Perinatal Risk Factors for Hay Fever — A Study Among 2550 Finnish Twin Families

Previous studies have suggested that perinatal factors influence the risk for asthma but population studies on perinatal factors and risk for hay fever are few. We studied the effect of perinatal factors on the risk for hay fever among adolescent twins by a questionnaire study involving five consecutive nation-wide birth cohorts of 16-year-old twins and their parents. The risk for parent-reported, doctor-diagnosed hay fever in the adolescents associated with several perinatal characteristics was assessed with logistic regression analysis among individuals and by a discordant pair analysis. In the univariate analysis of the birth factors, the risk for hay fever increased with increasing birth weight (p for trend = 0.048, OR for those ≥ 3000g 1.35, 95% CI 0.91–2.02 compared to those < 2000g) and gestational age (p for trend = 0.04, OR for those born after 40 weeks of gestation 2.24, 95% CI 1.03–4.86, compared to those born before 33 weeks of gestation) and was lower in those subjects hospitalised in the neonatal period (OR 0.74, 95% CI 0.58–0.93). Because of significant interactions between parental hay fever status and birth factors (ponderal index, p = 0.03 and maternal age p = 0.04), stratified analysis were performed. The positive association between birth weight and hay fever was most obvious among adolescents with no parental history of hay fever (p for trend = 0.03). Similar, though not significant, trends were found with other birth factors among these families, whereas no such trend was found among adolescents with parental hay fever, suggesting that gestational maturity increases the risk for hay fever in the absence of genetic predisposition. However, of the perinatal factors only neonatal hospitalisation (OR 0.75, 95% CI 0.59–0.96) remained a significant risk factor for the development of hay fever, when adjusted for non-perinatal factors.

Inflammatory effects on human lung epithelial cells after exposure to diesel exhaust micron sub particles (PM₁.₀) and pollen allergens

Asthma is currently defined as a chronic inflammatory disease of the airway. Several evidence indicate that vehicle emissions in cities is correlated with the allergic respiratory diseases. In the present study, we evaluated in the A549 cells the production and release of IL-4, IL-5 and IL-13 after treatment with sub-micron PM(1.0) particles (PM(1.0)), Parietaria officinalis (ALL), and PM(1.0) + ALL together. Our data demonstrated that PM(1.0) + ALL together exhibited the greatest capacity to induce A549 cells to enhance the expression of IL-4 and IL-5 compared with the only PM(1.0) or ALL treatment. Interestingly, IL-13 that is necessary for allergen-induced airway hyper responsiveness, is increased in cells treated with PM(1.0) + ALL together, but is higher expressed when the cells are treated only with the allergen. Our data support the hypothesis that the urban environment damage the acinar lung units and activates cells of the immune system.

Asthma management issues in infancy and childhood

The prevalence of asthma has been increasing worldwide over the past 2 decades, especially the prevalence of childhood asthma. Currently, the prevalence of childhood asthma is around 3-20% in different countries based on the report from the International Study of Asthma and Allergies in Children (ISAAC). Asthma in childhood is predominantly an extrinsic asthma. In general, countries in the coastal, temperate, and subtropical zones have the highest prevalence of mite- and cockroach-sensitive asthma. Countries in the sub-arctic or semi-arid areas have a lower prevalence of childhood asthma, mostly associated with sensitization to pet dander, moulds, and pollens. Many genes have been linked to asthma in different ethnic populations. A global consensus for the management of asthma in adults and children >5 years of age has been made possible in the Global Initiative for Asthma (GINA) guidelines, where a step-wise management program using inhaled medication with and without oral anti-inflammatory drugs is recommended. The management of asthma in children <5 years of age remains inconclusive. Recent studies suggest that inherited susceptibility associated with risk factors from the prenatal and postnatal environment is likely to promote allergic sensitization and development of asthma. Consequently, early prevention of prenatal sensitization in utero and environmental control of early life exposure to various allergens may decrease the incidence of childhood asthma. In the management of moderate persistent asthma in infants and young children <5 years of age, airway resistance tests (FEV(1) or PEF) are not of significance, but assessment of respiratory rate and skin pulse oximeter measurements of arterial oxygen saturation are helpful. Moreover, recent advances in pharmacogenetics and pharmacogenomics may provide better individualized care for early pharmacological prevention of childhood asthma via selective modulation of airway remodeling.

