title: Diagnostic accuracy of cytokine levels (TNF-alpha, IL-2 and IFN-gamma) in bronchoalveolar lavage fluid of smear-negative pulmonary tuberculosis patients.
abstract: BACKGROUND
  The determination of cytokine concentrations in serum and bronchoalveolar lavage fluid (BALF) may contribute to the diagnosis of tuberculosis (TB) since cytokines have been ascribed an important role in TB pathogenesis.
  
  
  OBJECTIVE
  To assess the diagnostic accuracy of TNF-alpha, IFN-gamma and IL-2 levels in serum and BALF of smear-negative pulmonary TB patients.
  
  
  METHODS
  BALF was obtained from the affected lobe in patients with smear-negative TB or other pulmonary diseases (OPD), and from the right middle lobe in healthy controls. ELISA and a nephelometric method were used to detect cytokine and albumin levels.
  
  
  RESULTS
  TNF-alpha levels in BALF were significantly elevated in the TB group (n = 15) compared with the OPD patients (n = 40) and controls (n = 17; p < 0.001). Although these three cytokines correlated well with each other in BALF (p < 0.0001, and r >or= 0.7, respectively), BALF IL-2 and IFN-gamma levels were not significantly different among the groups (p > 0.05). BALF TNF-alpha or IFN-gamma levels were significantly higher in patients with cavitary disease (n = 11) versus those without (n = 61; p < 0.05). However, no significant difference was found between cavitary (n = 7) and non-cavitary TB in cytokine levels (p > 0.05). Neither gender nor smoking status showed any statistical differences in cytokines in the groups (p > 0.05). Sensitivity and specificity of BALF TNF-alpha were found to be 73 and 76%, respectively. The positive and negative predictive values for BALF TNF-alpha were 44 and 91%, respectively.
  
  
  CONCLUSIONS
  In cases of smear-negative TB, BALF TNF-alpha can be a useful tool to identify healthy subjects rather than smear-negative TB patients.
authors.affiliation: Department of Chest Diseases, Ankara University School of Medicine, Ankara, Turkey.
authors.forename: Elif
authors.initials: E
authors.lastname: Küpeli
authors.forename: Demet
authors.initials: D
authors.lastname: Karnak
authors.forename: Sumru
authors.initials: S
authors.lastname: Beder
authors.forename: Oya
authors.initials: O
authors.lastname: Kayacan
authors.forename: Hüseyin
authors.initials: H
authors.lastname: Tutkak
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000032:analysis; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry*; D016022:Case-Control Studies; D015331:Cohort Studies; D016207:Cytokines / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007371:Interferon-gamma / Q000032:analysis; D007376:Interleukin-2 / Q000032:analysis; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D011237:Predictive Value of Tests; D011336:Probability; D012016:Reference Values; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013183:Sputum / Q000382:microbiology; D018709:Statistics, Nonparametric; D014374:Tuberculin Test; D014397:Tuberculosis, Pulmonary / Q000097:blood / Q000175:diagnosis*; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis
chemical_list: D015415:Biomarkers; D016207:Cytokines; D007376:Interleukin-2; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma