title: Circulating level of lipocalin 2 as a predictor of severity in patients with community-acquired pneumonia.
abstract: BACKGROUND
  The aim of this study was to investigate the differential plasma levels of lipocalin 2 (LCN2) and its complex with MMP-9 (where MMP is matrix metalloproteinase) before and after antibiotic treatment in hospitalized adult patients with community-acquired pneumonia (CAP).
  
  
  METHODS
  Plasma LCN2 and LCN2/MMP-9 complex levels were measured in 61 adult patients with CAP and 60 healthy controls using commercial enzyme-linked immunosorbent assay (ELISA).
  
  
  RESULTS
  A decrease in the number of white blood cells (WBCs) and neutrophils and decreases in the levels of C-reactive protein (CRP), LCN2, and LCN2/MMP-9 complex were observed after antibiotic treatment. The plasma level of LCN2, but not that of CRP, was correlated with the severity of CAP based on the Pneumonia Severity Index (PSI; r = 0.333, P = 0.009), confusion, urea, respiratory rate and blood pressure (CURB)-65 (r = 0.288, P = 0.024), and Acute Physiology And Chronic Health Evaluation II (APACHE II) scores (r = 0.328, P = 0.010). LCN2 levels were also significantly correlated with LCN2/MMP-9 levels and the numbers of WBCs or neutrophils.
  
  
  CONCLUSIONS
  Plasma levels of LCN2 and the LCN2/MMP-9 complex can act as adjuvant diagnostic biomarkers for CAP. Plasma LCN2 might play a further role in the clinical assessment of the severity of CAP, which could potentially guide the development of future treatment strategies.
authors.affiliation: Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan.
authors.forename: Yuan-Hung
authors.initials: YH
authors.lastname: Yeh
authors.forename: Junn-Liang
authors.initials: JL
authors.lastname: Chang
authors.forename: Pei-Ching
authors.initials: PC
authors.lastname: Hsiao
authors.forename: Shih-Ming
authors.initials: SM
authors.lastname: Tsao
authors.forename: Chien Huang
authors.initials: CH
authors.lastname: Lin
authors.forename: Shang-Jyh
authors.initials: SJ
authors.lastname: Kao
authors.forename: Ming-Chih
authors.initials: MC
authors.lastname: Chou
authors.forename: Shun-Fa
authors.initials: SF
authors.lastname: Yang
authors.forename: Ming-Hsien
authors.initials: MH
authors.lastname: Chien
mesh_terms: D018806:APACHE; D000209:Acute-Phase Proteins; D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D002097:C-Reactive Protein / Q000032:analysis; D017714:Community-Acquired Infections / Q000097:blood* / Q000188:drug therapy; D005260:Female; D006801:Humans; D007958:Leukocyte Count; D000071068:Lipocalin-2; D054834:Lipocalins / Q000097:blood*; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000097:blood; D008875:Middle Aged; D009504:Neutrophils; D011014:Pneumonia / Q000097:blood* / Q000188:drug therapy; D011518:Proto-Oncogene Proteins / Q000097:blood*; D012720:Severity of Illness Index; D013624:Taiwan
chemical_list: D000209:Acute-Phase Proteins; D000900:Anti-Bacterial Agents; C489506:LCN2 protein, human; D000071068:Lipocalin-2; D054834:Lipocalins; D011518:Proto-Oncogene Proteins; D002097:C-Reactive Protein; C579270:MMP9 protein, human; D020780:Matrix Metalloproteinase 9
keywords: Pneumonia Severity Index; community-acquired pneumonia; lipocalin 2; matrix metalloprotease-9