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Purpose of Review: It is well known that combination of sensitization and exposure to inhaled environmental allergens is related to both the development and elicitation of symptoms of asthma and that avoidance of allergens would exert beneficial effects in the prevention and control of the disease. Other important factors include the relevance of other allergens, exposure to sensitizing agents also outside patient's home, exposure to irritants (like chemical air pollutants), and the involvement of the patient with a correct education. It is also likely that clinical phase of allergic airway disease and the degree of airways remodeling represent relevant factors for the clinical outcome of allergen avoidance procedure. We reviewed existing evidence on prevention of asthma through allergen avoidance., Recent Findings: The management of respiratory allergy is a complex strategy (including prevention, drugs, immunological, and educational interventions). In addition, it is difficult in real life to distinguish the efficacy of single interventions. However, a combined strategy is likely to produce clinical results. A combined strategy is likely to produce satisfactory management of asthma. Allergens are an important trigger factor for the development of symptoms of respiratory allergy, and avoidance measures are able to reduce allergen levels. It is likely that clinical phase of allergic airway disease and the degree of airways remodeling represents relevant factors for the clinical outcome of allergen avoidance procedures. Considering the management of respiratory allergy is a complex strategy; it is difficult in real life to distinguish the efficacy of single interventions. However, further studies better quantifying the effects of allergens are needed.

Allergies are complex diseases that result from interactions between multiple genetic and environmental factors. However, the increase in allergies observed in the past decades is explained exclusively by environmental changes occurring in the same period. Presently, the exposome, the totality of specific and nonspecific external environmental exposures (external exposome) to which a subject is exposed from preconception onward and their consequences at the organ and cell levels (internal exposome), is being considered to explain the inception, development, and exacerbations of allergic diseases. Among the best-studied environmental factors of the specific external exposome, indoor and outdoor aeroallergens and air pollutants play a key role in the etiopathogenesis of the inflammatory response to allergens and in clinical manifestations of allergic disease. Climate change, urbanization, and loss of biodiversity affect sources, emissions, and concentrations of main aeroallergens and air pollutants and are among the most critical challenges facing the health and quality of life of the still increasing number of allergic patients today and in the coming decades. Thunderstorm-related asthma is a dramatic example of the effects of combined environmental factors and an in vivo model for understanding the mechanisms at work in respiratory allergy. Environment- or lifestyle-driven aberrancies in the gut and skin microbiome composition represent key mediators of allergic diseases. A better knowledge of the effect of the external exposome on allergy development is crucial for urging patients, health professionals, and policymakers to take actions to mitigate the effect of environmental changes and to adapt to them., (Copyright © 2018 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Objective: To recapitulate the more recent epidemiologic studies on the association of air pollution with respiratory allergic diseases prevalence and to discuss the main limitations of current approaches used to establish a link between pollinosis and pollution., Data Sources: Through the use of PubMed, we conducted a broad literature review in the following areas: epidemiology of respiratory allergic diseases, effect of pollution and climate changes on pollen grains, and immunomodulatory properties of pollen substances., Study Selections: Studies on short- and long-term exposure to air pollutants, such as gaseous and particulate materials, on allergic sensitization, and on exacerbation of asthma symptoms were considered., Results: Trend in respiratory allergic disease prevalence has increased worldwide during the last 3 decades. Although recent epidemiologic studies on a possible association of this phenomenon with increasing pollution are controversial, botanic studies suggest a clear effect of several pollutants combined to climatic changes on the increased expression of allergenic proteins in several pollen grains. The current literature suggests the need for considering both pollen allergen and pollutant contents for epidemiologic evaluation of environmental determinants in respiratory allergies. We propose that a measure of allergenic potential of pollens, indicative of the increase in allergenicity of a polluted pollen, may be considered as a new risk indicator for respiratory health in urban areas., Conclusion: Because public greens are located in strict proximity to the anthropogenic sources of pollution, the identification of novel more reliable parameters for risk assessment in respiratory allergic diseases is an essential need for public health management and primary prevention area., (Copyright © 2017 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

In this report we describe a case of respiratory allergy induced by an unusual occupational exposure to rabbit. The patient worked as a part-time magician in theatres and private parties and the most popular performance of his show was to pull out a white rabbit from a top hat. Unfortunately, a few minutes after the extraction of rabbit from top hat, the patient experienced the onset of upper and lower airway symptoms, and in some occasions he was forced to stop the show and to use short acting β₂agonists and intramuscular steroids. The results of SPT and evaluation of serological specific IgE (ImmunoCAP and ImmunoCAP ISAC IgE) revealed allergic sensitization to rabbit (Oryctolagus cuniculus) dander as well as to Parietaria and dust mites. ImmunoCAP ISAC IgE excluded allergic sensitization to other cross-reacting animal allergens. Rabbit constitutes a reliable risk factor for allergic sensitization in individuals working as professional / part-time magicians or as animators in some recreational settings (resorts, parties, charity shows, etc).

