A review of anti-IgE monoclonal antibody (omalizumab) as add on therapy for severe allergic (IgE-mediated) asthma

Bronchial asthma is recognized as a highly prevalent health problem in the developed and developing world with significant social and economic consequences. Increased asthma severity is not only associated with enhanced recurrent hospitalization and mortality but also with higher social costs. The pathogenetic background of allergic-atopic bronchial asthma is characterized by airway inflammation with infiltration of several cells (mast cells, basophils, eosinophils, monocytes, and T-helper (Th)2 lymphocytes). However, in atopic asthma the trigger factors for acute attacks and chronic worsening of bronchial inflammation are aeroallergens released by pollens, dermatophagoides, and pets, which are able to induce an immune response by interaction with IgE antibodies. Currently anti-inflammatory treatments are effective for most asthma patients, but there are asthmatic subjects whose disease is not completely controlled by inhaled or systemic corticosteroids and who account for a significant portion of the healthcare costs of asthma. A novel therapeutic approach to asthma and other allergic respiratory diseases involves interference in the action of IgE, and this antibody has been viewed as a target for novel immunological drug development in asthma. Omalizumab is a humanized recombinant monoclonal anti-IgE antibody approved for treatment of moderate to severe IgE-mediated (allergic) asthma. This non-anaphylactogenic anti-IgE antibody inhibits IgE functions, blocking free serum IgE and inhibiting their binding to cellular receptors. By reducing serum IgE levels and IgE receptor expression on inflammatory cells in the context of allergic cascade, omalizumab represents a new class of mast cells stabilizing drugs; it is a novel approach to the treatment of atopic asthma. Omalizumab therapy is well tolerated and significantly improves symptoms and disease control, reducing asthma exacerbations and the need to use high dosage of inhaled corticosteroids. Moreover, omalizumab improves quality of life of patients with severe persistent allergic asthma which is inadequately controlled by currently available asthma medications. In conclusion omalizumab may fulfil an important need in patients with moderate to severe asthma.

Effectiveness of vacuum-cleaning in removing Fel d 1 allergen from cotton fabrics exposed to cats

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.

Thunderstorm-asthma and pollen allergy

Thunderstorms have been linked to asthma epidemics, especially during the pollen seasons, and there are descriptions of asthma outbreaks associated with thunderstorms, which occurred in several cities, prevalently in Europe (Birmingham and London in the UK and Napoli in Italy) and Australia (Melbourne and Wagga Wagga). Pollen grains can be carried by thunderstorm at ground level, where pollen rupture would be increased with release of allergenic biological aerosols of paucimicronic size, derived from the cytoplasm and which can penetrate deep into lower airways. In other words, there is evidence that under wet conditions or during thunderstorms, pollen grains may, after rupture by osmotic shock, release into the atmosphere part of their content, including respirable, allergen-carrying cytoplasmic starch granules (0.5-2.5 microm) or other paucimicronic components that can reach lower airways inducing asthma reactions in pollinosis patients. The thunderstorm-asthma outbreaks are characterized, at the beginning of thunderstorms by a rapid increase of visits for asthma in general practitioner or hospital emergency departments. Subjects without asthma symptoms, but affected by seasonal rhinitis can experience an asthma attack. No unusual levels of air pollution were noted at the time of the epidemics, but there was a strong association with high atmospheric concentrations of pollen grains such as grasses or other allergenic plant species. However, subjects affected by pollen allergy should be informed about a possible risk of asthma attack at the beginning of a thunderstorm during pollen season.

Rabbit allergens: a significant risk for allergic sensitization in subjects without occupational exposure

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.

Sensitization to rabbit allergens in Italy--a multicentre study in atopic subjects without occupational exposure

BACKGROUND

Rabbits as pets are becoming popular in Italy, but few data are available on sensitization to rabbits in patients without occupational exposure. In a multicentre study, we assessed the prevalence of rabbit sensitization in atopic subjects and their modality of exposure.

METHODS

Allergists from the whole country were required to assess the presence of skin prick test positivity to rabbits in about 100 consecutive patients with allergic rhinitis and/or asthma. In the rabbit-positive patients, clinical history, pet ownership and modality of exposure were assessed.

RESULTS

Skin tests were performed on 2,329 outpatients, of whom 1,602 had at least one positivity. Among them, 39 (2.43%) were sensitized to rabbit dander (4 monosensitized). The prevalence of sensitization ranged between 0.65 and 4.72%. Nineteen patients reported direct rabbit contact (10 for ownership and 9 for occasional contact) and 5 patients only indirect exposure through the contact with rabbit owners. Fifteen subjects denied any direct or indirect exposure. All the monosensitized patients were rabbit owners and had persistent (moderate-severe) respiratory symptoms.

