Relationship of total serum IgE levels in cord and 9-month sera of infants

Prevalence of Food Allergy and Common Food Allergen Among Saudi Adults in Makkah Region, Saudi Arabia

Introduction

The prevalence of food allergy (FA) in the Makkah region has received little attention, so we conducted this study to estimate the prevalence of FA in adults.

Methods

This descriptive, cross-sectional, survey-based study was conducted online among 531 participants with or without a prior diagnosis of FA. The collected data related to socio-demographics (age and gender), whether the participant had been medically diagnosed with any food allergens, and assessing the prevalence of different food allergens.

Results

Only 93 (17.5%) of the 531 people screened positive for FA; females (65.6%) predominated, with 37.6% aged 40-59. The type of food for allergy was: eggs (47%), seafood (44%), fruits (40%), nuts and legumes (37%), milk and dairy products (25%), vegetables (17%), sesame (11%), wheat (9%), soy (8%), 2% to chili peppers, and only 1% honey and chocolate.

Conclusion

Both genders were allergic to eggs, followed by seafood, fruits, nuts, and legumes, and milk and dairy products, respectively.

Effect of season of birth on cord blood IgE and IgE at birth: A systematic review and meta-analysis

BACKGROUND

Elevated cord blood IgE is important on the pathway to allergic disease. The association between season of birth and infant cord blood IgE is not well-established. Study findings differ on which birth season is associated with higher cord blood IgE risk and its magnitude. We conducted a systematic review and meta-analysis of studies on season of birth and cord blood IgE.

METHODS

We searched Medline, Web of Science, Scopus and ProQuest Health databases, and reviewed reference lists of articles that met the inclusion criteria. All included studies measured IgE as a binary variable using various cut-off values. We performed multivariate-random-effects meta-analysis to handle an exposure with multiple categories of Season of Birth.

RESULTS

Our search identified 275 records and 10 had sufficient data to be included in a meta-analysis. Relative to summer, winter birth had the greatest odds of high IgE (≥ 0.1IU/ml), meta-analysis OR = 1.24 (95%CI: 1.01-1.52). A similar OR, was found for IgE ≥ 0.5 IU/ml, OR = 1.30 (95%CI: 0.99-1.71).

CONCLUSIONS

A winter season of birth was associated with statistically significant higher odds of elevated cord blood IgE at cut-off ≥ 0.1IU/ml but borderline at cut-off ≥ 0.5IU/ml. This winter effect is likely to be a marker for a range of other environmental exposures during specific stages of pregnancy, such as aeroallergen exposures, maternal infections and vitamin D levels. Further research is required to support our finding and to identify the exact mechanisms that lead to the winter season of birth effect on circulating IgE levels, as this may have implications for allergic disease prevention.

Particularities of allergy in the Tropics

Allergic diseases are distributed worldwide and their risk factors and triggers vary according to geographical and socioeconomic conditions. Allergies are frequent in the Tropics but aspects of their prevalence, natural history, risk factors, sensitizers and triggers are not well defined and some are expected to be different from those in temperate zone countries. The aim of this review is to investigate if allergic diseases in the Tropics have particularities that deserve special attention for research and clinical practice. Such information will help to form a better understanding of the pathogenesis, diagnosis and management of allergic diseases in the Tropics. As expected, we found particularities in the Tropics that merit further study because they strongly affect the natural history of common allergic diseases; most of them related to climate conditions that favor permanent exposure to mite allergens, helminth infections and stinging insects. In addition, we detected several unmet needs in important areas which should be investigated and solved by collaborative efforts led by the emergent research groups on allergy from tropical countries.

Sex and the lung: Observations, hypotheses, and future directions

Sex-related differences in a variety of lung diseases in infants and young children are reviewed, including respiratory distress syndrome, and chronic lung disease of prematurity, lower respiratory tract illnesses and wheezing, asthma, diffuse, and interstitial lung diseases, and cystic fibrosis. Differences in anatomy and physiology, such as airway size, airway muscle bulk, airway reactivity, airway tone, and cough reflexes may explain much of these sex differences. Better understanding of sex-related lung differences could help personalize respiratory treatment.

What are the main environmental exposures associated with elevated IgE in Cuban infants? A population-based study

OBJECTIVE

Immunoglobulin E (IgE) plays a key role in allergy disease pathogenesis, but little is known about the environmental factors associated with higher IgE levels in infants. The aim of this study was to determine the risk factors for elevated serum total IgE infants living in Havana.

METHODS

Eight hundred and seventy-seven infants provided blood samples. Data on allergic disease symptoms and a wide range of exposures were collected.

RESULTS

The median IgE was 35 IU/ml (interquartile range 13-96). The risk of having an IgE level above the median was higher for children who had been breastfed for 4 months or more (adjusted odds ratio (OR) 1.28; 95% confidence interval (CI): 1.02-1.61) and for children who reported cockroaches in their home (OR 1.30; 95% CI: 1.03-1.63). The risk was lower for children whose mother was in paid employment (OR 0.73; 95% CI: 0.54-0.97 compared with those who did not), for children living in homes where gas and electricity were used for cooking (OR 0.45; 95% CI: 0.32-0.62 compared with electricity only) and for children with domestic pets at birth (OR 0.83; 95% CI: 0.70-1.00). There was no association between paracetamol use and serum IgE levels.

CONCLUSIONS

Associations between gas fuel use and maternal employment indicate that IgE levels in early life are lower in children who may be living in relative affluence. The discrepancy in the effect of early exposure to pets or cockroaches may reflect differences in these allergens, or be confounded by relative affluence. Further investigation of this cohort will determine how these effects translate into the expression of allergic disease in later life.

Cord IgE and ECP levels of Malay neonates

BACKGROUND

Cord IgE and ECP levels are major atopic markers implicated in early childhood allergy development. Most epidemiological studies to date have not utilised current technology to establish baseline cord IgE levels, further aggravated by lack of data in this region. This study also attempts to identify a relationship between cord IgE and ECP levels as a mean to improve sensitivity for early prediction of atopy.

METHODS

A total of 3183 cord blood IgE including 44 cord ECP samples of term neonates from Malay parentage were recruited. Total IgE and ECP levels were determined by ImmunoCAP and fluoroimmunoenzymatic, respectively.

RESULTS

Cord IgE geometric mean was 0.15 kU/L. Males had higher IgE geometric mean than females (0.17 vs. 0.13). IgE values between 17 pair of twins was not significant (p=0.169). Frequency of males (29.9%) in >0.9 kU/L IgE category was higher than females (26.1%). In the <0.35 kU/L category, females had a higher frequency (44.8%) than males (39.1%). Males had significantly (p=0.023) higher IgE level than females. November and February had the highest mean and median cord IgE level whereas October and December were the lowest, respectively. IgE level across months was not significant (p=0.234). Cord ECP mean was 5.21 g/L and median was 3.75 μg/L. There was no significant correlation (p=0.513; r=-0.101) between cord blood ECP and IgE levels.

CONCLUSION

Cord blood IgE level of Malay male neonates was significantly higher than females. These results do not support cord ECP as plausible adjunct parameter to IgE for early atopic detection.

CD14 C-159T polymorphism and its association with chronic lung diseases: A pilot study on isocyanate exposed population of Central India

CONTEXT

CD14 functions as a multifunctional receptor for bacterial cell wall components including endotoxin and lipopolysaccharide and is likely to influence the cytokine profile and subsequent immunoglobulin E production in response to antigen/allergen contact in allergic phenotypes.

AIMS

The present study was to investigate genetic polymorphism in CD14 gene - 159C/T, which may be one of the risk factor for increased prevalence of Chronic Lung Diseases in the Central India.

SETTINGS AND DESIGN

Survivors of Methyl isocyanates toxicity in Bhopal still suffering from various respiratory ailments were examined.

MATERIALS AND METHODS

Polymerase chain reaction-restriction fragment length polymorphism was performed to determine the polymorphism of C-159T.

RESULTS

The genotype and allelic frequencies were in Hardy-Weinberg's equilibrium. Prevalence of CC, CT, and TT were 5.5%, 22.2% and 9.25% respectively in asthmatics; 16.6%, 20.3% and 5.5% respectively in chronic obstructive pulmonary disease (COPD) patients and 5.5%, 14.8% and 1.85 respectively among interstitial lung disorder (ILD) patients; whereas the control cohort with no methyl isocyanate exposure displayed (CC, CT, and TT) cytosine, thymine as 2%, 1.6% and 2% respectively. Increased risk of Asthma among those carrying TT genotype and T allele (odds ratio [OR] =2.61 and 2.02 respectively).

CONCLUSION

COPD risk significantly found among those with CC genotype and C allele (OR = 2.81 and 1.50 respectively), whereas ILD risk found significantly among CT genotype and C allele (OR = 1.75 and 1.40 respectively). Therefore, single nucleotide polymorphism (SNP) C-159T polymorphism in CD14 gene might be a risk factor for development of CLD in this population.

Intrauterine sensitization of allergen-specific IgE analyzed by a highly sensitive new allergen microarray

BACKGROUND

To design a rational allergy prevention program, it is important to determine whether allergic sensitization starts in utero under the maternal immune system.

OBJECTIVE

To investigate the origin of allergen-specific IgE antibodies in cord blood (CB) and maternofetal transfer of immunoglobulins.

METHODS

The levels of food and inhalant allergen-specific IgE, IgA, IgG, and IgG(4) antibodies in CB and maternal blood (MB) from 92 paired neonates and mothers were measured by using a novel allergen microarray of diamond-like-carbon-coated chip, with high-sensitivity detection of allergen-specific antibodies and allergen profiles.

RESULTS

The levels of allergen-specific IgE antibodies against food and inhalant allergens and allergen profiles were identical in CB and newborn blood, but the levels and profiles, specifically against inhalant allergens, were different from those in MB. The level of allergen-specific IgA antibodies was below the detection levels in CB despite clear detection in MB. Therefore, contamination with MB in CB was excluded on the basis of extremely low levels of IgA antibodies in CB and the obvious mismatch of the allergen-specific IgE and IgA profiles between CB and MB. However, the levels of allergen-specific IgG and IgG(4) antibodies and their allergen profiles were almost identical in both MB and CB.

CONCLUSION

Allergen-specific levels of IgE and IgA antibodies and their allergen profiles analyzed by the diamond-like-carbon allergen chip indicate that IgE antibodies in CB are of fetal origin. Food-allergen specific IgE antibodies were detected more often than inhalant-allergen specific IgE antibodies in CB, the reason of which remains unclarified.

Exposure to air pollution in critical prenatal time windows and IgE levels in newborns

The objective of this study was to analyze the mechanisms by which exposure to ambient air pollutants influences respiratory health may include altered prenatal immune development. To analyze associations between elevated cord serum Immunoglobulin E (IgE) levels and maternal air pollution exposure during each month of gestation. Total cord serum IgE was determined by the CAP system and mothers' total IgE levels by nephelometry for 459 births in the Czech Republic from May 1994 to mid-January 1997. Concentrations of polycyclic aromatic hydrocarbons (PAHs) and particulate matter <2.5 microns in diameter (PM(2.5) ) were measured in ambient air, and arithmetic means were calculated for each gestational month. Log binomial regression models were used to estimate prevalence ratios (PR) for elevated cord serum IgE (≥0.9 IU/ml) adjusting for district of residence, year of birth, and in further models, for maternal IgE (a surrogate for atopy) and gestational season. Heterogeneity by maternal atopy status was evaluated for associations of air pollution and of cigarette smoke. In adjusted models, PAH and PM(2.5) exposures in the second month of gestation were each associated with a lower prevalence of elevated cord serum IgE. For an average increase of 100 ng/m(3) of PAHs, the PR was 0.69 (95% confidence interval (CI): 0.50, 0.95); for 25 μg/m(3) increase in PM(2.5) , the PR was 0.77 (95% CI: 0.55, 1.07). Conversely, exposures later in gestation were associated with a higher prevalence of elevated cord IgE: in the fifth month, the PR for PAH exposure was 1.64 (95% CI: 1.29, 2.08), while for PM(2.5) in the sixth month, it was 1.66 (95% CI: 1.30, 2.13). In analyses stratified by maternal atopy, air pollutants were associated with altered cord serum IgE only among neonates with non-atopic mothers. Similarly, an association of cigarette smoke with elevated cord serum IgE was found only in non-atopic mothers. PAHs and PM(2.5) , constituents of both ambient air pollution and cigarette smoke, appear to influence fetal immune development, particularly among infants whose mothers are not atopic.

Transfer of maternal IgE can be a common cause of increased IgE levels in cord blood

BACKGROUND

IgE in cord blood is thought to be a product of the fetus. A high level of total IgE is therefore used as a measure of atopic propensity in the newborn. We recently found strong evidence that allergen-specific IgE in cord blood was the result of transfer of maternal IgE to fetal blood or cord blood (maternofetal transfer) rather than fetal production. This also suggests that total IgE in cord blood might primarily be a maternal product.

OBJECTIVE

We sought to determine to what extent increased levels of total IgE in cord blood is the result of maternofetal transfer of IgE.

METHODS

Total IgE in cord blood was analyzed in a prospective birth cohort study. Maternofetal transfer of IgE was detected by means of high-sensitivity analyses of cord blood IgA and allergen-specific IgE and comparison with parental IgE levels and levels at 6 months of age.

RESULTS

Forty-six percent of cord blood samples with increased IgE levels (>or=0.5 IU/mL) showed indication of maternofetal transfer of IgE. Maternal origin of IgE in these samples was validated by showing reduced levels of IgE at 6 months of age compared with samples with no indication of maternofetal transfer (geometric mean, 9.4 vs 5.4 IU/mL; P = .01). Maternofetal transfer was not appropriately accounted for by the conventional method of cord blood IgA measurement.

CONCLUSIONS

Maternofetal transfer might be a common cause of increased cord blood IgE levels. Future studies should take potential maternofetal transfer into account or use other markers of atopy.

Common variants in FCER1A influence total serum IgE levels from cord blood up to six years of life

BACKGROUND

In a recent genome wide scan, a functional promoter variant (rs2251746) in the gene encoding the alpha chain of the high affinity receptor for immunoglobulin E (IgE) (FCER1A) was identified as major determinant of serum IgE levels.

