title: GM-CSF production by CD4+ T cells in MS patients: regulation by regulatory T cells and vitamin D.
abstract: OBJECTIVE
  Data from animal models of MS suggest that GM-CSF(+)CD4(+)T cells are pathogenic cells. Therefore, GM-CSF production by CD4(+)T cells of MS patients and their susceptibility to regulatory mechanisms were investigated.
  
  
  METHODS
  Intracellular flowcytometry was performed to determine the GM-CSF(+)CD4(+)T cell fraction in PBMC and CSF of MS patients and controls. The effect of regulatory T cells (Tregs) on GM-CSF production by CD4(+)T cells was studied in MS patients using a proliferation-suppression assay. Finally, GM-CSF(+)CD4(+)T cell fraction and GM-CSF protein levels in supernatant were assessed in anti-CD3-stimulated CD4(+)T cell cultures derived from healthy controls and MS patients, in the presence or absence of the active vitamin D metabolite calcitriol.
  
  
  RESULTS
  The GM-CSF(+)CD4(+)T cell fraction in the peripheral blood did not differ between controls and MS patients. This T cell population could also be detected in the CSF of both subjects with MS as well as subjects with another diagnosis. In the CSF, it comprised a significant fraction of the T cell population. Upon in vitro stimulation of PBMC with anti-CD3 antibody, no differences were observed in GM-CSF(+)CD4(+)T cell frequencies. GM-CSF secretion was susceptible to regulation by Treg and vitamin D. Suppression of GM-CSF secretion by vitamin D was reduced in MS patients.
  
  
  CONCLUSIONS
  Our study showed no elevation in GM-CSF(+)CD4(+)T cell fractions in MS patients compared to controls. Furthermore, GM-CSF secretion was prone to regulation by Treg and vitamin D, the latter being less effective in MS patients.
authors.affiliation: School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands; Academic MS Center Limburg, Department of Neurology, Orbis Medical Center, Sittard, The Netherlands; Department of Internal Medicine, Division of Clinical and Experimental Immunology, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: Peelen
authors.affiliation: School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands; Academic MS Center Limburg, Department of Neurology, Orbis Medical Center, Sittard, The Netherlands; Department of Internal Medicine, Division of Clinical and Experimental Immunology, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: A-H
authors.initials: AH
authors.lastname: Muris
authors.affiliation: Central Diagnostic Laboratory, Maastricht University Medical Center, Maastricht, The Netherlands. Electronic address: jan.damoiseaux@mumc.nl.
authors.forename: J
authors.initials: J
authors.lastname: Damoiseaux
authors.affiliation: School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands; Academic MS Center Limburg, Department of Neurology, Orbis Medical Center, Sittard, The Netherlands; Department of Internal Medicine, Division of Clinical and Experimental Immunology, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: Knippenberg
authors.affiliation: Department of Clinical Chemistry and Hematology, Orbis Medical Center, Sittard, The Netherlands.
authors.forename: K
authors.initials: K
authors.lastname: Broens
authors.affiliation: School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Smolders
authors.affiliation: Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: J W
authors.initials: JW
authors.lastname: Cohen Tervaert
authors.affiliation: School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands; Academic MS Center Limburg, Department of Neurology, Orbis Medical Center, Sittard, The Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: Hupperts
authors.affiliation: Department of Internal Medicine, Division of Clinical and Experimental Immunology, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Thewissen
mesh_terms: D000328:Adult; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects* / Q000378:metabolism*; D016207:Cytokines / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000473:pathology*; D018709:Statistics, Nonparametric; D050378:T-Lymphocytes, Regulatory / Q000502:physiology*; D013997:Time Factors; D014807:Vitamin D / Q000494:pharmacology*; D055815:Young Adult
chemical_list: D016207:Cytokines; D014807:Vitamin D; D016178:Granulocyte-Macrophage Colony-Stimulating Factor
keywords: GM-CSF; Multiple sclerosis; Regulatory T cell; T helper cell; Vitamin D