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PubMedDate not supplied

[Four-year follow-up of a group of workers with allergic sensitization employed in breeding of insects for biological pest control].

In two previous papers we reported allergic diseases in workers employed in breeding insects for biological pest control. It was found that Ephestia kuehniella, Orius laevigatus and other insects caused allergic rhinoconjunctivitis and asthma. The aim of this new study was to assess the relationship between the implementation of the recommended preventive measures and the decrease in sensitization in exposed workers. We performed a four-year follow-up of exposed workers, using the prick test and RAST with specific allergens and pulmonary function test at the end of the work shift. The results showed a decrease in skin test sensitization for Orius and Ephestia, a decrease in allergic diseases in the previously studied workers, and no symptoms in recently employed workers. These results confirm the validity of the recommended preventive measures: semi-closed cycles, gloves, protective masks, overalls and sunglasses.

Adult↗
PubMed1996

Antigen presentation in allergic sensitization.

IgE antibodies, when cross-linked by allergen on the surface of effector cells such as mast cells and basophils, are known to be directly responsible for immediate type hypersensitivity reactions. In addition, IgE may be involved in other, indirect, mechanisms, fundamental to the pathogenesis of allergic diseases, such as enhancement of the antigen capturing capacity of antigen presenting cells. IgE mediated antigen presentation could lead to a continuous activation of the immune system by very low concentrations of allergen. As a result, Th2 cell populations may expand and may induce more B cells to switch to IgE production. Subsequently, the overproduction of IgE and Th2 cells in a patient may explain the clinical observation that certain allergic patients deteriorate from sensitivity to a single group of allergens to sensitivity to multiple groups of allergens. Therefore, control of IgE production is not only important for the treatment of allergic symptoms, but may also regulate deterioration of allergy via the mechanism of CD23/IgE mediated allergen presentation by naive B cells. The role that monocytes, which have recently been found to express Fc epsilon RI, play in the pathogenesis of allergy, remains speculative. We hypothesize that their role may be to remove IgE from the circulation and re-direct the immune response from naive B cells. IgG antibodies which cannot be used for antigen uptake by B cells also direct the immune response to monocytes.

Antigen Presentation↗
PubMed2001

Expression of the Th1 chemokine IFN-gamma-inducible protein 10 in the airway alters mucosal allergic sensitization in mice.

Although the preliminary characterization of chemokines and their receptors has been prolific, comparatively little is known about the role of chemokines in the evolution of immune responses. We speculate that the preferential recruitment of a particular immune cell population has implications for the short- and long-term features of an adaptive response. To test this hypothesis, we employed adenovirus-mediated gene transfer to express the Th1-affiliated, CXC chemokine IFN-gamma-inducible protein (IP) 10 in the airways of mice undergoing a mucosal sensitization regimen known to result in a Th2-polarized allergic response. This resulted in a approximately 60-75% inhibition of eosinophils in the bronchoalveolar lavage (BAL); these inflammatory changes were accompanied by enhanced IFN-gamma, ablated IL-4, and, peculiarly, unaltered IL-5 and eotaxin levels in the BAL. The effect of IP-10 expression was shown to be dependent on IFN-gamma, as there was no statistically significant reduction in BAL eosinophilia in IFN-gamma knockout mice subjected to the IP-10 intervention. Flow cytometric analysis of mononuclear cells in the lung revealed a approximately 60% reduction in the fraction of CD4(+) cells expressing T1/ST2, a putative Th2 marker, and a parallel increase in the proportion expressing intracellular IFN-gamma following IP-10 treatment. The effect of IP-10 expression at the time of initial Ag encounter is persistent, as mice rechallenged with OVA following the resolution of acute inflammation exhibited reduced eosinophilia and IL-4 in the BAL. Collectively, these data illustrate that local expression of the chemokine IP-10 can introduce Th1 phenomena to a Th2-predisposed context and subvert the development of a Th2 response.

Adenoviruses, Human↗
PubMedDate not supplied

TNF-alpha enhanced allergic sensitization to house dust mite in brown Norway rats.