OBJECTIVE

The aim of this study was to investigate the role of rs2251746 on total IgE levels measured at different stages of life from birth (cord blood) up to the age of 6 and to evaluate its interaction with the environmental influences in two German birth cohorts.

METHOD

Data from two German birth cohorts were analysed (n = 1043 for the LISA cohort and n = 1842 for the GINI cohort). In the studies, total serum IgE was measured from cord blood, and blood samples taken at the age of 2/3 and 6 years. In a subgroup of the LISA study, house dust samples were collected at age of 3 months and the amount of endotoxin was determined. Random effect models were used to analyse the longitudinal health outcomes.

RESULTS

In the two cohorts, the heterozygote and the rare homozygote of rs2251746 was consistently associated with lower total IgE levels from birth up to the age of 6 years with an allele-dose effect (P < 0.02 for blood samples taken at each time point in both cohorts). No interaction between the two FCER1A encoding gene and environmental exposures including endotoxin, worm infestation and day care centre attendance during early childhood were observed.

CONCLUSION

Common variants in FCER1A strongly influence basal IgE production independently from environmental stimuli. These effects can be observed already in cord blood pointing to altered gene expression in foetus.

Sex Disparity in Food Allergy: Evidence from the PubMed Database

Food allergies are potentially fatal immune-mediated disorders that are growing globally. The relationship between sex and food allergy remains incompletely understood. Here we tested the hypothesis that, should sex influence the clinical response to food allergens, this would be reflected by a sex disparity in published studies of food allergy. We performed a systematic search of the PubMed literature for IgE-mediated allergy to 11 allergenic foods of international regulatory importance. No date restriction was used and only articles in English were considered. Of the 4744 articles retrieved, 591 met the inclusion criteria representing 17528 subjects with food allergies. Whereas among children with food allergies, 64.35% were males and 35.65% were females (male/female ratio, 1.80), among adults 34.82% were males and 65.18% were females (male/female ratio, 0.53). Consequently, these data argue that there is need for further investigation to define the role of sex in the pathogenesis of food allergy.

Effects of early cigarette smoke exposure on early immune development and respiratory disease

Exposure to tobacco constituents during early development remains a common but avoidable toxic exposure, which has been clearly linked with decreased lung growth and subsequent wheezing illness. There is also now emerging evidence that tobacco smoke can influence early immune function. This includes alterations in cytokine production by the fetoplacental unit, as detected ex vivo in cord blood, as well as in patterns of fetal mononuclear cell responses in vitro. Recent studies also suggest that the newborns of smoking mothers have altered signalling through Toll-like receptors (TLRs) that are essential for innate microbial responses. This may be implicated in the increased predisposition to infection in exposed infants. TLR-mediated innate response pathways are also believed to be important in promoting regulatory pathways that inhibit allergic immune responses. However, although a number of studies have documented associations between early cigarette smoke exposure and subsequent allergic disease, this remains controversial. This review explores the consequences of smoking on these important aspects of early development, including potential mechanisms, interactions with predisposing asthma genes and a potential role in epigenetic regulation. Although parental smoking may not be the primary factor in the changing prevalence of asthma and respiratory disease, we propose that it is an important contributor, with significant potential to interact with other genetic factors and environmental risk factors to influence disease propensity.

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.

Maternal smoking in pregnancy: do the effects on innate (toll-like receptor) function have implications for subsequent allergic disease?

Subtle increases in immaturity of immune function in early infancy have been implicated in the rising susceptibility to allergic disease, particularly relative impairment of type 1 interferon (IFN)-γ responses in the neonatal period. Although genetic predisposition is a clear risk factor, the escalating rates of allergic disease in infancy suggest that environmental factors are also implicated. We previously showed that maternal smoking in pregnancy may impair neonatal IFN-γ responses. Our more recent studies now indicate that this common avoidable toxic exposure is also associated with attenuation of innate immune function, with attenuated Toll-like receptor (TLR)-mediated microbial responses (including TLR-2, -3, -4, and -9 responses). Most notably, the effects were more marked if the mothers were also allergic. In this review, we discuss the significance of these observations in the context of the emerging hypothesis that variations in TLR function in early life may be implicated in allergic propensity. There is now growing evidence that many of the key pathways involved in subsequent T-cell programming and regulation (namely, antigen-presenting cells and regulatory T cells) rely heavily on microbe-driven TLR activation for maturation and function. Factors that influence the function and activity of these innate pathways in early life may contribute to the increasing predisposition for allergic disease. Although "cleaner" environments have been implicated, here we explore the possibility that other common environmental exposures (such as maternal smoking) could also play a role.

Sex-specific linkage to total serum immunoglobulin E in families of children with asthma in Costa Rica

Serum total immunoglobulin E (IgE) is a critical intermediate phenotype of allergic diseases. Although total IgE exhibits sexual dimorphism in humans (with males demonstrating higher IgE than females), the molecular basis of this difference is unknown. A genome-wide scan of 380 short-tandem repeat (STR) markers was performed in eight extended pedigrees of asthmatic children (n=655) from the Central Valley of Costa Rica. Genome-wide linkage analysis of total IgE was performed by variance component models. Among all subjects, only one genomic region (chromosome 7p15) showed modest evidence of linkage to total IgE (LOD=1.60). In contrast, a sex-stratified analysis revealed distinct genetic architectures of total IgE in males and females and identified significant linkage to total IgE on a novel male-specific locus on chromosome 20p12 (LOD=3.63 at 36 cM). Genotyping of additional STRs on chromosome 20 resulted in improved evidence for linkage (LOD=3.75 at 33 cM) and a 1.5 LOD-unit support interval for the linkage peak between 26 and 38 cM. Three polymorphisms in two genes on chromosome 20p12 (JAG1 and ANKRD5) were then found to be associated with total IgE in 420 nuclear families of Costa Rican children with asthma. Two of these polymorphisms (in JAG1) were significantly associated with total IgE in families of boys (n=264) but not in families of girls (n=156) with asthma. JAG1 is a hematopoetic cell growth factor that may regulate normal B-cell development. This is the first demonstration of a possible genetic basis for differences in total IgE between sexes.

Association between first-degree familial predisposition of asthma and atopy (total IgE) in newborns

BACKGROUND

It is generally thought that infants with a first-degree familial predisposition of asthma are at higher risk of developing asthma than infants without predisposition.

OBJECTIVE

To investigate whether there is an association between being at high risk for developing asthma and increased level of total IgE in newborns and whether total IgE is influenced by gender, family size, birth season, maternal smoking, birth weight, gestational age, and maternal diet.

METHODS

Two hundred and twenty-one high risk and 308 low-risk infants were prenatally selected in a 5-year-period. Three to 5 days after birth, the total IgE was measured in capillary heel blood.

