determinants of frequent wheezing (23%). Doctor's diagnosis of asthma (3%) was related to in utero smoking, being born in spring, infantile colic and respiratory infections. A simultaneous exposure to in utero smoking and infantile colic put the infants to a fourfold higher risk of frequent wheezing and to a ninefold risk of asthma, respectively. Having a pet and washing blankets at < 60 degrees C were inversely related to frequent wheezing. Data confirmed also that maternal phenotype influences the inheritance of atopic disease. No event, except a low intake of fruit (< 3/week), was significantly associated with positive SPT (20%) or eczema. Besides allergic sensitization, other events, which occur early in life, seem critical to the development of IgE-mediated allergy.

Thymus size and head circumference at birth and the development of allergic diseases

BACKGROUND

The positive association between a large head circumference at birth and total serum IgE levels has been suggested to be due to negative associations between head circumference at birth and thymus development and between thymus development and total serum IgE levels.

OBJECTIVES

To examine the associations between head circumference and thymus size at birth and the development of allergic disease.

METHODS

The size of the thymus was assessed by sonography during the first week of life in 149 healthy term infants. Information on birth characteristics and mode of delivery was collected at delivery. The presence of allergic disease was assessed 5 years later by mailed questionnaires, which were returned by 85% of the eligible families.

RESULTS

At birth, head circumference was positively associated with thymus size (P < 0.001). In all, 27 (23%) of the children had developed at least one allergic disease. Multivariate analysis revealed that both parental allergy (Prevalence Ratio and 95% CI) = 3.18 (1.49-6.78)) and caesarean delivery (2.62 (1.48-4.64)) were independently correlated with allergic disease, whereas thymus size was not.

CONCLUSIONS

Our study does not support that a large head circumference is associated with a small thymus size, nor that a small thymus size is associated with allergic disease. Whether thymus size at birth is related to total serum IgE levels still remains to be elucidated.

In utero and perinatal complications preceding asthma

BACKGROUND

It has been suggested that pregnancy and early life may influence the development of asthma in the offspring, but published studies have not carefully controlled for potential biases.

METHODS

In a large British birth cohort of 4065 natural children of 2583 mothers, we investigated whether in utero and perinatal influences contribute to the development and the severity of asthma in childhood, allowing for possible confounders of the relationship, and considering the nonindependence of familial data.

RESULTS

Child asthma (10.1%) was more frequently reported by mothers when there had been health complications during pregnancy (prevalence =14.3%; adjusted odds ratio [ORadj] =2.01; 95% confidence interval, 1.52-2.67), labor, or delivery (19.3%, ORadj =1.35, 1.01-1.81); child illness or health complications during the first week of life (22.6%, ORadj =1.35, 1.01-1.82); and birth weight of < 2.5 kg (7.0%, ORadj =1.57, 1.10-2.25). Specific causes of health complications during pregnancy which significantly related to asthma were early or threatened labor (ICD: 644) (4.8%, ORadj =1.58, 1.03-2.40) and the malposition or malpresentation of the fetus (ICD: 652) (1.6%, ORadj =3.63, 1.47-8.91).

CONCLUSION

The results provide further evidence that in utero and perinatal factors may increase the risk of developing asthma.

Allergy markers in respiratory epidemiology

Assessing allergy by measurement of serum immunoglobulin (Ig) E antibodies is fast and safe to perform. Serum antibodies can preferably be assessed in patients with dermatitis and in those who regularly use antihistamines and other pharmacological agents that reduce skin sensitivity. Skin tests represent the easiest tool to obtain quick and reliable information for the diagnosis of respiratory allergic diseases. It is the technique more widely used, specific and reasonably sensitive for most applications as a marker of atopy. Measurement of serum IgE antibodies and skin-prick testing may give complimentary information and can be applied in clinical and epidemiological settings. Peripheral blood eosinophilia is less used, but is important in clinical practice to demonstrate the allergic aetiology of disease, to monitor its clinical course and to address the choice of therapy. In epidemiology, hypereosinophilia seems to reflect an inflammatory reaction in the airways, which may be linked to obstructive airflow limitation.