CONCLUSIONS

Sensitization to rabbit in Italy is not to be neglected. In atopic subjects without occupational exposure, contact and indirect exposure to rabbits may induce sensitization. A progressive increase in rabbit sensitization is expected in the future as consequence of the increased rabbit ownership.

New insights in allergen avoidance measures for mite and pet sensitized patients. A critical appraisal

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.

Environmental risk factors and allergic bronchial asthma

The prevalence of allergic respiratory diseases such as bronchial asthma has increased in recent years, especially in industrialized countries. A change in the genetic predisposition is an unlikely cause of the increase in allergic diseases because genetic changes in a population require several generations. Consequently, this increase may be explained by changes in environmental factors, including indoor and outdoor air pollution. Over the past two decades, there has been increasing interest in studies of air pollution and its effects on human health. Although the role played by outdoor pollutants in allergic sensitization of the airways has yet to be clarified, a body of evidence suggests that urbanization, with its high levels of vehicle emissions, and a westernized lifestyle are linked to the rising frequency of respiratory allergic diseases observed in most industrialized countries, and there is considerable evidence that asthmatic persons are at increased risk of developing asthma exacerbations with exposure to ozone, nitrogen dioxide, sulphur dioxide and inhalable particulate matter. However, it is not easy to evaluate the impact of air pollution on the timing of asthma exacerbations and on the prevalence of asthma in general. As concentrations of airborne allergens and air pollutants are frequently increased contemporaneously, an enhanced IgE-mediated response to aeroallergens and enhanced airway inflammation could account for the increasing frequency of allergic respiratory allergy and bronchial asthma. Pollinosis is frequently used to study the interrelationship between air pollution and respiratory allergy. Climatic factors (temperature, wind speed, humidity, thunderstorms, etc) can affect both components (biological and chemical) of this interaction. By attaching to the surface of pollen grains and of plant-derived particles of paucimicronic size, pollutants could modify not only the morphology of these antigen-carrying agents but also their allergenic potential. In addition, by inducing airway inflammation, which increases airway permeability, pollutants overcome the mucosal barrier and could be able to "prime" allergen-induced responses. There are also observations that a thunderstorm occurring during pollen season can induce severe asthma attacks in pollinosis patients. After rupture by thunderstorm, pollen grains may release part of their cytoplasmic content, including inhalable, allergen-carrying paucimicronic particles.

Systemic reactions from skin testing: literature review

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.

Sensitization to horse allergens without apparent exposure to horse. Report of two cases

It has been well established that occupational exposure to horses increases the risk of allergic sensitization to horse hair, on the contrary very few data have been published in individuals without direct contact with horses. We describe two cases of severe respiratory symptoms triggered by a single direct exposure in two patients with only 4-5 previous short contacts with horses during the entire their life, since they live in urban area of Naples. Cutaneous and serological diagnostic tests showed significant sensitization to horse dander other than some common inhalant allergens. Our report suggests that, in already (but unaware) horse-sensitized patients, the last direct contact with a horse has triggered severe respiratory symptoms. Passive carriage of horse allergen by the clothes of individuals in contact with horses/horse environments or a cross-reactivity between horse allergen (a lipocalin) and the major allergens (also lipocalins) of several furred animals are likely to explain our findings. Some other considerations can be derived by the clinical observation. First, it is likely that allergic sensitization to horse allergens could be more frequent than expected also in subjects without direct exposure to horse because of living in urban areas. Secondly, individuals suspected to be highly atopic or those already sensitized to some pet dander should be tested by SPTs/radio-allergo-sorbent test before the introduction of a pet indoors or, in the case of a big animal as the horse, a direct horse contact/entering into environments containing a horse.

Human Hair: An Unexpected Source of Cat Allergen Exposure

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.

The effect of pet ownership on the risk of allergic sensitisation and bronchial asthma

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.

The degree of serological sensitization to cat allergen in patients with or without cat at home

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).

Safety of celecoxib in patients with adverse skin reactions to acetaminophen (paracetamol) and nimesulide associated or not with common non-steroidal anti-inflammatory drugs

BACKGROUND

Acetaminophen (paracetamol--P) and Nimesulide (N) are widely used analgesic-antipyretic/anti-inflammatory drugs. The rate of adverse hypersensitivity reactions to these agents is generally low. On the contrary non-steroidal anti-inflammatory drugs (NSAIDs) are commonly involved in such reactions. Celecoxib (CE) is a novel drug, with high selectivity and affinity for COX-2 enzyme.

