title: In vitro effects of budesonide on eosinophil-basophil lineage commitment.
abstract: IL-5 is the primary cytokine that stimulates the production and survival of eosinophils and basophils from progenitor cells. The inhaled glucocorticoid, budesonide, has been shown to exert a therapeutic effect via suppression of eosinophil/basophil progenitors in vivo. Since various steroids have exhibited the ability to enhance eosinophil/basophil progenitor differentiation, we examined the effects of budesonide in vitro. Bone marrow and cord blood samples were obtained and cultured in the presence of IL-5 alone or IL-5 plus budesonide. Eosinophil/basophil colony-forming units were enumerated from cultured nonadherent mononuclear cells and from purified CD34⁺ cells. CD34⁺ cells with and without budesonide were also examined for up-regulation of ERK1/2, MAPK and GATA-1 using real time-PCR.
  
  
  RESULTS
  i) up-regulation of eosinophil/basophil colony-forming units is due to the direct effects of budesonide on IL-5-stimulated progenitors; ii) GATA-1 is likely involved in the early amplification of eosinophil/basophil progenitor commitment leading to increased differentiation. A potential transcriptional pathway has been identified which may mediate the effects of budesonide on eosinophil/basophil lineage commitment.
authors.affiliation: Division of Clinical Immunology and Allergy, McMaster University, Hamilton, ON, Canada.
authors.forename: Michael M
authors.initials: MM
authors.lastname: Cyr
authors.forename: Adrian J
authors.initials: AJ
authors.lastname: Baatjes
authors.forename: Sandra C
authors.initials: SC
authors.lastname: Dorman
authors.forename: Lynn
authors.initials: L
authors.lastname: Crawford
authors.forename: Roma
authors.initials: R
authors.lastname: Sehmi
authors.forename: Ronan
authors.initials: R
authors.lastname: Foley
authors.forename: Rafeul
authors.initials: R
authors.lastname: Alam
authors.forename: Paul O'
authors.initials: PO
authors.lastname: Byrne
authors.forename: Judah A
authors.initials: JA
authors.lastname: Denburg