title: Changes in peripheral immune cell numbers and functions in octogenarian walkers - an acute exercise study.
abstract: BACKGROUND
  Age-related changes of the immune system, termed immunosenescence, may underlie the increased risk of infections and morbidity in the elderly. Little is known about the effects of acute exercise on peripheral immune parameters in octogenarians. Therefore, we investigated acute exercise-induced changes in phenotype and function of the immune system in octogenarians participating in the 2013 edition of the Nijmegen Four Days Marches. Blood sampling was performed at baseline and immediately after 4 days of the walking exercise (30 km/day). A comprehensive set of adaptive and innate immune traits were enumerated and analyzed by flow-cytometry. Peripheral blood mononuclear cells, isolated before and after walking were stimulated with LPS and supernatants were analysed for IL-1β, IL-6, IL-8 and TNF-α concentrations by ELISA. CMV serostatus was determined by ELISA.
  
  
  RESULTS
  The walking exercise induced a clear leucocytosis with numerical increases of granulocytes, monocytes and lymphocytes. These exercise-induced changes were most profound in CMV seropositive subjects. Within lymphocytes, numerical increases of particularly CD4+ T cells were noted. Further T cell differentiation analysis revealed profound increases of naïve CD4+ T cells, including naïve Treg. Significant increases were also noted for CD4+ memory T cell subsets. In contrast, only slight increases in naïve and memory CD8+ T cell subsets were detected. Exercise did not affect markers of immune exhaustion in memory T cell subsets. NK cells demonstrated a numerical decline and a change in cellular composition with a selective decrease of the mature CD56dimNK cells. The latter was seen in CMV seronegative subjects only. Also, a higher IL-6 and IL-8 production capacity of LPS-stimulated PBMC was seen after walking.
  
  
  CONCLUSIONS
  In this exceptional cohort of octogenarian walkers, acute exercise induced changes in immune cell numbers and functions. A clear response of CD4+ T cells, rather than CD8+ T cells or NK cells was noted. Remarkably, the response to exercise within the CD4+ T cell compartment was dominated by naïve CD4+ subsets.
authors.affiliation: Departments of Rheumatology and Clinical Immunology and Translational Immunology Groningen (TRIGR), University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9700RB Groningen, The Netherlands.
authors.forename: Kornelis S M
authors.initials: KSM
authors.lastname: van der Geest
authors.affiliation: Departments of Rheumatology and Clinical Immunology and Translational Immunology Groningen (TRIGR), University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9700RB Groningen, The Netherlands.
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Department of Physiology, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors.forename: Thijs M H
authors.initials: TMH
authors.lastname: Eijsvogels
authors.affiliation: Department of Laboratory Medicine, Laboratory Medical Immunology, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors.forename: Hans J P
authors.initials: HJP
authors.lastname: Koenen
authors.affiliation: Department of Laboratory Medicine, Laboratory Medical Immunology, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors.forename: Irma
authors.initials: I
authors.lastname: Joosten
authors.affiliation: Departments of Rheumatology and Clinical Immunology and Translational Immunology Groningen (TRIGR), University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9700RB Groningen, The Netherlands.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Brouwer
authors.affiliation: Department of Physiology, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors.forename: Maria T E
authors.initials: MTE
authors.lastname: Hopman
authors.affiliation: Department of Laboratory Medicine, Laboratory Medical Immunology, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors.forename: Joannes F M
authors.initials: JFM
authors.lastname: Jacobs
authors.affiliation: Departments of Rheumatology and Clinical Immunology and Translational Immunology Groningen (TRIGR), University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9700RB Groningen, The Netherlands.
authors.forename: Annemieke M H
authors.initials: AMH
authors.lastname: Boots
keywords: Ageing; Immune System; Monocytes; NK cells; Recent thymic emigrants; T cells