Background: Although cockroach (CR) is an important cause of allergic sensitization worldwide, only a few data are available in Italy and in a previous study we have observed, in Naples area, a low prevalence of CR sensitization., Objectives: We sought to perform a prospective study for assessing the prevalence of allergic sensitization to CR in a sample of atopic population living in Campania district area (Southern Italy)., Methods: Ten Allergy Units or Centres of Campania district participated in this cross-sectional study. Each centre was required to collect the results of at least 100 allergy consultations in consecutive outpatients referred for actual or suspected respiratory allergy. We registered demographic data, type and duration of respiratory symptoms, pets ownership, possible exposure to CR allergens, results of the skin prick tests (SPTs)., Results: A total of 1477 patients were examined, 985 (66.68%) had a SPTs positivity to at least one allergen. In this context, ninety were sensitized to CR, thus the overall sensitization prevalence in subjects with respiratory allergy was 6.09% ranging between 0-11% and only five patients were mono-sensitized. Thirteen patients reported rhinitis (R) + bronchial asthma (A), twenty-one R + A + conjunctivitis (C), thirty-seven R + C, five only A and eleven individuals only R. Sixty-seven patients exhibited persistent and twenty-three intermittent symptoms. Dust mite constituted the first cause of associated sensitization to CR., Conclusions: The prevalence of allergic sensitization to CR is not negligible in population living in Campania district and shows a higher trend in comparison to that found recently and some years ago in Naples area. Finally, we suggest atopic individuals and especially those highly sensitized to mite allergens or those living in low-income areas to be tested by SPTs / evaluation of serum specific IgE to CR allergens to exclude the occurrence of CR allergic sensitization.

Most studies on the sensitization to horse allergens in populations without professional exposure have been carried out in geographical areas where the rate of horse ownership is high and horse riding is popular. Very few studies have been carried out in populations living in large urban areas. This gap in the literature probably reflects the widespread view that prevalence of horse-related allergy is low in urban populations because the latter are not regularly exposed to horses. On the contrary, we suggest that urban areas constitute a model useful to study potential modalities of exposure and sensitization to horse allergen by other routes of exposure than horse-riding. In this article, we describe the risks related to various modalities of exposure to horse allergen, clinical aspects of airway sensitization to horse allergens in patients living in urban areas, and non-occupational exposure to horse allergen. In addition, we illuminate some aspects related to dispersion of horse allergens from sources such as stables to indoor environments.

Serum albumin (SA) constitutes an intriguing puzzle that is involved in allergic sensitizations from different sources and induces different clinical manifestations. In this article, we describe the role of sensitization to SAs in inducing allergic diseases and the complex interactions and cross-reactivity between SA resulting from its presence in various mammalian tissues and fluids. SAs alone are an uncommon cause of allergic sensitization in airways, but these allergenic proteins likely play a significant role as cross-reacting allergens in individuals sensitized to several types of animal dander. SAs are a minor allergen in milk but a major allergen in meats. Recently, bovine SA has been added to the culture medium of spermatozoids used for artificial insemination. As a consequence, some case reports have shown that bovine SA may be a causative agent in severe anaphylaxis after standard intrauterine insemination or in vitro fertilization.

Background: Horses play a significant role in people's leisure time in Italy and other countries, but few data are available on IgE-mediated sensitization to horse allergens in patients without occupational exposure. We assessed, in a multicentric survey, the prevalence of horse sensitization in atopic subjects and its clinical characteristics., Methods: Allergists from the whole Italian territory were required to collect the results of skin prick tests from at least 100 consecutive subjects. Those patients with a positive skin test to horse dander underwent a detailed interview concerning clinical history, pet ownership and possible exposure., Results: Data from 3,235 outpatients were collected and 2,097 had at least 1 skin positivity. Among them, 113 (5.38%) were sensitized to horse dander (9 monosensitized). Thirty patients reported direct horse contact (4 owners and 26 for riding or occasional contact), 23 patients were sometimes in contact with horse owners and 60 subjects denied any direct or indirect exposure. Among 9 horse monosensitized patients, 6 had intermittent and mild rhinitis and 3 persistent moderate/severe rhinitis plus asthma. Three of them were horse owners or riders and the remaining had no contact with the animal., Conclusions: Our data evidence that the rate of sensitization to horse dander is not negligible and probably underestimated. In susceptible, not occupationally exposed individuals, horse contact, but also indirect or no apparent exposure, may induce sensitization. We recommend inclusion of horse allergen in the routine panel for the diagnosis of respiratory allergy., (Copyright © 2011 S. Karger AG, Basel.)