Does maternal immunoglobulin E decrease with increasing order of live offspring? Investigation into maternal immune tolerance

BACKGROUND

Identifying the protective effect of a higher number of siblings is a significant finding in understanding the aetiology of allergic sensitization, asthma, eczema, and hayfever. Knowledge about causes behind the sibling effect may allow us to prevent atopic manifestations.

OBJECTIVE

We tested the hypothesis that rising order of live offspring increases maternal immune tolerance (immune non-reactivity) against allergens. To this end, we investigated whether maternal IgE levels are associated with the number of live offspring.

METHODS

In a cohort of 1456 newborns recruited between January 1989 and February 1990 on the Isle of Wight, UK, we determined maternal and cord serum IgE, and the order of live offspring. The data were analysed by means of linear and path analysis.

RESULTS

Maternal and cord serum IgE were available in 820 mother-infant pairs with birth order information. We found that the number of live offspring significantly reduces maternal IgE. The decline was more prominent in mothers with atopy (n=268). The geometric means of IgE after the first, second, and third or higher delivery were 74.4, 66.6, and 43.0 kU/L, respectively. Findings of path analysis suggest a significant direct effect of birth order on maternal IgE, but no direct effect of birth order on cord serum IgE.

CONCLUSION

The findings support that maternal immune tolerance against allergens may increase with increasing order of live offspring and thus pass on a lower risk of developing atopy in children of higher birth order.

Prenatal prediction of infant atopy by maternal but not paternal total IgE levels

BACKGROUND

The atopic history of parents has long been used to predict infant atopy. However, bias from questionnaires of allergic history are also frequently suspected, because a large number of vasomotor rhinitis, intrinsic asthma, and seborrheic dermatitis cases are probably misinterpreted to be atopic diseases.

OBJECTIVE

We attempted to identify a risk factor other than parental atopic history to predict elevated infant IgE levels and infant atopy.

METHODS

A total of 655 core families were prenatally recruited, and finally 545 families completed the study for the prospective analysis of infant atopy at 6 months of age. Atopic history and blood samples of parents were collected in the third trimester during pregnancy. Cord blood (CB) was collected immediately after birth. Infant blood samples and history of infant eczema were collected in the 6-month physical checkup clinic. Blood total IgE and specific IgE levels were determined by use of the Pharmacia CAP system.

RESULTS

In univariate analysis, maternal, but not paternal, atopic history correlated with elevated CB IgE levels and the occurrence of infant eczema. Elevated maternal, but not paternal, total IgE levels (>150 KU/L) significantly correlated with increases of CB IgE levels (median, 0.54 vs 0.17 KU/L, P <.001), infant IgE levels (log-transformed mean values, 1.32 +/- 0.51 vs 1.13 +/- 0.51 KU/L, P <.001), and infant eczema (P =.008). Multivariate logistical regression analysis, however, showed that only maternal total IgE levels correlated with CB and infant IgE levels and the development of infant eczema.

CONCLUSIONS

The maternal, but not paternal, total IgE level correlates with elevated infant IgE levels and infant atopy. This provides a high specificity (83%) and a sensitivity of 34% for prediction of infant atopy. This suggests that maternal factors, placental factors, or both have an impact on perinatal allergic sensitization.

Development of bronchial hyperresponsiveness during childhood

Bronchial hyperresponsiveness (BHR) produces the characteristic pathological abnormalities seen in asthma and clearly plays a central role in the pathophysiology of asthma. The presence of BHR has been demonstrated in infants with asthma, as has the possibility of BHR persisting through the childhood period. The level of BHR may not only reflect the state of the airways, as a marker of airway dysfunction, but may also predict the persistent prognosis of the disease. Thus, measurement of BHR may provide important information about the symptoms and lung function in children with asthma. In view of multiple pathophysiological mechanisms, BHR does not seem to have a single cause. Many potential confounding variables, such as age, gender and genetic status, and some environmental factors, such as allergens, infections, and pollutants, could be responsible for the establishment of childhood BHR. There may be differences between the mechanisms that induce transient BHR and the mechanisms that induce persistent BHR. Also, there may be differences between the causes that induce BHR in the infantile period and the causes that maintain persistent BHR during childhood asthma. There is also disagreement as to the most suitable method to measure BHR in children, especially in infants. The assessment of BHR in young children has not been uniformly successful, and measurements of BHR changes over the childhood period (are associated with a number of problems. To resolve these problems, there may be two ways to study childhood BHR. One is to use age-matched specific techniques to clarify the precise BHR in each age group; the other is to use simple techniques that can be performed over the childhood period on a large number of subjects. In studies of infantile respirator, dysfunction the ultimate goal is to establish a simple, noninvasive method by which measurements of respiratory function may be obtained in infants. Further investigations and acceptable methods will be needed to clarify, the mechanisms involved in the establishment of asthma throughout the childhood period.

