title: Expression of YKL-40 and MIP-1a proteins in exudates and transudates: biomarkers for differential diagnosis of pleural effusions? A pilot study.
abstract: BACKGROUND
  YKL-40 is an extracellular matrix glycoprotein with a significant role in tissue inflammation and remodeling. MIP-1a has chemotactic and pro-inflammatory properties, and is induced by YKL-40 in several lung disorders. The aim of this study was to determine the levels of YKL-40 and MIP-1a in blood serum and pleural fluids of various pulmonary diseases, and to evaluate their potential role as differential diagnosis biomarkers.
  
  
  METHODS
  We recruited 60 patients (age: 62.5 ± 20.6 years) with pleural effusions: 49 exudates and 11 transudates (T). Exudates were further classified based on the underlying disease: ten with tuberculosis (TB), 13 with lung cancer (LCa), 15 with metastatic cancer (MCa) of non-lung origin and 11 with parapneumonic (PN) effusions. YKL-40 and MIP-1a levels were measured by ELISA.
  
  
  RESULTS
  Pleural YKL-40 levels (ng/ml) were similar among all patient groups (TB: 399 ± 36, LCa: 401 ± 112, MCa: 416 ± 34, PN: 401 ± 50, T: 399 ± 42, p = 0.92). On the contrary, YKL-40 was significantly lower in the serum of TB patients (TB: 58 ± 22, LCa: 212 ± 106, MCa: 254 ± 140, PN: 265 ± 140, T: 229 ± 123, p < 0.001). Pleural MIP-1a protein levels (ng/ml) were statistically lower only in patients with LCa (TB: 25.0 ± 20.2, LCa: 7.3 ± 6.0, MCa: 16.1 ± 14.9, PN: 25.4 ± 27.9, T: 18.5 ± 7.9, p = 0.012), a finding also observed in serum MIP-1a levels (TB: 17.1 ± 7.6, LCa: 9.4 ± 7.0, MCa: 28.7 ± 28.7, PN: 33.3 ± 24.0, T: 22.9 ± 8.7, p = 0.003).
  
  
  CONCLUSIONS
  Our data suggest that both YKL-40 and MIP-1a, particularly in serum, could prove useful for the differentiation of pleural effusions in clinical practice, especially of TB or LCa origin. However, large-scale studies are needed to validate these findings.
authors.affiliation: Department of Thoracic Medicine, Nicosia General Hospital, Nicosia, Cyprus.
authors.forename: Tonia
authors.initials: T
authors.lastname: Adamidi
authors.affiliation: Laboratory of Molecular and Cellular Pneumology, Medical School, University of Crete, Heraklion, Crete, Greece. ngsoul@gmail.com.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Soulitzis
authors.affiliation: Laboratory of Molecular and Cellular Pneumology, Medical School, University of Crete, Heraklion, Crete, Greece.
authors.forename: Eirini
authors.initials: E
authors.lastname: Neofytou
authors.affiliation: Department of HealthCare Management, Open University of Cyprus, Nicosia, Cyprus.
authors.forename: Savvas
authors.initials: S
authors.lastname: Zannetos
authors.affiliation: Department of Thoracic Medicine, Nicosia General Hospital, Nicosia, Cyprus.
authors.forename: Andreas
authors.initials: A
authors.lastname: Georgiou
authors.affiliation: Department of Thoracic Medicine, Nicosia General Hospital, Nicosia, Cyprus.
authors.forename: Kleomenis
authors.initials: K
authors.lastname: Benidis
authors.affiliation: Department of Thoracic Medicine, Nicosia General Hospital, Nicosia, Cyprus.
authors.forename: Alexis
authors.initials: A
authors.lastname: Papadopoulos
authors.affiliation: Laboratory of Molecular and Cellular Pneumology, Medical School, University of Crete, Heraklion, Crete, Greece.|Department of Thoracic Medicine, University Hospital of Heraklion, Heraklion, Crete, Greece.
authors.forename: Nikolaos M
authors.initials: NM
authors.lastname: Siafakas
authors.affiliation: Laboratory of Molecular and Cellular Pneumology, Medical School, University of Crete, Heraklion, Crete, Greece.|Department of Thoracic Medicine, University Hospital of Heraklion, Heraklion, Crete, Greece.
authors.forename: Sophia E
authors.initials: SE
authors.lastname: Schiza
mesh_terms: D054392:Adipokines / Q000378:metabolism*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000378:metabolism; D054405:Chemokine CCL3 / Q000378:metabolism*; D000071451:Chitinase-3-Like Protein 1; D003937:Diagnosis, Differential; D005122:Exudates and Transudates / Q000378:metabolism*; D005260:Female; D006801:Humans; D037102:Lectins / Q000378:metabolism*; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000556:secondary; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D010996:Pleural Effusion / Q000209:etiology / Q000378:metabolism*; D011014:Pneumonia / Q000150:complications / Q000175:diagnosis* / Q000378:metabolism; D012189:Retrospective Studies; D014397:Tuberculosis, Pulmonary / Q000150:complications / Q000175:diagnosis* / Q000378:metabolism
chemical_list: D054392:Adipokines; D015415:Biomarkers; C515429:CCL3 protein, human; C084533:CHI3L1 protein, human; D054405:Chemokine CCL3; D000071451:Chitinase-3-Like Protein 1; D037102:Lectins