Perinatal environmental factors influencing the development of allergy

Long-term Breastfeeding in the Prevention of Allergic Rhinitis: Allergic Rhinitis Cohort Study for Kids (ARCO-Kids Study)

OBJECTIVES

There is a great deal of interest in the possibility that environmental factors may influence the risk of developing allergic rhinitis (AR) in early life. We investigated the simultaneous effects of mode of delivery and duration of breastfeeding on the development of AR in children.

METHODS

Data from 1,374 children participating in the Allergic Rhinitis Cohort Study for kids (ARCO-kids study) was analyzed. All subjects were divided into AR or non-allergic rhinitis (NAR) groups. Data on environmental factors, mode of delivery and duration of breastfeeding were collected using a questionnaire.

RESULTS

Compared with short-term breastfeeding (<6 months), long-term breastfeeding (≥12 months) was significantly associated with a lower prevalence of AR (adjusted odds ratio [aOR], 0.54; 95% confidence interval [CI], 0.34 to 0.88). Children in the AR group also had a higher cesarean delivery rate than those in the NAR group (39.1% vs. 32.8%, P=0.05). Regarding the combined effects of mode of delivery and duration of breastfeeding, long-term breastfeeding with a vaginal delivery strongly suppressed the development of AR, compared to short-term breastfeeding with a cesarean delivery (aOR, 0.47; 95% CI, 0.30 to 0.73).

CONCLUSION

Long-term breastfeeding (≥12 months) and a vaginal delivery are associated with a lower risk of developing childhood AR.

Role of vitamin A elimination or supplementation diets during postnatal development on the allergic sensitisation in mice

Vitamin A (VA) and its derivatives, the retinoids, are important factors for the development of the immune system. It has been shown in adult animals that proliferation of lymphocyte populations and antibody secretion are retinoid dependent, while little is known about the effects of retinoids during postnatal development. The aim of this study was to investigate the role of VA on allergic sensitisation during lactation and after weaning using an in vivo system for postnatal allergic sensitisation in mice. Different VA diets (basal/VA elimination/VA (as retinyl palmitate) supplemented) were fed to the dams throughout lactation and directly to the pups after weaning. Allergic sensitisation was induced with a single peritoneal ovalbumin (OVA) injection at day 28 after weaning. The phenotype of lymphocytes was analysed by flow cytometry and functional data were obtained by analysis of (IL-4/IFN-gamma) cytokine production and antibody production (OVA-specific IgG1 and IgE) in the offspring. VA/retinyl palmitate supplementation during lactation and after weaning decreased CD3+, CD4+, CD8+ and B220+ populations in splenic lymphocytes but also significantly enhanced IL-4 production and OVA-specific IgE after sensitisation. In contrast, mice fed VA-elimination diet displayed no significant alteration of lymphocyte numbers and a slightly increased IL-4 production. Our results showed that a single allergen injection during postnatal development induces allergic sensitisation whose degree is modified by the VA content of the maternal diet during lactation and the diet of the pups after weaning, indicating an important role of VA on the severity of the allergic sensitisation.

THE ECOLOGIES OF HUMAN IMMUNE FUNCTION

Immune function is notoriously complex, and current biomedical research elaborates this complexity by focusing on the cellular and molecular mechanisms that characterize immune defenses. However, the human immune system is a product of natural selection that develops and functions in whole organisms that are integral parts of their surrounding environments. A population-level, cross-cultural, adaptationist perspective is therefore a necessary complement to the micro levels of analysis currently favored by biomedical immunology. Prior field-based research on human immunity is reviewed to demonstrate the relevance of cultural ecological factors, with an emphasis on the ecologies of nutrition, infectious disease, reproduction, and psychosocial stress. Common themes and anthropological contributions are identified in an attempt to promote future research in human ecological immunology that integrates theory and method for a more contextualized understanding of this important physiological system.

Prenatal and early postnatal environments are significant predictors of total immunoglobulin E concentration in Filipino adolescents

BACKGROUND

Recent evidence suggests that atopic disease may in part be mediated by fetal growth, as well as exposure to infectious disease early in life. Few studies have been able to evaluate these associations simultaneously, or to investigate prospectively the long-term effects of early environments while adequately controlling for potentially confounding variables.