Climate change is unequivocal and represents a possible threat for patients affected by allergic conditions. It has already had an impact on living organisms, including plants and fungi with current scenarios projecting further effects by the end of the century. Over the last three decades, studies have shown changes in production, dispersion and allergen content of pollen and spores, which may be region- and species-specific. In addition, these changes may have been influenced by urban air pollutants interacting directly with pollen. Data suggest an increasing effect of aeroallergens on allergic patients over this period, which may also imply a greater likelihood of the development of an allergic respiratory disease in sensitized subjects and exacerbation of symptomatic patients. There are a number of limitations that make predictions uncertain, and further and specifically designed studies are needed to clarify current effects and future scenarios. We recommend: More stress on pollen/spore exposure in the diagnosis and treatment guidelines of respiratory and allergic diseases; collection of aerobiological data in a structured way at the European level; creation, promotion and support of multidisciplinary research teams in this area; lobbying the European Union and other funders to finance this research.

Background: Data on allergic sensitization to horse allergen in modern urban areas are scarce. The aim of this study was to investigate the characteristics of allergic sensitization and the modality of exposure to horse allergens in atopic patients living in an urban area and without occupational exposure to horse and/or horse-derived materials., Methods: From among 1822 consecutive outpatients, we selected all subjects who had an immediate skin reaction to horse dander. We recorded the patients' clinical history including a meticulous evaluation of the possibility and eventual modality of horse exposure, and the results of skin-prick tests (SPT) and total/specific IgE antibody analyses., Results: Of 1201 SPT-positive patients, 35 (3.43%) were sensitized to horse dander. No patient was mono-sensitized. Six individuals reported having direct horse contact, 10 subjects had occasional contact with horse owners (indirect exposure), and 19 denied direct or indirect exposure to horses or horse allergens. Twenty of the 35 horse-sensitized patients reported both nasal and bronchial symptoms, 14 had rhinitis without asthma and one had asthma without rhinitis., Conclusions: Our results suggest that allergic sensitization to horse allergens is more frequent than expected in urban-dwelling subjects without direct or occupational exposure to horses. Highly atopic individuals or individuals who are sensitized to common pet dander should undergo SPT and evaluation of serum specific IgE before starting activities involving regular contact with horses such as riding, and before entering environments associated with horses.

The allergenic content of the atmosphere varies according to climate, geography and vegetation. Data on the presence and prevalence of allergenic airborne pollens, obtained from both aerobiological studies and allergological investigations, make it possible to design pollen calendars with the approximate flowering period of the plants in the sampling area. In this way, even though pollen production and dispersal from year to year depend on the patterns of preseason weather and on the conditions prevailing at the time of anthesis, it is usually possible to forecast the chances of encountering high atmospheric allergenic pollen concentrations in different areas. Aerobiological and allergological studies show that the pollen map of Europe is changing also as a result of cultural factors (for example, importation of plants such as birch and cypress for urban parklands), greater international travel (e.g. colonization by ragweed in France, northern Italy, Austria, Hungary etc.) and climate change. In this regard, the higher frequency of weather extremes, like thunderstorms, and increasing episodes of long range transport of allergenic pollen represent new challenges for researchers. Furthermore, in the last few years, experimental data on pollen and subpollen-particles structure, the pathogenetic role of pollen and the interaction between pollen and air pollutants, gave new insights into the mechanisms of respiratory allergic diseases.

Background: The major cat allergen, Fel d 1, is ubiquitous, and clothes of cat owners are important vehicles for its distribution and dispersal in cat-free environments., Objective: We assessed the efficiency of a standard vacuum-cleaning in removing the cat allergen from cotton fabrics, experimentally contaminated by a prolonged contact with cats., Methods: Fifteen rectangles (80 x 100 cm) of a widely used cotton material were kept in baskets of male cats for 1 week. Afterwards, the squares were cut in half. One half was immediately sampled for cat allergen, and the other half was vacuum-cleaned for 15 minutes by a commercially available device before sampling. Five identical cotton rectangles not exposed to cats served as controls. Samples were collected with a high-volume vacuum air-sampler. Particulate material was harvested onto filters with 25-mm diameter and 2 microm pore size, extracted in phosphate buffer with BSA and then assayed for the Fel d 1 allergen with an ELISA method. The results were expressed as micrograms of allergen per filter., Results: After vacuum-cleaning the amounts of Fel d 1 extracted from cat-exposed fabrics were not significantly reduced ( t = 3.118; P > 0.005), with respect to the non vacuum-cleaned tissues. No Fel d 1 was found in control fabrics., Conclusions: Our study suggest that vacuum-cleaning by using a commercially available device is not able to remove significant amounts of cat allergen from cotton fabrics exposed to cats.

