P C Schröder1, S Illi1, V I Casaca1, A Lluis2, A Böck1, C Roduit3,4, M Depner1, R Frei4,5, J Genuneit6, P I Pfefferle7,8, M Roponen9, J Weber1, C Braun-Fahrländer10,11, J Riedler12,13, J C Dalphin14, J Pekkanen15,16, R Lauener4,17, E von Mutius1,18, B Schaub1,18. 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.
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+ CD25high FOXP3upper20% ). 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.
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+ CD25high FOXP3upper20% ). 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.
Authors: Cara L Hrusch; Michelle M Stein; Justyna Gozdz; Mark Holbreich; Erika von Mutius; Donata Vercelli; Carole Ober; Anne I Sperling Journal: J Allergy Clin Immunol Date: 2019-08-08 Impact factor: 10.793