Skin prick test reactivity to common aeroallergens in relation to total IgE, respiratory symptoms, and smoking in a general population sample of northern Italy

Asthma Comorbidities: Frequency, Risk Factors, and Associated Burden in Children and Adolescents

Identifying asthma comorbidities in children is fundamental for improving disease management. We aimed to investigate the frequency of allergy-related comorbidities in children and adolescents with asthma, and to identify associated risk factors and disease burden. Between September 2015 and December 2018, 508 asthmatic patients (5–17 years) were consecutively enrolled. Parents answered a standardized questionnaire on the history of disease and risk factors. Comorbidities were classified based on the involvement of respiratory and/or extra-respiratory districts: asthma only (A, 13%), asthma with respiratory comorbidities (AR, 37%), asthma with extra-respiratory comorbidities (AER, 10%), and asthma with both respiratory and extra-respiratory comorbidities (ARER, 40%). Multinomial logistic regression showed that membership in the AR group was significantly associated with a maternal history of asthma (OR = 3.08, 95% CI: 1.23–7.72), breastfeeding ≥ three months (OR = 1.92, 1.06–3.46), early mold exposure (OR = 2.39, 1.12–5.11), and current environmental tobacco smoke exposure (OR = 2.06, 1.11–3.83). Membership in the AER group was significantly associated with the female gender (OR = 3.43, 1.54–7.68), breastfeeding ≥ three months (OR = 2.77, 1.23–6.22). ARER was significantly associated with all the aforementioned exposures. Patients with AR reported exacerbations in the last 12 months more frequently (p = 0.009). Several personal and environmental risk factors are associated with comorbidities in asthmatic children and adolescents, possibly worsening the disease burden.

Skin Testing Is Useful in Assessing Aeroallergen Sensitization in IgE Deficient Patients with Environmental Allergy-Like Symptoms

BACKGROUND

The value of aeroallergen skin testing is not known in IgE deficient individuals (IgE<2.5 kU/L).

OBJECTIVE

To investigate the utility of skin prick (SPT), intradermal skin testing (IDST) and measuring serum specific IgE (ssIgE) in IgE deficient patients presenting with environmental allergy-like symptoms.

METHODS

Individuals with IgE deficiency who had both SPT and IDST performed between 2010 to 2020 were matched (age and gender) to three different groups of non-IgE deficient patients with IgE≥2.5 kU/L (normal IgE [2.5 ≤ IgE<100], high IgE [100≤IgE<1000] and very high IgE levels [≥1000 kU/L]) who also had skin testing performed for evaluation of environmental allergy-like symptoms.

RESULTS

Among 34 IgE deficient patients who completed SPT and IDST, 52.9% (18/34) had at least one positive skin test (4 ± 3 positive tests/patient), compared with 91.2% in those with normal, 94.1% with high or 97.1% with very high IgE levels (p < 0.01). In contrast, only one of the IgE deficient patients had detectable ssIgE, while ssIgE levels were significantly higher in all other IgE subgroups. Allergic immunotherapy was prescribed for 22.2% of the IgE-deficient patients with positive skin tests, similar to those with normal (2/31, 6.5%, p = 0.21), high IgE (9/32, 28.1%, p = 0.25) and very high IgE levels (8/33, 23.5%, p = 0.07), with similar efficacy in their symptoms control.

CONCLUSION

Individuals with IgE deficiency may present with environmental allergy-like symptoms. A combination of SPT and IDST is useful for diagnosing aeroallergen sensitizations in these patients, indicating the presence of skin mast cell-bound IgE in some of these individuals, despite very low serum IgE levels. Further studies are needed to assess the exact significance of positive skin tests and the benefits of immunotherapy in this group.

Urban grey spaces are associated with increased allergy in the general population

BACKGROUND

the built environment in urban areas may have side effects on children's respiratory health, whilst less is known for adulthood.

AIM

to assess the association between increasing exposure to grey spaces and allergic status in an adult general population sample.

METHODS

2070 subjects (age range 15-84 yrs), living in Pisa/Cascina, Italy, were investigated in 1991-93 through a questionnaire on health status and risk factors, skin prick test (SPT), serum Immunoglobulins E (IgE), and serum antibodies to benzo(a)pyrene diol epoxide (BPDE)-DNA adducts. Land-cover exposure within a 1000 m buffer from each subject's home address was assessed through the CORINE Land Cover program (CLC 1990) within the FP7/HEALS project (2013-2018). Participants' residential addresses were geocoded and the proportion of surrounding grey spaces was calculated. Through logistic regression models, adjusting for potential confounding factors, the effect of a 10% increase in grey spaces exposure on allergic biomarkers/conditions was assessed; the relationship with serum antibodies to BPDE-DNA adducts positivity was also analyzed.

RESULTS

A 10% increase in grey spaces coverage was associated with a higher probability of having SPT positivity (OR 1.07, 95% CI 1.02-1.13), seasonal SPT positivity (OR 1.12, 1.05-1.19), polysensitization (OR 1.11, 1.04-1.19), allergic rhinitis (OR 1.10, 1.04-1.17), co-presence of SPT positivity and asthma/allergic rhinitis (OR 1.16, 1.08-1.25), asthma/allergic rhinitis (OR 1.06, 1.00-1.12), presence of serum antibodies to BPDE-DNA adducts positivity (OR 1.07, 1.01-1.14).

CONCLUSIONS

grey spaces have adverse effects on allergic status and are related to a biomarker of polycyclic aromatic hydrocarbons exposure in adulthood. Thus, they may be used as a proxy of urban environmental exposure.

Prevalence of airway hyperresponsiveness and its seasonal variation in children with asthma

BACKGROUND

Airway hyperresponsiveness (AHR) is a key feature of asthma and can be detected using various bronchoprovocation tests. In pediatric populations, the percentage of a positive methacholine challenge test (MCCTs) in children with asthma varies among studies, and some have reported seasonal variability. However, these studies have mostly been conducted in temperate regions. This study evaluated the prevalence of AHR to methacholine and its seasonal variation in asthmatic children in Taiwan, a subtropical country.

METHODS

A total of 276 children with asthma and their MCCT results were retrospectively reviewed. All were diagnosed with asthma and received asthma controllers regularly. They were assigned to four season groups depending in which season MCCTs were administered, with seasons categorized by the Central Weather Bureau of Taiwan. Subgroup analyses, including for sex, age, and atopy level, were compared for seasonal difference.

RESULTS

The prevalence of methacholine hyperresponsiveness was 70.7% (n = 195), and the children who were younger and had higher total serum IgE were more sensitive to methacholine (p = 0.019 and p < 0.005, respectively). No significant difference in AHR prevalence among seasons was observed (p = 0.480). The percentage of borderline, mild, and moderate severity of MCCT results was almost equally distributed among the seasons. In subgroup analysis, the children with a higher IgE level (≥75th percentile of all data) had a higher proportion of positive MCCTs in summer (88.6%, p = 0.016).

CONCLUSION

In total, 70% of the children with asthma in Taiwan had AHR to methacholine, which varied among seasons. Children with a higher total serum IgE level may be more seasonally dependent, particularly in summer.

High incidence and persistence of airborne allergen sensitization up to age 19 years

BACKGROUND

Longitudinal population-based studies about the natural history of allergic sensitization are rare. The aim was to study incidence and persistence of airborne allergen sensitization up to young adulthood and risk factors for early and late onset of sensitization.

METHODS

All children aged 7-8 years in two municipalities in Northern Sweden were invited to a parental questionnaire and skin prick tests (SPTs) to ten airborne allergens, and 2148 (88%) participated. The protocol was repeated at age 11-12 and 19 years, and 1516 participated in all three examinations.

RESULTS

Prevalence of any positive SPT increased from 20.6% at age 7-8 years to 30.6% at 11-12 years, and 42.1% at 19 years. Animals were the primary sensitizers at age 7-8 years, 16.3%, followed by pollen, 12.4%. Mite and mold sensitization was low. Mean annual incidence of any positive SPT varied between 2.8 and 3.4/100 per year, decreased by age for animal, and was stable for pollen. Sensitization before age 7-8 years was independently associated with family history of allergy, OR 2.1 (95% CI 1.6-2.8), urban living, OR 1.9 (95% CI 1.2-2.9), and male sex, OR 1.3 (95% CI 1.0-1.7), and negatively associated with birth order, OR 0.8 (95% CI 0.7-1.0), and furry animals at home, OR 0.7 (95% CI 0.7-0.9). Incidence after age 11-12 years was associated only with family history of allergy. Multisensitization at age 19 years was significantly associated with early age at sensitization. Remission of sensitization was uncommon.

