title: Elevated intracellular calcium in neutrophils in patients with Down syndrome.
abstract: BACKGROUND
  Neutrophils of patients with Down syndrome (DS) are known to have numerous abnormalities associated with diminished resistance to infection. The intracellular calcium (Ca(2+)i) acts as a second messenger and regulates diverse functions in many cell types. The purpose of the present study was to compare the intracellular calcium concentration ([Ca(2+)]i) at baseline and stimulated conditions in DS patients and in normal subjects to investigate [Ca(2+)]i regulation in neutrophils.
  
  
  METHODS
  The study group consisted of 27 subjects with DS (age, 8.6 +/- 4.6 years) and 14 healthy subjects (age, 12.0 +/- 3.9 years). Using a fluorescent probe, fura-2, the baseline levels and changes in [Ca(2+)]i were examined after stimulation of neutrophils with N-formyl-methionyl-leucyl-phenylalanine (fMLP).
  
  
  RESULTS
  At baseline, the [Ca(2+)]i of neutrophils from DS subjects was significantly higher than that of the controls (70.6 +/- 28.0 nmol/L vs 44.4 +/- 16.0 nmol/L, P < 0.01). The absolute [Ca(2+)]i after addition of fMLP in the DS subjects was also significantly higher than that of the control group (250 +/- 91 nmol/L vs 167 +/- 60 nmol/L, respectively: P < 0.01). The neutrophils from the DS subjects had a consistently and significantly prolonged response to fMLP as compared to the neutrophils of control subjects.
  
  
  CONCLUSIONS
  The higher [Ca(2+)]i and the prolonged response of [Ca(2+)]i to fMLP appear to be phenotypic traits of neutrophils in subjects with DS. This suggests intrinsic cellular defects in DS.
authors.affiliation: Department of Pediatrics, Kansai Medical University, Osaka, Japan. fkotekote@yahoo.co.jp
authors.forename: Fumiko
authors.initials: F
authors.lastname: Yamato
authors.forename: Junji
authors.initials: J
authors.lastname: Takaya
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yasuhara
authors.forename: Masayuki
authors.initials: M
authors.lastname: Teraguchi
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Ikemoto
authors.forename: Kazunari
authors.initials: K
authors.lastname: Kaneko
mesh_terms: D000293:Adolescent; D002118:Calcium / Q000032:analysis* / Q000502:physiology; D002648:Child; D002675:Child, Preschool; D004314:Down Syndrome / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D009504:Neutrophils / Q000737:chemistry* / Q000378:metabolism
chemical_list: D002118:Calcium