OBJECTIVE

We evaluated the tolerability of CE in a group of patients with documented history of adverse cutaneous reactions to P and N associated or not to classic NSAIDs.

METHODS

We studied 9 patients with hypersensitivity to P and N with or without associated reactions to classic NSAIDs. The diagnosis of P and N-induced skin reactions was based in vivo challenge. The placebo was blindly administered at the beginning of each challenge. After three days, a cumulative dosage of 200 mg of CE in refracted doses were given. After 2-3 days, a single dose of 200 mg was administered. All patients were observed for 6 hours after each challenge, and controlled again after 24 hours to exclude delayed reactions. The challenge was considered positive if one or more of the following appeared: erythema, rush or urticaria-angioedema.

RESULTS

No reaction was observed with placebo and eight patients (88.8%) tolerated CE. Only one patient developed a moderate angioedema of the lips.

CONCLUSION

Only one hypersensitivity reaction to CE was documented among 9 P and N-highly NSAIDs intolerant patients. Thus, we conclude that CE is a reasonably safe alternative to be used in subjects who do not tolerate P and N.

Safety of celecoxib in patients with adverse skin reactions to acetaminophen (paracetamol) and other non-steroidal anti-inflammatory drugs

BACKGROUND

Acetaminophen (paracetamol-P) is a widely used analgesic-antipyretic drug with no anti inflammatory effects and its rate of adverse hypersensitivity reactions is very low. On the contrary non-steroidal anti-inflammatory drugs (NSAIDs) are commonly involved in side effects. Celecoxib (CE) is a novel drug, with high selectivity and affinity for COX-2 enzyme.

OBJECTIVE

We evaluated the tolerability of CE in a group of patients with documented history of adverse cutaneous reactions to P and to classic NSAIDs.

METHODS

We studied 29 patients with hypersensitivity to P and classic NSAIDs. The diagnosis of P-induced skin reactions was based on in vivo challenge. The placebo was blindly administered at the beginning of each challenge. After three days, a cumulative dosage of 200 mg of CE in refracted doses was given. After 2-3 days, a single dose of 200 mg was administered. All patients were observed for 6 hours after each challenge, and they were controlled again after 24 hours to exclude delayed reactions. The challenge was considered positive if one or more of the following appeared: erythema, rash or urticaria-angioedema.

RESULTS

No reaction was observed with placebo and twenty eight patients (96.5 %) tolerated CE. Only one patient developed a moderate angioedema of the lips.

CONCLUSION

Only one hypersensitivity reaction to CE was documented among 29 P-intolerant patients. Thus, we conclude that CE is a reasonably safe alternative which can be used in subjects who do not tolerate P.

Direct and prolonged exposure to dogs does not influence the degree of skin prick test positivity to dog allergen

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.

Anti-IgE monoclonal antibody (omalizumab) in the treatment of atopic asthma and allergic respiratory diseases

Since the discovery of immunoglobulin E (IgE) antibodies thirty-six years ago, our understanding of the mechanisms of allergy has improved to such an extent that we can now better differentiate allergy from non-allergic hypersensitivity, and allergic/atopic from intrinsic/non-atopic bronchial asthma. IgE antibodies are crucial immune mediators of airway inflammation in allergic atopic asthma and IgE-mediated hypersensitivity reactions are the likely mechanisms of allergen-induced airway obstruction. In addition, IgE may cause chronic airway inflammation in asthma through effector cells activated via high-affinity (Fcepsilon RI) or low-affinity (Fcepsilon RII) IgE receptors. Therapeutic anti-IgE antibodies able to reduce free IgE levels and to block the binding of IgE to Fcepsilon RI without cross-linking IgE and triggering degranulation of IgE-sensitised cells have been developed. This non-anaphylactogenic anti-IgE monoclonal antibody (rhuMAb-E25; omalizumab) binds IgE at the same site as these antibodies bind Fcepsilon RI and Fcepsilon RII. As a consequence, omalizumab inhibits IgE effector functions by blocking IgE binding to high-affinity receptors on IgE effector cells and does not cause mast cell or basophil activation because it cannot bind to IgE on cell surfaces where the Fcepsilon R1 receptor already masks the anti-IgE epitope. Studies in patients with atopic asthma demonstrated that omalizumab decreases serum IgE levels and allergen-induced bronchoconstriction during both the early and late-phase responses to inhaled allergen. In several clinical controlled trials omalizumab resulted to be able to reduce asthma-related symptoms, to decrease corticosteroid use and to improve quality of life of asthmatic patients. The anti-IgE approach to asthma treatment has several advantages, including concomitant treatment of other IgE-mediated diseases (allergic rhinitis, allergic conjunctivitis, atopic dermatitis and food allergies), a favourable side-effect profile and a twice-monthly dosing frequency.