CONCLUSION

The increasing prevalence of allergic sensitization by age was explained by high incidence and persistence. After age 11-12 years, the factors urban living, number of siblings, and male sex lost their importance.

Are allergic multimorbidities and IgE polysensitization associated with the persistence or re-occurrence of foetal type 2 signalling? The MeDALL hypothesis

Allergic diseases [asthma, rhinitis and atopic dermatitis (AD)] are complex. They are associated with allergen-specific IgE and nonallergic mechanisms that may coexist in the same patient. In addition, these diseases tend to cluster and patients present concomitant or consecutive diseases (multimorbidity). IgE sensitization should be considered as a quantitative trait. Important clinical and immunological differences exist between mono- and polysensitized subjects. Multimorbidities of allergic diseases share common causal mechanisms that are only partly IgE-mediated. Persistence of allergic diseases over time is associated with multimorbidity and/or IgE polysensitization. The importance of the family history of allergy may decrease with age. This review puts forward the hypothesis that allergic multimorbidities and IgE polysensitization are associated and related to the persistence or re-occurrence of foetal type 2 signalling. Asthma, rhinitis and AD are manifestations of a common systemic immune imbalance (mesodermal origin) with specific patterns of remodelling (ectodermal or endodermal origin). This study proposes a new classification of IgE-mediated allergic diseases that allows the definition of novel phenotypes to (i) better understand genetic and epigenetic mechanisms, (ii) better stratify allergic preschool children for prognosis and (iii) propose novel strategies of treatment and prevention.

A Pitfall to Avoid When Using an Allergen Microarray: The Incidental Detection of IgE to Unexpected Allergens

The introduction of new laboratory techniques to detect specific IgE antibodies against single allergen molecules rather than whole extracts represents a significant advance in allergy diagnostics. The advantages of such component-resolved diagnosis can be summarized as follows: (1) the ability to identify the truly responsible allergens in polysensitized patients, whether they be genuine (causing specific sensitization to their corresponding allergen source) or primary (the original sensitizing molecule); (2) distinguishing these allergens from simply cross-reactive components; (3) improving the appropriateness of the prescribed specific immunotherapy; and (4) identifying a risk profile for food allergens. Component-resolved diagnosis is performed using either a singleplex (1 assay per sample) platform or a multiplex (multiple assays per sample) platform. Using an immuno solid-phase allergen chip microarray that falls into the latter category--it currently tests sensitivity to 112 allergens--may lead to a pitfall: detecting IgE to unexpected allergens, such as Hymenoptera venom. In fact, testing insect venom sensitivity in individuals with no history of reactions to stings is contrary to current guidelines and presents the physician with the dilemma of how to manage this information; moreover, this may become a legal issue. Based on what is currently known about venom allergy, it remains likely that a positive sensitization test result will have no clinical significance, but the possibility of reacting to a future sting cannot be completely ruled out. Because this problem has not been previously encountered using the more common allergy tests, no indications are currently available on how to effectively manage these cases.

Geographical variation in the prevalence of sensitization to common aeroallergens in adults: the GA(2) LEN survey

BACKGROUND

Geographical variation in the prevalence of sensitization to aeroallergens may reflect differences in exposure to risk factors such as having older siblings, being raised on a farm or other unidentified exposures.

OBJECTIVE

We wanted to measure geographical variation in skin prick test positivity and assess whether it was explained by differences in family size and/or farm exposure. We also compared prevalence in younger and older subjects.

METHODS

Within the Global Allergy and Asthma European Network (GA(2) LEN) survey, we measured the prevalence of skin prick positivity to a panel of allergens, and geometric mean serum total immunoglobulin E (IgE), in 3451 participants aged 18-75 years in 13 areas of Europe. Estimated prevalence was standardized to account for study design. We compared prevalence estimates in younger and older subjects and further adjusted for age, gender, smoking history, farm exposure, number of older siblings and body mass index (BMI).

RESULTS

Skin prick test positivity to any one of the measured allergens varied within Europe from 31.4% to 52.9%. Prevalence of sensitization to single allergens also varied. Variation in serum total IgE was less marked. Younger participants had higher skin prick sensitivity prevalence, but not total IgE, than older participants. Geographical variation remained even after adjustment for confounders.

CONCLUSION

Geographical variation in the prevalence of skin prick test positivity in Europe is unlikely to be explained by geographical variation in gender, age, smoking history, farm exposure, family size and BMI. Higher prevalence in younger, compared to older, adults may reflect cohort-associated increases in sensitization or the influence of ageing on immune or tissue responses.

Role of serological markers of activated eosinophils in inflammatory bowel diseases

BACKGROUND

Activated eosinophils can infiltrate the intestinal mucosa in patients with inflammatory bowel disease (IBD), and eosinophils are also implicated in the histological damage seen in allergic diseases.

AIM

To assess, in a group of patients with IBD in remission or with a mild disease activity, whether serological markers of eosinophil activation, eosinophil cationic protein (ECP) and eosinophil protein X (EPX), are related to evidence of IgE hypersensitivity and to the eosinophilia in gut mucosa.

METHODS

Sixty-one patients with IBD (21 Crohn's disease and 40 ulcerative colitis) in remission or with a mild disease activity were screened for IgE hypersensitivity and serological levels of ECP and EPX. Colonic biopsies were taken to assess mucosal eosinophilic infiltration.

RESULTS

Skin prick test were positive in 31.1% of the patients with IBD, showing skin reactions to food allergens in 17.7%. Skin prick test findings were unrelated to ECP or EPX levels, or to clinical activity or eosinophil counts in the gut mucosa. A significant correlation was found between ECP and EPX levels (r=0.77; P<0.0001).

CONCLUSION

Serological ECP and EPX findings did not correlate with IgE hypersensitivity findings or eosinophilic colonic infiltration in patients with IBD in remission or with mild disease activity. The role of eosinophils in IBD needs to be better characterized in the colonic mucosa, instead of relying on serological tests.

Role of allergen sensitization in older adults

There is a common perception among physicians and patients that allergic diseases are not relevant in older adults. There is also recognition that innate and adaptive immune functions decline with aging. It is the function of a variety of immune cells in the form of allergic inflammation that is a hallmark of allergic diseases. In fact, there is a fairly consistent observation that measures of allergic sensitization, such as skin prick testing, specific IgE, or total IgE, decline with age. Nonetheless, the association between allergic sensitization and allergic diseases, particularly asthma and allergic rhinitis, remains robust in the older adult population. Consequently, an appropriate evaluation of allergic sensitivities is warranted and indicated in older asthma and rhinitis patients to provide optimal care for the individual and minimize any resultant morbidity and mortality.

Proportional Venn diagram and determinants of allergic respiratory diseases in Italian adolescents

Large variations in prevalence of atopy and allergic diseases are reported worldwide in children, but in epidemiological studies the use of skin prick tests (SPT) and spirometry along with questionnaires is not common in the Mediterranean Area. The present work was aimed at evaluating the prevalence of current asthma (CA), rhinoconjunctivitis (RC), and eczema (E), with atopy and respiratory function, and the role of risk factors for allergic respiratory diseases. A total of 2150 Italian schoolchildren were cross-sectionally investigated through respiratory questionnaire, SPT, and spirometry. A proportional Venn diagram quantified the distribution of CA, RC, and E, stratifying for allergic sensitization to show differences in prevalence of allergic diseases among subjects with and without positive SPT. CA prevalence was 4.2%, RC 17.9%, and E 5.3%. CA and RC increased, while E decreased, with respect to previous local studies. Allergic sensitization prevalence (evaluated as positive response to at least one SPT) was 39.2%. A double Venn diagram identified 15 categories. Atopic CA was threefold more frequent than non-atopic CA. Atopic vs non-atopic RC and E were 9.6% vs 10.3% and 2.0% vs 3.3%, respectively. Atopic vs non-atopic RC associated with CA were 1.6% vs 0.5%; the same figures for RC associated with E were 0.8% vs 1.3%. Asymptomatic atopic subjects were 27.0%. Atopy, RC, parental asthma, and environmental risk factors were associated with CA. Atopy and environmental factors were risk factors also for RC. Asthma and traffic exposure were linked to reduced lung function. Respiratory allergic diseases are still increasing and largely concomitant in Italian adolescents. Atopy is more important for CA than RC. Avoiding exposures to measured environmental risk factors would prevent 41% of current asthma and 34% of rhinoconjunctivitis.

