title: Serum surfactant protein D during acute exacerbations of chronic obstructive pulmonary disease.
abstract: BACKGROUND
  There is a paucity of lung specific biomarkers to diagnose exacerbations of chronic obstructive pulmonary disease (COPD) and to track their progression. Surfactant protein D (SP-D) is a pulmonary collectin regulating the innate immunity of the lung and its serum expression is perturbed in COPD. However, it is not known whether serum levels change during exacerbations. We sought to determine whether serum SP-D levels are raised in COPD exacerbations.
  
  
  OBJECTIVE
  To determine whether or not patients with exacerbations have elevated serum SP-D levels compared with asymptomatic controls, stable disease.
  
  
  METHODS
  case control study.
  
  
  METHODS
  We measured serum SP-D levels from patients with stable COPD (n= 14), patients experiencing acute exacerbations (n=13) and in control subjects (n=54) using a specific immunoassay and compared the levels using analysis of variance.
  
  
  RESULTS
  Serum SP-D levels were significantly increased in patients who experienced an acute exacerbation (227 +/- 120 ng/mL) compared to patients with stable disease (151 +/- 83 ng/mL) or control subjects (128 +/- 65 ng/mL; p=0.003). Serum SP-D levels were also found to be inversely related to various lung function parameters including FEV<formula>_{1}</formula>/FVC% predicted.
  
  
  CONCLUSIONS
  Our study suggests that serum SP-D levels are increased in patients during exacerbations and may be a potential diagnostic biomarker for COPD exacerbations.
authors.affiliation: Shaikh Zayed Medical Complex, Lahore, Pakistan. drtaniashakoori@yahoo.com
authors.forename: Tania Ahmed
authors.initials: TA
authors.lastname: Shakoori
authors.forename: Don D
authors.initials: DD
authors.lastname: Sin
authors.forename: Farkhanda
authors.initials: F
authors.lastname: Ghafoor
authors.forename: Saira
authors.initials: S
authors.lastname: Bashir
authors.forename: S Nazim Hussain
authors.initials: SN
authors.lastname: Bokhari
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D018450:Disease Progression; D004417:Dyspnea / Q000097:blood / Q000473:pathology; D005541:Forced Expiratory Volume; D006801:Humans; D008168:Lung / Q000378:metabolism / Q000503:physiopathology; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood / Q000473:pathology; D037663:Pulmonary Surfactant-Associated Protein D / Q000097:blood*
chemical_list: D015415:Biomarkers; D037663:Pulmonary Surfactant-Associated Protein D