We have recently demonstrated that pulmonary exposure to residual oil fly ash (ROFA) resulted in enhanced sensitization to house dust mite (HDM) and augmented the development of allergic lung disease after allergen challenge. This effect was associated with increased tumor necrosis factor alpha (TNF-alpha), a macrophage- and epithelial cell-derived cytokine that promotes granulocyte migration to the lung. The present study examined whether exogenous administration of TNF-alpha enhances sensitization to HDM. One day prior to pulmonary sensitization with 10 microg HDM (5 microg each on days 1 and 3), female Brown Norway rats were instilled via the trachea with either 2.0 microg recombinant rat TNF-alpha, 2.0 microg bovine serum albumin (BSA), or 1,000 microg ROFA, and were challenged with 10 microg HDM 14 days later. Antigen-induced immediate bronchoconstriction responses, antigen-specific immunoglobulin E (IgE) titers, lymphocyte proliferation, (cytokines (TNF-alpha and interleukin [IL]-13), and eosinophils were elevated in rats treated with ROFA or TNF-alpha compared with BSA-treated controls after HDM challenge. Intratracheal administration of anti-TNF-alpha monoclonal antibody during ROFA exposure did not reduce ROFA-enhanced lymphocyte proliferation or IgE titers, but had a trend for reduced pulmonary inflammation. This study demonstrates that TNF-alpha has similar adjuvant activity as ROFA, but other factors may fulfill this function when TNF-alpha activity is blocked.

Animals↗
PubMed1999

Prevalence of hay fever and allergic sensitization in farmer's children and their peers living in the same rural community. SCARPOL team. Swiss Study on Childhood Allergy and Respiratory Symptoms with Respect to Air Pollution.

INTRODUCTION: Lower prevalence rates of allergic diseases in rural as compared with urban populations have been interpreted as indicating an effect of air pollution. However, little is known about other factors of the rural environment which may determine the development of atopic sensitization and related diseases. OBJECTIVE: The authors tested the hypothesis that children growing up on a farm were less likely to be sensitized to common aerollergens and to suffer from allergic diseases than children living in the same villages but in nonfarming families. MATERIALS AND METHODS: Three age groups of schoolchildren (6-7 years, 9-11 years, 13-15 years) living in three rural communities were included in the analyses. An exhaustive questionnaire was filled in by 1620 (86.0%) parents. A blood sample was provided by 404 (69.3%) of the 13-15 year olds to determine specific IgE antibodies against six common aeroallergens. RESULTS: Farming as parental occupation was reported for 307 children (19.0%). After adjustment for potential covariates such as family history of asthma and allergies, parental education, number of siblings, maternal smoking, pet ownership, indoor humidity and heating fuels, farming as parental occupation was significantly associated with lower rates of sneezing attacks during pollen season (adjusted OR 0.34, 95% CI 0.12-0.89) and atopic sensitization (adjusted OR 0.31, 95% CI 0.13-0.73) whereas the association with wheeze (adjusted OR 0.77 95% CI 0.38-1.58) and itchy skin rash (adjusted OR 0.86, 95% CI 0.49-1.50) was not statistically significant. The risk of atopic sensitization was lower in children from full-time farmers (adjusted OR 0.24, 95% CI 0.09-0.66) than from part-time farmers (adjusted OR 0.54, 95% CI 0.15-1.96). CONCLUSION: Factors directly or indirectly related to farming as parental occupation decrease the risk of children becoming atopic and developing symptoms of allergic rhinitis.

Adolescent↗
PubMed2006

An unexpected role for the anaphylatoxin C5a receptor in allergic sensitization.

The anaphylatoxins complement component 3a and 5a (C3a and C5a, respectively) are classically seen as proinflammatory mediators of allergic asthma that recruit inflammatory cells, induce edema, and cause bronchoconstriction. A few years ago, controversy arose when it was shown that C5-deficient mice were more susceptible to experimental asthma compared with C5-sufficient mice. In a study by Köhl et al. in this issue of the JCI, it is shown in a series of truly "complementary" experiments that C5a receptor (C5aR) blockade promotes Th2 sensitization upon first exposure to inhaled allergen, whereas C5aR blockade during established inflammation suppresses the cardinal features of asthma (see the related article beginning on page 783). Blockade of C5aR alters the function of airway DCs, crucial for inducing and maintaining Th2 responses in the lung. Targeting C5aR as a treatment for established asthma could be beneficial, but might be accompanied by sensitization to novel antigens.

Allergens↗
PubMed2001

Intranasal treatment with a recombinant hypoallergenic derivative of the major birch pollen allergen Bet v 1 prevents allergic sensitization and airway inflammation in mice.