The hammock: a reservoir of allergens

INTRODUCTION

Asthma affects approximately 10% of the world's population. Sensitization to allergens is an important risk factor, and exposure to allergens is associated with disease severity.

METHODS

We performed skin tests to evaluate allergen sensitization to mites, cockroaches, cats, dogs, and molds in 73 asthmatic patients. Enzyme Linked Immunosorbent Assay was used to assay the mite and cockroach allergens found in dust from the bedding, hammocks, bedroom floors, living rooms, and kitchens of 29 patients and 14 controls.

RESULTS

Fifty patients (68.5%) had positive skin test responses. There were positive responses to D. pteronyssinus (52.0%), B. tropicalis (53.4%), T. putrescentiae (15.0%), E. maynei (12.3%), L. destructor (8.2%), B. germanica (20.5%), P. americana (21.9%), Felis catus (10.9%), C. herbarium (2.7%), A. alternata (4.1%), and P. notatun (1.3%). The exposure to mite and cockroach allergens was similar in the patients and the controls. The Dermatophagoides pteronyssinus Group 1 levels were highest in the beds and hammocks. The Blattella germanica Group 1 levels were highest in the kitchens, living rooms and hammocks.

DISCUSSION

The positive skin tests to mites, cockroaches and cats were consistent with previous studies. D pteronyssinus was the most prevalent home dust mite, and hammocks were a source of allergens. To improve asthma prophylaxis, it is important to determine its association with mite allergen exposure in hammocks.

Nicotine inhibits Fc epsilon RI-induced cysteinyl leukotrienes and cytokine production without affecting mast cell degranulation through alpha 7/alpha 9/alpha 10-nicotinic receptors

Smokers are less likely to develop some inflammatory and allergic diseases. In Brown-Norway rats, nicotine inhibits several parameters of allergic asthma, including the production of Th2 cytokines and the cysteinyl leukotriene LTC(4). Cysteinyl leukotrienes are primarily produced by mast cells, and these cells play a central role in allergic asthma. Mast cells express a high-affinity receptor for IgE (FcepsilonRI). Following its cross-linking, cells degranulate and release preformed inflammatory mediators (early phase) and synthesize and secrete cytokines/chemokines and leukotrienes (late phase). The mechanism by which nicotine modulates mast cell activation is unclear. Using alpha-bungarotoxin binding and quantitative PCR and PCR product sequencing, we showed that the rat mast/basophil cell line RBL-2H3 expresses nicotinic acetylcholine receptors (nAChRs) alpha7, alpha9, and alpha10; exposure to exceedingly low concentrations of nicotine (nanomolar), but not the biologically inactive metabolite cotinine, for > or = 8 h suppressed the late phase (leukotriene/cytokine production) but not degranulation (histamine and hexosaminidase release). These effects were unrelated to those of nicotine on intracellular free calcium concentration but were causally associated with the inhibition of cytosolic phospholipase A(2) activity and the PI3K/ERK/NF-kappaB pathway, including phosphorylation of Akt and ERK and nuclear translocation of NF-kappaB. The suppressive effect of nicotine on the late-phase response was blocked by the alpha7/alpha9-nAChR antagonists methyllycaconitine and alpha-bungarotoxin, as well as by small interfering RNA knockdown of alpha7-, alpha9-, or alpha10-nAChRs, suggesting a functional interaction between alpha7-, alpha9-, and alpha10-nAChRs that might explain the response of RBL cells to nanomolar concentrations of nicotine. This "hybrid" receptor might serve as a target for novel antiallergic/antiasthmatic therapies.

Maternal exposure to secondhand cigarette smoke primes the lung for induction of phosphodiesterase-4D5 isozyme and exacerbated Th2 responses: rolipram attenuates the airway hyperreactivity and muscarinic receptor expression but not lung inflammation and atopy

Airway hyperreactivity (AHR), lung inflammation, and atopy are clinical signs of allergic asthma. Gestational exposure to cigarette smoke (CS) markedly increases the risk for childhood allergic asthma. Muscarinic receptors regulate airway smooth muscle tone, and asthmatics exhibit increased AHR to muscarinic agonists. We have previously reported that in a murine model of bronchopulmonary aspergillosis, maternal exposure to mainstream CS increases AHR after acute intratracheal administration of Aspergillus fumigatus extract. However, the mechanism by which gestational CS induces allergic asthma is unclear. We now show for the first time that, compared with controls, mice exposed prenatally to secondhand CS exhibit increased lung inflammation (predominant infiltration by eosinophils and polymorphs), atopy, and airway resistance, and produce proinflammatory cytokines (IL-4, IL-5, IL-6, and IL-13, but not IL-2 or IFN-gamma). These changes, which occur only after an allergen (A. fumigatus extract) treatment, are correlated with marked up-regulated lung expression of M1, M2, and M3 muscarinic receptors and phosphodiesterase (PDE)4D5 isozyme. Interestingly, the PDE4-selective inhibitor rolipram attenuates the increase in AHR, muscarinic receptors, and PDE4D5, but fails to down-regulate lung inflammation, Th2 cytokines, or serum IgE levels. Thus, the fetus is extraordinarily sensitive to CS, inducing allergic asthma after postnatal exposure to allergens. Although the increased AHR might reflect increased PDE4D5 and muscarinic receptor expression, the mechanisms underlying atopy and lung inflammation are unrelated to the PDE4 activity. Thus, PDE4 inhibitors might ease AHR, but are unlikely to attenuate lung inflammation and atopy associated with childhood allergic asthma.

Messages from the Aalst Allergy Study

BACKGROUND

The prevalence of sensitization and allergic disease has increased significantly worldwide. The aim of the "Aalst Allergy Study" was to document prevalences of sensitization and allergic symptoms, and to evaluate the effect of personal and environmental influences on these prevalences in an unbiased Belgian pediatric population.

METHODS

A cross-sectional study was performed in an unbiased population of 2021 Belgian schoolchildren (3.4-14.8 years). Skin prick testing with the most common aeroallergens was performed. Allergic symptoms as well as potential risk factors for sensitization and allergic disease were documented by a parental questionnaire.

RESULTS

The prevalence of sensitization to the most common aeroallergens and the prevalence of allergic diseases (eczema, asthma and rhinoconjunctivitis) were in line with the data in the literature. The association of current allergic symptoms with sensitization was only significant in the children aged > or =6 years. Age, gender, body mass index, bedroom environment and exposure to pets were the factors significantly associated with sensitization and allergic symptoms.

CONCLUSIONS

Our study corroborates the reported prevalences of sensitization and allergic diseases. Moreover the study illustrates the complexity of the search for factors involved in the process of sensitization and allergic disease. The impact of different potential causative factors is not only influenced by mutual interactions of these factors, but also by the existence of distinct subtypes of disease.

The association of allergic symptoms with sensitization to inhalant allergens in childhood

Although it is generally agreed that sensitization is an important risk factor for allergic diseases, the extent to which sensitization accounts for allergic symptoms in children is controversial. As part of the Aalst Allergy Study, this cross-sectional study investigated the prevalence of allergic symptoms and their association with sensitization in an unselected population of Flemish children aged 3.4-14.8 yr. Skin prick testing with the most common aeroallergens was performed and allergic symptoms were documented by a parental questionnaire. In the children older than 6 yr, a significant association of current wheezing, current dyspnea, airway hyperreactivity, rhinoconjunctivitis, and current eczema with sensitization was found, while in the pre-school children these associations were less pronounced. The association with sensitization was strongest for rhinoconjunctivitis and current respiratory symptoms - the association was less striking for children with current eczema. The impact of a positive family history of allergy on the association with sensitization was more important for eczema than for the other analyzed allergic symptoms. Persistent and late-onset wheezers were significantly more likely than non-wheezers and transient early wheezers to be associated with sensitization and a personal history of rhinoconjunctivitis. Late-onset wheezing was associated with a positive family history of allergy, while transient early wheezing was associated with day-care attendance. An association with eczema was found for all three childhood wheezing phenotypes. The association of allergic symptoms with sensitization is significant in the older but less pronounced in pre-school children and is more pronounced for current allergic symptoms. Diagnosis and disease definition of allergy symptoms remains difficult at pre-school age. The influence of a positive family history of allergy on the association of the respective allergic symptoms with sensitization was most important for eczema. Our data confirm the atopic characteristics of the different wheeze phenotypes.

