title: Indoor fungal diversity in primary schools may differently influence allergic sensitization and asthma in children.
abstract: Childhood exposure to microbiologic agents may influence the development of allergic and respiratory diseases. Apart from home, children spend most of their time at school, which represents an environment of significant exposure to indoor air microbes. Therefore, we aimed to assess how the prevalence of allergic sensitization and asthma in schoolchildren is affected by microbiologic exposure within classrooms.
  
  
  
  Spirometry with bronchodilation, exhaled nitric oxide measurements and skin-prick tests data were retrieved from 858 children aged 8-10 years attending 71 classrooms in 20 primary schools. Air samples were collected in all classrooms using a single-stage microbiologic air impactor through agar plates. Gram-negative endotoxins were collected using flow control pumps and analysed by limulus amebocyte lysate assay. Diversity scores were established as the number of different fungal species found in each classroom.
  
  
  
  Classrooms with increased diversity scores showed a significantly lower prevalence of children with atopic sensitization, but not asthma. The risk of sensitization increased with increasing endotoxin exposure in classrooms. Similarly, significantly higher concentrations of Penicillium spp were found in classrooms with a higher number of children with atopic sensitization.
  
  
  
  Although no causal relationships could be established, exposure to higher fungal diversity was protective against allergic sensitization but this was not seen for asthma. In contrast, higher exposure to Gram-negative endotoxins and Penicillium spp in primary school's classrooms was associated with increasing odds of allergic sensitization in children.
authors.affiliation: Basic and Clinical Immunology, Faculty of Medicine, University of Porto, Porto, Portugal.|Centro Hospitalar São João, Porto, Portugal.|INEGI - Institute of Science and Innovation in Mechanical Engineering and Industrial Management, Porto, Portugal.|Epidemiology Research Unit, Institute of Public Health (EPIUnit), University of Porto, Porto, Portugal.
authors.forename: João
authors.identifier: 0000-0003-1175-242X
authors.initials: J
authors.lastname: Cavaleiro Rufo
authors.affiliation: INEGI - Institute of Science and Innovation in Mechanical Engineering and Industrial Management, Porto, Portugal.
authors.forename: Joana
authors.initials: J
authors.lastname: Madureira
authors.affiliation: Basic and Clinical Immunology, Faculty of Medicine, University of Porto, Porto, Portugal.|Centro Hospitalar São João, Porto, Portugal.|INEGI - Institute of Science and Innovation in Mechanical Engineering and Industrial Management, Porto, Portugal.|Epidemiology Research Unit, Institute of Public Health (EPIUnit), University of Porto, Porto, Portugal.
authors.forename: Inês
authors.initials: I
authors.lastname: Paciência
authors.affiliation: Epidemiology Research Unit, Institute of Public Health (EPIUnit), University of Porto, Porto, Portugal.|National Institute of Health Dr Ricardo Jorge, Porto, Portugal.
authors.forename: Lívia
authors.initials: L
authors.lastname: Aguiar
authors.affiliation: Epidemiology Research Unit, Institute of Public Health (EPIUnit), University of Porto, Porto, Portugal.|National Institute of Health Dr Ricardo Jorge, Porto, Portugal.
authors.forename: Cristiana
authors.initials: C
authors.lastname: Pereira
authors.affiliation: Basic and Clinical Immunology, Faculty of Medicine, University of Porto, Porto, Portugal.|Centro Hospitalar São João, Porto, Portugal.
authors.forename: Diana
authors.initials: D
authors.lastname: Silva
authors.affiliation: Faculty of Nutrition and Food Sciences, University of Porto, Porto, Portugal.
authors.forename: Patrícia
authors.initials: P
authors.lastname: Padrão
authors.affiliation: Faculty of Nutrition and Food Sciences, University of Porto, Porto, Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Moreira
authors.affiliation: Basic and Clinical Immunology, Faculty of Medicine, University of Porto, Porto, Portugal.|Centro Hospitalar São João, Porto, Portugal.
authors.forename: Luís
authors.initials: L
authors.lastname: Delgado
authors.affiliation: Epidemiology of Allergic and Respiratory Diseases Department, Institut Pierre Louis d'Epidémiologie et de Santé Publique, INSERM and UPC, Paris, France.
authors.forename: Isabella
authors.initials: I
authors.lastname: Annesi-Maesano
authors.affiliation: INEGI - Institute of Science and Innovation in Mechanical Engineering and Industrial Management, Porto, Portugal.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Oliveira Fernandes
authors.affiliation: Epidemiology Research Unit, Institute of Public Health (EPIUnit), University of Porto, Porto, Portugal.|National Institute of Health Dr Ricardo Jorge, Porto, Portugal.
authors.forename: João Paulo
authors.initials: JP
authors.lastname: Teixeira
authors.affiliation: Basic and Clinical Immunology, Faculty of Medicine, University of Porto, Porto, Portugal.|Centro Hospitalar São João, Porto, Portugal.|Epidemiology Research Unit, Institute of Public Health (EPIUnit), University of Porto, Porto, Portugal.|Faculty of Nutrition and Food Sciences, University of Porto, Porto, Portugal.
authors.forename: André
authors.initials: A
authors.lastname: Moreira
mesh_terms: D016902:Air Pollution, Indoor; D000485:Allergens / Q000276:immunology; D000946:Antigens, Fungal / Q000276:immunology; D001249:Asthma / Q000453:epidemiology / Q000382:microbiology*; D044822:Biodiversity; D002648:Child; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000453:epidemiology / Q000382:microbiology*; D008297:Male; D009181:Mycoses / Q000453:epidemiology / Q000382:microbiology*; D010407:Penicillium / Q000502:physiology*; D011174:Portugal / Q000453:epidemiology; D012574:Schools; D013147:Spirometry
chemical_list: D000485:Allergens; D000946:Antigens, Fungal
keywords: endotoxins; exposure; fungi; indoor air; microbiologic diversity; microbiome; schools; sensitization