The miseries of passive smoking

Passive smoking is defined as an involuntary exposure to a combined but diluted cigarette sidestream smoke (SS, gas and particle phases that are evolved from the smoldering end of a cigarette while the smoker is not puffing) and the exhaled smoke from smokers. SS contains numerous cytotoxic substances such as polycyclic aromatic hydrocarbons (PAHs), aromatic amines, nitrosamines, heavy metals, poisonous gases, pesticide residues, and radioactive elements in quantities much higher than those found from the cigarette mainstream smoke (MS) which is puffed by smokers. Passive smoking is found to be the cause of death from cancers and cardiac disease. Furthermore, it damagingly involves reproductive organs, the nervous system, genetic materials, and is particularly hazardous to mother and child during pregnancy and to those with a history of asthma, chronic infections, induced or earned immune deficiency, or predisposed susceptibility.

Atopy, lung function, and obstructive airways disease after prenatal exposure to famine

BACKGROUND

Associations have been found between a large head size at birth and atopy, and between low birth weight and obstructive airways disease. A study was undertaken of people born around the time of the Dutch famine in 1944-5 to determine the effects of maternal malnutrition during specific periods of gestation on the prevalence of obstructive airways disease and atopy.

METHODS

Nine hundred and twelve people aged about 50, born at term between November 1943 and February 1947 in Amsterdam, were asked about their medical history. Lung function was measured in 733 and serum concentrations of total IgE and specific IgE against mite, pollen and cat were measured in 726. Those exposed in late, mid, and early gestation (exposed participants) were compared with those born before or conceived after the famine (non-exposed participants).

RESULTS

Exposure to famine during gestation affected neither the concentrations of total or specific IgE nor lung function values. The prevalence of obstructive airways disease was increased in people exposed to famine in mid gestation (odds ratio adjusted for sex 1.7, 95% confidence interval (CI) 1.1 to 2.6) and tended to be higher in those exposed in early gestation (odds ratio 1.5, 95% CI 0. 9 to 2.6).

CONCLUSIONS

The observed increase in the prevalence of obstructive airways disease in people exposed to famine in mid and early gestation was not parallelled by effects on IgE concentrations or lung function. The link between exposure to famine in mid and early gestation and obstructive airways disease in adulthood suggests that fetal lungs can be permanently affected by nutritional challenges during periods of rapid growth.

Relationships of active and passive smoking to total IgE in adults of the Epidemiological Study of the Genetics and Environment of Asthma, Bronchial Hyperresponsiveness, and Atopy (EGEA)

The increase of total IgE in relation to active smoking has been shown in the general population, but little is known about subjects with a personal or family history of asthma. The objective of this report is to analyze the relationships of active and passive smoking to total IgE in the Epidemiological Study of the Genetics and Environment of Asthma, Bronchial Hyperresponsiveness, and Atopy (EGEA). The sample studied includes 122 asthmatic probands, 430 first-degree relatives, and 190 control subjects, age 25 to 54 yr. As expected, first-degree relatives had total IgE intermediate between cases and control subjects and men had higher values than women. Current smokers had significantly higher IgE than never smokers. The relationship was statistically significant restricting the analysis in asthmatic probands. In a model taking into account gender, personal and familial history of asthma, socio- occupational class, and the nonindependence of subjects from the same family, IgE were in current smokers, ex-smokers, and never smokers 128, 61, and 76 IU/ml and 77, 41, and 55 IU/ml in men (p = 0.01) and women (p = 0. 05), respectively. The relation was independent of skin test response. Some increase in IgE was observed in both men and women first-degree relatives in relation to passive smoking. That relation was statistically significant in women only (adjusted for asthma values: 103 IU/ml versus 48 IU/ ml, p = 0.02). Results show that an increase in total IgE in relation to active smoking may be evidenced even in asthmatics despite the healthy smoker effect. Susceptible subjects, such as women who are first-degree relatives of asthmatics, may increase total IgE in relation to passive smoking.