Urban residence is associated with bronchial hyperresponsiveness in Italian general population samples

BACKGROUND

The role of different risk factors for bronchial hyperresponsiveness (BHR), such as gender, atopy, IgE, and environmental factors (smoking, occupational exposure, infections), has been described. Indoor and outdoor pollution play an important role too, but few studies have analyzed the association with BHR. The aim of this study was to assess the effect of urban residence on BHR.

METHODS

We studied two general population samples enrolled in two cross-sectional epidemiological studies performed in Northern Italy (Po Delta, rural area) and Central Italy (Pisa, urban area). We analyzed 2,760 subjects (age range, 8 to 74 years). We performed analysis of variance and logistic regression analysis using ln slope of the dose-response curve of the methacholine challenge test as dependent variable, and sex, age, smoking habits, respiratory symptoms, skin-prick test results, IgE value, residence, and airway caliber as independent variables.

RESULTS

The mean value of ln slope of the dose-response curve adjusted for initial airways caliber (by baseline FEV(1) percentage of predicted value) was significantly higher in female subjects, in smokers, in subjects with respiratory symptoms, in younger and older ages, in subjects with high values of IgE, and in subjects with positive skin-prick test results. After controlling for the independent effects of all these variables, living in urban area was an independent risk factor for having BHR (odds ratio, 1.41; 95% confidence interval, 1.13 to 1.76).

CONCLUSION

Living in urban area is a risk factor for increased bronchial responsiveness.

Nicotine primarily suppresses lung Th2 but not goblet cell and muscle cell responses to allergens

Allergic asthma, an inflammatory disease characterized by the infiltration and activation of various leukocytes, the production of Th2 cytokines and leukotrienes, and atopy, also affects the function of other cell types, causing goblet cell hyperplasia/hypertrophy, increased mucus production/secretion, and airway hyperreactivity. Eosinophilic inflammation is a characteristic feature of human asthma, and recent evidence suggests that eosinophils also play a critical role in T cell trafficking in animal models of asthma. Nicotine is an anti-inflammatory, but the association between smoking and asthma is highly contentious and some report that smoking cessation increases the risk of asthma in ex-smokers. To ascertain the effects of nicotine on allergy/asthma, Brown Norway rats were treated with nicotine and sensitized and challenged with allergens. The results unequivocally show that, even after multiple allergen sensitizations, nicotine dramatically suppresses inflammatory/allergic parameters in the lung including the following: eosinophilic/lymphocytic emigration; mRNA and/or protein expression of the Th2 cytokines/chemokines IL-4, IL-5, IL-13, IL-25, and eotaxin; leukotriene C(4); and total as well as allergen-specific IgE. Although nicotine did not significantly affect hexosaminidase release, IgG, or methacholine-induced airway resistance, it significantly decreased mucus content in bronchoalveolar lavage; interestingly, however, despite the strong suppression of IL-4/IL-13, nicotine significantly increased the intraepithelial-stored mucosubstances and Muc5ac mRNA expression. These results suggest that nicotine modulates allergy/asthma primarily by suppressing eosinophil trafficking and suppressing Th2 cytokine/chemokine responses without reducing goblet cell metaplasia or mucous production and may explain the lower risk of allergic diseases in smokers. To our knowledge this is the first direct evidence that nicotine modulates allergic responses.

Determinants of exhaled nitric oxide levels in healthy, nonsmoking African American adults

BACKGROUND

Asthma is a significant cause of morbidity and mortality for African Americans. Fraction of exhaled nitric oxide (FeNO) levels are increased in patients with asthma, and airway levels of nitric oxide metabolites regulate airway inflammation and airway diameter. More needs to be known about the factors that regulate FeNO. There is a need for FeNO reference values for African Americans.

OBJECTIVE

We sought to establish reference values and identify factors associated with FeNO levels in healthy African American adults.

METHODS

FeNO levels were measured in 895 healthy, nonsmoking African Americans between the ages of 18 and 40 years. FeNO measurements were repeated in 84 subjects. Factors potentially associated with FeNO were measured, including blood pressure, height, weight, and serum total IgE, eosinophil cationic protein, C-reactive protein, and nitrate levels. Data on respiratory symptoms, including upper respiratory tract infection (URI) symptoms, were collected. Univariate and multivariate analyses of the relationship between these variables and FeNO levels were performed.

RESULTS

In healthy, nonsmoking African Americans FeNO levels were stable during repeated measurements (intraclass correlation coefficient, 0.81). Sex (P < .0001), serum total IgE levels (P < .0001), and current URI symptoms (P = .0002) contributed significantly to FeNO variability but together accounted for less than 50% of the variation in FeNO levels.

CONCLUSION

The high correlation between repeated measurements of FeNO and the low correlation coefficients of known factors associated with FeNO suggest that other factors might contribute substantially to variability of FeNO levels in African Americans.

Skin prick-test reactivity to aeroallergens and allergic symptoms in an urban population of central Italy: a longitudinal study

BACKGROUND

Cross-sectional studies report an increasing prevalence of allergic diseases, such as rhinitis and asthma. Not thoroughly known, instead, is the natural history of allergic sensitization and the progress of the allergic disease-related symptoms.

AIM

The purpose of this study was to evaluate longitudinally the skin reactivity for the most common aeroallergens and the allergic symptoms in an urban population living in Perugia, a town of central Italy with a low-level of air pollution exposure.

METHODS

In the 1998-1999 period 788 subjects were tested for skin reactivity to a panel of aeroallergens and underwent the administration of a questionnaire. These same subjects were part of a cohort of 1200 subjects who participated in a previous epidemiological study performed in 1984-1985 using the same tools. Subjects were aged between 14 and 64 years at the time of the first survey.

RESULTS

In the present survey 196 subjects (24.9%) had skin reactivity to at least one aeroallergen, while in the previous survey 143 subjects (18.1%) had skin prick-test reactivity. The increase of the skin reactivity between the two observations was highly significant (P<0.001) and was mainly observed in subjects <40-years old. The greatest increment in skin reactivity was seen to Dermatophagoides pteronyssinus (house dust mite) allergen. Data obtained from questionnaires showed that subjects who declared allergic symptoms increased from 341 (43.3%) to 380 (48.2%). However, the increase was significant (P<0.01) only in subjects who had a positive association between allergic symptoms and prick-test reactivity and was greater for rhino-conjunctivitis than for asthma-related symptoms.

CONCLUSIONS

In a cohort of urban population of the centre of Italy, exposed to a low and stable level of air pollution, the sensitization to common aeroallergens increased with time, mostly in people <40-years of age. The greatest increment was found for indoor allergens such as Dermatophagoides pteronysimus. A significant increase in allergic symptoms, mainly related to rhino-conjunctivitis, was observed only in the presence of positive prick test.

High prevalence of skin test positivity in severe or difficult-to-treat asthma

BACKGROUND

Skin tests are considered the gold standard for detecting allergen-specific immunoglobulin E (IgE) in the clinical setting and are an important tool for diagnosing and managing allergic asthma.

OBJECTIVE

To assess the prevalence of skin testing in patients > or = 12 years enrolled in The Epidemiology and Natural History of Asthma: Outcomes and Treatment Regimens (TENOR) study.

METHODS

Patients were asked whether they had ever been skin tested and, if so, they were asked to provide the test results. Clinical characteristics were used to compare positive (ST+), negative (ST-), and skin test not done (STND) patients.

RESULTS

Of 2,985 patients eligible, 85.8% recalled being skin tested. Of those tested, 93.5% were positive (allergist 95.7%, pulmonologist 87.3%). A high proportion of Whites (93.5%) and non-Whites (94.0%) were ST+; however, more non-Whites had never been skin tested (21.7% vs. 12.3%, respectively; p < 0.0001). Total serum IgE was 104.6 IU/mL for ST+ patients, 87.1 IU/mL for STND patients, and 32.4 IU/mL for ST- patients. Age at asthma onset, duration of asthma, and the prevalence of atopic disorders and asthma triggers differentiated the ST+ from the ST- group. Disease severity appeared similar between the two groups. In general, values for STND patients were closer to the ST+ group, suggesting that those not tested would have been ST+ if administered a test.

CONCLUSIONS

The prevalence of ST+ patients was high in allergy and pulmonology practices, and in White and non-White patients. These data support the utility of a more complete allergic evaluation in severe asthmatics. Skin testing appears associated with disease pathophysiologies in asthma.

