Mesure des allergènes de pollens d’arbre dans l’air (bouleau, olivier)

The information provided by pollen counts cannot be ignored by allergists and allergic individuals, but the divergence sometimes observed with clinical observations has led the réseau national de la surveillance aérobiologique (RNSA) to initiate the monitoring network of allergens by immunosampling (Monalisa) project. Moreover, some recent papers has shown the influence of pollution in the region and even of the year on the content in pollen allergens, particularly that of birch pollen. Thus, the goal of the Monalisa project was to set up a measuring system based on an immunological method that would result in validation of this new way of measuring airborne pollen counts. This European Life Environment project includes nine partners: Bertin Technologies (France), RNSA (France), NPARU (England), UCO (Spain), UTU (Finland), UAM (Poland), UEVORA (Portugal), AIA (Italy), and Meteoswiss (Switzerland). The results obtained during the 2006 season and then in the 2007 campaign, after modifications made in the sampler, were not very good. The principal results concern the measurement of birch and olive allergens, captured essentially in the prepollination period and sometimes in the postpollination period. Detection of these allergens may be due either to their presence on submicroscopic particles emitted independently of pollination, these allergens cross-reacting with birch and olive allergens. The difficulties encountered in this study lead us to say that pollen counts, phenological observations and clinical data are still the best way to assess the effects of airborne pollen.     

Urticaire médicamenteuse et imputabilité

In France, adverse reactions due to drugs affect 10% of hospitalized patients, which means about one million patients per year. Cutaneous reactions are among the most frequent type of adverse drug reaction, occurring in 2-3% of hospitalized patients. The imputability of drugs that may be responsible calls for a standardized approach leading to a precise score for each drug, and this is a matter that falls in the domain of competence of Pharmacovigilance (PHVG) physicians, not in that of clinicians. Cutaneous reactions can be allergic (implying specific immunity) or pseudoallergic (a non-specific immune reaction). In 95% of the cases of drug-induced urticaria, the mechanism is non-specific and due to a toxic or irritant action of the drug, i.e. a pseudoallergic reaction. There is a true IgE mediated allergy in only about 5% of cases. Drug-induced urticaria has no semiological particularity. CRPVs are responsible for the collection and registration of the reports of adverse effects that are received spontaneously from health professionals. For each report to the PHVG, the causal relation between taking the drug and the onset of the adverse reaction is evaluated according to the official French imputability method. This method includes four chronological criteria and three semiological criteria, and it is accompanied by a bibliographic score. A report of cutaneoallergic effects to the PHVG allows identification of the causative molecule among the many that are potentially responsible, an understanding of the mechanism of action (immunoallergic or pseudoallergic), and results in personalized advice to the patient.     

Prise en charge des urticaires médicamenteuses non allergiques

Drug-induced urticaria occurs frequently and is benign in most cases. It is most often a consequence of intolerance (not a specific allergy), but occasionally it may be the consequence of an authentic IgE-mediated immediate hypersensitivity reaction (IHR). The etiological-pathogenic diagnosis is three-pronged, including history, skin tests and, if necessary, laboratory investigations. In cases of IHR, re-introduction of the medicament is definitely contra-indicated since desensitization is not efficacious. In such cases, one should carry out a battery of skin and/or laboratory tests looking for an allergic cross-reaction caused by molecules of the same class. In cases of intolerance, the medicament can be reintroduced in the large majority of cases, sometimes accompanied by pre-medication with an antihistamine and/or an antileukotriene.     

Allergologie et auto-immunité : médecine interne aux frontières de l'allergologie

At the crossroad of numerous medical specialties, Internal Medicine incorporates a number of different fields, including autoimmune diseases and other immunological conditions, the symptoms of which can simulate those of allergies, particularly allergies of the skin and lungs. We will limit our discussion to only a few aspects of this subject: 1) concerning immunological aspects, CD4+ IL17+ lymphocytes and the detection of autoantibodies in chronic urticaria; 2) concerning pharmacological aspects, discussion of the eventual role of acetaminophen in the recent increase in the frequency of asthma and allergic diseases; and 3) concerning other clinical matters, mastocytosis and insect stings, eosinophilic esophagitis, mosquito bites, allergy and NK lymphoma.     