BACKGROUND: The major birch pollen allergen Bet v 1 represents one of the most prevalent environmental allergens responsible for allergic airway inflammation. OBJECTIVE: In the present study we sought to compare the complete recombinant Bet v 1 allergen molecule with genetically produced hypoallergenic fragments of Bet v 1 regarding mucosal tolerance induction in a mouse model of allergic asthma. METHODS: BALB/c mice were intranasally treated with recombinant Bet v 1 or with two recombinant Bet v 1 fragments (F I: aa 1-74; F II: aa 75-160) prior to aerosol sensitization with birch pollen and Bet v 1. RESULTS: Intranasal application of F II, containing the major T cell epitope, led to significant reduction of IgE/IgG1 antibody responses, in vitro cytokine production (IL-5, IFN-gamma, IL-10) and negative immediate cutaneous hypersensitivity reactions comparable to the pretreatment with the complete rBet v 1 allergen. Moreover, airway inflammation (eosinophilia, IL-5) was inhibited by the pretreatment with either the complete Bet v 1 or F II. However, for prevention of airway hyperresponsiveness the complete molecule was required. The mechanisms leading to immunosuppression seemed to differ in their dependence on the conformation of the molecules, since tolerance induced with the complete Bet v 1, but not with F II, was transferable with spleen cells and associated with increased TGF-beta mRNA levels. CONCLUSION: We conclude that mucosal tolerance induction with recombinant allergens and genetically engineered hypoallergenic derivatives thereof could provide a convenient and safe intervention strategy against type I allergy.

Administration, Intranasal↗
PubMed1976

Studies of HLA antigen frequencies, IgE levels, and specific allergic sensitivities in patients having ragweed hayfever, with and without asthma.

In order to study genetic and immunological features which might be important in the pathogenesis of asthma, forty-one ragweed allergic seasonal asthmatics were first matched with forty-one ragweed allergic nonasthmatics on the basis of similar total IgE levels. No significant differences were observed in their sensitivity to ragweed antigen E (measured by histamine release), or in their skin response to ragweed antigens E, Ra3 and Ra5. An increased frequency of HLA-B5 was observed in nonasthmatics as compared to asthmatics (P = 0-03). Although frequencies of HLA-A1 and B8 were also elevated in nonasthmatics and HLA-B40 in asthmatics, these differences were not significant. The forty-one asthmatic patients were than paired with forty-one nonasthmatics patients were then paired with forty-one nonasthmatics on the basis of leucocyte sensitivity to ragweed antigen E. Similar HLA differences were found which were non-significant. No significant difference in total IgE levels were found between the two groups. Whereas no differences in IgE synthesis or antigen sensitivity was found in the two populations, the frequency of HLA antigens needs further study in larger groups.

Asthma↗
PubMed2001

[Association between soybean dust exposure, allergic sensitivity and profile of respiratory symptoms].

The purpose of this study was to correlate soybean dust (SD) exposure, skin reactivity to soybean hull (SH) allergens, and symptoms of asthma and/or allergic rhinitis. A group of 365 subjects with asthma and/or allergic rhinitis and a control group of 50 individuals without respiratory symptoms were studied. The level of exposure to SD is defined as follows: 1) direct (DE); 2) indirect (ID), and 3) urban (UE). All subjects completed standard questionnaires. Skin tests with a SH extract and with common allergens were performed by the prick technique (SPT). Fifty-six (15.3%) patients and no subjects from control group had positive SPT (histamine index > or = 0.5) with a SH allergen extract. The percentages of positive SPT to SH extract were 38.7%, 20.3% and 8.4% in subjects with DE, IE and UE, respectively (p < 0.001). Monosensitization to SH was absent in all subjects. The percent of subjects with positive SPTs to mites (p < 0.01), pollen (p < 0.01) and molds (p < 0.05) were higher in subjects with a positive SPT to SH versus those with a negative SPT to SH. Sixty-six percent of subjects with DE and 13.6% of subjects with IE or UE reported respiratory symptoms after SD inhalation (Odds Ratio: 12.67 [2.4-74.9], p < 0.001). Compared to subjects exclusively sensitized to mites, patients sensitized to SH presented significantly different clinical characteristics. Soybean production has been increasing in Argentina during the last 20 years, determining an increase in the population exposed to chronic SD inhalation. This fact determines a high risk of sensitization and triggering of respiratory symptoms in atopic subjects. This study demonstrates that there is: 1) a high prevalence of skin reactivity to SH in subjects with asthma and/or allergic rhinitis from Argentina and that this prevalence is associated with the level of exposure to SD, and 2) an association between sensitivity to SH and severity of asthma. Measures to avoid release and inhalation of SD in rural areas from Argentina are needed.

Adolescent↗
PubMed2002

Cockroach allergen Bla g 2: structure, function, and implications for allergic sensitization.