Factors responsible for differences between asymptomatic subjects and patients presenting an IgE sensitization to allergens. A GA2LEN project

The synthesis of allergen-specific IgE is required for the development of allergic diseases including allergic rhinitis and allergic asthma (patients), but many individuals with allergen-specific IgE do not develop symptoms (asymptomatic subjects). Differences may exist between asymptomatic subjects and patients. Whether the presence of allergen-specific IgE translates into clinical allergy most likely depends on a complex interplay of multiple factors. These include a family history of atopy, the levels of total serum IgE and, allergen-specific IgE or IgG, epitope-specificity of IgE and their degree of polyclonality (mono- vs polysensitized), as yet unidentified serum factors, the balance of T regulatory cells (Treg) and Th1/Th2 cells, the polymorphisms of the high affinity receptor for IgE (FcepsilonRI) and other factors regulating the activation of FcepsilonRI-bearing cells. Asymptomatic subjects may be more often monosensitized than patients who may be more often polysensitized. There are many unanswered important questions that need to be addressed in order to better understand how IgE sensitization translates into clinical allergy. The assessment of differences between the asymptomatic and symptomatic groups of subjects represent one of the scientific programs of Global Allergy and Asthma European Network funded by the European Union and the hypotheses underlying these differences are presented in this paper.

Prevalence and clinical relevance of specific immunoglobulin E to pollen caused by sting- induced specific immunoglobulin E to cross-reacting carbohydrate determinants in Hymenoptera venoms

BACKGROUND

Hymenoptera stings can induce specific IgE (sIgE) to carbohydrate determinants (CD) on venom glycoproteins that cross-react with CD in pollen. sIgE to such cross-reacting CD (CCD) are believed to have little or no biological activity and thus may cause misdiagnosis of pollen sensitization after a sting.

OBJECTIVE

To determine the prevalence of multiple false positive CAP results to pollen because of sting induced anti-CCD sIgE in Hymenoptera venom (HV) allergic patients and to investigate the association of such anti-CCD sIgE with features of 'atopy'.

METHODS

Skin prick tests (SPT) and CAP tests with grass, tree and weed pollen and with house dust mite (HDM) were carried out prospectively in 259 HV allergic patients and CAP tests with honeybee (HBV) and yellow jacket (YJV) venom were performed. Patients with negative pollen SPT associated with positive CAP tests to all three pollen groups were operationally defined as 'CCD positive'. We investigated in selected 'CCD positive' patients the presence of anti-CCD sIgE by CAP tests with bromelain and studied the identity of CD in HVs and pollen by mutual sIgE inhibition tests with CD from proteinase treated HBV (HBV-CD) and Lolium perenne (Lol-CD) extracts.

RESULTS

sIgE to all three pollen groups without positive SPT or history was found in 16% of 259 patients. The presence of anti-CCD sIgE was substantiated by positive CAP tests with bromelain in 14/14 and by inhibition of all pollen CAP tests with HBV-CD in 8/9 and with Lol-CD in 2/2 patients. Double venom (DV) positive CAP tests were present in 93% of 'CCD positive' patients and were in some associated with DV skin test positivity and allergy. The prevalence of 'CCD positivity' was significantly higher among HBV (23%) than among YJV (11%) allergic patients, but was also unexpectedly high among those with DV allergy (47%). 'CCD positive' patients were younger, had a higher total IgE and more sIgE to HDM than 'CCD negative' patients.

CONCLUSION

We have shown that the risk in HV allergic patients for misdiagnosis of multivalent pollen sensitization is 16%, and we have confirmed that sting induced anti-pollen sIgE are directed to similar CD in venoms and pollen. We found evidence that the recognition of CCD might be related to the 'atopic' trait. Importantly, a positive bromelain CAP test does not exclude clinical reactivity to both venoms in 'CCD positive' HV allergic patients.

Segregation analysis of bronchial hyperresponsiveness in a general population in north Italy

Bronchial hyperresponsiveness (BHR) is an intermediate phenotype of asthma, with a heritability component of 30-67% and possible linkage to regions on chromosome arms 5q, 11q, and 20p. Familial correlation analysis and segregation analysis for BHR, using the FCOR and REGC programs of the S.A.G.E package, were performed to examine inheritance patterns of BHR in a general population of 1167 subjects in 550 families from the Po River Delta. BHR was assessed using the log(10) of the slope of the methacholine dose-response curve (log slope) for each subject who met inclusion criteria. Using multiple linear regression analysis, the log slope values were adjusted for age, age(2), sex, and height, and used in the familial correlation and segregation analyses. Father-offspring correlations are statistically significant, due specifically to high father-son correlations (r = 0.296, P < 0.001, adjusted values). Segregation analysis of BHR in the overall population, with and without a smoking covariate (number of packyears smoked), indicates an apparent absence of genetic transmission within families. However, in a segregation analysis of BHR in smoking families only, after adjusting for number of packyears smoked, the Mendelian transmission models could not be rejected. This may be evidence of a gene by smoking effect, and suggests that in families of smokers, a single locus gene may in part explain the inheritance of a compound phenotype (BHR x packyears).

The role of atopy in Maltese patients with chronic rhinitis

The global prevalence of allergic rhinitis has been on the increase and recent clinical experience in Malta has shown a similar trend. The aim of this study was to investigate the role of atopy in 415 patients presenting with rhinitis of at least 3 months duration, and to identify the common allergens responsible. Presenting clinical features, past and family history of seasonal allergic symptoms, exposure to cigarette smoking, pet ownership and occupation were analysed. All patients were skin tested for common allergens. Fifty-five per cent of patients were atopic, the main allergens responsible being house dust mite, cat dander and grass pollen. Rhinorrhoea and sneezing were significantly more common in atopic patients, who were more likely to have a past history and family history of seasonal asthma, eczema or rhinoconjunctivitis. Skin test-negative patients with idiopathic rhinitis were mostly females and tended to present a decade later. Differentiation between atopic and idiopathic chronic rhinitis may be helpful in the clinical setting in order to help predict response to treatment.

IgE level and Phadiatop in an elderly population from the PAQUID cohort: relationship to respiratory symptoms and smoking

BACKGROUND

In the last decades in industrialized countries, the increase of life expectancy has resulted in an increase in the population of the elderly. However, little is known about the prevalence of allergies in the elderly population. The aim of the study was to investigate the specific relationship of serum IgE and Phadiatop, with asthma, rhinitis, and smoking in a sample of an elderly population.

METHODS

Subjects from the Paquid cohort living in Gironde Department (age 65 years and over) in France were followed up since 1988 (PAQUID cohort).

RESULTS

Among the randomized sample of 352 subjects, there were 158 men (45%) and 194 women (55%). The lowest levels of IgE were in subjects with chronic sputum; and in normal subjects (47.1 +/- 56.4 vs 56.2 +/- 73.9, NS). Multiple linear regression was performed with log(10) IgE values as a dependent variable and age, Phadiatop test, smoking, and respiratory symptoms independently in men and in women. In men, a significant relationship was observed between IgE values and Phadiatop test (P < 0.001), asthma history (P = 0.002), and smoking (P = 0.019).

CONCLUSIONS

Respiratory allergy is present in persons >65 years of age. There is an association between smoking and IgE level independent of allergic reactivity to common allergens in the elderly.

Allergic sensitization among adults in Tallinn, Estonia

BACKGROUND

The prevalence of allergic sensitization has increased worldwide during recent years.

OBJECTIVE

The aim of the study was to estimate the prevalence of allergic sensitization and to evaluate the influence of age, gender, number of siblings, pet keeping in childhood, and residential area before the age of five on allergic sensitization among adolescents and adults aged 17-66 years in the capital of Estonia, Tallinn. A cross-sectional study was carried out between March 1997 and December 1998.

METHODS

The sensitization to 15 inhalant allergens was assessed. The associations between sensitization based on skin prick tests (SPTs), symptoms based on a structured interview, and possible risk factors were estimated. A random sample of 516 subjects was included in the study analysis.

RESULTS

The prevalence of allergic sensitization was 34.5%, while it was 39.3% in subjects aged 20-44 years. The most prevalent sensitization was against the German cockroach, 15.5%, and it was particularly high among adolescents. It was followed by mugwort, dog, two storage mites species, and cat dander. Subjects with wheezing during the last 12 months, attacks of shortness of breath, wheezing due to furred animals, and allergic rhinitis or conjunctivitis had a significantly higher prevalence of positive SPT.