Background: Although rabbits are becoming popular as pets, data about the characteristics of allergic sensitization to rabbit allergens in patients without professional exposure are scarce., Aims of the Study: To determine the characteristics of allergic sensitization to pet rabbits, and the role of direct and indirect exposure to rabbits and rabbit allergens in non-professionally exposed patients., Methods: From among 1124 consecutive outpatients, we selected all subjects with an immediate skin reaction to rabbit dander. A clinical history including a careful evaluation of the modality of rabbit exposure, the results of skin-prick tests (SPTs) and total/specific IgE antibodies were recorded. The prevalence of rabbit ownership in the Naples area was also calculated., Results: Among 753 SPT-positive patients, 20 (2.65%) were sensitized to rabbit dander (5 patients were mono-sensitized). Fifteen patients reported direct rabbit contact (7 were rabbit owners and 8 had occasional contact outside the home); 3 patients had indirect exposure through contact with rabbit owners and 2 patients denied any direct or indirect exposure. Rabbit mono-sensitized owners of pet rabbits had persistent (moderate-severe) symptoms. The prevalence of rabbit ownership is 1.56%., Conclusions: In susceptible not professionally exposed individuals, direct rabbit contact and, in some cases, indirect or no apparent exposure, may induce allergic sensitization to rabbit allergens. A progressive increase in rabbit sensitization (also by indirect exposure) may be expected as a consequence of the increase in rabbit ownership.

The skin prick test (SPT) is the most appropriate diagnostic approach to identify IgE sensitization to aeroallergens, foods, hymenoptera venom and some pharmacological compounds. SPT is considered a safe diagnostic approach, but several fatal or near-fatal reactions have been described. Based on the literature, the occurrence of systemic reactions with inhalant allergens has diminished over the last thirty years, whereas fresh food, hymenoptera venom and antibiotic SPT still carry some risk. In general, the risk of systemic reactions is lower with SPT than with intradermal testing. Some patients (history of previous anaphylactic reactions, small children, pregnant women, uncontrolled asthma, high degree of reactivity) should be considered at higher risk of systemic/anaphylactic reactions. Based on the literature, the risk of fatality due to SPT is extremely remote, and severe/anaphylactic reactions are rare. Nevertheless, this risk cannot be completely excluded, especially in highly susceptible subjects. Physicians who perform SPT should be aware of this and apply simple precautional rules.

It is widely acknowledged that avoidance of allergens such as those derived from foods, drugs, latex and stinging insects results in a complete disappearance of symptoms. By contrast, although it has been clearly shown that allergens are an important risk factor for the development of respiratory symptoms and that several avoidance measures reduce allergen levels, whether this gives clinical improvement in symptoms is debatable. Many reasons could be invoked to justify this evident discrepancy. Apart from the intrinsic methodological aspects (e.g. single or combined interventions measure, population studied, severity of respiratory symptoms, outcomes, evaluated parameters, etc.), it is important to outline that a successful approach requires that the avoided allergen is the only and real factor responsible for symptoms, the patient's education and the use of a comprehensive protocol to reduce allergen exposure. Other important factors include the involvement of the patient, the relevance of other allergens/non-specific agents, and exposure to sensitizing agents also outside patient's home. It is likely that the clinical phase of allergic airway disease and the degree of bronchial (and also nasal) remodelling, in each individual, represent relevant factors for the clinical outcome of allergen avoidance procedures. Since the management of respiratory allergy is a complex strategy (including drugs, allergen avoidance, immunological and educational interventions), it is difficult in real life to distinguish the efficacy of a single intervention in comparison to the others. A combined strategy is likely to produce better clinical results.

Background: Cat allergens are ubiquitous because the clothing of cat owners constitutes an important source of distribution of Fel d 1 in cat-free environments. Since Fel d 1 can adhere to a variety of surfaces, we sought to verify if human hair belonging to individuals with or without a cat at home might represent a reservoir and be a possible carrier of cat allergens., Methods: Seventy-three women (25 with a non-neutered male cat and 25 with a dog at home, and 23 controls without any direct contact with these animals) were recruited. The collection of material from hair was carried out using a modified version of a battery-powdered portable sampler. Particulate material was harvested onto glass fiber filters (25 mm in diameter, with a pore size of 2 microm; AP 20 Millipore, Milan Italy), extracted in phosphate buffer with BSA and then assayed for the evaluation of cat allergen using an ELISA based on anti-Fel d 1 monoclonal antibody., Results: Detectable levels of cat allergen were found in 2 controls, in 2 women with a dog at home and in 13 women with a cat at home, respectively., Conclusions: In some women with a cat at home, hair constitutes a significant reservoir of Fel d 1. It is likely that these amounts of cat allergen might contribute to allergic sensitization when released in cat-free environments.