Exposure to German cockroach (Blattella germanica) allergens is associated with the development of chronic respiratory diseases, especially asthma. The mechanism by which allergic patients develop specific immunoglobulin E (IgE) responses to environmental allergens is unknown. However, recent reports provided evidence that enzyme activity, especially proteolytic activity, was a major contributor to allergenicity. Bla g 2 is one of the most potent cockroach allergens (prevalence of IgE responses of 60 to 80%) and shows homology to the aspartic proteinase family of enzymes. We investigated whether the allergenicity of Bla g 2 was linked to its putative enzymatic function. A molecular model of Bla g 2, based on the high resolution crystal structures of pepsin and chymosin, showed that the overall three-dimensional structure of Bla g 2 was similar to that of aspartic proteinases with a well-defined binding pocket. However, critical amino acid substitutions in the catalytic triads and in the "flap" region of the molecule suggested that Bla g 2 was inactive and homologous to mammalian pregnancy-associated glycoproteins. This was confirmed experimentally by enzyme assay. The results show dissociation between enzymatic activity and allergenicity for Bla g 2 and suggest that other genetic and environmental factors are important determinants of sensitization.

Amino Acid Sequence↗
PubMedDate not supplied

[Prevalence of respiratory symptoms, reduction in lung function and allergic sensitization in a group of traffic police officers exposed to urban pollution].

BACKGROUND: Environmental factors are believed to play a critical role in the development of allergic respiratory diseases, such as asthma and rhinitis. Particularly, the role of urban pollution in the pathogenesis of these diseases is debated. OBJECTIVES: The aim of the study was to investigate whether subjects with a well-defined occupational history of exposure to road traffic fumes presented an increased prevalence of respiratory symptoms of chronic bronchitis (cough), asthma (wheeze), and allergic sensitisation to the most common allergens and reduced lung function compared with an unexposed control group. METHODS: The study was conducted on 484 traffic police in Catania (465 men and 19 women), with a mean age of 45 +/- 7.9 years, who were subdivided into three groups. The first group included traffic police assigned to traffic direction, the second group included traffic police working in administrative offices, the third group included all traffic police who did not fall into the previous groups. In the first group, "truly exposed" subjects were identifed as police officers assigned to traffic direction in the last 8 years. Similarly, in the second group, "truly non-exposed" subjects were identified as police officers working in offices in the last 8 years. RESULTS: Statistical analysis showed a significant difference in mean age between the truly exposed group and the truly non-exposed group (p < 0.01). The truly exposed group showed a greater prevalence of symptoms (cough, wheeze and dyspnoea), and positive reaction to skin allergy tests compared with the "truly non-exposed group", but this increase did not reach statistical significance. Alterations of the respiratory function tests were more frequent in the non-exposed (14.3%) compared to the exposed group (9.6%). The highest prevalence of cough, dyspnoea and wheezing was detected in smokers compared to non-smokers and to ex-smokers within each group. CONCLUSIONS: Our results show a major prevalence of respiratory symptoms and allergic sensitisation in exposed traffic police compared with non-exposed police, although this did not reach statistical significance. Further epidemiological studies conducted on larger samples are required to better understand the role of road traffic pollution in inducing allergic respiratory diseases.

Female↗
PubMed1987

Keratinocyte expression of MHC class II antigens in allergic sensitization and challenge reactions and in irritant contact dermatitis.

Keratinocytes expressed major histocompatibility complex class II antigens during the development of irritant contact dermatitis, and during the induction of contact hypersensitivity, as well as in established allergic contact dermatitis. A battery of anti-class II monoclonal antibodies, some of which are specific for class II subregion products (DP, DQ, DR), was used in an immunohistochemical study of the sequential changes in the allergic challenge reactions to dinitrochlorobenzene (DNCB) and nickel, the irritant response to anthralin, and the induction of sensitization to DNCB. The induction of keratinocyte class II expression paralleled the influx of Leu-3a+ T cells into the skin and had occurred by 24 or 48 h in each type of reaction. Differential expression of class II subregion products on keratinocytes was noted: DR was the most frequently expressed molecule, followed by DP and DQ, although in the irritant response, DP expression was not observed. The importance of these observations can be decided only by functional studies.

Anthralin↗
PubMed2001

The association of allergic sensitization in mother and child in breast-fed and formula-fed infants.