RESULTS

Data on total IgE and first-degree familial predisposition were available for 170 high-risk and 300 low-risk infants. There was a statistically significant relationship between being at high-risk (maternal asthma) and increased levels of total IgE in newborns (total IgE cut-off levels: 0.6-0.9 IU/mL (odds ratio (OR)=2.1, 95% confidence interval (CI): 1.2-3.7 to 3.0, 95% CI: 1.5-5.9)), between being born in autumn and increased levels of total IgE in newborns [total IgE cut-off levels: 0.5-0.6 IU/mL (OR=2.5, 95% CI: 1.2-5.1 to 2.5, 95% CI: 1.2-5.4)] and between maternal vitamin supplements intake and decreased levels of total IgE in newborns (total IgE cut-off level: 0.9 IU/mL (OR=0.5, 95% CI:0.3-1.0)). There was no interaction between the effects of maternal asthma and birth season on total IgE, as well as between the effects of maternal asthma and maternal vitamin supplements intake. Gender, family size, maternal smoking, birth weight, and gestational age did not influence the associations. CONCLUSION; Being at high-risk of asthma (maternal asthma) and birth season are positively associated with the presence of increased levels of total IgE at birth, whereas maternal vitamin supplements intake is negatively associated with the presence of total IgE at birth.

Phenotype definition, age, and gender in the genetics of asthma and atopy

When studying genetics of complex diseases it is important to have a clearly described and objective phenotype. When drawing conclusions in association studies, age and gender of the population should be considered. Until we know what causes phenotypic differences between males and females and between children and adults, we should try to study longitudinal cohorts with phenotype assessment at different time points and stratify our analyses for gender. To acquire sufficient power for these types of analyses, international collaboration may be the only way to elucidate the intricate, gene-environmental interactions in atopy and asthma in an age- and gender-dependent manor.

Applying epidemiologic concepts of primary, secondary, and tertiary prevention to the elimination of racial disparities in asthma

Despite medical and scientific advances, racial and ethnic disparities persist in US asthma morbidity and mortality rates. Progress in the elimination of these disparities will involve disentangling the contribution of social constructs, such as race, socioeconomic status, and culture, from that of the physical environment and genetic susceptibility. One approach to reducing asthma disparities is through the traditional disease prevention stages of intervention. As such, primary prevention targets reductions in asthma incidence; secondary prevention is the mitigation of established disease and involves disease detection, management, and control; and tertiary prevention is the reduction of complications caused by severe disease. Once causative factors at each level of disease prevention are understood, this knowledge can be translated into clinical practice and public health policy.

A CD14 gene polymorphism is associated with the IgE level for Dermatophagoides pteronyssinus

CONCLUSION

CD14/-159 plays a role in sensitization to Dermatophagoides pteronyssinus in Japanese patients with allergic rhinitis.

OBJECTIVE

An association between a polymorphism in the 5'-flanking region of the CD14 gene and atopic phenotypes has been identified in a pediatric American population and an adult Dutch population. The aim of this study was to determine whether the CD14/-159 polymorphism is associated with specific IgE levels in allergic rhinitis patients in a Japanese population.

MATERIAL AND METHODS

The CD14/-159 genotypes of 81 unrelated patients with allergic rhinitis and 78 healthy subjects were determined and compared. The total IgE level and the specific IgE levels for three aeroallergens were determined. The IgE levels for each genotype were compared.

RESULTS

The frequencies of CD14/-159 genotypes did not differ between the two groups. Among the allergic rhinitis patients, TT homozygotes had significantly fewer positive CAP-radioallergosorbent tests (CAP-RASTs) than CC homozygotes and CT heterozygotes, suggesting that the C allele is dominant. TT homozygotes also had significantly lower CAP-RAST scores for Dermatophagoides pteronyssinus, but not for Cryptomeria japonica or Dactylis glomerata, than CC homozygotes and CT heterozygotes. There was no significant association between total serum IgE levels and CD14/-159 genotypes in the allergic rhinitis patients.

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.

Dynamic changes in sensitization to specific aeroallergens in children raised in a desert environment

BACKGROUND

Allergen skin test reactivity and total serum IgE are objective measures used to characterize and help diagnose allergic diseases. Cross-sectional studies have shown that overall aeroallergen skin test reactivity increases throughout childhood. However, little attention has been paid to whether individual aeroallergen remittance occurs, which could distort or mask relationships to disease.

OBJECTIVE

To access the incidence and remittance of skin test reactions to individual allergens in children aged 6-11 years.

METHODS

Longitudinal sensitization to six aeroallergens and total IgE were assessed in 828 children raised in the semi-arid US southwest at ages 6 and 11 years.

RESULTS

New sensitization (to any allergen) between 6 and 11 years occurred in 30.2% of children compared with 39.7% before age 6 years. The rate of complete remittance from positive to negative between ages 6 and 11 years was 8.2%, and total IgE at age 6 years was not predictive. Remittance rates for individual allergens were high and variable (19-49%). The perennial allergens Bermuda and Alternaria were early sensitizers and had low remittance rates. Early sensitization to the four seasonal allergens was less common and more subject to remittance with the bulk of sensitization occurring between 6 and 11 years.

CONCLUSION

This study shows that sensitization to individual aeroallergens in childhood is dynamic and indicates the limitation of single point assessment of skin test reactivity.

Maternal smoking in pregnancy alters neonatal cytokine responses

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Tucson Children's Respiratory Study: 1980 to present

The Tucson Children's Respiratory Study (TCRS), begun in 1980, has followed 1246 subjects from birth together with their family members to delineate the complex interrelationships between a large number of potential risk factors, acute lower respiratory tract illnesses, and chronic lung disorders later in childhood and early adult life, especially asthma. Nine hundred seventy-four (78%) of the original subjects are still being followed. Among its numerous findings, the TCRS has (1) described various wheezing disorders (transient, nonatopic, atopic) and their characteristics; (2) developed an Asthma Predictive Index; (3) delineated the respiratory and atopic outcomes for children who had respiratory syncytial virus-related wheezing illnesses in infancy; and (4) evaluated a large number of risk factors for acute respiratory tract illnesses during the first 3 years of life. Future TCRS studies will focus on (1) factors in infancy and early childhood that relate to persistent asthma and atopy; (2) role of genetic factors in persistent asthma; and (3) determinants of lung function decline in early adult life.

Anti-filarial and total IgG4 and IgE antibody levels are correlated in mothers and their offspring

In mothers who suffer from helminth infections or allergic diseases, prenatal sensitization with antigens/allergens is suspected to bias the immune system of the offspring towards a Th2-type response. To investigate this at the antibody level, we collected 113 blood samples on filter paper from a paediatric population aged 3 months to 10 years and their mothers, who resided in an area endemic for brugian filariasis in Indonesia. The results showed that antibody levels in children were strongly correlated with maternal antibody levels. However, for anti-filarial IgG4 and IgE this relationship was manifested directly after birth, whereas for total antibody levels a positive correlation could be detected only with children aged > or = 2 years. To investigate the influence of paternal antibody on progeny, specific IgG4 was determined in a different set of samples from 229 children and both of their parents. Interestingly, the influence of paternal IgG4 became apparent only after the age of 4 years. In contrast, maternal antibody levels were already correlated to levels produced by their offspring at a young age (3 months onwards). Taken together, it appears that children can become sensitized to parasite antigens in utero, allowing them to produce Th2-dependent specific IgG4 and IgE antibodies at a young age, whereas with increasing age, the influence of environmental factors, shared in households, such as filarial transmission and other helminth infections, becomes dominant.

Dog exposure in infancy decreases the subsequent risk of frequent wheeze but not of atopy

BACKGROUND

Influence of household pets in the development of childhood asthma or atopy has been controversial.