Background: The relationship between exposure to cat/dog in domestic environments and development of allergic sensitization to pet allergens is still controversial., Objective: To test the role of indirect exposure to cat, we aimed to evaluate the amounts of cat specific IgE in sensitized subjects with or without cat at home., Methods: Three hundred six adult patients with a previous diagnosis of allergic sensitization to cat allergens (by skin prick test) were enrolled for this study. Among 306 men and women sensitized to cat (and other allergens), 150 owned a cat for at least 10 years ( direct exposure) and 156 had never owned this animal (indirect exposure). An internal questionnaire specifically designed for the study was completed by the same allergists during the screening consultation: the results of skin prick tests, personal and clinical data, periods of symptoms and characteristics of cat ownership were carefully recorded. Specific IgE to cat extract was determined by the Pharmacia CAP System FEIA (Pharmacia Diagnostics, Uppsala, Sweden) and Immulite 2000 (Diagnostic Products Corporation, Los Angeles, USA) RESULTS: Although specific IgE to cat allergen were significantly higher in patients with cat at home (F = 42.77; p < 0.001), high amounts of these antibodies were found also in sera of subjects indirectly exposed to cats., Discussion: The results of our study demonstrate that the degree of serological sensitization to cat allergens may be relevant also in subjects without any direct contact with cats (indirect exposure).

An increasing volume of evidence suggests that early contact of children with the allergens of furred pets (especially those produced by cats) may determine a lower risk of developing allergic sensitisation to these materials. A possible explanation of this data is that an early inhalation of high levels of the major cat allergen Fel d 1 induces the production of IgG and IgG4 antibodies with a "protective" effect. Other authors have shown that the prevalence of allergic sensitisation to cats, in adults, is reduced in those patients exposed to the lowest and highest levels of the allergens. On the contrary, the risk of developing sensitisation to cats is significantly higher when the patients were exposed to intermediate levels of Fel d 1. Moreover, epidemiological studies have demonstrated a relatively low prevalence of cat allergy (about 10%) in some countries where rates of cat ownership are high. This data confirms the role of indirect exposure to pet allergens in inducing allergic sensitisation. Clothes of pet owners have been indicated as the carriers for the dispersal of these allergens in pet-free environments. However, it is important to point out that exposure of highly sensitised patients to relevant amounts of pet allergens (such as in a pet shows/shops) may determine a dramatic exacerbation of nasal and/or bronchial symptoms.

Background: The relationship between pet ownership and the risk of developing allergic sensitization to pet allergens is still controversial. We assessed the possible effect of direct exposure to dog allergen on skin reactivity in dog-sensitized patients., Methods: We studied, in a case-control trial, 116 adults sensitized to dog allergens (55 with a dog at home for at least 10 years and 61 without it). The degree of response was assessed by skin prick test, performed in quadruplicate with three concentrations of allergenic extract: A (1:20 w/v), B (1:200 w/v) and C (1:2000 w/v). The mean diameter of each wheal was assessed using a visilog image analysis software., Results: No significant difference between the two groups in the wheal diameters induced by the three concentrations of dog allergen could be demonstrated., Conclusion: The results of this study suggest that direct dog exposure in adults with respiratory allergy is not associated with greater cutaneous response to dog allergens, as compared to non exposed subjects.

Both the prevalence and severity of respiratory allergic diseases such as bronchial asthma have increased in recent years. Among the factors implicated in this "epidemic" are indoor and outdoor airborne pollutants. Urbanisation with its high levels of vehicle emissions and Westernised lifestyle parallels the increase in respiratory allergy in most industrialised countries, and people who live in urban areas tend to be more affected by the disease than those of rural areas. In atopic subjects, exposure to air pollution increases airway responsiveness to aeroallergens. Pollen is a good model with which to study the interrelationship between air pollution and respiratory allergic diseases. Biological aerosols carrying antigenic proteins, such as pollen grains or plant-derived paucimicronic components, can produce allergic symptoms. By adhering to the surface of these airborne allergenic agents, air pollutants could modify their antigenic properties. Several factors influence this interaction, i.e., type of air pollutant, plant species, nutrient balance, climatic factors, degree of airway sensitisation and hyperresponsiveness of exposed subjects. However, the airway mucosal damage and the impaired mucociliary clearance induced by air pollution may facilitate the penetration and the access of inhaled allergens to the cells of the immune system, and so promote airway sensitisation. As a consequence, an enhanced immunoglobulin E-mediated response to aeroallergens and enhanced airway inflammation favoured by air pollution could account for the increasing prevalence of allergic respiratory diseases in urban areas.

