Daniel Vervloet

Indoor allergens and asthma:Report of the Third International Workshop

In parallel with changes in lifestyle over the last 50 years (sedentary living in warm houses with extensive furnishing and low ventilation rates), there has been a progressive increase in the prevalence and morbidity of asthma in many parts of the world. The increase has been in perennial rather than seasonal asthma, and a large proportion of the patients are sensitized to one or more of the allergens found predominantly inside houses, that is, indoor allergens. The Third International Workshop on Indoor Allergens and Asthma was designed to discuss recent progress in basic and clinical research in this area, to formulate recommendations for allergen-specific management of asthma, and to consider future research directions. As with the two previous workshops, discussion topics included biology; allergen immunochemistry; molecular biology and immune response; epidemiology of asthma; and the role of allergen avoidance, a, 2 Because of dramatic progress in recent years, the Third International Workshop was expanded to cover not only house dust mite allergens but also allergens from cat, dog, and cockroach, for which immunochemical and epidemiologic data are available. Over the past 5 years there have been significant advances in several areas of research on indoor allergens, including: (1) cloning and expression of recombinant allergens, 3-7 (2) analysis of T-cell responses to indoor allergens, derivation of T-cell clones, and analysis of T-cell epitope specificity and cytokine profiles, s, 9 (3) investigation of the dose-response relationship between exposure to mite, cat, and cockroach allergens and sensitization, 1°-13 and (4) epidemiologic studies on indoor allergens as risk factors for the symptoms of asthma and bronchial hyperreactivity (BHR)? 4-17 Better definition of the allergens has made it possible to analyze their structure and biologic function and to define epitopes recognized by antibodies or T cells. Information obtained from those studies has provided exciting possibilities for developing new vaccines for safe and effective immunotherapy. 9, 18. 19 Studies of T-cell responses to dust mites have confirmed the dominance of T-helper cell (Tin) responses in allergic individuals.

Prevalence of latex allergy in operating room nurses

The twofold purpose of this study was to assess the prevalence of latex sensitivity in a large group of operating room nurses and to evaluate the relationship between questionnaire responses and skin tests. Of the total target population of 268 operating room nurses, 248 (93%) answered the questionnaire and 197 had skin prick tests to latex (1/10 wt/vol solution). Symptoms associated with glove wearing were acknowledged by 41.1% of nurses. Skin tests to latex were positive in 21 nurses (10.7%), 4.4 times more often in atopic nurses. Among nurses complaining of local symptoms, only 18.6% had positive skin tests. Itching of the hands during glove wearing correlated poorly with latex sensitivity, but correlation with local urticaria was better. Atopic nurses complaining of urticaria had latex allergy in 70% of cases. Thus latex allergy is common in nurses, especially atopic nurses. A questionnaire is unreliable in predicting latex sensitivity and must be supported by latex skin test. More data will be needed to assess the risk of anaphylactic perioperative reactions in operating room nurses.

Twenty five year mortality and air pollution: results from the French PAARC survey.

Aims and Methods: Long term effects of air pollution on mortality were studied in 14 284 adults who resided in 24 areas from seven French cities when enrolled in the PAARC survey (air pollution and chronic respiratory diseases) in 1974. Daily measurements of sulphur dioxide, total suspended particles, black smoke, nitrogen dioxide, and nitric oxide were made in 24 areas for three years (1974–76). Cox proportional hazards models controlling for individual confounders (smoking, educational level, body mass index, occupational exposure) were applied, and frailty models used to take into account spatial correlation. Indicators of air pollution were the mean concentration. Results: Models were run before and after exclusion of six area monitors influenced by local traffic (NO/NO2 >3 in ppb). After exclusion of these areas, analyses showed that adjusted risk ratios (95% CI) for TSP, BS, NO2, and NO for non-accidental mortality were 1.05 (1.02 to 1.08), 1.07 (1.03 to 1.10), 1.14 (1.03 to 1.25), and 1.11 (1.05 to 1.17) for 10 μg/m3 respectively. Consistent patterns for lung cancer and cardiopulmonary causes were observed. Conclusions: Urban air pollution assessed in the 1970s was associated with increased mortality over 25 years in France.