OBJECTIVE

To examine how prenatal growth and infectious disease in infancy are related to total IgE production in adolescence.

METHODS

Ninety-nine adolescents (aged 14-15 years) were selected from a larger cohort study according to the following criteria: full-term birth, currently healthy, and small-for-gestational age (N=53) or appropriate-for-gestational age (N=46). Plasma total IgE was measured with ELISA, and analysed in relation to anthropometric, nutritional, and environmental quality data collected prospectively beginning in the third trimester prior to birth.

RESULTS

Each episode of infectious morbidity recorded at bimonthly intervals in the first 6 months of life was associated with a 0.12 log IU/mL reduction in total IgE in adolescence (P=0.004). Prenatal undernutrition was associated with increased adolescent IgE, but only under conditions of an unsanitary household environment (P=0.002). Each additional kilogram gained per month in the first 6 months of life was associated with an increase in adolescent IgE of 0.74 log IU/mL (P=0.03). Each quartile increase in weekly household income at the time of blood sampling was associated with a 0.10 log IU/mL reduction in total IgE (P=0.02).

CONCLUSION

Infectious disease in infancy, as well as interactions between prenatal and postnatal environments, appear to have long-term effects on adolescent total IgE production. Future research should investigate the mechanisms behind these effects, and their implications for symptoms of atopic disease.

Maternal oral contraceptive use and atopic diseases in the offspring

BACKGROUND

This study examined the association of maternal oral contraceptive (OC) use - before and after birth - and atopic manifestations in the offspring.

METHODS

A total of 2754 East German children aged 5-14 years participated in a cross-sectional survey in 1998-99. The standardized parental questionnaire in 1998-99 included data on atopic diseases, socio-economic factors, parental atopy and maternal OC use. Specific immunoglobulin E against common inhalant allergens was measured by radioallergosorbent test (RAST).

RESULTS

Maternal OC use before birth was associated with a higher risk of atopic diseases in the offspring compared with children of mothers who had never taken OC [asthma: odds ratio (OR) 1.6; 95% confidence interval (CI): 0.9-3.0; allergic rhinitis: OR 1.5; CI: 0.96-2.2; atopic eczema: OR 2.6; CI: 1.6-4.3; atopic sensitization: OR 1.5; CI: 0.97-2.2]. However, the effect estimates for maternal OC use after birth compared with the never users showed quite similar effects for these atopic conditions. No relations were observed between the prevalences of atopic diseases and maternal age at beginning of OC use, the duration of OC use, the type of contraceptive or maternal age at birth.

CONCLUSION

This study raises doubts in a true biological association between OC use and atopic diseases.

Maternal deprivation of rat pups increases clinical symptoms of experimental autoimmune encephalomyelitis at adult age

Maternal deprivation of neonatal animals has been shown to induce long-lasting changes in the reactivity of the neuroendocrine system. The aim of the present study was to investigate whether maternal deprivation also affects susceptibility to immune-mediated diseases such as experimental autoimmune encephalomyelitis (EAE) in adult life. To this end, 9-day-old rat pups were subjected to a short-lasting maternal deprivation for a period of 24 h. At the age of 8 weeks, we induced EAE in these rats by immunization with myelin basic protein (MBP) in complete Freund's adjuvant. Our data demonstrate that short-lasting maternal deprivation induces a marked increase in the severity of EAE in the animals in later life. The histopathological evaluation of spinal cord and cerebellum corresponded with the observed differences in clinical symptoms of EAE. Moreover, neonatal maternal deprivation affects macrophage functioning at adult age. In contrast, no differences were observed in in vitro mitogen- and MBP-induced cytokine production by splenocytes. LPS-induced corticosterone release did not differ either between maternally deprived and control animals. We conclude that short-lasting neonatal maternal deprivation of rat pups has long-lasting consequences for macrophage activity and for susceptibility to the inflammatory autoimmune disease EAE.