Human milk contains immunologically active substances potentially capable of altering infant immune response. As part of the prospective Children's Respiratory Study, we assessed whether the association between maternal allergic status and allergic status of the child was altered by breast-feeding. Skin-prick tests for 7 common allergens were administered to 702 6-year-old children and their mothers. The percentage of children sensitized to specific allergens, maternal skin test response to that allergen, and whether or not the child was ever breast-fed was determined. Findings indicated that specific sensitization in the mother was associated with specific sensitization in the child only if the child was breast-fed. This indirectly supports the hypothesis that contents of milk differ with maternal allergic status, and appear to affect allergic status in the child. These results suggest that milk from allergic mothers either promotes a Th2 type immune response or suppresses Th1 immune response in the child.

Allergens↗
PubMedDate not supplied

[Allergic sensitivity in different groups of patients with atopic dermatitis].

69 patients with atopic dermatitis, aged 16-42 years, were examined. The patients were divided into two groups: group 1 consisted of patients with atopic dermatitis and bronchial asthma and/or allergic rhinitis (25 patients), group 2 consisted of patients without the respiratory syndrome (44 patients). Scarification skin tests made it possible to find out the essential difference in the sensitivity of the examinees in these two groups. In group 1 the prevalence of sensitization to house-dust mites in 23 patients (92%) with monosensitization in 8 patients (32% of the group) was observed. In group 2 sensitivity of house-dust mites was lower: it was registered in 16 patients (36%) with monosensitization in 2 patients (4% of the group). The presence of cross-sensitivity between mite allergens and Candida albicans was established. In accordance with the results of scarification skin tests, treatment included the use of antihistamine preparations, antipruritic remedies and hormonal ointments as well as the elimination of sensitizing allergens. Improvement was registered in 21 patients.

Adolescent↗
PubMed1997

Childhood antecedents of allergic sensitization in young British adults.

OBJECTIVE: This study was designed to investigate whether associations of self-reported hay fever with sibship size, birth order, infant feeding, and childhood socioeconomic status reflect variations in sensitization to common aeroallergens. METHODS: One thousand three hundred sixty-nine persons born throughout Britain in 1958 were followed up to age 34 to 35 years. The cohort included 1050 subjects with a history of asthma, wheezy bronchitis, wheezing, or pneumonia and 319 with no history of wheezing illness at ages 7, 11, 16, 23, or 33 years. Skin prick tests with extracts of mixed grass pollen, house dust mite (Der p 1), and cat fur were performed; and wheal diameters were measured. RESULTS: The prevalence of positive skin test results (> or = 3 mm wheal) was independently related (p < 0.01) to male sex, reduced numbers of older siblings (but not younger siblings), and higher socioeconomic status in childhood. Current cigarette smoking and maternal smoking during pregnancy were independently associated (p < 0.01) with a reduced prevalence of skin prick test positivity. No significant independent effects (p > 0.10) were found for adult social class, maternal age, birth weight, gestation, breast feeding, preschool nursery attendance, urban birthplace, or gas stove exposure. CONCLUSION: Factors related to small families and relative affluence in childhood promote atopic sensitization to a variety of aeroallergens in later life. These observations are consistent with the suggestion that early infection may protect against subsequent allergic disease.

Adult↗
PubMed2003

Allergic sensitization, symptoms, and lung function among bakery workers as compared with a nonexposed work population.

Only few studies have assessed relative risks on occupational asthma and allergy among bakery workers, and none of them have included respiratory and work-related symptoms as well as sensitization to occupational allergens and pulmonary function. A random sample of 246 workers from traditional and industrial bakeries in two regions of Belgium were compared with a reference population of 251 workers from a petrochemical plant in the same region. Data on skin test positivity, symptoms, and lung function were collected by standardized procedures. Differences between the two subpopulations were analyzed using multiple logistic and linear regression analyses. On average, bakery workers did not more often have skin test positivity than reference workers (39.4% and 42.6%, respectively). However, bakery workers had a strongly increased risk of sensitization to specific bakery allergens (OR 22.0, 95% CI = 6.3-77.1.), whereas their risks of positive skin tests to common allergens, including wheat pollen and storage mite, were significantly decreased (OR 0.6, 95% CI = 0.4-0.9). Bakery workers had significantly more often respiratory and work-related symptoms. Accordingly, they had lower lung function parameters. Atopy and sensitization to bakers' allergens were independent and additional risk factors for work-related symptoms. Bakery workers are at increased risk of respiratory and allergic symptoms and skin test reactivity to specific bakers' allergens wheat flour and alpha-amylase. Wheat pollen and storage mite should not be regarded as baker's allergens. Nevertheless, pulmonary function of bakery workers can be characterized as mild airway obstruction only.

Adult↗