title: [Changes and clinical significance of peripheral blood natural killer cells in neonates with bacterial pneumonia].
abstract: OBJECTIVE
  To detect the percentage of total natural killer (NK) cells and its different populations in the peripheral blood from neonates with bacterial pneumonia and discuss the clinical significance of NK cells in the pathogenesis of bacterial pneumonia.
  
  
  METHODS
  Flow cytometry was performed to detect the percentages of NK cells and its subsets in peripheral blood lymphocytes from 38 cases of neonatal bacterial pneumonias and 18 cases of normal neonates. Patients recruited were divided into two groups according to hospitalization days and numbers of peripheral leukocytes: hospitalization days within 10 days (including 10 days) as group A, and more than 10 days as group B; the number of peripheral blood leukocytes <5.0×10(9)/L or >20.0×10(9)/L as severe infection group, and 5.0×10(9)/L< number of peripheral blood leukocytes <20.0×10(9)/L as mild infection group.
  
  
  RESULTS
  The percentages of peripheral blood NK cells and CD3(-)CD56(neg)CD16(bright) subset in the neonates with bacterial pneumonia were significantly lower than those of the normal newborns (P<0.01), but there were no statistically significant differences in CD3(-)CD56(bright)CD16(neg/dim) and CD3(-)CD56(dim)CD16(bright) subsets. The percentage of CD3(-)CD56(neg)CD16(bright) subset in group A was significantly lower than that of the normal newborns (P<0.01), while the percentages of the total NK cells and other subsets had no statistical significance. The neonates with bacterial pneumonia had significantly lower percentages of the total NK cells and CD3(-)CD56(neg)CD16(bright) subset in group B as compared with the normal neonates (P<0.01). And the percentages of the total NK cells and its subsets in group B were also lower than those in group A (P<0.05). The percentages of NK cells and each subset in severe infection group were significantly lower than those in mild infection group (P<0.05).
  
  
  CONCLUSIONS
  To the neonates who suffer from bacterial pneumonia, the more serious and the longer hospital stay, the lower the percentages of NK cells and its subsets are.
authors.affiliation: Department of Nursing, Zhangzhou Health Vocational College, Zhangzhou 363000, China.
authors.forename: Qiuling
authors.initials: Q
authors.lastname: Li
authors.affiliation: Department of Pediatrics, Zhangzhou Municipal Hospital Affiliated to Fujian Medical University, Zhangzhou 363000, China.
authors.forename: Kaizhi
authors.initials: K
authors.lastname: Weng
authors.affiliation: Department of Immunology, Fujian Medical University, Fuzhou 350108, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Zhu
authors.affiliation: Department of Laboratory Medicine, Zhangzhou Municipal Hospital Affiliated to Fujian Medical University, Zhangzhou 363000, China.
authors.forename: Xuqiao
authors.initials: X
authors.lastname: Mei
authors.affiliation: Department of Pediatrics, Zhangzhou Municipal Hospital Affiliated to Fujian Medical University, Zhangzhou 363000, China.
authors.forename: Liping
authors.initials: L
authors.lastname: Xu
authors.affiliation: Department of Obstetrics, Zhangzhou Municipal Hospital Affiliated to Fujian Medical University, Zhangzhou 363000, China.
authors.forename: Jiehua
authors.initials: J
authors.lastname: Lin
mesh_terms: D017252:CD3 Complex / Q000276:immunology; D019002:CD56 Antigen / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007231:Infant, Newborn; D007694:Killer Cells, Natural / Q000276:immunology*; D007902:Length of Stay; D007958:Leukocyte Count; D007962:Leukocytes / Q000276:immunology; D018655:Lymphocyte Count; D016131:Lymphocyte Subsets / Q000276:immunology; D008297:Male; D018410:Pneumonia, Bacterial / Q000097:blood* / Q000276:immunology*; D017452:Receptors, IgG / Q000276:immunology
chemical_list: D017252:CD3 Complex; D019002:CD56 Antigen; D017452:Receptors, IgG