Réactions allergiques et pseudoallergiques aux médicaments et substances biologiques chez l’enfant

Five to 20% of subjects of all ages report suspected allergic reactions to drugs and biological substances. Children may be less affected than adults, but this difference is disputed and probably results from differences in drug exposure. Most frequently suspected drugs are antibiotics, betalactams especially, antipyretics, analgesics and nonsteroidal anti-inflammatory drugs. Most frequent reactions are morbilliform/maculopapular rashs, urticaria and angioedema. Other cutaneous and respiratory reactions, and severe anaphylactic and anaphylactoid reactions, are rare. The results of allergological studies suggest that, except for a few types of reactions (anaphylactic and immediate reactions, potentially harmful toxidermias) and for very specific drugs (i.e. latex and myorelaxants), most reactions to commonly used drugs and biological substances in children do not result from drug hypersensitivity, but are rather a consequence of the infectious and/or inflammatory diseases for which the drugs have been prescribed. The reactions may also result from complex interactions between drugs, immune system and “danger” signals provided or induced by infectious and/or inflammatory diseases. Diagnosis is based above all on a detailed analysis of clinical history, skin tests (if validated) and challenge tests (if indicated). In children with drug allergy or intolerance, prevention of relapse is based on a rigourous avoidance of the responsible drug and cross-reacting drugs.     

Quoi de neuf en allergologie pédiatrique en 2005 ? Partie 4. Allergie cutanée,alimentaire, médicamenteuse et aux insectes (Une revue de la littérature internationale d'octobre 2004 à octobre 2005)

Allergological work-up and treatment of french children with atopic dermatitis have been the subject of a recent consensus. Food avoidance is useless for prevention of atopic dermatitis, and should be indicated in children with severe atopic dermatitis associated with food allergy only. Exposure, sensitization and allergy rates to nuts increase with age, and avoidance of nuts (even tolerated) is recommended in young children allergic to one or several nuts to prevent the risk of sensitization and allergy to an increasing number of nuts. Threshold values of skin prick-tests and specific IgE determinations with a 90-100% predictive value for food allergy are highly variable from one study to another one, and depend on numerous factors such as age of the children, the allergens used, etc. The diagnostic value of patch-tests and skin application food tests remains controversial. Treatment of food allergy is based on the eviction of the allergenic foods. However, probiotics and « desensitization » to foods may be efficacious in some patients. In children that have outgrown their food allergy, tolerance should be maintened by regular consumption of the foods. However, the parents should be informed that relapses requiring an emergency treatment may occur. Finallly, in children as in adults, repeated mosquito bites induce a desensitization, and most children outgrow their allergy between five to fourteen years.     

Changement climatique et évolution du contenu pollinique de l’air dans sept pays européens : exemple du bouleau

The aim of this paper is to study the relation between climate change and the earliness of Birch pollination, a tree that produces allergenic pollen, which is of particular importance in north-western Europe. The study allowed us to make projections for the next few years in order to evaluate the evolution of Birch pollination starting date according to spring temperatures. It has been done in ten European locations, Kevo and Turku (Finland), London (United Kingdom), Paris and Lyon (France), Brussels (Belgium), Zürich (Switzerland), Vienna (Austria), Poznan and Cracow (Poland). The study period ranged from six to twenty-eight years depending on the city. Pollens were recorded daily thanks to volumetric Hirst traps, and the data were compared to monthly temperatures from January to May using correlations and multiple regressions. Except in Kevo where the trend is towards colder springs and a later pollination, in the other cities the results showed a spring warming associated with an earlier starting date of pollination: this trend is very well marked in Turku, Zürich, London, Vienna and Brussels, less evident in France while there is no trend in Poland. The results of this work should lead to an updating of the pollen calendars and the pollen forecast models, in the cities where there is a pronounced trend.     