OBJECTIVE

The purpose of this study was to investigate whether pet exposure in early life decreases the subsequent risk of frequent wheezing and/or allergic sensitization.

METHODS

This was a prospective observational birth cohort study. The setting was a large health maintenance organization in Tucson, Ariz; the subjects were a population sample of 1246 newborns enrolled at birth and followed prospectively to age 13 years. The main outcome measures were as follows: time to first report of frequent wheezing (>3 episodes in the past year), skin prick test reactivity at 6 years and 11 years of age, and total serum IgE at 9 months, 6 years, and 11 years of age.

RESULTS

Children living in households with > or =1 indoor dogs at birth were less likely to develop frequent wheeze than those not having indoor dogs (P =.004). This inverse association was confined to children without parental asthma (hazard ratio = 0.47; P <.001 [Cox regression]) and was not evident for children with parental asthma (hazard ratio = 0.96; P =.87). Adjustment by potential confounders did not change the results. Indoor cat exposure was not significantly associated with the risk of frequent wheezing. Neither cat exposure in early life nor dog exposure in early life was associated with skin prick test reactivity or total serum IgE at any age.

CONCLUSION

Dog exposure in early life might prevent the development of asthma-like symptoms, at least in low-risk children with no family history of asthma. Nevertheless, early pet exposure does not seem to significantly influence the development of allergic sensitization.

IgE in unselected like-sexed monozygotic and dizygotic twins at birth and at 6 to 9 years of age: high but dissimilar genetic influence on IgE levels

BACKGROUND

IgE is a major determinant of allergic disease. Twin analysis of serum levels of IgE has been carried out previously in children and adults with heritability estimates of 30% to 70% on the basis of ANOVA.

OBJECTIVE

This study included the analysis of serum IgE in a population of 126 twins, 27 monozygotic pairs and 36 dizygotic pairs, studied at birth (cord blood [CB] IgE) and consecutively at the age of 6 to 9 years of age (serum IgE).

METHODS

IgE was determined by means of RIA. ANOVA, correlation analysis, and structural equation modeling by maximal likelihood analysis was used for genetic analysis.

RESULTS

Structural equation modeling by maximal likelihood analysis showed the best-fitting model to be the AE model (A for additive genetic variance and E for environmental variance) both at birth and later in childhood. The estimated heritability was 0.92 (95% CI, 0.84-0.95) for CB IgE and 0.78 (95% CI, 0.60-0.87) for serum IgE. The correlation between CB IgE and serum IgE was 0.04.

CONCLUSIONS

The study demonstrated a higher genetic dependency of serum IgE than previously recognized. The low correlation between the IgE levels at birth and later in childhood suggested that different effector mechanisms may be operating at different ages.

[Epidemiology of respiratory allergy in children]

Epidemiology of paediatric respiratory allergic disorders allows the approach to causal and preventive risk factors by studying groups or sub groups of children in different locations and under different conditions. This is, however, complicated by the lack of consensus on disease definitions, which renders comparisons between studies difficult. Atopy is usually defined by the presence of positive skin tests (wheal size of at least a mean diameter > or = 3 mm), by the presence of specific IgE, or by the presence of increased total IgE (> or = 100 UI/mL). Infantile asthma is not well defined, complicated by the high prevalence of bronchiolitis; one thus questions between wheezing or wheezy bronchitis. Prevalence is high: among early wheezers, two populations will be defined by the medium term evolution: transient wheezers and persistent wheezers. Risk factors for these two conditions are different. Childhood asthma may be defined by the diagnosis of asthma (specific but fairly non-sensitive), by asthmatic symptoms (wheezing, waking by an attack of shortness of breath) (sensitive but not very specific), or by the combination of symptoms and airway hyperresponsiveness. The ISAAC study has standardised a questionnaire to assess the prevalence of asthma. The preliminary results show that there are wide variations across the world. The prevalence is low in Africa and Asia, intermediate in Europe, and high in Anglo-Saxon countries. The prevalence of asthma has gradually increased over the past 20 years in developed countries. Asthma and atopy are closely associated in children. Risk factors are genetic, associated with sex and environmental factors. Among these, allergic sensitisation is associated with the degree of exposure to allergens. Westernization of way of life is associated with increased prevalence of atopy, allergic rhinitis and asthma. Atopy seems inversely correlated to certain infections. Passive smoking is clearly associated with early wheezing. This and atmospheric pollution aggravate childhood asthma. However, the inducing role of pollution on asthma is still controversial.

A cluster of seven tightly linked polymorphisms in the IL-13 gene is associated with total serum IgE levels in three populations of white children

BACKGROUND

Increased levels of total serum IgE are a strong risk factor for the development of asthma. IgE is also involved in host defenses against parasites and fungi. Linkage of total serum IgE with markers located close to the 3 Mb cluster of cytokine genes in chromosome 5q31 has been reported. IL-4 or IL-13 are regarded as essential for IgE synthesis.

OBJECTIVE

We tested whether polymorphisms in the IL-13 gene might explain the linkage between chromosome 5q31 and total serum IgE levels.

METHODS

We used denaturing HPLC to detect polymorphisms in overlapping PCR fragments of the IL-13 gene including promoter and 3' untranslated regions. After sequencing was performed to identify the locations of the polymorphisms, PCR and primer-induced restriction site assays were used to genotype subjects in 3 unselected populations.

RESULTS

We report here 7 polymorphisms (6 novel) in IL-13. Four of these polymorphisms are tightly linked to a variant in the terminal portion of the coding region of the gene that results in a predicted amino acid change in residue 130 (Arg130Gln). The Gln form is strongly associated (P =.000002) with increased serum IgE levels in 3 different populations comprising a total of 1399 children. Two additional polymorphisms in the promoter region of IL-13 are more loosely linked to Arg130Gln and are also less significantly associated with total serum IgE levels.

CONCLUSION

These data suggest that the Arg130Gln polymorphism in IL-13, or others in close linkage with it, is associated with the development of the elevated serum IgE phenotype.

Cord blood IgE: its determinants and prediction of development of asthma and other allergic disorders at 12 months

BACKGROUND

The value of cord blood IgE in predicting the development of asthma and other IgE-mediated allergic diseases is unclear.

OBJECTIVE

The purpose of this study is twofold: (1) to determine factors affecting cord blood IgE level and (2) to determine whether cord blood IgE predicts the development of asthma and other IgE-mediated allergic diseases in high risk (defined as those with at least one first degree relative with asthma or 2 first degree relatives with other IgE-mediated allergic diseases) infants at 12 months.

METHODS

The study utilized cord blood obtained from a group of high risk infants who took part in a randomized controlled trial to assess the effectiveness of an intervention program in the primary prevention of asthma and other IgE-mediated allergic diseases. Total IgE and cotinine in the cord blood were measured. Assessment of the infants was done at 12 months for these diseases.

RESULTS

Sixty-four (17.8%) infants had detectable total IgE in cord blood >0.5 kU/L. The proportion of infants with elevated cord blood IgE was significantly higher among nonwhites, birth during winter months, and those with a maternal history of asthma. There was no correlation between cord blood IgE and cord blood cotinine level. Cord blood IgE was found to be a significant predictor for the development of urticaria due to food allergy but not for other outcomes.