Respiratory allergic diseases such as rhinitis and bronchial asthma appear to be increasing worldwide, affecting in particular subjects living in urban areas, and the reasons for this increase are still largely unknown. Although the role played by air pollution has yet to be clarified, a body of evidence suggests that urbanization, with its high levels of vehicle emissions and a westernised lifestyle are linked to the rising frequency of these diseases observed in most industrialized countries. Laboratory studies confirm the epidemiological evidence that inhalation of some pollutants, either individually or in combination, adversely affect lung function in asthmatics. Air pollutants may not only increase the frequency and intensity of symptoms in already allergic patients but may promote airway sensitization to airborne allergens in predisposed subjects. By attaching to the surface of pollen grains and of plant-derived paucimicronic particles, pollutants can modify the morphology of these antigen-carrying agents and alter their allergenic potential. In addition, by inducing airway inflammation, pollutants may overcome the mucosal barrier and so "prime" allergen-induced responses. In other words airway mucosal damage and impaired mucociliary clearance induced by air pollution may facilitate the access of inhaled allergens to the cells of the immune system.

The increasing prevalence of allergic sensitization to indoor allergens such as dust mites, pets and cockroaches is the result of the changes in indoor environments induced by human activities. The Westernized lifestyle and the increasing time spent indoors determine a reduction in natural air ventilation and, consequently, higher levels of allergen concentrations and longer exposure to allergens. The major cat allergen Fel d 1 is carried by small-dimension particles (< 5 microm diameter) that readily become airborne and persist immodified for a long time. Fel d 1 must be considered a ubiquitous allergen because it has been found in indoor environments and even in public places where a cat has never been kept. Recent research has demonstrated that clothing of cat owners may contribute to the dispersal of Fel d 1 in cat-free environments. Therefore, washing Fel d 1-contaminated clothes should be considered a simple and effective method for removing this allergen from clothing and, consequently, reducing the risk of Fel d 1 dispersion. Cockroach allergens constitute another important cause of environment-related respiratory allergy and may trigger asthma exacerbations in sensitized individuals. In the prevention of cockroach allergy, the use of chemical agents associated with an intensive vacuum cleaning of indoor environments is an important tool in removing cockroach material containing allergenic proteins. Early recognition of allergy-predisposed babies, monitoring indoor allergens and adequate strategies of allergen avoidance are likely to be important means for reducing the prevalence of bronchial asthma.

Respiratory allergic diseases (rhinitis, rhinosinusitis, bronchial asthma and its equivalents) appear to be increasing in most countries, and subjects living in urban and industrialized areas are more likely to experience respiratory allergic symptoms than those living in rural areas. This increase has been linked, among various factors, to air pollution, which is now an important public health hazard. Laboratory studies confirm the epidemiological evidence that inhalation of some pollutants, either individually or in combination, adversely affect lung function in asthmatics. The most abundant air pollutants in urban areas with high levels of vehicle traffic are respirable particulate matter, nitrogen dioxide and ozone. While nitrogen dioxide does not exert consistent effects on lung function, ozone, respirable particulate matter and allergens impair lung function and lead to increased airway responsiveness and bronchial obstruction in predisposed subjects. However, besides acting as irritants, airborne pollutants can modulate the allergenicity of antigens carried by airborne particles. By attaching to the surface of pollen grains and of plant-derived paucimicronic particles, pollutants can modify the morphology of these antigen-carrying agents and after their allergenic potential. In addition, by inducing airway inflammation, which increases airway epithelial permeability, pollutants overcome the mucosal barrier and so facilitate the allergen-induced inflammatory responses. Moreover, air pollutants such as diesel exhaust emissions are thought to modulate the immune response by increasing immunoglobulin E synthesis, thus facilitating allergic sensitization in atopic subjects and the subsequent development of clinical respiratory symptoms.