Sublingual‐swallow immunotherapy (SLIT) in patients with asthma due to house‐dust mites: a double‐blind, placebo‐controlled study

A double‐blind, placebo‐controlled study was carried out in 85 patients with a well‐documented history of perennial asthma caused by house‐dust mites. Patients received either placebo or sublingual immunotherapy (SLIT) with a standardized Dermatophagoides pteronyssinus (DP)–D. farinae (DF) 50/50 extract. After a run‐in period, patients received increasing doses up to 300 IR every day for 4 weeks and then three times a week for the following 24 months. The cumulative dose was about 104 000 IR, equivalent to 4.2 mg Der p 1 and 7.3 mg Der f 1. Symptom and medication scores and respiratory function were assessed throughout the trial. Serum specific IgE and IgG4 were determined before SLIT (t0) and after 6 (t1), 11 (t2), 17 (t3), and 25 months (t4) of SLIT. Mite exposure was evaluated at t0, t2, and t4 by semiquantitative guanine determinations. Patients aged 15 years and older were asked to assess their quality of life (QoL) by completing the SF20 (Short Form Health Status Survey) plus two items at t0, t2, and t4. Use of inhaled corticosteroids and β2‐agonists was significantly decreased after 25 months of treatment in both groups (P<0.03). SLIT patients showed significant improvements in respiratory function at t4 (% predicted FEV1 (P=0.01), VC (P=0.002), morning (P=0.01) and evening (P=0.03) PEFR), and reduction in daytime asthma score (P=0.02). In the SLIT group, the post‐treatment PD20 was 1.75 times higher than the baseline value. There was no change in PD20 in the placebo group. Compared to the placebo group, the SLIT group showed a significant increase in specific IgE DP (P=0.05), IgE DF (P=0.02), IgG4 DP (P=0.001), and IgG4 DF (P=0.001) levels after SLIT. QoL scores were similar in both groups at t0 and t2. At t4, all scores were better in the SLIT group than in the placebo group, with the differences being most marked for the general perception of health (P=0.01) and physical pain (P=0.02). Adverse events were similar in the two groups. This study shows that SLIT in house‐dust‐mite‐related asthma has a good safety profile and improves respiratory function, bronchial hyperreactivity, and QoL.

Allergic vs nonallergic asthma: what makes the difference?

Background: The aim of this work was to describe clinical similarities and differences between allergic and nonallergic asthmatics, notably concerning the nasosinusal involvement.

Drugs and other agents involved in anaphylactic shock occurring during anaesthesia. A French multicenter epidemiological inquiry

An epidemiological inquiry was carried out in departments of anaesthesia and immunology in French University and General Hospitals, as well as among those who were already known to have an allergo-anaesthesia outpatient clinic. This inquiry aimed to find out how many patients had undergone diagnostic investigations after as well as an anaphylactoid reaction during an anaesthetic in 1990 and 1991, as well as the demographic data, the kind of assessment, the accident mechanism and the drugs involved. Twenty-one French centres replied to the questionnaire and a series of 1,585 patients tested over a two-year period was thus collected. There were three female patients to one male. The reactions occurred mostly in the adult (80%), but 9% were observed in children. Allergological tests for IgE-dependent anaphylaxis were the skin tests (21 centres), combined with radioimmunological assays of specific serum antibodies to muscle relaxants (10 centres), propofol (9 centres), latex (5 centres), leukocyte histamine release (9 centres) and human basophil degranulation test (4 centres). The criteria for a positive result were the same for all centres. Among these 1,585 patients, 813 were recognized as having had a reaction of immunological origin (52%). The substances involved were identified in these 813 patients as being muscle relaxants (70%), latex (12.6%), hypnotics (3.6%), benzodiazepines (2.0%), opioids (1.7%), colloids (4.7%), and antibiotics (2.6%). Suxamethonium was responsible for 43% of the IgE-dependent reactions involving a muscle relaxant, vecuronium for 37%, pancuronium for 13%, alcuronium for 7.6%, atracurium for 6.8% and gallamine for 5.6%.(ABSTRACT TRUNCATED AT 250 WORDS)