Le profil métallique : un nouveau concept médical

Over the past decade great progress has been made in metals and metalloids analysis. This analysis is a basic stage in toxicity assessment and is indispensable in achieving a realistic evaluation of substance toxicity. A recently introduced technique, inductively coupled plasma mass spectrometry (ICP-MS) is progressively replacing atomic absorption. This analysis permits multi-elementary determinations, approximately 30 elements, with an optimal gain in sensitivity in many biological matrices: i.e. whole blood, plasma, urine, hair, nail, biopsy samples. Moreover, this method allows semiquantitative determination with an additional 30 supplementary elements, which enables the toxicologist to sufficiently estimate the toxic levels and metal exposure. The authors demonstrate that the ICP-MS could be very useful for a wide range of clinical applications. Furthermore, this procedure offers new exploration possibilities in various fields such as clinical toxicology, forensic toxicology as well as work place testing or environmental exposure and permits epidemiologic studies. This analytical method in fact also provides a new scientific approach. To our knowledge we are the first to propose: the metallic profile.     

L'allergie au tournesol et à son huile : rôles du contact,de l'ingestion et de l'inhalation

We report the case of a 5-years old girl with food allergy to sunflower oil. Sensitivity to sunflower oil and seeds was demonstrated by skin tests whereas assays of serum for sunflower-specific IgE were negative. An oral challenge test with 54 ml of sunflower oil was positive. The patient also reacted to cutaneous contact and inhalation of sunflower seeds. Depending on the route of contact –– skin contact, ingestion or inhalation –– sunflower oil and seeds can trigger symptoms such as urticaria, erythema, vomiting, dyspnea or fatigue.     

Quoi de neuf en allergologie pédiatrique en 2006-2007 ? Partie 3: Allergie cutanée, alimentaire, médicamenteuse et aux insectes (une revue de la littérature internationale d’octobre 2005 à septembre 2007)

Most sensitizations in children with atopic dermatitis are non pathogenic. Thus, responses in prick-tests, specific IgE determinations and patch-tests should be carefully evaluated based on the clinical history of the children or responses in challenge tests. Moreover, although atopy patch-tests are highly specific, they have a low sensitivity. Food eviction is indicated in a few children only, since they may be responsible for anaphylactic reactions induced by accidental ingestion of the food or oral challenge tests. The predictive value of serum specific IgE to foods depends on the food investigated, the age of the children, their allergic disease (atopic dermatitis, urticaria/angioedema, anaphylaxis) and, may be, on their ethnical origin. The prevention of food-induced severe reactions is based on eviction. However, several studies suggest that oral desensitization to foods may be efficient. Most frequent reactions in children hypersensitive to antalgics, antipyretics and nonsteroidal antiinflammatory drugs are oedema (facial oedema especially) and urticaria. Usually, the severity of the reactions increases from one treatment to another one and with the dose of drug administered to the children. Diagnosis is based on a convincing clinical history or on challenge tests. Skin tests with vaccines should be performed according to a standardized procedure because they may give false positive responses. Most latex sensitizations detected by skin prick-tests and, especially, specific IgE determinations are non pathogenic. The prevention of reactions to latex is based on eviction. However, preliminary results suggest that sublingual desensitization with a latex extract is efficient and well-tolerated.     

Hypersensibilité au formaldéhyde : mécanisme d’action

Formaldehyde is an industrial and domestic pollutant that has several effects on the respiratory system. In exposed workers, formaldehyde can trigger asthma, although this does not occur very frequently. Indoor exposure to formaldehyde can promote sensitization to common aeroallergens, the development of asthma, and it may increase the bronchial response to allergen in asthmatic individuals. In the present article, we review the mechanisms that may explain these respiratory effects. The reactivity of formaldehyde and its capacity to form adducts with proteins can explain the IgE immune response that occurs in some exposed workers. They may also allow formaldehyde to enhance the immunogenicity of aeroallergens, thus explaining the increased risk of sensitization and of asthma associated with indoor exposure to this substance. Formaldehyde is also a potent irritant. This property, which may cause neurogenic inflammation, mast cell degranulation, inhibition of mucociliary clearance and an increase in the permeability of the airway epithelium, may explain most of the respiratory effects of formaldehyde. Formaldehyde is able to activate structural cells to induce pro-inflammatory cytokine production, adhesion molecule expression and oxidative stress, effects which can also contribute to the development of asthma or to exacerbation of the bronchial response to aeroallergens. Thus, published data suggest that the respiratory activity of formaldehyde involves several different mechanisms. However, further investigation is necessary to confirm and to characterize these mechanisms more fully.