Cutaneous and serological responses to cat allergen in adults exposed or not to cats

BACKGROUND

The relationship between pet ownership and the risk of developing respiratory allergic sensitization to pet allergens is still controversial.

OBJECTIVE

To determine the degree of cutaneous immediate hypersensitivity and the levels of specific IgE and IgG4 antibodies to cat allergen in cat sensitized patients directly or indirectly exposed to this animal.

METHODS

We studied 112 adolescents and adults sensitized to cat allergens (43 with and 69 without a cat at home). There were also 52 control subjects, 27 atopic non-sensitized to cat and 25 non-atopic. The degree of immediate hypersensitivity was assessed by using, in duplicate, skin prick test with four five-fold dilutions of cat hair allergen extract with the content of its major allergen Fel d 1 quantified in micrograms plus positive (10 mg/ml histamine chlorhydrate) and negative (saline solution) controls. The resulting wheal areas were analysed by means of Parallel Line Assay. A blood sample was collected from every patient and control subjects for the evaluation of serological cat specific IgE and IgG4 antibodies.

RESULTS

Patients with cat at home had a lower cutaneous response than patients without this pet. The difference in the skin sensitivity was estimated in 3.4 times (P<0.01). There was no statistical difference between the levels of cat specific IgE antibodies in the two groups of patients (P=0.065). The levels of Fel d 1 specific IgG4 antibodies showed a statistically significant association with the presence of cat at home, with higher levels in patients owing cat at home than in patients without this pet (P<0.001).

CONCLUSION

The results of this study demonstrate that direct cat exposure in adolescents and adults with respiratory allergy is associated with a lower cutaneous response to cat allergenic extract, assessed by SPT and compared with indirect exposure. In patients with cat at home mean levels of specific IgE are statistically comparable whereas the levels of IgG4 are higher in comparison with subjects not exposed to cats. The role of indirect exposure to cat allergens in airways sensitization also in adults is emphasized. Moreover, patients with cat at home show a cutaneous and serological sensitization to cat allergen not higher in comparison with subjects not exposed to cats.

Evaluation of the nocebo effect during oral challenge in patients with adverse drug reactions

The nocebo effect is the onset of untoward reactions following the administration of an indifferent substance. The oral challenge with alternative drugs plays a central role in the management of drug allergy and the use of inert substances is part of this procedure. We evaluated the occurrence and clinical characteristics of nocebo effect in patients with adverse drug reactions. Six hundred patients, seen in three different centres (Genoa, Naples and Verona) with a history of reactions to drugs, underwent a blind oral challenge with the administration of an indifferent substance and active drugs. The administration of an inert substance provoked untoward reactions in 54 patients (27%) in Verona, 60 (30%) in Naples and 48 (24%) in Genoa. The overall occurrence of nocebo effect was 27%. The majority of reactions were subjective symptoms (itching, malaise, headache etc), perceived as troublesome by all subjects. The occurrence was significantly higher in women than in men. Our data, collected in a large population, confirm that the nocebo effect occurs frequently in clinical practice. In managing adverse drug reactions through oral challenge the nocebo effect is mandatory to recognize false positive responses.

Severe systemic allergic reaction induced by accidental skin contact with cow milk in a 16-year-old boy. A case report

The symptoms of food allergy are rarely induced by skin contact. A 16-year-old boy was referred to our Allergology Centre after an episode of systemic symptoms triggered by accidental skin contact with a drop of cow milk (CM) dripped from a sandwich containing fresh cheese. The patient had been allergic to CM from the age of 24 months and had experienced several episodes of urticaria-angioedema after the ingestion of tiny or "hidden" amounts of CM proteins. In vivo and in vitro diagnostic procedures showed intense sensitisation to all CM proteins (1/100 dilutions of allergenic extracts produced large wheals, and class 4 specific IgE antibodies. Total IgE antibodies were elevate (770.0 UI/). A moderate degree of bronchial hyperresponsiveness was found (PC20 metacholine: 3.90 milligrams). This case report suggests that patients with a high degree of sensitisation to CM proteins should be alert to the danger of skin contact and should beware of "hidden" CM allergens.