CONCLUSION

Both genetic and environmental risk factors play a role in determining the level of IgE in cord blood. Cord blood IgE was a significant risk factor for the development of urticaria due to food allergy at 12 months of life. As urticaria due to food allergy is a prodrome for anaphylaxis, measurement of IgE in cord blood may be indicated in infants at high risk for developing allergic diseases so that preventive measures can be applied.

Breast-feeding, maternal IgE, and total serum IgE in childhood

BACKGROUND

There is controversy regarding the relationship of the effect of breast-feeding on markers of allergy such as total serum IgE in childhood.

OBJECTIVE

This study, using longitudinal data, tested the hypothesis that the relation of breast-feeding to IgE in childhood differs depending on maternal total IgE level.

METHODS

Total serum IgE was assessed with the paper radioimmunosorbent test at 4 ages in nonselected children enrolled at birth into the prospective Tucson Children's Respiratory Study. Children were classified as never breast-fed, breast-fed less than 4 months, or breast-fed 4 months or longer, on the basis of physician report or questionnaires completed by parents by the time the child was 18 months old. A longitudinal random effects model was used to test for group differences and temporal trends in IgE for children classified with reference to maternal IgE (high tertile vs all others) and breast-feeding history. A total of 664 children with 1457 observations were included.

RESULTS

Among children whose mothers were in the 2 lower tertiles of IgE, breast-feeding was associated with lower total serum IgE at age 6 years (24.2 vs 44.3 IU/mL for never breast-fed children; P <.02); similar trends existed at age 11 years. In contrast, for children whose mothers were in the highest tertile of IgE, breast-feeding of 4 months or longer was associated with higher IgE levels in the child compared with those never breast-fed or breast-fed less than 4 months (97.0 vs 38.9 IU/mL; P <. 005). These cross-sectional analyses were confirmed with the longitudinal random effects model, which also showed no effect of confounders. Paternal IgE showed no similar relation with child IgE.

CONCLUSION

Breast-feeding appears to have paradoxic relations with IgE in childhood, depending on maternal IgE level. These findings may help explain the contradictory results found in other investigations of the relation of breast-feeding to allergic symptoms and markers.

On early sensitization to allergens and development of respiratory symptoms

BACKGROUND

Various studies have suggested that a sequence of events occurring in childhood may affect the development of asthma in susceptible individuals. We have investigated whether early childhood sensitization to aeroallergens is an important risk factor in the later development of asthma symptoms.

OBJECTIVE AND METHODS

In this study we examine this issue in children enrolled in the Tucson epidemiology study of obstructive airways disease, who had at least two allergen skin tests, one before and one after 8 years of age. Respiratory symptom data were available from 12 survey questionnaires, spanning a period of 20 years. During the first, sixth, seventh and eleventh surveys, skin tests were performed with commercially available allergens.

CONCLUSION

As compared with children who were sensitized after 8 years of age, children over 8 years who were sensitized to any allergen before age 8 years were significantly more likely to report shortness of breath with wheeze (SOBWZ), wheeze apart from colds or wheeze most days (OR = 4.1 SOBWZ; OR = 3.88 WZ apart from colds; and OR = 2.83 WZ most days). Children who were sensitized after 8 years were no more likely to have the symptoms described above than children who were never found to be sensitized. Based on these results we conclude that early allergic sensitization is a significant risk factor for later development of wheezy symptoms, where as late sensitization is not.

A Polymorphism* in the 5' flanking region of the CD14 gene is associated with circulating soluble CD14 levels and with total serum immunoglobulin E

Total serum immunoglobulin (Ig)E levels are genetically regulated, but the mechanism of inheritance is not well understood. Cytokines produced by T-helper (Th)1 and Th2 lymphocytes control IgE synthesis. Bacterial antigens may favor the development of Th1 cells from naive CD4-positive T cells through a CD14-dependent pathway. CD14 is constitutively expressed on the surface of monocytes and macrophages, and is also present in serum in a soluble form (sCD14). The CD14 gene maps to chromosome 5q31.1, a candidate region for loci regulating total serum IgE. We hypothesized that genetic variants in the CD14 gene could influence Th-cell differentiation and thus total serum IgE. We identified a C-to-T transition at base pair -159 from the major transcription start site (CD14/-159). Among 481 children recruited from a general population sample, frequency of allele C was 51.4%. TT homozygotes had significantly higher sCD14 levels than did carriers of both the CC and CT genotypes (P = 0.01). TT homozygotes also had significantly lower levels of IgE than did carriers of the other two genotypes, but differences were significant only among children who were skin test-positive to local aeroallergens (P = 0.004). There was no association between CD14/-159 and either interleukin (IL)-4 or interferon (IFN)-gamma responses by peripheral blood mononuclear cells. However, IFN-gamma and IL-4 responses were positively and negatively correlated, respectively, with serum sCD14 levels. We conclude that CD14/-159 plays a significant role in regulating serum sCD14 levels and total serum IgE levels.

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

BACKGROUND

A recent study reported an association between a large head circumference at birth and adult total IgE. However, no study has yet looked at the relation between head circumference and cord blood IgE.

OBJECTIVES

To assess the relationship between child's cord blood total IgE and head circumference at birth taking parental allergy and smoking habits as well as placental calcifications into account.

METHODS

Two samples of unselected newborns and their mothers with uncomplicated pregnancies were studied: 235 in study A with data on parental allergy and 99 in study B with data on placental calcifications.

RESULTS

In both studies, cord blood IgE was significantly related to large head circumference at birth (0.07 vs 0.15 IU/mL for newborns < 37 cm vs >/= 37 cm, respectively, P = 0. 03 for study A and 0.09 vs 0.28 IU/mL, P = 0.04 for study B). Cord blood IgE was unrelated to parental smoking habits. Maternal IgE significantly increased in mothers exposed to both active and passive smoking during pregnancy compared with other pregnant women. High cord blood IgE were associated with high maternal IgE (r = 0. 38; P < 0.001). Multiple linear regression showed that large head circumference, maternal IgE and clinical manifestations of maternal, but not paternal, allergy were independently related to cord blood IgE (study A). Large head circumference and placental calcifications were independently related to a higher cord blood IgE level (study B).

CONCLUSIONS

Besides the role of genetic factors, results on the preferential role of maternal vs paternal allergy and associations to large head circumference and placental calcifications support the hypothesis of the role of environmental factors during pregnancy on the level of cord blood IgE.