The aim of this study was to evaluate the prevalence of allergic sensitization to cockroach allergens in a group of atopic patients living in the urban area of Naples. Four hundred and fourteen consecutive patients were submitted to the following diagnostic procedures: anamnestic data; clinical examination; and skin prick test by using a standardized pricker and allergenic extracts, one of which contained a mix of whole bodies of Blattella orientatis, Blattella germanica and Periplaneta americana. The evaluation of cockroach serum specific IgE antibodies was carried out in the 19 patients (4.58%) who showed a positive skin prick test to cockroach allergens. The majority of cockroach sensitive individuals were males and exhibited perennial respiratory symptoms; 17 of these patients were also sensitized to Dermatophagoides pteronyssinus allergens. The results of our study demonstrated that the prevalence of cockroach sensitization as determined by skin prick test in our urban area (Naples) is lower in comparison to other European studies. Up to now, it is not clear if the association between cockroach-D. pteronyssinus sensitization can be determined by a cross-reactivity between the allergens or by their coexistence in the same indoor environments. Considering the absence of a visual presence of cockroaches in the indoor environments of our cockroach-sensitive patients we suggest the possibility of unrecognized exposure to cockroach materials and, moreover, the possibility of the carrying of such allergens from infested places on clothing, as we demonstrated for Fel d I.

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.

In the last few years interest in the clinical aspects of Olea europaea (O.e.) pollen allergy has increased. For many years we have observed in our geographical area a perennial pattern of clinical symptoms in subjects with monosensitization to O.e. allergens without any worsening during the olive pollen season. We tried to demonstrate the clinical relevance of O.e. sensitization in our patients and, moreover, to determine why this pattern is elicited. We selected a group of 26 patients with rhinitis and/or bronchial asthma and an immediate positive skin reaction only to O.e. pollen extract. Using commercially available extracts and reagents, the following diagnostic procedures were performed: Skin prick tests (SPT), specific O.e. IgE assays, nonspecific bronchial provocation tests (NsBPT) and specific nasal provocation tests (sNPT), respectively, in patients with bronchial asthma and rhinitis. Pollen counts and a statistical analysis using Spearman's correlation test were also carried out. 21 of 26 O.e. monosensitive patients showed perennial type of clinical symptoms without any particular worsening during olive pollination season. We found a high degree of statistical significance between the results of SPT/sNPT and serum specific IgE determination. Many patients exhibited a late response after sNPT. No definitive data were derived from our findings, even though the occurrence of many late reactions after sNPT could in part explain the perennial type of nasal symptoms. We would like to emphasize the necessity of better purification and standardization of diagnostic materials and, moreover, suggest further studies with a greater number of O.e. monosensitive patients living in different geographical areas.

In the Oleaceae family, the most allergenic pollen is produced by Olea europaea, the olive tree, which in the Mediterranean area has been recognized as one of the most important cause of seasonal respiratory allergy. The olive pollination season lasts from May to the end of June and sometimes causes severe symptoms (oculorhinitis and/or bronchial asthma). Olive pollinosis is quite rare in the form of monosensitization. Although adults are affected the most, olive sensitization can be recognized in children, too. However, it is not easy to be sure about the clinical relevance of allergic sensitization to olive, even in patients with positivity to this pollen, as results from allergological tests in vivo and/or in vitro, because positivity to Olea pollen is not equivalent to clinical responsibility, above all in patients without seasonal respiratory symptomatology. Studies on the allergenic content of O. europaea pollen are currently in progress. In Northern and Central Europe, where there are no olive trees, there are two commonly occurring genera of the Oleaceae family, namely Fraxinus and Ligustrum, but these have a low frequency of allergic sensitization. A fourth anemophilous member of the Oleaceae, Phillyrea, has a more regional distribution in some parts of the Mediterranean. Other nonanemophilous and usually not allergenic Oleaceae genera are Forsythia, Jasminum and Syringa.

Background: Allergenic pollens are usually detected in outdoor air by using volumetric spore traps, which allow measurement of atmospheric concentration as pollen grains per m3 of air. The results of the pollen count are useful primarily for outdoor environments while most people spend most of the day indoors., Objective: The purpose of our study was to compare outdoor pollen levels with allergenic activity measured both outdoors and indoors., Methods: We used a Lanzoni spore trap to measure airborne Urticaceae pollen and filters collecting particles simultaneously indoors and outdoors and assayed each filter for Parietaria judaica allergenic activity. Samples were collected at the Allergological Service of the "A. Cardarelli" Hospital in Naples with the balcony open on some days and closed on others. Allergenic activity (ng/m3) was measured using the immunocapture RAST., Results: With the balcony open there was no great difference between outdoor and indoor allergenic activity, but with the balcony closed there was a reduction of indoor allergenic activity of about one-third in comparison with outdoor allergenic activity. Statistical analysis (Pearson correlation test) indicated a significant correlation between outdoor allergen levels and indoor allergen levels with the balcony open (r = .4415, P < .05), but not with the balcony closed (r = .3160, P > .05); a significant correlation between outdoor pollen count and indoor allergen levels with the balcony open (r = .4809, P < .05), but not with the balcony closed (r = .3858, P > .05); and a highly significant correlation (r = .5225, P < .001) between outdoor pollen count and outdoor allergen levels., Conclusions: These data provide scientific evidence for the recommendation to hay fever patients to remain indoors during seasons with high levels of outdoor pollens.