CONCLUSION

We found a surprisingly high prevalence of allergic sensitization among adults in Tallinn. Our results suggest that the cockroach allergen should be included in the investigation panel in order to reach a true prevalence of allergic sensitization in Estonia. Further, the pattern of allergic sensitization in Estonia appears to be different from published data about allergic sensitization in Scandinavia.

Effects of specific immunotherapy on the development of new sensitisations in monosensitised patients

BACKGROUND

Specific immunotherapy (SIT) is the only treatment that interferes with the basic pathophysiological mechanisms of allergic disease and is widely used in the management of clinically significant respiratory IgE-mediated diseases. Nevertheless, until recently, information on the influence of SIT on the development of new allergic sensitisations has been scant.

METHODS

One hundred consecutive patients (45 males and 55 females, aged 6 to 69 years) with respiratory allergic diseases and attending the allergy unit of a general hospital were selected. All had been diagnosed by clinical history and skin prick tests of allergic rhinitis and/or asthma, were monosensitised (71 to Dermatophagoides spp, 22 to Parietaria judaica pollen and 7 to grass pollen) and had been followed up as outpatients between 1990-98. Sixty-six patients had been treated with conventional SIT for at least 3 years, while thirty-four followed only environmental measures and drug treatment. Family atopy status (first-degree relatives), smoking, family pets (cat and/or dog), rhinitis and/or asthma symptom score and inhalant skin prick tests to the same aeroallergens were compared between baseline and after 3 to 5 years of treatment.

RESULTS

No statistically-significant differences in the development of new sensitisations were observed between the two groups (36.4 % of SIT-treated patients versus 38.2 % in control group, RR = 0.97, CI 95 %: 0.72-1.3). Smoking, family atopy history and pets did not appear to be risk factors for the development of neosensitisations (p < 0.05). Nevertheless, SIT-treated patients presented a better clinical score than the control group, with improvements of 89.4 % and 61.8 %, respectively (p = 0.007).

CONCLUSIONS

Three-year SIT did not protect against development of new sensitisations in monosensitised allergic rhinitis or asthma. Smoking, family atopy history and pets were not associated with development of new sensitisations. Clinical score improved significantly in the SIT-treated group compared with drug-treated patients.

Methodologic aspects of the quantification of skin prick test responses: the EGEA study

BACKGROUND

The expression of responses of allergy skin prick tests is not standardized. Usual definitions of atopy are not quantitative.

OBJECTIVE

We sought to perform a biometric analysis of responses to various allergens to propose synthetic, quantitative indices independent of the heterogeneity of responses to various allergens.

METHODS

Adults (N = 1286) from the Epidemiological Study on the Genetics and Environment of Asthma, Bronchial Hyperresponsiveness, and Atopy (EGEA) were included in the analysis. The first step, conducted for 678 subjects with at least 1 wheal >0, was to perform a standardization of wheal diameters to obtain comparable figures for 10 allergens through use of the means of the squares of wheal size as a scaling factor. The second step was a factor analysis of the standardized responses conducted not only for all subjects but also separately for asthmatic case and nonasthmatic control subjects. Finally, the strength of the link between various dichotomous and quantitative scores was assessed with multiRAST, total IgE, and asthma. Analyzed quantitative scores were based on the number of positive responses and on the nonstandardized and standardized sizes of the wheals.

RESULTS

The standardization was efficient. Among asthmatic subjects but not other subjects, factor analysis evidenced a pattern with 3 factors, corresponding to outdoor, indoor, and mold allergens. The link study showed that all scores performed very similarly.

CONCLUSION

The number of positive tests is a quantitative score with valid biometric properties. It should be used more widely in clinical settings and in epidemiology to assess the severity of atopy.

Association of alcohol consumption with total serum immunoglobulin E levels and allergic sensitization in an adult population-based survey

BACKGROUND

Chronic alcoholism is associated with increased total serum IgE levels.

OBJECTIVE

The study aimed to investigate the relationship between alcohol intake and both total serum IgE levels and allergic sensitization in a general adult population.

MATERIALS AND METHODS

A total of 720 subjects was randomly selected (stratified by age) from the population older than 18 years of A-Estrada (Spain) and invited to participate in the study. From 697 eligible subjects, 469 (67%, median age 54 years, range 18 to 92 years, 44% males, 75% of cases from a rural environment) agreed to participate. A battery of 13 skin prick tests to common aeroallergens was performed in all subjects. Cases with at least one positive test (n = 121, 26%) were considered to have allergic sensitization. The most frequent sensitisers were mites and pollens (24% and 10% of subjects, respectively). Total serum IgE was measured in 465 subjects (99%). Alcohol consumption was registered as the number of standard (approximately 10 g) drinking units habitually consumed per week. A total of 244 subjects (52%) were alcohol consumers (median intake, 14 units/week, range 1 to 147 units/week). Abstainers (n = 225, 48%) constituted the reference category.

RESULTS

Alcohol consumption of more than 14 units/week was associated with an increase in serum IgE levels after adjusting for age, gender, allergic sensitization and smoking (P = 0.02). Alcohol consumption was not significantly associated with either overall allergic sensitization or mite sensitization after adjusting for age, gender and smoking. However, alcohol consumption of more than 14 units/week was associated with an increased prevalence of pollen sensitization (adjusted OR 3.15, 95% CI 1.19 to 8.34, P = 0.02).

CONCLUSION

Alcohol consumption above a certain threshold is associated with an increase in total serum IgE levels. Alcohol consumption may also be associated with an increased prevalence of pollen sensitization.

The IL1A genotype associates with atopy in nonasthmatic adults

BACKGROUND

The skin prick test is used to examine specific IgE-mediated allergic responses. Generally, results accord well with anamnestic information on atopy. Several genetic factors probably affect the strength of allergen-mediated skin test reactions.

OBJECTIVE

We sought to investigate skin test findings in a population-based sample of adult asthmatic patients and control subjects and to establish whether the IL1A genotype affects allergy testing.

METHODS

We analyzed the single G-to-T base exchange polymorphism in exon 5 at +4845 of the gene encoding IL-1alpha (IL1A) in adult asthmatic patients (n = 245) and nonasthmatic control subjects (n = 405). The data were assessed for correlation with data on the skin test responses of these subjects to 22 common allergens.

RESULTS

The IL1A genotype distribution and allele frequencies proved similar in patients and control subjects. Surprisingly, the IL1A genotype distribution was markedly different in control subjects with positive (ie, >/=1 positive reaction) and negative skin test responses (P =.006). This difference was caused by an increase in the frequency of the rarer allele 2 in control subjects with negative skin test responses (P =.004).

CONCLUSION

Our study demonstrates that the IL1 gene complex is involved in the regulation of IgE-mediated atopic reactions. The results suggest that skin test responses to specific allergens are differently regulated in nonasthmatic and asthmatic subjects. Because of the potential role of the IL1A genotype as a confounding factor in skin prick testing, these results require special attention and should be further evaluated in other clinical settings.

Increase in the prevalence of allergen skin sensitization in successive birth cohorts

BACKGROUND

Little is known about longitudinal trends in the prevalence of allergen skin sensitization in the general population.

OBJECTIVE

We sought to measure the change in prevalence of allergen skin sensitization over a 9-year period in a cohort of adults and hence to determine whether cross-sectional differences in prevalence between age groups are due to an aging or cohort effect.

METHODS

In 1991 and 2000, we measured skin sensitization, defined as a wheal diameter of 3 mm or larger than that elicited by a saline control, to Dermatophagoides pteronyssinus, cat fur, mixed grass, Aspergillus fumigatus, and Cladosporium herbarum in a cohort of 1339 adults from Nottingham aged between 18 and 71 years in 1991. Subjects were divided into six 9-year successive birth cohorts, and the effects of birth cohort and the within-subject change from 1991 to 2000 were analyzed in a generalized estimating equation logit model.

RESULTS

The unadjusted prevalence of sensitization to any allergen was 30.5% in 1991 and 31.8% in 2000. In cross-sectional analyses the prevalence of sensitization decreased with increasing age at both surveys (risk ratio, 2.15; 95% confidence interval [CI], 1.45-3.17 for 18- to 26-year-old patients relative to 63- to 70-year-old patients in the 1991 survey). In longitudinal analysis there was no within-subject change in sensitization from 1991 to 2000 (adjusted odds ratio, 1.07; 95% CI, 0.97-1.19), but there was a significant cohort effect (adjusted odds ratio per successive 9 year cohort, 1.27; 95% CI, 1.18-1.37).

CONCLUSION

The cross-sectional decrease in allergen sensitization with age in the general population arises predominantly from a secular increase in sensitization prevalence with successive birth cohorts and not to a loss of sensitization within subjects over time. As a result of this cohort effect, the prevalence of allergic sensitization has increased in this general adult population sample.

The Po River Delta epidemiological survey: reference values of total serum IgE levels in a normal population sample of North Italy (8-78 yrs)

The aim of this paper was to define, for the first time in Italy, normal levels of total serum IgE in a general population sample of North Italy. Total serum IgE in 1905 subjects, living in Po Delta area (near Venice), were measured by PRIST method. Normal values were derived from 558 subjects without asthma and/or asthmatic/rhinitic symptoms, noncurrent smokers, skin prick-test negatives ('normals'). Cut-off values to differentiate 'normals' from the remaining part of the sample ('others'), from asthmatic, and from rhinitic subjects, were established with the IgE value midway between the upper limit of the 95% confidence intervals (CI) of the geometric mean for 'normals' and the lower limit for 'others', asthmatics, and rhinitics, respectively. Geometric mean of normal children-adolescents was 45 kU/L (SD: 2.6; 95% CI: 38-63). In normal adults geometric mean was 29 kU/L (SD: 3.3; 95% CI: 25-40) in males and 19 kU/L (SD: 3.8; 95% CI: 16-22) in females. The diagnostic sensitivity of IgE test was low, while the specificity was very high. A good positive predictive value in discriminating 'normals' from 'others' was found, on the contrary, we found a good negative predictive value in discriminating 'normals' from asthmatics or from rhinitics. In conclusion, our results confirm that it is necessary to provide separate total serum IgE reference values for what concerns age in children-adolescents and in adults, and gender, in adults. Low serum IgE are helpful to exclude allergic asthma or rhinitis level of total.

Factors related to allergic sensitization to aeroallergens in a cross-sectional study in adults: The Copenhagen Allergy Study

BACKGROUND

The factors underlying recent increases in the prevalence of respiratory allergy are largely unknown.

OBJECTIVE

To assess the association between allergic sensitization and several lifestyle/environmental factors.

METHODS

A cross-sectional population-based study of 15-69-year-olds in Copenhagen was carried out in 1990. The participation rate was 77.5% (1112/1435). Different lifestyle/environmental factors (explanatory variables) were defined based on questionnaire data. Dependent (outcome) variables were skin prick test (SPT) positivity or specific IgE positivity to common aeroallergens. Explanatory variables associated with outcome in univariate analysis (P < 0.25) were selected for multivariate analysis. Subsequently, a final model for each dependent variable was obtained by stepwise regression analysis (cut-off for entry/removal of variables: P < 0.1).

RESULTS

Male sex, young age, low number of siblings, a positive family history of hay fever and never smoking, were independently associated with both SPT positivity and specific IgE positivity. Furthermore, SPT positivity was positively associated with alcohol consumption (dose-response relationship only), and negatively associated with previous keeping of a dog in the household. The association between alcohol consumption and SPT positivity was mainly due to the consumption of wine and remained after adjustment for educational level. Specific IgE positivity was furthermore associated with body mass index with no apparent dose-response relationship.

CONCLUSION

Being male, young age, a positive family history of hayfever, low number of siblings and never smoking, were independently associated with allergic sensitization. In addition, the results indicated a possible relationship of alcohol consumption, body mass index and previous keeping of a dog in the household to allergic sensitization. There is a need for prospective studies of risk factors for respiratory allergy.

Smoking and the development of allergic sensitization to aeroallergens in adults: a prospective population-based study. The Copenhagen Allergy Study

BACKGROUND

Several cross-sectional population-based studies have reported a negative association between smoking and allergic sensitization to aeroallergens. In a prospective study, we investigated the association between smoking and the development (incidence) of allergic sensitization as reflected by skin prick test (SPT) positivity and specific IgE positivity.

METHODS

Participants in a population-based study of 15 69-year-olds in 1990 were invited to a follow-up in 1998. Thus, SPT positivity and specific IgE positivity to common aeroallergens were assessed in 734 subjects (participation rate: 69.0%) on two occasions 8 years apart. The effect of smoking on the development of allergic sensitization was adjusted for potential confounders such as age, sex, family history of hay fever, educational level, and total IgE.

RESULTS

During the follow-up period, 58 and 33 subjects developed SPT positivity and specific IgE positivity, respectively. The risk of developing SPT positivity (adjusted odds ratio: 0.45, 95% CI 0.21-0.98) and specific IgE positivity (adjusted odds ratio: 0.62, 95%, CI 0.26-1.49) was lower among sustained smokers than never-smokers.

CONCLUSIONS

In this adult population, sustained smoking was negatively associated with the development of allergic sensitization to aeroallergens during an 8-year follow-up. This negative association, if real, might be due to an immunosuppressive effect of smoking.

Allergy markers in respiratory epidemiology

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

The association of sensitization to inhalant allergens with allergy symptoms: the influence of bronchial hyperresponsiveness and blood eosinophil count

BACKGROUND

We investigated whether the association of allergy symptoms with sensitization to inhalant allergens depends on bronchial hyperresponsiveness, blood eosinophil count, or the degree and nature of sensitization.

METHODS

Data on asthma and rhino-conjunctivitis symptoms were obtained from 1904 subjects from a random sample of the Dutch population, aged 20-70 years by the ECRHS questionnaire. Total IgE and specific IgE to four inhalant allergens were measured using CAP System. Bronchial hyperresponsiveness (BHR) was defined as PD20 </= 2 mg methacholine and 'high eosinophil count' as an eosinophil count in the highest quartile.

RESULTS

Forty-three percent of the subjects with specific IgE to inhalant allergens was asymptomatic. These subjects had a lower degree of sensitization than symptomatic sensitized subjects and had 'normal' prevalences of BHR and 'high eosinophil count'. Logistic regression showed that the presence of BHR increased the risk of having symptoms for subjects who were sensitized to indoor allergens. Low levels of specific IgE to indoor allergens were only associated with symptoms when BHR was present. Sensitization to outdoor allergens was associated with symptoms at all levels of specific IgE, independently of BHR or eosinophils.

CONCLUSION

Our epidemiological data suggest that whether low levels of specific IgE to indoor allergens lead to allergic symptoms is probably determined by the concurrent existence of inflammation of the airways.

Allergy and mucosal eosinophil infiltrate in ulcerative colitis

BACKGROUND

Data on allergy in ulcerative colitis (UC) have led to conflicting conclusions without proving any causal association. In this report we have investigated the presence of allergy and its possible relation with chronic colonic inflammation in patients with UC.

METHODS

Fifty UC patients underwent clinical, endoscopic, and histologic evaluations. The allergologic study included family/personal history; prick/patch exposition to airborne, food, and contact allergens; total serum IgE; and quantification of eosinophils in peripheral blood and intestinal mucosa. Diagnosis of rhinitis, conjunctivitis, and asthma was confirmed by specific provocation tests. Fifty healthy subjects were studied as control group.

RESULTS

A higher prevalence of allergic symptoms was found in patients (56%) and their first-degree relatives (52%) than in controls (18% and 26%) (P < 0.0001; P = 0.008). In patients skin tests showed increased rates of immediate (54%) and delayed-type (20%) hypersensitivity compared with controls (30% and 6%) (P= 0.01; P= 0.03). Diagnosis of allergic IgE-mediated disease was made in 19 cases and 6 controls (P= 0.01), and allergic contact dermatitis in 10 and 3, respectively (P= 0.03). IgE levels were higher in UC patients than in controls (P=0.02). No dose-response relationship was found between degree of colonic tissue eosinophilia and clinical. endoscopic, and histologic disease severity. The degree of colonic tissue eosinophilia was higher in the presence of skin reactivity to food allergens.

CONCLUSIONS

UC patients frequently show several markers of allergy. In particular, our data suggest an association between ulcerative colitis, tissue eosinophilia, and type-I allergy.