Focus on cat allergen (Fel d 1): immunological and aerodynamic characteristics, modality of airway sensitization and avoidance strategies

The increasing frequency of pet ownership (especially cats) in many industrialized countries has raised the level of exposure to the allergens produced by these animals. Moreover, it is likely that modern energy-saving systems and the wide use of upholstered furniture has resulted in closer contact between cats (and their allergens) and humans. Many different methods have been developed to quantify the main cat allergen (Fel d 1) in settled dust and in ambient air. The threshold levels of cat allergen inducing sensitization or triggering respiratory symptoms in sensitized patients have been calculated in settled dust, but airborne amounts of Fel d 1 probably represent a more reliable index of allergen exposure. Noticeably, the amount of Fel d 1 may be relatively high also in confined environments where cats have never been kept. It has been demonstrated that clothes of cat owners are the main source for dispersal of allergens in cat-free environments. This fact may be of relevance, because recent studies have shown that allergic sensitization to cats is more likely to develop in children exposed to moderate levels of this allergen than in children exposed to high amounts of Fel d 1. The ubiquity of cat allergen may justify the common observation that allergen avoidance is often insufficient to reduce the risk of developing allergic sensitization and/or symptom exacerbation in highly susceptible patients. Further efforts are needed to improve the efficacy of Fel d 1 avoidance strategies to try to reduce the risk of allergic sensitization to this allergen.

A multicenter evaluation of the CARLA system for the measurement of specific IgE antibodies vs. other different methods and skin prick tests

The evaluation of specific IgE by using appropriate immunoassays represents a useful alternative diagnostic procedure where skin prick tests (SPTs) are not conclusive in clarifying the etiological role of suspected allergens. This study compares the results of the evaluation of specific IgE by using the CARLA system vs. other commercially available immunoassays (CAP system, Ala-STAT Medical system, ALLERgen IFCI Clone System) carried out on the same blood samples obtained from allergic/SPTs negative patients and vs. SPTs. We evaluated serum specific IgE produced against five selected allergens (Dermatophagoides pteronyssinus, Olea europaea, Parietaria judaica, Lolium perenne and Phleum pratense) by using these immunoassays and the correlations between the results of SPTs and IgE evaluations. We demonstrated a good correlation between these last parameters including a high degree of sensitivity and specificity. The reproducibility of the CARLA system was very high by comparing the results obtained by two different laboratories. The results of the CARLA system were well correlated to those of other well-known immunoassays such as CAP system and Ala STAT system. In conclusion, the CARLA system represents an efficient and reliable immunoassay for the evaluation of serum specific IgE.

General strategy for the management of bronchial asthma in pregnancy

Epidemiological studies showed that bronchial asthma is one of the most common diseases which can complicate pregnancy (1-7%). In about 0.05-2% of the cases, asthma occurs as a life-threatening event. In the common medical practice a waiting strategy or, even, the complete refusal for drug therapies are frequently observed. This is justified by the fear of the possible adverse effects of drugs on developing fetus. On the contrary, several studies have demonstrated that severe and uncontrolled asthma may produce serious maternal and fetal complications, such as gestational hypertension and eclampsia, fetal hypoxemia and an increased risk of perinatal death. Therefore, all pregnant women suffering from bronchial asthma should be considered as potentially at high risk of complications and adequately treated. Since asthma is a chronic disease with acute exacerbations, a continuous treatment is mandatory to control symptoms, to prevent acute episodes and to reduce the degree of airway inflammation. The global strategy for asthma management in pregnancy includes five main topics: (1) objective evaluation of maternal/ fetal clinical conditions; (2) avoidance/control of triggering factors; (3) pharmacological treatment; (4) educational support; (5) psychological support. As far as drug therapy is concerned, the International Guidelines and Recommendations suggest that the general strategy does not differ significantly from management outside pregnancy. We herein review and discuss the available data and the criteria for the management of asthma in pregnant patients.

