title: Serum Levels of Surfactant Proteins in Patients with Combined Pulmonary Fibrosis and Emphysema (CPFE).
abstract: BACKGROUND
  Emphysema and idiopathic pulmonary fibrosis (IPF) present either per se or coexist in combined pulmonary fibrosis and emphysema (CPFE). Serum surfactant proteins (SPs) A, B, C and D levels may reflect lung damage. We evaluated serum SP levels in healthy controls, emphysema, IPF, and CPFE patients and their associations to disease severity and survival.
  
  
  METHODS
  122 consecutive patients (31 emphysema, 62 IPF, and 29 CPFE) and 25 healthy controls underwent PFTs, ABG-measurements, 6MWT and chest HRCT. Serum levels of SPs were measured. Patients were followed-up for 1-year.
  
  
  RESULTS
  SP-A and SP-D levels differed between groups (p = 0.006 and p<0.001 respectively). In post-hoc analysis, SP-A levels differed only between controls and CPFE (p<0.05) and CPFE and emphysema (p<0.05). SP-D differed between controls and IPF or CPFE (p<0.001 for both comparisons). In IPF SP-B correlated to pulmonary function while SP-A, correlated to the Composite Physiological Index (CPI). Controls current smokers had higher SP-A and SP-D levels compared to non-smokers (p = 0.026 and p = 0.023 respectively). SP-D levels were higher in CPFE patients with extended emphysema (p = 0.042). In patients with IPF, SP-B levels at the upper quartile of its range (≥26 ng/mL) presented a weak association with reduced survival (p = 0.05).
  
  
  CONCLUSIONS
  In conclusion, serum SP-A and SP-D levels were higher where fibrosis exists or coexists and related to disease severity, suggesting that serum SPs relate to alveolar damage in fibrotic lungs and may reflect either local overproduction or overleakage. The weak association between high levels of SP-B and survival needs further validation in clinical trials.
authors.affiliation: 2nd Respiratory Medicine Department, "Attikon" University Hospital, Athens Medical School, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Andriana I
authors.initials: AI
authors.lastname: Papaioannou
authors.affiliation: 2nd Respiratory Medicine Department, "Attikon" University Hospital, Athens Medical School, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Kostikas
authors.affiliation: 2nd Respiratory Medicine Department, "Attikon" University Hospital, Athens Medical School, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Effrosyni D
authors.initials: ED
authors.lastname: Manali
authors.affiliation: 2nd Respiratory Medicine Department, "Attikon" University Hospital, Athens Medical School, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Georgia
authors.initials: G
authors.lastname: Papadaki
authors.affiliation: 2nd Respiratory Medicine Department, "Attikon" University Hospital, Athens Medical School, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Aneza
authors.initials: A
authors.lastname: Roussou
authors.affiliation: Department of Cytopathology, "Attikon" University Hospital, Athens Medical School, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Aris
authors.initials: A
authors.lastname: Spathis
authors.affiliation: Department of Radiology, "Attikon" University Hospital, Athens Medical School, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Argyro
authors.initials: A
authors.lastname: Mazioti
authors.affiliation: 2nd Respiratory Medicine Department, "Attikon" University Hospital, Athens Medical School, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Tomos
authors.affiliation: Respiratory Medicine Department, "Corfu General Hospital", Corfu, Greece.
authors.forename: Ilias
authors.initials: I
authors.lastname: Papanikolaou
authors.affiliation: 2nd Respiratory Medicine Department, "Attikon" University Hospital, Athens Medical School, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Stelios
authors.initials: S
authors.lastname: Loukides
authors.affiliation: Respiratory Medicine Department, "Corfu General Hospital", Corfu, Greece.
authors.forename: Kyriakos
authors.initials: K
authors.lastname: Chainis
authors.affiliation: Department of Cytopathology, "Attikon" University Hospital, Athens Medical School, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Petros
authors.initials: P
authors.lastname: Karakitsos
authors.affiliation: Hauner Children's University Hospital, Ludwig-Maximilians-University, German Center for Lung Research, Lindwurmstrasse 4, 80337, Munich, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Griese
authors.affiliation: 2nd Respiratory Medicine Department, "Attikon" University Hospital, Athens Medical School, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Spyros
authors.initials: S
authors.lastname: Papiris
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D005260:Female; D005355:Fibrosis; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D010809:Physical Fitness; D011379:Prognosis; D011656:Pulmonary Emphysema / Q000097:blood* / Q000150:complications* / Q000175:diagnosis / Q000401:mortality; D011658:Pulmonary Fibrosis / Q000097:blood* / Q000150:complications* / Q000175:diagnosis / Q000401:mortality; D037661:Pulmonary Surfactant-Associated Proteins / Q000097:blood*; D012129:Respiratory Function Tests; D012907:Smoking
chemical_list: D037661:Pulmonary Surfactant-Associated Proteins