Trends in bronchial hyperresponsiveness, respiratory symptoms and lung function among adults: West and East Germany. INGA Study Group. Indoor Factors and Genetics in Asthma

Previous studies have shown higher prevalences of bronchial hyperresponsiveness (BHR), respiratory symptoms and atopic sensitization among adults in Western Germany than in Eastern Germany. One of the aims of the joint project INGA (INdoor Factors and Genetics in Asthma) is to assess incidence, prevalence and trends for asthma, BHR and atopic diseases over a time period of 11 years (1990-2001) in the former West (Hamburg) and East Germany (Erfurt), with special reference to indoor exposure. INGA was designed as a case-control study following a cross-sectional study performed from 1990 to 1992 within the European Community Respiratory Health Survey (ECRHS). The database consisted of 1159 subjects in Hamburg and 731 subjects in Erfurt from the ECRHS (age 20-44). In 1995-1996, 107 cases (diagnosed asthma, positive specific serum IgE, positive skin prick or PD20FEV1< or =2.0 mg methacholine at ECRHS) and 106 controls (none of the previous findings) participated in Hamburg (115 cases and 109 controls in Erfurt). The methodology was identical to the ECRHS and dose-response slopes (DRS) of the methacholine challenge were calculated as an index of responsiveness. In the control group, median values of DRS were 0.028% mg(-1) (1990-1992) and 0.044 (1995-1996) (P<0.01) in Erfurt. Corresponding values for Hamburg were 0.028 and 0.022 (NS). Corresponding values within the case groups were 0.041 and 0.049 (NS) for Erfurt, and 0.069 and 0.052 (P<0.05) for Hamburg. Thus, 4 years after the first survey, we found an increased BHR in the Erfurt control group while the bronchial responsiveness remained unchanged for the Hamburg group. These trends in BHR, which indicate the expected converging tendency between East and West Germany, have to be confirmed within the next INGA-survey in 2000-2001.

Immune and inflammatory responses in sudden infant death syndrome

Infancy is a time of unparalleled infection exposure. Coming from the privilege of the uterus, the newborn infant must make appropriate immune responses following infection that eliminates the infection but protects the host. There is evidence that in sudden infant death syndrome (SIDS) subjects there is a background of recent 'trivial' infection and immunological/inflammatory reactivity. This immunological/inflammatory reactivity is seen in enhanced pulmonary immunoglobulins and T-cell activation. It may be that in certain SIDS cases a trivial infection triggers an exaggerated inflammatory response, inducing cytokine cascades and eventual demise of the infant.

The environmental influence on childhood asthma

The pathogenesis of allergy depends on the interaction between the time and amount of allergen exposure and the presence of nonspecific "adjuvant" factors in genetically susceptible individuals. There seems to be a period in early life during which the individual is particularly susceptible to sensitization, and there are variations in susceptibility over time. Allergens are almost ubiquitous, but the relative importance of the individual allergens varies between regions. In many temperate regions, house-dust mites used to be absent but are now more common. This may be due to modern methods of building houses. Differences in the prevalence of a particular allergy cannot explain variations in the prevalence of allergy in general. Various environmental factors that may enhance sensitization include tobacco smoke, NO2, SO2, ozone, and diesel particles. Passive smoking is by far the best established risk factor, particularly in early childhood. The indoor environment probably plays a larger role than outdoor air pollution in the development of allergic disease. The mother is not only a source of genetic information, but also an "environmental factor", as there is a close immunologic interaction between the mother and her offspring, mediated through the placenta and the breast milk, which may affect the likelihood of allergic disease. The concepts of "lifestyle" and "environment" should be expanded to include, for example, dietary changes, the microbial environment, and extensive traveling, as all the currently suspected risk factors taken together can only explain a small proportion of the geographic differences in and increasing prevalence of allergy. The future search for significant environmental factors should be interdisciplinary and be directed toward areas that have not yet been explored, thus giving "lifestyle" a broader interpretation.