Severe oral symptoms after the use of an oral solution containing ketoprofen in two NSAIDs-sensitive patients

Cutaneous application of the nonsteroidal anti-inflammatory drug (NSAID) ketoprofen has been reported to induce contact dermatitis. However, there is no report of intraoral symptoms after the use of solutions containing this drug. In this report we describe two cases of severe intraoral symptoms after the use of a gargle containing ketoprofen in two patients with NSAIDs hypersensitivity. The patients underwent diagnostic procedures 6 months after the episodes of intraoral symptoms. Procedures included skin prick test for inhalant and food allergens, and total- and specific-IgE determinations to evaluate the presence of atopy. A single-blind, placebo-controlled challenge with different dilutions (1/1000, 1/100, 1/10, and 1/1) of ketoprofen oral solution was carried out by a modified version of a standardized protocol. We used the same commercial solution without the drug as placebo. Diagnostic procedures failed to demonstrate allergic sensitization to the common inhalant and food allergens. Both patients experienced a slight intraoral itching and edema of the lips a few minutes after the intraoral use of 1/100 dilution of active drug. Our cases suggest that the contact of an oral solution containing ketoprofen with oral mucosa may induce locally severe oral manifestations. Patients with NSAIDs sensitivity should be warned on the potential risk of using an oral solution containing this class of drugs.

Outdoor air pollution, climatic changes and allergic bronchial asthma

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 induced by outdoor air pollution in urban areas

A wealth of evidence suggests that allergic respiratory diseases such as rhinosinusitis and bronchial asthma have become more common worldwide in recent years and a great deal of etiologic and pathogenic research has been carried out to evaluate the possible causes of this increasing trend. There is also some evidence that increased atmospheric concentrations of pollutants such as ozone (O3), oxides of nitrogen (NOX), respirable particulate (PM10) and volatile organic chemicals (VOC5), which result from increased use of liquid petroleum gas or kerosene, may be linked to the increased prevalence of allergic diseases which develop more frequently in urban areas of developed countries. Since bronchial asthma is a disease which can be aggravated by inhaled compounds, health effects of air pollutants have received attention. In fact various studies have demonstrated that inhalation of air pollutants such as O3, nitrogen dioxide (NO2) and sulphur dioxide (SO2), either individually or in combination, can enhance the airway response to inhaled allergens in atopic subjects inducing asthma exacerbations. Moreover, experimental studies have shown that diesel exhaust particulate (DEP) causes respiratory symptoms and is able also to modulate the immune response by increasing immunoglobulin (Ig)E synthesis in predisposed animals and humans. There is also some evidence that air pollutants can interact with aeroallergens in the atmosphere and/or on human airways, potentiating their effects. In fact, by inducing airway inflammation which increases epithelial permeability, some pollutants overcome the mucosal barrier and so prime allergen-induced responses. However, air pollution and climatic changes may also have an indirect effect on the allergic response by influencing quantitatively and qualitatively the pollen production of allergenic plants.

Efficacy of dry-cleaning in removing Fel d 1 allergen from wool fabric exposed to cats

BACKGROUND

The main cat allergen (Fel d 1) is ubiquitous, having been found even in indoor environments and public places where a cat has never been kept. Clothes of cat owners constitute a carrier for the distribution of Fel d 1 allergen in these environments. Schools, for example, may be a site of indirect exposure to cat allergens.

OBJECTIVE

Our goal was to investigate the efficacy of commercial dry-cleaning in removing cat allergens from wool fabrics that had been exposed to cats to evaluate a possible preventive procedure.

METHODS

Twenty-six identical wool "squares" (80 x 100 cm) were put in cat baskets for 1 week. In our laboratory, the squares were cut in half (40 x 50 cm), and one half was subjected to high-volume sampling for 5 minutes in a cat-free room. The other half was subjected to commercial dry-cleaning and then the high-volume sampling. Five wool squares not exposed to cats served as controls. Dust was collected from the wool squares with a high-volume air sampler. Particulate material was harvested onto glass fiber filters (AP 20 Millipore, Milan, Italy) with 25-mm diameter and 2-microm pore size. Each dust sample was assayed by affinity-purified monoclonal antibody against purified Fel d 1. The results were expressed as micrograms per filter. Statistical analysis was done by using the paired t test.

RESULTS

Before dry-cleaning, Fel d 1 allergen was detected on all cat-exposed wool squares. No appreciable cat allergen was detected on control materials. After commercial dry-cleaning, the amounts of Fel d 1 extracted from cat-exposed squares were significantly reduced (t = 14.63; P < 0.001) but not abolished. Three of the five control squares were contaminated by Fel d 1.

CONCLUSIONS

Commercial dry-cleaning effectively removes large amounts of cat allergen from wool materials exposed to cats but does not completely abolish this protein. Further, low Fel d 1 contamination may occur during this procedure.