Allergies in children

Allergic diseases in children have increased significantly in recent years and now affect up to 35% of children. They are a major cause of morbidity in children. Although there is a genetic predisposition, it is the exposure to environmental allergens, irritants and infections that will determine the sensitization to different dietary and inhalant allergens. As the genetic and environmental factors that act on an immature cellular immune system are better elucidated and their roles established, the implementation of more enduring preventive efforts will be developed. However, at present, the best approach to the child at high risk for the development of allergies is to institute dietary and environmental control measures early to decrease sensitization, and to recognize and appropriately treat the evolving signs and symptoms of allergic disease.

Identification of the human beta-casein C-terminal fragments that specifically bind to purified antibodies to bovine beta-lactoglobulin

The presence of foreign proteins in human milk after the ingestion of bovine dairy products is thought to be one of the possible causes of allergic sensitization in exclusively breast-fed predisposed infants. The immunologic determination of bovine beta-lactoglobulin (LG) concentration in human milk has been reported by several researchers, but the results are conflicting. Moreover, a strong cross-reactivity between antibodies to bovine beta-LG and human milk proteins and peptides was reported, throwing doubt on the reliability of radioimmunoassay and enzyme-linked immunosorbent assay detection and quantification assays for bovine beta-LG in human milk. Thus, the goal of this study was to isolate human milk peptides with a molecular mass >or= 1,000 Da cross-reactive with antibodies to bovine beta-LG in order to identify possible common epitopes between human and bovine milk proteins. The proteins were first isolated by affinity chromatography with purified polyclonal antibodies to bovine beta-LG, followed by gel filtration fast phase liquid chromatography and reverse phase-high performance liquid chromatography purification of the components specifically bound in the affinity separation step. Affinity-bound peptides were identified by determining their amino acid sequence. All the sequenced peptides belonged to the C-terminal part of human beta-casein, which confirms the cross-reactivity of human milk proteins and peptides with antibodies to bovine beta-LG and allows the identification of possible common epitopes between the two proteins. No bovine beta-LG peptides with a molecular mass >or= 1,000 Da were found in our milk samples from healthy mothers on a diet rich in bovine milk and dairy products.

Human milk proteins may interfere in ELISA measurements of bovine beta-lactoglobulin in human milk

It is widely believed that cow's milk proteins ingested by the mother, in particular beta-lactoglobulin (beta-LG), can pass into breast milk and thus sensitize predisposed infants. However, studies to evaluate bovine beta-LG in human milk have given conflicting results. The aim of this study was to analyse the correlation between the amount of cow's milk in the mother's diet and the presence of bovine beta-LG in breast milk. Human milk samples from 14 healthy non-atopic women on diets with different cow's milk contents were examined. The total concentration of bovine beta-LG or beta-LG immuno-like proteins (beta-LGIP) was determined by enzyme-linked immunosorbent assay (ELISA). Two separation procedures utilizing ELISA plates and an affinity chromatography column were set up to identify the human whey components recognized by the anti-beta-LG antibodies. beta-LGIP reactivities of milk from three groups on different diets were not significantly different. After splitting the antigen-antibody complexes, three main protein components, human lactoferrin, human beta-casein and human alpha-lactalbumin, were identified. This study would suggest that, at least in healthy subjects, false-positive results in ELISA determinations of bovine beta-LG in human milk might be due to cross-reactions between polyclonal antibodies and different protein antigens.

Human immune toxicity

This review examines xenobiotic toxicity to the immune system, stressing in particular those aspects of most relevance to humans. Immunotoxicity is examined especially from three points of view: by what immunological component is affected, by classes of foreign agents that adversely affect the human immune system and by critical evaluation of human case reports and epidemics. Mechanisms by which xenobiotics interrupt cytokine networks are emphasized. The concept that microbial agents, both environmental as well as infectious, may act as immunotoxicants, either alone or in synergism with conventional agents is introduced. Instances of human immunotoxicology are critically evaluated in terms of clinical relevance, i.e. whether increased susceptibility to opportunistic infections or tumor emergence takes place in the affected individuals.