The prevalence of asthma and allergy among university freshmen in Eskisehir, Turkey

The aim of this study was to determine the current and cumulative prevalence of asthma, allergic rhinitis, atopic dermatitis and reactivities to allergen skin prick tests (SPT) among university freshmen. The data at the first stage were collated through the application of the European Community Respiratory Health Survey (-ECRHS-Stage I) questionnaire on 1603 students registering at various faculties and vocational colleges of Osmangazi University in Eskisehir, Turkey, in the academic year 1997-1998. At the second stage a physical examination as well as allergen SPTs were conducted on 151 students. Of the students within the study group, six (0.4%) had experienced an asthma attack within the previous 12 months, 11 (0.7%) had a past of asthma attacks and 123 (8.1%) reported wheezing attacks within the previous 12 months. The prevalence of asthma-like symptoms, rhinoconjunctivitis and dermatitis were found to be 17.0%, 10.0% and 5.9% respectively. Asthma and asthma-like symptoms were found to be significantly more prevalent among students who smoked. A positive SPT reaction to more than one allergen was found in 14.6% of the students. SPT positivity was 8.3% in asymptomatic students, 27.3% in asthmatic students, 14.5% in those with asthma-like symptoms, 28% in those with non-infectious rhinitis and 7.1% in those with dermatitis. In analysis of logistic regression, a history of atopy, as ascertained in the questionnaire, was seen to have a significant effect on SPT positivity. The rate of self-reported asthma and/or asthma-like symptoms among newly enrolled freshmen at the Osmangazi University was found to be lower than in other countries. Cigarette smoking was seen to increase such symptoms significantly, in comparison to non-smokers.

The prevalence of allergic rhinosinusitis: a review

A review of the literature indicates that there is an increase in the prevalence of self-reported symptoms suggestive of seasonal allergic rhinitis over the last 70 years. The reason for this remains unclear. Epidemiological studies which relate to the effect of pollution suggest that while pollution can exacerbate respiratory tract symptoms, there is no consistent evidence that high levels result in an increase in the prevalence of allergic rhinitis. The increased prevalence of house-dust mite, an alteration in immunity--possibly related to the number of childhood respiratory tract infections, and increased disease awareness, are all factors which may influence the reported prevalence of allergic rhinitis. At present the inconsistencies which exist in the literature mean that it is possible to 'pick' publications which support one view and ignore the rest, so that a variety of views may be held, each with apparently well referenced endorsement. The criteria defined by Bradford Hill (1965) to establish causation and not mere association between any of these factors and allergic rhinitis have, as yet, not been met (see Table V).

Asthma-like symptoms, atopy, and bronchial responsiveness in furniture workers

OBJECTIVES

To study the role of individual and occupational risk factors for asthma in furniture workers.

METHODS

296 workers were examined (258 men, 38 women) with a questionnaire of respiratory symptoms and diseases, baseline spirometry, bronchial provocative test with methacholine, and skin prick tests. Non-specific bronchial hyperreactivity was defined as when a provocative dose with a fall of 20% in forced expiratory volume in 1 second (PD20FEV1) was < 0.8 mg and atopy in the presence of at least one positive response to skin prick tests. Workers were subdivided into spray painters (exposed to low concentrations of diisocyanates and solvents), woodworkers (exposed to wood dusts), and assemblers (control group).

RESULTS

The prevalences of attacks of shortness of breath with wheezing and dyspnoea were higher in spray painters (13.5% and 11.5% respectively) than in woodworkers (7.7% and 6.3%) or in assemblers (1.6% and 1.6%); prevalences of chronic cough, asthma, and rhinitis were also slightly but not significantly higher in spray painters and in woodworkers than in assemblers. The difference in the prevalence of respiratory symptoms among the job titles was due to the atopic subjects, who showed a higher prevalence of chronic cough, wheeze, shortness of breath with wheeze, dyspnoea, and asthma in spray painters than in the other groups. The prevalence of non-specific bronchial hyperreactivity in subjects who performed bronchial provocative tests was 17.7%, with no significant difference among groups. Asthma symptoms were significantly associated with non-specific bronchial hyperreactivity. Asthma-like symptoms plus non-specific bronchial hyperreactivity was found in 4% of assemblers, 10% of woodworkers, and 13.3% of spray painters (chi 2 = 2.6, NS). Multiple logistic analysis taking into account individual (smoke, atopy, age) and occupational (job titles) risk factors confirmed that spray painters had higher prevalence of chronic cough than assemblers, and a trend in increasing the prevalence of shortness of breath with wheeze, dyspnoea, and asthma.

CONCLUSIONS

Painters in the furniture industry, particularly atopic subjects, are at higher risk of asthma-like symptoms than other job titles. In these workers asthma-like symptoms are more sensitive than non-specific bronchial hyperreactivity in detecting a negative effect of the occupational exposure.

Pollen-related allergy in Europe

The increasing mobility of Europeans for business and leisure has led to a need for reliable information about exposure to seasonal airborne allergens during travel abroad. Over the last 10 years or so, aeropalynologic and allergologic studies have progressed to meet this need, and extensive international networks now provide regular pollen and hay-fever forecasts. Europe is a geographically complex continent with a widely diverse climate and a wide spectrum of vegetation. Consequently, pollen calendars differ from one area to another; however, on the whole, pollination starts in spring and ends in autumn. Grass pollen is by far the most frequent cause of pollinosis in Europe. In northern Europe, pollen from species of the family Betulaceae is a major cause of the disorder. In contrast, the mild winters and dry summers of Mediterranean areas favor the production of pollen types that are rarely found in central and northern areas of the continent (e.g., the genera Parietaria, Olea, and Cupressus). Clinical and aerobiologic studies show that the pollen map of Europe is changing also as a result of cultural factors (e.g., importation of plants for urban parklands) and greater international travel (e.g., the expansion of the ragweed genus Ambrosia in France, northern Italy, Austria, and Hungary). Studies on allergen-carrying paucimicronic or submicronic airborne particles, which penetrate deep into the lung, are having a relevant impact on our understanding of pollinosis and its distribution throughout Europe.

Prevalence of atopy in students from Málaga, Spain

BACKGROUND

Epidemiologic studies are necessary to determine the prevalence of allergic diseases. This varies widely depending on allergen preparations and patients studied.

OBJECTIVE

To investigate the prevalence of atopic disease, skin test reactivity, total and specific IgE to common allergens, and other variables in a sample of students from Málaga, southern Spain.

METHODS

Three hundred sixty-five students (age 17.9 +/- 1.18) were interviewed by an allergist. Skin prick tests were performed with Dermatophagoides pteronyssinus, Artemisia vulgaris, Plantago lanceolata, Chenopodium album, Olea europaea, Phleum pratense, Parietaria judaica, Cynodon dactylon, Alternaria tenuis, and cat dander. Total and specific IgE to D. pteronyssinus, Olea, and Parietaria were determined.

RESULTS

Of all subjects studied, 19.9% suffered from rhinoconjunctivitis, 4.1% rhinoconjunctivitis plus asthma, 3.1% asthma alone, and 0.8% atopic dermatitis; 46.4% had a positive skin test to at least one allergen (28.2% to D. pteronyssinus, 20.4% to Olea, 13.8% to Phleum); and 43% had total IgE > 100 kU/L and 44.7% a family history of atopy. Allergic symptoms were strongly associated with skin test positivities and family allergic history. Patients with asthma or skin prick test positive had higher total IgE values than others (P < .01). There was a significant correlation between specific IgE values and wheal size in skin test.

CONCLUSIONS

Our findings confirm the high prevalence of atopic diseases, and the close relationship of skin tests reactivity (or presence of specific IgE) to allergens with symptoms of asthma and rhinitis. The presence of a family history of allergic diseases influences the development of positive skin tests and atopic illness. Dermatophagoides pteronyssinus and pollen of Olea europaea were found to be the most common allergens.

Serum immunoglobulins E are related to menstrual cycle

During a cross sectional epidemiological survey on a general population sample, 596 fertile women underwent total serum IgE determination. They completed an interviewer-administered standardized questionnaire and were categorized according to their menstrual period. They were divided into two groups: those from days 10 to 20, who were considered to be in the periovulatory phase, and those in the other phases. IgE mean values were significantly different (p = 0.01) in the two groups: particularly, lower IgE values were found in those in periovulatory phase, after accounting for smoking habit and atopic status. By multiple regression analysis, taking into account the independent effects of menstrual period, age, smoking habit, hours of fast, skin prick test reactivity and presence of cough, significantly lower IgE values in the periovulatory phase were found. We hypothesize the possibility that a decrease of IgE concentration occurs during midcycle: a reduced immune response might facilitate the ovuli implantation. Further studies are necessary to longitudinally investigate the trend of IgE in the same women, as well as the distributions and the trends of other immunoglobulins.