The role of outdoor air pollution and climatic changes on the rising trends in respiratory allergy

Evidence suggests that allergic respiratory diseases such as hay fever and bronchial asthma have become more common world-wide in the last two decades, and the reasons for this increase are still largely unknown. A major responsible factor could be outdoor air pollution, derived from cars and other vehicles. Studies have demonstrated that urbanization and high levels of vehicle emissions and westernized lifestyle is correlated with the increasing frequency of pollen-induced respiratory allergy. People who live in urban areas tend to be more affected by pollen-induced respiratory allergy than those from of rural areas. Pollen allergy has been one of the most frequent models used to study the interrelationship between air pollution and respiratory allergic diseases. Pollen grains or plant-derived paucimicronic components carry allergens that can produce allergic symptoms. They may also interact with air pollution (particulate matter, ozone) in producing these effects. There is evidence that air pollutants may promote airway sensitization by modulating the allergenicity of airborne allergens. Furthermore, 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. In addition, vegetation reacts with air pollution and environmental conditions and influence the plant allergenicity. Several factors influence this interaction, including type of air pollutants, plant species, nutrient balance, climatic factors, degree of airway sensitization and hyperresponsiveness of exposed subjects.

Mechanisms and characteristics of airway sensitization to indoor allergens

The increasing prevalence of allergic respiratory diseases, and particularly of bronchial asthma, has been linked to changes induced by human activities in outdoor and indoor environments. People living in industrialized countries spend most of their time indoors: in private homes, offices and means of transport. Indoor environments are not a refuge from outdoor air pollution. Modern systems for energy saving such as insulated windows and doors reduce the indoor natural ventilation and consequently increase the rate of indoor humidity. These conditions may determine an increase in the level of indoor pollutants (tobacco smoke, gases produced by cooling processes etc.) and of allergens derived from mites, domestic animals and cockroaches. Upholstered furniture, wall-to-wall carpets, central heating systems and/or humidifiers may also contribute to the growth of mite populations. The increasing levels of exposure to pollutants and allergens in indoor environments represents a risk factor for the development of airway sensitization, especially if these materials are inhaled early in life. The major cat allergen Fel d 1 is considered an ubiquitous allergen, since it has been found in many indoor environments where a cat has never been kept. The clothing of cat owners seems to help spread Fel d 1 in cat-free environments. Sensitization to cockroach allergens is very common in patients living in urban areas where unhygenic conditions may favour the growth of cockroach populations. Monitoring of the levels of allergens and strategies of allergen and pollutant avoidance in indoor environments are the main ways to reduce the prevalence of respiratory allergies induced by these materials.

Pets and cockroaches: two increasing causes of respiratory allergy in indoor environments. Characteristics of airways sensitization and prevention strategies

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.

Cat allergen sampling by a new personal collector (Partrap FA 52)

Recent studies carried out by us and others have demonstrated that Fel d 1, the main cat allergen, may be passively transferred by human clothing in cat-free environments. Consequently, the monitoring of the Fel d 1 levels either in indoor environments or on allergen-contaminated clothes of sensitized cat owners should be considered an important tool in prevention strategies. The aim of this study was to evaluate the efficacy of a personal air sampler (Partrap FA 52) in capturing cat allergen from wool fabrics. Seven identical wool webs (80 x 100 cm) were put in the baskets of seven male cats for 1 week. In our laboratory each web was divided into two parts (80 x 50 cm), the first of which was then divided in two parts (40 x 50 cm) and each was vacuumed directly by one collector. The second part was dry-cleaned at a professional cleaners, divided in two parts and then vacuumed. For the dust collection from wool webs we used a fixed high volume air sampler (CF/20 Gelaire Flow Labs, Milan, Italy) and a personal collector (Partrap FA 52, Coppa Biella, Italy). Fel d 1 content was determined using a two site ELISA (ALK-Abelló Group, Madrid, Spain). Both air samplers collected cat allergens from cat-exposed wool fabrics before and after dry cleaning. There were significant differences between the levels of Fel d 1 before and after dry cleaning by using either CF/20 or Partrap FA52 and between the levels of Fel d 1 before dry cleaning using CF/20 and Partrap FA 52. The results of our study suggest that Partrap FA 52, although its air flow is half that of the CF/20, is able to collect even residual amounts of cat allergen from wool webs after dry cleaning and consequently may constitute a simple and effective means of monitoring the levels of Fel d 1 on the clothes of cat owners.