Cord blood leucocytes/basophils produce and release sulfidoleucotrienes in response to allergen stimulation

BACKGROUND

Leucocyte-derived sulfidoleucotrienes (SLT) from children and adults can be detected in vitro in response to specific allergen stimulation, a mechanism thought to require the presence of allergen-specific immunoglobulin (Ig)E antibodies on the surface of basophils. It is unknown whether this mechanism is functional in cord blood basophils.

OBJECTIVE

We studied the in vitro SLT-release of leucocytes in response to allergen and anti-IgE stimulation in term newborns and children with allergic diseases.

METHODS

Cord blood from randomly selected term newborns were analysed for total IgE-antibodies and in vitro SLT-release in response to allergen and anti-IgE stimulation. Children from an allergy outpatient clinic were used as the control group. The Cellular Allergen Stimulation Test (CAST) was used as read-out system. Allergen stimulation was performed with an allergen-mix containing 21 nutritive and inhalant allergens.

RESULTS

Peripheral blood leucocytes/basophils derived from allergic children (n = 56; median SLT release 1049 pg/mL) were more responsive to anti-IgE stimulation as cord blood leucocytes/basophils (n = 104; median 419 pg/mL P < 0.0001). In response to stimulation with an allergen-mix, the two groups did not differ significantly from each other. Only SLT-releasability in response to anti-IgE showed a correlation with cord blood IgE.

CONCLUSIONS

Sulfidoleucotriene-release of cord blood basophils is functional in response to allergens. It appears possible that cord blood basophils are armed with allergen-specific IgE-antibodies though not detectable in serum. Therefore, cord blood SLT-release may indirectly reflect prenatal priming with allergens with subsequent production of allergen-specific IgE.

Perinatal risk factors for atopic disease in conscripts

BACKGROUND

There is evidence to suggest that atopic disease in adulthood could be manifestations of events in early life.

OBJECTIVES

To investigate the relationship between perinatal risk factors and the prevalence of allergic rhinitis and asthma in conscripts.

METHODS

A retrospective cohort study, where information from the Military Service Enrolment Register was linked to the national Medical Birth Register. The study included 149 398 male conscripts who were born in Sweden in 1973, 1974 and 1975. Outcome measures were current asthma and allergic rhinitis recognized at the compulsory military conscript examinations.

RESULTS

Unifactorial analyses demonstrated that number of older siblings, young maternal age, multiple gestation, prematurity, low birth weight, growth retardation and perinatal asphyxia were all significantly related to a decreased risk of allergic rhinitis among male conscripts. The prevalence rates of allergic rhinitis among conscripts with and without older siblings were 14.1% and 16.2%, respectively (odds ratio 0.85; 95% confidence interval 0.82-0.87). The prevalence rates of allergic rhinitis among those with term birth (>36 weeks), moderately preterm birth (33-36 weeks) and very preterm birth (<33 weeks) were 15.2%, 13.1% and 11.6%, respectively. Older siblings, multiple gestation and young maternal age were highly significant independent determinants of allergic rhinitis. By contrast, the effects of prematurity, low birthweight and asphyxia were weaker and highly correlated. The only independent determinants of asthma were maternal age, birthweight and multiple gestation. Furthermore, maternal age and birthweight had opposite effects on asthma and allergic rhinitis.

CONCLUSIONS

In contrast to asthma, allergic rhinitis in young adult men was strongly associated with perinatal events. This may reflect the close relationship between allergic rhinitis and atopic sensitization, whereas asthma has a more multifactorial aetiology.