Linkage of circulating eosinophils to markers on chromosome 5q

Although peripheral blood eosinophilia is strongly associated with the risk of developing asthma, genetic determinants of eosinophilia have not been extensively studied. We used sib-pair analysis to assess linkage of circulating eosinophils (as a percent of total white blood cells [WBC]) to nine markers located in chromosome 5q31-33. The study was divided into two phases. Of 246 sib pairs available for the first phase, 35 were classified as low concordant (LC) (both sibs had <= 2% circulating eosinophils), 18 were defined as high concordant (HC) (both sibs had 5% or more circulating eosinophils), and 26 were defined as discordant (one sib had <= 2% and the other sib had 5% or more circulating eosinophils). Significant evidence for linkage among low concordant sib pairs was found for several markers in the region under study, with a peak for marker D5S500 (proportion of alleles shared identical by descent [ibd] = 0.68 +/- 0.05 [mean +/- SE], p = 0.0004). A cross-validating study was done in which an additional 19 sib pairs that were low concordant for circulating eosinophils were studied. Evidence for linkage was also observed in this subset. Results were independent of current wheezing, total serum IgE levels, and other potential confounders. A multipoint analysis done for all low-concordant sib pairs available showed that the maximal logarithm of the odds favoring genetic linkage (LOD) score (2.4, p = 0.0004) was observed in correspondence with marker D5S658. We conclude that a locus or loci may be present in chromosome 5q31-33 that controls for circulating eosinophils as a proportion of total WBC.

Peak flow variability, methacholine responsiveness and atopy as markers for detecting different wheezing phenotypes in childhood

BACKGROUND

There is increasing evidence that wheezing during childhood may be a heterogeneous condition, and that different forms of wheezing may be associated with different risk factors and prognosis. The aim of this study was to determine if measures of airway lability and of atopy could identify distinct wheezing phenotypes during childhood.

METHOD

In a cohort of children followed from birth peak flow variability (n = 600) was evaluated and methacholine challenge responsiveness (n = 397) was measured at age 11 in relation to wheezing before the age of three, and at age six and 11 years total serum IgE and skin test reactivity to allergens were determined.

RESULTS

Neither positive peak flow variability nor methacholine hyperresponsiveness measured at age 11 were associated with wheezing occurring only during the first three years of life. Both methacholine hyperresponsiveness and positive peak flow variability were associated with wheezing at both ages six and 11 (OR 5.1 (95% CI 2.4 to 10.6) and 2.3 (1.2 to 4.5), respectively). In addition, positive peak flow variability was associated with wheezing up to the age of six but not at age 11 in non-atopic children (OR 2.9 (95% CI 1.0 to 8.8)). Methacholine hyperresponsiveness measured at age 11 was more frequently observed in boys (OR 2.1 (95% CI 1.2 to 3.5)) and was strongly associated with serum IgE levels measured at ages six and 11 (p < 0.001) and with positive skin test reactivity (OR 4.5 (95% CI 2.0 to 10.1)). Peak flow variability was unrelated to sex or markers of atopy (IgE and skin test reactivity).

CONCLUSIONS

Methacholine responsiveness and peak flow variability assessed at age 11, together with markers of atopy (IgE and skin test reactivity to allergens) identify three different wheezing phenotypes in childhood: "transient early wheezing" limited to the first three years of life and unrelated to increased airway lability; "non-atopic wheezing" of the toddler and early school years associated with positive peak flow variability but not with methacholine hyperresponsiveness; and "IgE-associated wheeze/asthma" associated with persistent wheezing at any age and with methacholine hyperresponsiveness, peak flow variability, and markers of atopy.

Use of urinary cotinine and questionnaires in the evaluation of infant exposure to tobacco smoke in epidemiologic studies

Exposure to environmental tobacco smoke is an important variable in many pediatric epidemiologic studies. We measured urinary cotinine, a specific metabolite of nicotine, in a population-based cohort of children every other month from birth through two years of age. Extensive data regarding exposure to smokers (people in the home, in home and away from home day care, home visitors, visits to smokers) were collected monthly by way of home interviews. We evaluated, with multiple cotinine measurements as the gold standard, other measures of exposure that are more feasible to obtain in large-scale studies. Comparing one cotinine to the average of multiple measurements, we found that 33.7% were in error in excess of 100 ng/mg, but 84% of the infants could be correctly classified into categories of low versus high. Parental smoking patterns had the highest predictive accuracy (fathers 67.0% and mothers 64.1%). Combining selected smoker categories (either parent, other home residents outside day care workers) resulted in improved accuracy of 79.3%.

Development of immune functions related to allergic mechanisms in young children

The newborn immune system differs quantitatively and functionally from that of adults. Development of the immune system has important implications for childhood diseases. The immaturity of the immune system in the first years of life may contribute to failure of tolerance induction and in the development of allergic disease. T cell function is diminished, especially the capacity to produce cytokines; production of interferon (IFN)-gamma, and IL-4 is strongly reduced. IFN-gamma has been found to be even lower in cord blood of newborns with a family history of atopy. Differences in other cell types (natural killer cells, antigen-presenting cells, and B cells) could also play a role in the development of allergic disease. Current data suggest that irregularities in IgE synthesis, helper T cell subsets (Th1, Th2, CD45RA, and CD45RO), cytokines (IL-4, IFN-gamma), and possibly other cell types may play a role in the development of allergy in childhood. Moreover, the role of cell surface molecules, like co-stimulatory molecules (CD28, CD40L), activation markers (CD25), and adhesion molecules (LFA-1/ICAM-1, VLA-4/ VCAM-1) is also discussed. These variables are modulated by genetic (relevant loci are identified on chromosome 5q, 11q, and 14) and environmental forces (allergen exposure, viral infections, and smoke). The low sensitivity of current predictive factors for the development of allergic diseases, such as cord blood IgE levels, improves in combination with family history and by measurement of in vitro responses of lymphocytes and skin reactivity to allergens. New therapeutic approaches are being considered on the basis of our current understanding of the immunopathology of allergic disease, for instance cytokine therapy and vaccination with tolerizing doses of allergen or peptides.

The relation between physician-diagnosed sinusitis, asthma, and skin test reactivity to allergens in 8-year-old children

The purpose of this study was to assess the prevalence of sinusitis in a nonselected sample of children, and the relation of sinusitis to allergic rhinitis (AR), atopy, asthma, and cough in the same population sample. Of 1246 children enrolled at birth in the Tucson Children's Respiratory Study, 835 were studied at a mean age +/-SD of 8.6 +/- 0.7 years. Questionnaires asking about MD-Sinusitis, MD-AR, MD-Asthma, and cough were completed by parents. Skin tests for seven common aeroallergens in the Tucson area had been performed in 630 of the participating children at the mean age +/-SD of 6.3 +/- 0.9 years. Prevalence of MD-Sinusitis was 13.1%; 78% of subjects with MD-Sinusitis also had MD-AR. Detailed analysis of the relation between MD-Sinusitis and individual environmental allergens tested for showed that only a response to Bermuda grass pollen was significantly associated with MD-Sinusitis after controlling for MD-AR [adjusted odds ratio 2.3 (95% CI 1.2-4.3)]. Having MD-Sinusitis was also significantly associated with MD-Asthma and cough [odds ratios 3.0 (95% CI 1.8-5.2)] and 2.5 (95% CI 1.6-3.8), respectively]. However, logistic regression demonstrated that, after controlling for MD-AR and skin test reactivity, MD-Sinusitis was no longer significantly associated with MD-Asthma or cough. We conclude that MD-Sinusitis is a common condition in childhood. The main independent risk factors in our community for MD-Sinusitis were grass pollen and current MD-AR. MD-Sinusitis was not associated with MD-Asthma or with cough after controlling for skin test reactivity and for MD-AR.

