Latent class analysis reveals clinically relevant atopy phenotypes in 2 birth cohorts

Phenotypes of childhood-onset asthma are characterized by distinct trajectories and functional features. For atopy, definition of phenotypes during childhood is less clear.; We sought to define phenotypes of atopic sensitization over the first 6 years of life using a latent class analysis (LCA) integrating 3 dimensions of atopy: allergen specificity, time course, and levels of specific IgE (sIgE).; Phenotypes were defined by means of LCA in 680 children of the Multizentrische Allergiestudie (MAS) and 766 children of the Protection against allergy: Study in Rural Environments (PASTURE) birth cohorts and compared with classical nondisjunctive definitions of seasonal, perennial, and food sensitization with respect to atopic diseases and lung function. Cytokine levels were measured in the PASTURE cohort.; The LCA classified predominantly by type and multiplicity of sensitization (food vs inhalant), allergen combinations, and sIgE levels. Latent classes were related to atopic disease manifestations with higher sensitivity and specificity than the classical definitions. LCA detected consistently in both cohorts a distinct group of children with severe atopy characterized by high seasonal sIgE levels and a strong propensity for asthma; hay fever; eczema; and impaired lung function, also in children without an established asthma diagnosis. Severe atopy was associated with an increased IL-5/IFN-γ ratio. A path analysis among sensitized children revealed that among all features of severe atopy, only excessive sIgE production early in life affected asthma risk.; LCA revealed a set of benign, symptomatic, and severe atopy phenotypes. The severe phenotype emerged as a latent condition with signs of a dysbalanced immune response. It determined high asthma risk through excessive sIgE production and directly affected impaired lung function

Latent class analysis reveals clinically relevant atopy phenotypes in 2 birth cohorts

Background: Phenotypes of childhood-onset asthma are characterized by distinct trajectories and functional features. For atopy, definition of phenotypes during childhood is less clear. Objective: We sought to define phenotypes of atopic sensitization over the first 6 years of life using a latent class analysis (LCA) integrating 3 dimensions of atopy: allergen specificity, time course, and levels of specific IgE (sIgE). Methods: Phenotypes were defined by means of LCA in 680 children of the Multizentrische Allergiestudie (MAS) and 766 children of the Protection against allergy: Study in Rural Environments (PASTURE) birth cohorts and compared with classical nondisjunctive definitions of seasonal, perennial, and food sensitization with respect to atopic diseases and lung function. Cytokine levels were measured in the PASTURE cohort. Results: The LCA classified predominantly by type and multiplicity of sensitization (food vs inhalant), allergen combinations, and sIgE levels. Latent classes were related to atopic disease manifestations with higher sensitivity and specificity than the classical definitions. LCA detected consistently in both cohorts a distinct group of children with severe atopy characterized by high seasonal sIgE levels and a strong propensity for asthma; hay fever; eczema; and impaired lung function, also in children without an established asthma diagnosis. Severe atopy was associated with an increased IL-5/IFN-gamma ratio. A path analysis among sensitized children revealed that among all features of severe atopy, only excessive sIgE production early in life affected asthma risk. Conclusions: LCA revealed a set of benign, symptomatic, and severe atopy phenotypes. The severe phenotype emerged as a latent condition with signs of a dysbalanced immune response. It determined high asthma risk through excessive sIgE production and directly affected impaired lung function.Peer reviewe

Maturation of the gut microbiome during the first year of life contributes to the protective farm effect on childhood asthma

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Working with argan cake: a new etiology for hypersensitivity pneumonitis

International audienceAbstractBackgroundArgan is now used worldwide in numerous cosmetic products. Nine workers from a cosmetic factory were examined in our occupational medicine department, following the diagnosis of a case of hypersensitivity pneumonitis (HP) related to handling of argan cakes.MethodsOperators were exposed to three forms of argan (crude granulates, powder or liquid) depending on the step of the process. All workers systematically completed standardized questionnaires on occupational and medical history, followed by medical investigations, comprising, in particular, physical examination and chest X-rays, total IgE and a systematic screening for specific serum antibodies directed against the usual microbial agents of domestic and farmer’s HP and antigens derived from microbiological culture and extracts of various argan products. Subjects with episodes of flu-like syndrome several hours after handling argan cakes, were submitted to a one-hour challenge to argan cakes followed by physical examination, determination of Carbon Monoxide Diffusing Capacity (DLCO) and chest CT-scan on day 2, and, when necessary, bronchoalveolar lavage on day 4.ResultsSix of the nine workers experienced flu-like symptoms within 8 hours after argan handling. After challenge, two subjects presented a significant decrease of DLCO and alveolitis with mild lymphocytosis, and one presented ground glass opacities. These two patients and another patient presented significant arcs to both granulates and non-sterile powder. No reactivity was observed to sterile argan finished product, antigens derived from argan cultures (various species of Bacillus) and Streptomyces marokkonensis (reported in the literature to contaminate argan roots).ConclusionsWe report the first evidence of hypersensitivity pneumonitis related to argan powder in two patients. This implies preventive measures to reduce their exposure and clinical survey to diagnose early symptoms. As exposure routes are different and antibodies were observed against argan powder and not the sterile form, consumers using argan-based cosmetics should not be concerned

[Home-related hypersensitivity pneumonitis].

International audienc

[Follow-up of subjects occupationally exposed to asbestos, what are the objectives, the benefits, and the possible risks?].

International audienceThe follow-up of workers occupationally exposed to asbestos has two possible beneficial effects: (1) individually, both medical by screening for diseases related to asbestos and social by notification of occupational disease and/or compensation from the indemnity funds for asbestos victims; (2) collectively, by the establishment of epidemiological surveillance (follow-up of cohorts) and evaluation of the impact of follow-up in terms of health benefits and compensation. The respiratory disorders related to asbestos are: cancer (malignant pleural mesothelioma and bronchial carcinoma), asbestos-related pulmonary fibrosis, and pleural disease (plaques, pleural fibrosis and benign pleurisy). In the light of the data currently available and the effectiveness of the tools used, medical and public health benefits of screening for mesothelioma have not been demonstrated. The early diagnosis of primary bronchial carcinoma can theoretically improve the prognosis of the subjects screened, particularly by identification of stage I disease on CT (pulmonary nodules). This is a common finding but there are a large number of false-positives. While we await the results of several international randomised trials, the benefits of a screening programme for bronchial carcinoma in the population at risk have not been demonstrated. There is no effective treatment for asbestosis but this is an independent risk factor for bronchial carcinoma and it is evidence of heavy asbestos exposure. Stopping smoking in subjects suffering from asbestosis will reduce the incidence of bronchial carcinoma. There is no effective treatment for asbestos-related benign pleural diseases but these are markers of exposure. The presence of pleural plaques has not been shown to be an aetiological factor for thoracic cancers. Post-occupational follow-up may involve risks to health, particularly repeated irradiation and invasive diagnostic procedures. It is also necessary to consider the psychological consequences inherent in all screening programmes. In conclusion, post-occupational follow-up might reduce the mortality of lung cancer by screening for localised disease and its incidence by a targeted anti-smoking programme. The theoretical benefits, that have not yet been demonstrated, have to be seen in perspective with the risks to physical and psychological health related to both screening and diagnostic procedures

[In the agricultural environment there is asthma and asthma... or the paradox of agricultural asthma]

International audienc

[Immuno-allergic testing in agricultural professions]

International audienc