Prevalence of allergic rhinitis and atopic dermatitis among children in four regions of Finland

The primary aim of the study was to evaluate the prevalences of allergic rhinitis and atopic dermatitis and their regional differences among Finnish children. The secondary objective was to determine whether the responses to the questions used are affected by the pollen season if asked during such a season. In 1994-5, the self-reported prevalence of allergic symptoms in four regions of Finland was studied among 11,607 schoolchildren aged 13-14 years, as part of the International Study of Asthma and Allergies in Childhood (ISAAC). The prevalence of rhinoconjunctivitis during the preceding year was 16% in eastern Finland (Kuopio County, n=2821), 23% in southern Finland (Helsinki area, n=2771), 15% in southwestern Finland (Turku and Pori County, n=2983), and 16% in northern Finland (Lapland, n=3032). The respective prevalences of flexural dermatitis were 15%, 19%, 16%, and 18%. The surveys were performed in winter, except in the Helsinki area where the survey was carried out mainly in the spring pollen season. Among the children studied in autumn in Helsinki, the prevalence of rhinoconjunctivitis was 19% and that of flexural dermatitis 17%. In multivariate analysis, flexural dermatitis was slightly more common in Lapland than in all other areas. In contrast, no significant differences were found in rhinoconjunctivitis. The prevalences of both disorders were twice as high in girls as in boys. In conclusion, regional differences in the prevalence of allergic rhinitis and atopic dermatitis were small in our country, and the prevalence figures were rather similar to those reported from other European countries. Almost half of the children had suffered from at least one atopic disorder, and over one-third had had symptoms in the past year. A clear season-of-response effect was observed; the prevalence of rhinoconjunctivitis was 25% when studied during the pollen seasons in the Helsinki area.

Increasing prevalence of hay fever and atopy among children in Leipzig, East Germany

BACKGROUND

Several surveys in children and adults have shown significantly lower prevalences of asthma and allergic diseases in eastern Europe than in western countries. In the former East Germany tremendous changes towards western lifestyle have occurred since unification. The aim of this survey was to investigate time trends in the prevalence of asthma and allergic diseases among children living in the eastern part of Germany.

METHODS

In 1995-96, 2334 (87.5%) schoolchildren in Leipzig participated in a cross-sectional study that used the same methods as a previous survey done shortly after the fall of communism in 1991-92. A self-administered questionnaire was distributed to the parents. Children underwent cold-air challenge and allergy skinprick tests to six common aeroallergens.

FINDINGS

The prevalence of hay fever (2.3% [34/1454] vs 5.1% [115/2252], p<0.0001) and atopic sensitisation (19.3% [252/1303] vs 26.7% [434/1624], p<0.0001) increased significantly between 1991-92 and 1995-96. However, there was no significant change in the prevalence of asthma, asthma-related symptoms, or bronchial hyper-responsiveness.

INTERPRETATION

These findings suggest important differences in the development of atopic disorders. The children were born about 3 years before unification and were therefore exposed to western living conditions only after the third birthday. Thus, factors operating very early in life may be particularly important for the acquisition of childhood asthma, whereas the development of atopic sensitisation and hay fever may also be affected by environmental factors occurring beyond infancy.

Asthma: a dynamic disease of inflammation and repair

It is now widely accepted that asthma in its varied forms is an inflammatory disorder of the airways in which mediator release from activated mast cells and eosinophils plays a major role. T lymphocytes take a primary role in orchestrating these processes through their capacity to generate a range of cytokines of the interleukin 4 gene cluster encoded on the long arm of chromosome 5. Additional cytokines derived from mast cells and eosinophils also play a key role, especially tumour necrosis factor alpha, which is responsible for initiating the up-regulation of vascular adhesion molecules involved in the recruitment of eosinophils and other inflammatory cells from the circulation. The importance of C-X-C and C-C chemokines as local chemoattractants and activating stimuli is also recognized. In addition to releasing an array of pharmacologically active autacoids, the inflammatory response in asthma results in the generation of proteolytic activities from mast cells (tryptase, chymase), eosinophils (MMP-9) and the epithelium itself (MMP-2, MMP-9), which exert tissue-destructive and cell-signalling effects. The epithelium is also highly activated, as evidenced by the up-regulation of cytokine production, inducible enzymes and soluble mediators. Increased surface expression of the epithelial isoform of CD44 (9v) and subepithelial proliferation of myofibroblasts are indicative of a simultaneous active repair process and the laying down of new interstitial collagens. Together, inflammatory and repair processes create the complex phenotype that characterizes asthma and its progression.