An epidemiological survey on the allergological importance of some emerging pollens in Italy

Epidemiological studies on the pollens responsible for allergic diseases throughout Italy are lacking. Routine diagnostic panels consist prevalently of grass, Parietaria, weeds, birch, olive and mugwort. Considering the great variety of Italian geographical areas and the observation of the growing allergological importance of new botanical species (e.g., ambrosia), a survey on pollen species considered "minor" was necessary. A panel of "emerging" pollens (birch, hazelnut, alder, hornbeam, cypress, ragweed) and a routine panel were used to skin prick test 2,934 consecutive outpatients with respiratory pathology of suspected allergic origin, in 21 centers across Italy. A specific questionnaire was compiled. It was found that 20.1% of patients did not react to allergens tested, 28.2% were positive for at least one emerging pollen and 51.7% did not react to emerging pollens but tested positive for at least one allergen from the routine panel. The prevalence of single pollen species was related to geographical areas. Ragweed pollen was shown to provoke asthma much more frequently than other pollens. Hitherto scarcely considered pollens play a considerable role in causing allergic diseases in Italy. In the great majority of patients, positivity for these pollens was associated with positivity to the better recognized group of pollen allergens, although in some cases they were the primary pathogenic agent. We suggest that these more recently considered allergens be included in routine diagnostic panels.

Environmental risk factors (outdoor air pollution and climatic changes) and increased trend of respiratory allergy

A wealth of evidence suggests that allergic respiratory diseases such as rhinosinusitis and bronchial asthma have become more common worldwide in recent years and a great deal of etiological and pathogenic research has been carried out to evaluate the possible causes of this increasing trend. There is also some evidence that increased atmospheric concentrations of pollutants such as ozone (O3), nitric oxides (NOx), respirable particulate (PM10) and volatile organic chemicals (VOC5), which result from increased use of liquid petroleum gas or kerosene, may be linked to the increased prevalence of allergic diseases which develop more frequently in urban areas of developed countries. Since bronchial asthma is a syndrome which can be aggravated by inhaled compounds, the effects of air pollutants on health have been the focus of attention. In fact, various studies have demonstrated that inhalation of air pollutants such as O3, nitrogen dioxide (NO2) and sulfur dioxide (SO2), either individually or in combination, can enhance the airway response to inhaled allergens in atopic subjects, thus inducing asthma exacerbations. Moreover, experimental studies have shown that diesel exhaust particulate causes respiratory symptoms and is able also to modulate the immune response by increasing IgE synthesis in predisposed animals and humans. There is also some evidence that air pollutants can interact with aeroallergens in the atmosphere and/or on human airways, potentiating their effects. In fact, by inducing airway inflammation which increases epithelial permeability, some pollutants overcome the mucosal barrier and lead to allergen-induced responses. However, air pollution and climatic changes should also have an indirect effect on allergic response by influencing quantitatively and qualitatively the pollen production by allergenic plants.

Clinical study on Alternaria spores sensitization

BACKGROUND

sensitization to fungi spores is often associated with sensitization to other allergens and so it is difficult to estabilish the exact cause of illness.

OBJECTIVE

the aim of the study was to evaluate a group of patients monosensitized to Alternaria and to establish the prevalence, periodicity and clinical profile of this kind of sensitization.

METHODS

37 subjects who were monosensitized to Alternaria (prick-test positive), according to a previous epidemiological study were evaluated. Clinical symptoms and the period of their occurrence were taken into consideration as well as immunological parameters (RAST).

RESULTS

20 patients (over 50%) included in the study proved to be affected by asthma associated with other allergic symptoms and 22 patients (60%) presented perennial symptoms. The RAST carried out on 34 monosensitized subjects proved positive in 11 and negative in 23.

CONCLUSIONS

Alternaria sensitization is characterized by a perennial periodicity with severe respiratory symptoms (asthma) which occur primarily in children. Prick test is preferable to and more reliable than RAST as a diagnostic test.

A study on bronchial responsiveness to methacholine in subjects with untreated autoimmune hyperthyroidism

Because hyperthyroidism can mimic respiratory disorders with dyspnoea, this study was carried out in order to determine whether bronchial hyperresponsiveness is more frequent in hyperthyroid patients versus controls. Eighteen nonatopic subjects with newly-diagnosed untreated Graves' disease and 18 control subjects entered the study. All subjects underwent an aspecific bronchial provocation test with methacholine. Bronchial hyperresponsiveness was diagnosed in seven patients with hyperthyroidism and in two controls, with no statistically significant difference between the groups (Fisher's exact test; p = 0.1212). In conclusion, these results suggest that hyperthyroidism is not associated with a higher frequency of bronchial hyper-responsiveness to methacholine with respect to euthyroid subjects.

Sensitization to cockroach allergens in a sample from the urban population living in Naples (southern Italy)

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.

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.