title: Superoxide dismutase 2 as a marker to differentiate tuberculous pleural effusions from malignant pleural effusions.
abstract: OBJECTIVE
  Our previous study demonstrated that superoxide dismutase levels were higher in tuberculous pleural effusions than in malignant pleural effusions, but that this difference could not be used to discriminate between the two. The objective of the present study was to investigate the levels of superoxide dismutase 2 in pleural effusions and to evaluate the diagnostic significance of pleural effusion superoxide dismutase 2.
  
  
  METHODS
  Superoxide dismutase 2 concentrations were determined in pleural effusions from 54 patients with tuberculous pleural effusion and 33 with malignant pleural effusion using an enzyme-linked immunosorbent assay (ELISA) kit. Pleural effusion interferon gamma and tumor necrosis factor alpha levels were also analyzed by ELISA. The Mann-Whitney U test was used to evaluate the significance of differences. Associations between superoxide dismutase 2 concentrations and sex, age and smoking habits were assessed using Spearman's or Pearson's correlation coefficient analysis. Receiver operator characteristic analysis was performed to evaluate the value of superoxide dismutase 2 levels in the discrimination of tuberculous pleural effusion from malignant pleural effusion.
  
  
  RESULTS
  Superoxide dismutase 2 levels were significantly higher in patients with tuberculous pleural effusion compared with those with malignant pleural effusion (p<0.05). When superoxide dismutase 2 was used to differentiate between tuberculous pleural effusions and malignant pleural effusions, the area under the receiver operator characteristic curve was 0.909 (95% confidence interval, 0.827-0.960; p<0.01). With a cut-off value of 54.2 ng/mL, the sensitivity, specificity, positive likelihood ratio and negative likelihood ratio were 75.8% (95%CI: 57.7-88.9%), 98.1% (95%CI: 90.1-99.7%), 40.91 and 0.25, respectively. Furthermore, significant correlations between pleural effusion superoxide dismutase 2 and interferon gamma (r=0.579, p<0.01) and between pleural effusion superoxide dismutase 2 and tumor necrosis factor alpha (r=0.396, p<0.01) were observed.
  
  
  CONCLUSIONS
  Pleural effusion superoxide dismutase 2 can serve as a biomarker for differentiating between tuberculous pleural effusions and malignant pleural effusions. Because of the high correlations of superoxide dismutase 2 with pleural effusion interferon gamma and tumor necrosis factor alpha levels, this marker may act as an inflammatory factor that plays an important role in the development of tuberculous pleural effusion.
authors: Department of Lab Medicine, Shandong Provincial Chest Hospital, Jinan City, PR, China.
authors: Maoshui
authors: M
authors: Wang
authors: Department of Lab Medicine, Shandong Provincial Chest Hospital, Jinan City, PR, China.
authors: Zhiqiang
authors: Z
authors: Zhang
authors: Department of Lab Medicine, Shandong Provincial Chest Hospital, Jinan City, PR, China.
authors: Xinfeng
authors: X
authors: Wang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000032:analysis; D001706:Biopsy; D004796:Clinical Enzyme Tests; D003937:Diagnosis, Differential; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000032:analysis; D008297:Male; D008875:Middle Aged; D010996:Pleural Effusion / Q000175:diagnosis*; D016066:Pleural Effusion, Malignant / Q000175:diagnosis*; D012372:ROC Curve; D017382:Reactive Oxygen Species / Q000378:metabolism; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D013482:Superoxide Dismutase / Q000032:analysis*; D014396:Tuberculosis, Pleural / Q000175:diagnosis*; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis; D055815:Young Adult; D000099156:Superoxide Dismutase 2
chemical_list: D015415:Biomarkers; D007371:Interferon-gamma; D017382:Reactive Oxygen Species; D013482:Superoxide Dismutase; D014409:Tumor Necrosis Factor-alpha; D000099156:Superoxide Dismutase 2
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