Allergy to latex

The first reported case of an immediate hypersensitivity reaction to latex was described by Nutter in 1979 (52), although this allergy had certainly occurred before that date. During the past 5 years, allergic reactions to products made of natural rubber latex have been reported with increasing frequency, especially in health care personnel and their patients. This phenomenon has been attributed to the recent dramatic rise in the use of latex gloves by medical, dental and auxiliary personnel for protection against the AIDS and hepatitis viruses, although not all authors agree (74), and it might not explain the apparently increased incidence in children with spina bifida and in the general population. It is likely that the increased incidence of allergy to latex among hospital personnel and their patients is related to changes in the manufacturing of gloves and/or to the change from reusable, steam-sterilized to single-use gloves that followed the increased demand for these products. In addition it might be related to better recognition of the clinical problem by the medical community.

T cell activation, from atopy to asthma: more a paradox than a paradigm

During the last 15 years, it was largely shown that allergic inflammation was orchestrated by activated Th2 lymphocytes, leading to IgE production and eosinophil activation. Indeed, Th2 activation was shown to be necessary to induce allergic sensitization in animal models. In humans, a Th2 skewing was shown in atopic children soon after birth. In asthma, descriptive studies showed that Th2 cells were more numerous in patients than in controls. In addition, during specific allergen stimulation, an increase of Th2 cells was described in most cases. According to this Th2 paradigm, it was proposed that early avoidance of microbial exposure could explain the increase of atopic diseases seen in the last 20 years in developed countries, as the ‘hygiene hypothesis’. Recently, it was proposed that early exposure to lipopolysaccharide (LPS) could be protective against atopic diseases.

Phenotypic determinants of uncontrolled asthma

BACKGROUND Although uncontrolled asthma remains frequent, determinants of asthma control are poorly studied. OBJECTIVES The aim was to estimate the distribution and the phenotypic characteristics of asthma control in 2 groups of subjects defined by the use of inhaled corticosteroids (ICS) in the past 12 months, in the Epidemiological study on the Genetics and Environment of Asthma, bronchial hyperresponsiveness and atopy (EGEA). METHODS Five hundred one adult current patients with asthma who participated in the follow-up of the EGEA study were included. Asthma control was assessed from survey questions reflecting asthma control, as defined in the 2006 Global Initiative for Asthma guidelines. The factors analyzed were age, sex, educational level, body mass index, active and passive smoking, sensitization to aeroallergens, total IgE, rhinitis, chronic cough/phlegm, and age at asthma onset. Analyses were stratified according to ICS use. RESULTS Uncontrolled asthma was more frequent in ICS users (27.6%, 35.0%, and 37.4% with controlled, partly-controlled, and uncontrolled asthma respectively) compared with non-ICS users (60.0%, 23.9%, and 16.1%, respectively). In ICS users, chronic cough or phlegm and female sex were independently and significantly related to uncontrolled asthma. In non-ICS users, high total IgE and sensitization to molds were associated with uncontrolled asthma. Smoking and rhinitis were not associated with asthma control. CONCLUSION Optimal asthma control remained unachieved in the majority of patients with asthma in this study. Factors associated with uncontrolled asthma were different in ICS users (chronic cough/phlegm, female sex) and non-ICS users (high total IgE and sensitization to molds).

Seasonal allergic symptoms and their relation to pollen exposure in south‐east France

In order to evaluate the relationship between pollen exposure and prevalence of allergic respiratory symptoms, we performed a cross‐sectional epidemiological study in 2 areas with contrasted exposure to cypress and grass pollens. The study population consisted of 5427 subjects 18 to 65‐years‐old representative of the general population. All answered an abridged version of the 1978 ATS questionnaire and a sample had a skin test evaluation including grass and cypress pollens. Prevalence of hay fever symptoms was equal to 31.5% and 14.1%, respectively, in exposed and less exposed community (P < 0.001). Prevalence of hay fever symptoms together with a positive skin test to pollen was also significantly higher in the exposed (13.6%) vs less exposed community (5.5%, P<0.001). In contrast, overall prevalence of asthma was equal to 4.5% and 3.4%, respectively. Prevalence of asthma with positive skin tests was also not statistically significant, equal to 2.5% and 1.9%, respectively. Thus, high exposure to pollen is a risk factor for developing hay fever but not asthma.