Evaluation of IgA measurements as a method for detecting maternal blood contamination of cord blood samples

Several studies have evaluated the value of cord blood IgE concentrations for predicting the risk of allergic disease in children. In all of these studies it is necessary to exclude cord blood samples in which the IgE may be falsely elevated due to admixing of maternal and fetal blood during parturition. The most common method for detecting mixing of fetal and maternal blood is measurement of cord blood IgA concentrations. We have examined the theoretical basis of IgA measurements for detecting maternal blood contamination and reexamined our own data to evaluate IgA measurements. Our data suggest that the average IgA concentration of 28.2 micrograms/ml used in previous studies may not adequately exclude contaminated cord blood sample. Failure to reject contaminated cord blood samples would reduce the positive predictive value of cord blood IgE measurements.

Serum levels of the soluble low affinity receptor for IgE and soluble interleukin-2 receptor in childhood, and their relation to age, gender, atopy and allergic disease

Identifying immune factors associated with the development of atopy can enhance our understanding of the in vivo mechanisms involved and may have utility in paradigms designed to prevent disease. Two candidates suggested for such roles are the soluble low affinity receptor for IgE (sCD23) and the soluble interleukin-2 receptor (sCD25). To assess serum levels of these factors blood samples were collected at birth and at age 6 in a large nonselected population from Tucson, AZ. Log mean sCD23 and sCD25 levels decreased from birth to age 6, (for sCD23 0.60 ffi 0.26pg/l, n = 340 and 0.53 + 0.28pg/l, n = 333 and for sCD25 1.95 i 0.14pM, n = 304 and 1.86 ffi 0.20pM, n = 327, for the two ages respectively. Anglo children had lower sCD23 levels at birth compared to Hispanic children (p < 0.01); no effect of gender was observed. Skin test reactivity at age 6 was directly related to sCD25 levels at age 6 (p = 0.007) and even levels at birth showed a similar trend (p = 0.06). These relations were distinct from any relation to total serum IgE. No relation was observed with sCD23 levels for either skin test reactivity or serum IgE. The prevalences of asthma, rhinitis and eczema by age 6 were unrelated to sCD25 or sCD23 levels. The results indicate that soluble CD23 and CD25 have higher levels at birth than later in childhood and that the development of skin test reactivity may be associated with regulatory mechanisms involving sCD25, whereas sCD23 was not similarly implicated.

Association of interleukin-2 and interferon-gamma production by blood mononuclear cells in infancy with parental allergy skin tests and with subsequent development of atopy

The mechanisms regulating the onset of atopic sensitization in human beings are not yet fully clarified. We assessed the capacity of mitogen-stimulated umbilical and peripheral blood mononuclear cells to produce interferon-gamma (IFN-gamma) and interleukin-2 (IL-2) at birth and at 9 months of age in 159 infants. Mononuclear cell production of both IFN-gamma and IL-2 at 9 months, but not at birth, was found to be inversely related to parental immediate skin test reactivity to seven local aeroallergens. Skin test reactivity at the age of 6 years was also inversely related to IFN-gamma and IL-2 production at 9 months of age. However, no relationship was evident between total serum IgE levels at 6 years and production of these cytokines at 9 months. The proportions of circulating lymphocytes and CD4+ or CD8+ cells were also unrelated to skin test reactivity at the age of 6 years. These data suggest that mechanisms regulating skin test reactivity to inhaled allergens may involve deficient IFN-gamma production, deficient IL-2 production, or both during or preceding the time of initial sensitization and that additional mechanisms are involved in regulating total serum IgE level.

Association of non-wheezing lower respiratory tract illnesses in early life with persistently diminished serum IgE levels. Group Health Medical Associates

BACKGROUND

The role of lower respiratory tract illnesses (LRIs) in the development of allergies is not well understood. The relation of wheezing and non-wheezing LRIs to serum IgE levels and atopy was studied in 888 children.

METHODS

Total serum IgE levels were measured at birth, nine months and six years of age; and interferon gamma production by blood mononuclear cells was measured at birth and nine months. Atopy was determined by skin prick tests at age six. Wheezing and non-wheezing LRIs up to age three were diagnosed by a physician.

RESULTS

Cord serum IgE levels were similar between all LRI groups and the no LRI group. Children who had wheezing LRIs until the age of three had IgE levels at nine months and at six years within normal ranges for age. In contrast, children who had a non-wheezing LRI before the nine month IgE sample had lower IgE levels at nine months and six years (geometric mean 1.8 IU/ml and 9.9 IU/ml, respectively) compared with children who had no LRIs (3.9 IU/ml and 38.3 IU/ml, respectively). Children who had non-wheezing LRIs after the nine month IgE sample had normal nine month IgE levels (3.2 IU/ml) but decreased IgE levels at six years of age (15.7 IU/ml). Children with more than one non-wheezing LRI before the age of three were less likely to be atopic than those with no LRI (odds radio 0.2). Interferon gamma production was higher in the non-wheezing LRI group at nine months than in the no LRI or wheezing LRI groups.

CONCLUSIONS

Non-wheezing LRIs are associated with subsequent depression of IgE levels and reduced skin test reactivity.

Determinants of cord-blood IgE concentrations in 6401 German neonates

For screening atopy risk in 6401 (84%) of all infants born during the year 1990 in six obstetric departments of five German cities, cord-blood IgE values were determined with CAP-RAST-FEIA. After cases with elevated IgA values had been excluded, 25% of the values were above the detection limit of 0.35 kU/l, and 8.5% were above 0.9 kU/l. Boys had significantly higher values than girls (P < 0.001). The distribution of values was significantly different for different nationalities of mothers (P < 0.001). The percentage of elevated values (> 0.9 kU/l) increased significantly with the number of close family members with atopic history (P < 0.001). Regarding the atopic history of the father, siblings, and mother separately, only the mother's history had a significant association with the cord-blood IgE class (P < 0.001). The IgE values of 81 twin pairs correlated significantly with a coefficient of r = 0.4909 (P < 0.001). The smoking history of the parents during pregnancy showed an association with cord-blood IgE values (P < 0.02). No significant association could be shown between cord-blood IgE distribution and other variables, i.e., gestational age, birth size, birth modus, Apgar score, cord-blood pH value, neonatal problems, parity, age of the mother, medication during pregnancy, educational level of mother or father, time of year, or obstetric department. It is hypothesized that, in addition to some postpartum contamination or placental transfer of maternal IgE, cord-blood IgE values are also determined by the fetal immunologic reaction to intrauterine exposure to allergens and trigger factors, and by genetic influences.

Role of clinical laboratory in allergy testing

The clinical laboratory has a well defined role to play in the diagnosis and management of patients with allergy. Elevated serum levels of total IgE and/or allergen-specific IgE indicate that an IgE mediated event has occurred. Methods such as basophil degranulation and basophil or leukocyte histamine release can provide similar information. Sensitive and precise methods suitable for automation are available for quantitation of histamine in whole blood or plasma. Methyl histamine can be assayed in urine. Eosinophil cationic protein levels in serum can be used as an indicator of eosinophil activation in disorders such as asthma and atopic dermatitis. Similarly, serum mast cell tryptase levels can confirm or exclude an anaphylactic reaction both in life and as a cause of death. This review documents and compares commercially available methods for these assays and discusses their application to screening, diagnosis, and management of patients with allergy.