A switch in regulatory T cells through farm exposure during immune maturation in childhood

P C Schröder; S Illi; V I Casaca; A Lluis; A Böck; C Roduit; M Depner; R Frei; J Genuneit; P I Pfefferle; M Roponen; J Weber; C Braun-Fahrländer; J Riedler; J C Dalphin; J Pekkanen; R Lauener; E von Mutius; B Schaub; PASTURE study group

doi:10.1111/all.13069

A switch in regulatory T cells through farm exposure during immune maturation in childhood

Allergy. 2017 Apr;72(4):604-615. doi: 10.1111/all.13069. Epub 2016 Nov 17.

Authors

P C Schröder¹, S Illi¹, V I Casaca¹, A Lluis², A Böck¹, C Roduit^{3

4}, M Depner¹, R Frei^{4

5}, J Genuneit⁶, P I Pfefferle^{7

8}, M Roponen⁹, J Weber¹, C Braun-Fahrländer^{10

11}, J Riedler^{12

13}, J C Dalphin¹⁴, J Pekkanen^{15

16}, R Lauener^{4

17}, E von Mutius^{1

18}, B Schaub^{1

18}; PASTURE study group

Collaborators

PASTURE study group:
Anne Hyvärinen, Anne M Karvonen, Maija-Riitta Hirvonen, Pekka Tiittanen, Sami Remes, Vincent Kaulek, Marie-Laure Dalphin, Markus J Ege, Georg J Loss, Harald Renz, Gert Doekes, Michael Kabesch

Affiliations

¹ LMU Munich, University Children's Hospital, Munich, Germany.
² National Jewish Health, Denver, CO, USA.
³ Children's Hospital, University of Zürich, Zürich, Switzerland.
⁴ Christine Kühne - Center for Allergy Research and Education (CK-CARE), Davos, Switzerland.
⁵ Swiss Institute of Allergy and Asthma Research (SIAF), University of Zurich, Davos, Switzerland.
⁶ Institute of Epidemiology and Medical Biometry, Ulm University, Ulm, Germany.
⁷ Comprehensive Biomaterial Bank Marburg CBBM, Fachbereich Medizin der Philipps Universität Marburg, Zentrum für Tumor und Immunbiologie ZTI, Marburg, Germany.
⁸ Member of the German Centre for Lung Research (DZL), Munich, Germany.
⁹ Department of Environmental Science, Inhalation Toxicology Laboratory, University of Eastern Finland, Kuopio, Finland.
¹⁰ Swiss Tropical and Public Health Institute, Basel, Switzerland.
¹¹ University of Basel, Basel, Switzerland.
¹² Children's Hospital Schwarzach, Schwarzach, Austria.
¹³ Teaching Hospital of Paracelsus Medical Private University Salzburg, Salzburg, Austria.
¹⁴ Department of Respiratory Disease, University Hospital, University of Besançon, Besançon, France.
¹⁵ Department of Health Protection, National Institute for Health and Welfare, Kuopio, Finland.
¹⁶ Department of Public Health, University of Helsinki, Helsinki, Finland.
¹⁷ Children's Hospital of Eastern Switzerland, St. Gallen, Switzerland.
¹⁸ Comprehensive Pneumology Centre Munich (CPC-M), German Centre for Lung Research (DZL), Munich, Germany.

PMID: 27732759
DOI: 10.1111/all.13069

Abstract

Background: Farm exposure protects against development of allergies early in life. At 4.5 years, protection against asthma by farm-milk exposure was partially mediated by regulatory T cells (Tregs). The aim of this study was to investigate the critical time window of the 'asthma-protective' farm effect via Tregs during childhood immune maturation.

Methods: Tregs were assessed longitudinally at 4.5 and 6 years in 111 children (56 farm and 55 reference children) from the PASTURE/EFRAIM birth cohort (flow cytometry). Peripheral blood mononuclear cells were cultured unstimulated (U), with phorbol 12-myristate 13-acetate/ionomycin (PI) or lipopolysaccharide (LPS), and stained for Tregs (CD4⁺ CD25^high FOXP3^upper20% ). mRNA expression of Treg/Th1/Th2/Th17-associated cell markers was measured ex vivo. Suppressive capacity of Tregs on effector cells and cytokines was assessed. Detailed questionnaires assessing farm exposures and clinical phenotypes from birth until age 6 years were answered by the parents.

Results: Treg percentage before and after stimulation and FOXP3mRNA expression ex vivo decreased from age 4.5 to 6 years (P(U,LPS) < 0.001; P(PI) = 0.051; P(FOXP3) < 0.001). High vs low farm-milk and animal-stable exposure was associated with decreased LPS-stimulated Treg percentage at age 6 years (P(LPS) = 0.045). Elevated LPS-stimulated-Treg percentage at age 6 was associated with increased risk of asthma (aOR = 11.29, CI: 0.96-132.28, P = 0.053). Tregs from asthmatics vs nonasthmatics suppressed IFN-γ (P = 0.015) and IL-9 (P = 0.023) less efficiently. mRNA expression of Th1/Th2/Th17-associated cell markers decreased between 4.5 and 6 years (P < 0.001).

Conclusions: Tregs at the age of 6 years were decreased with farm exposure and increased within asthmatics, opposite to age 4.5 years. This immunological switch defines a critical 'time window' for Treg-mediated asthma protection via environmental exposure before age 6 years.

Keywords: animal-stable; asthma; farming; milk; regulatory T cells (Tregs).

Publication types

Multicenter Study

MeSH terms

Age Factors
Allergens / immunology
Animals
Asthma / epidemiology
Asthma / etiology
Biomarkers
Child
Child, Preschool
Cytokines / metabolism
Environmental Exposure*
Farms*
Female
Follow-Up Studies
Gene Expression
Humans
Immunity*
Immunoglobulin E / immunology
Infant
Infant, Newborn
Lymphocyte Count
Male
Phenotype
Population Surveillance
Pregnancy
RNA, Messenger / genetics
Surveys and Questionnaires
T-Lymphocyte Subsets / immunology*
T-Lymphocyte Subsets / metabolism
T-Lymphocytes, Regulatory / immunology*
T-Lymphocytes, Regulatory / metabolism

Substances

Allergens
Biomarkers
Cytokines
RNA, Messenger
Immunoglobulin E