Parietaria, a plant belonging to the family of Urticaceae, is a major source of allergenic pollen in Europe. In the context of a multinational study, we investigated whether in allergic subjects antibody response towards Par o 1, the major allergen from P. officinalis, was associated with defined HLA-DRB1* alleles. The study population consisted of 234 allergic patients: 65 from Bulgaria, 30 from Israel, 99 from Italy, and 40 from Spain. In the Italian study group, the prevalence of ST positivity to Parietaria was 77%. In Parietaria ST-positive subjects, the prevalences of IgG and IgE serum Ab towards Par o 1 were 91% and 75%, respectively. HLA-DRB1*1101 and/or 1104 were significantly positively associated with the presence of IgG Ab and with high levels of IgE Ab towards this allergen (p = 0.0007 and p = 0.012, respectively). In the Spanish study group, the positive association of DR1100 with responsiveness to Par o 1 was confirmed (p = 0.02, RR = 4, and p = 0.002, RR = 7, for IgG and IgE Ab, respectively). None of the Bulgarian patients had IgE Ab to Par o 1, whereas IgG Ab response was observed in 7 out of 65 subjects and was positively associated with DRB1*1101 and/or 1104 (p = 0.025). In the Israeli study group, responsiveness to Par o 1 was not associated with specific HLA-DRB1* alleles. In conclusion, this study shows that in allergic patients from three European populations antibody response to the major allergen from the pollen of Parietaria is associated with HLA-DRB1*1101 and/or 1104. Our data suggest that this association is stronger in subjects monosensitized to Parietaria.

The aim of our study was the evaluation of clinical and epidemiological aspects of P pollen allergy, which is a very frequent cause of respiratory allergy in the Mediterranean area, in a homogeneous group of 442 monosensitive subjects (235 females and 207 males, mean age about 30 years) living in Naples. All patients underwent the following diagnostic procedures: anamnestic evaluation with an internal questionnaire, physical examination, SPT with commercially available allergenic extracts (DHS-Bayropharm Milan Italy); sNPT, NsBPT, and serum specific IgE determinations were also carried out in three groups of 50 different subjects. The results of our study show a highly relevant intensity of SPT positivity (4+ and 3+ in about 95% of patients). The age of onset of clinical symptoms ranged between 20-25 years, and the majority of P monosensitized patients were born in the spring months, with an early exposure to P allergens. Rhinoconjunctivitis and bronchial asthma, alone or association, represent the most common clinical manifestation of this allergy. The season in which patients experience clinical symptoms is prevalently spring (75, 12%). However, many people show a multiseasonal pattern (18, 55%). The frequency of SPT positivity to P allergens is increasing in the last 15 years, probably due to increased urban air pollution. In conclusion, the results of this study demonstrate the high frequency and severity of this pollinosis and seem to confirm some epidemiological aspects connected with other allergenic pollens (birth during the seasonal period of pollination and association with a high urban air pollution).

Allergy to Parietaria judaica pollen causes significant morbidity in many areas of the world. In addition to rhinitis, patients who are allergic to this pollen have a high incidence of asthma. The pollinating season is long, making this particular allergy challenging for clinicians to treat. This study was designed to determine if immunotherapy with an alum adsorbed partially purified Parietaria extract (Alpare Parietaria) containing a targeted maintenance dose of 12,500 BUs was effective in decreasing rhinitis symptoms in patients allergic to Parietaria. Using a double-blind placebo-controlled technique 36 patients received placebo or active extract for 2 years. Twenty (11 placebo and nine active) completed the 2 year study. Efficacy of treatment was evaluated by determining changes in skin reactivity, visual analog scores, diary symptom scores and end of study assessments. Reactions were monitored as well. Skin-test suppression was marginally significant in the actively treated group after 1 year and showed even more significant suppression after the second year. Nasal block, rhinorrhoea and sneezing all were significantly decreased in the active group. The nasal provocation test did not show a significant change after 1 year, in either group, but after 2 years of treatment the active group did show significant improvement. Although almost all patients in the actively treated group experienced local reactions, the incidence of systemic reactions was not different between the two groups. In conclusion, immunotherapy with this extract at this dose was effective in ameliorated rhinitis symptoms in patients allergic to Parietaria judaica.