title: Diagnostic value of CD103 expression in bronchoalveolar lymphocytes in sarcoidosis.
abstract: BACKGROUND
  Pulmonary sarcoidosis is frequently characterized by a CD4(+)/CD8(+) ratio ≥3.5 in bronchoalveolar lavage fluid (BALF), although up to 40% of the cases present a normal or even decreased ratio, pointing out its variability and limitation as a diagnostic marker for sarcoidosis. Lung lymphocytes within the bronchial epithelium, the alveolar walls, and BALF express the integrin CD103. Our aim was to compare the expression of CD103 in BALF T-lymphocytes between sarcoidosis and other interstitial lung diseases (ILD) and to evaluate its relevance as a BALF diagnostic marker for sarcoidosis.
  
  
  METHODS
  A total of 86 patients with ILD (mean age ± standard deviation, 42.6 ± 16.6 years; 60.5% female), who underwent BALF as part of their initial diagnostic work-up, were enrolled into 2 groups: sarcoidosis (n = 41) and other ILD (n = 45). Area under the receiver operating characteristic (ROC) curve (AUC) was used to describe the performance of CD103 for sarcoidosis diagnosis.
  
  
  RESULTS
  Sarcoidosis patients presented a significantly reduced CD103 expression in BALF T-lymphocytes, more pronounced in the CD4(+) subset. The BALF CD103(+)CD4(+)/CD4(+) ratio for a cutoff point of 0.45 was associated with a better diagnostic performance for sarcoidosis (AUC: 0.86 [95% confidence interval (95% CI): 0.78-0.94]; sensitivity: 81%; specificity: 78%), even for those with a CD4(+)/CD8(+) ratio <3.5 (AUC: 0.79 [95% CI: 0.64-0.93]; sensitivity: 75%; specificity: 78%).
  
  
  CONCLUSIONS
  Assessment of CD103 expression in BALF CD4(+) T-lymphocytes may be a reliable tool for sarcoidosis diagnosis, independently of CD4(+)/CD8(+) ratio, pointing out the relevance of evaluating the CD103(+)CD4(+)/CD4(+) ratio in the ILD diagnostic work-up.
authors.affiliation: Pulmonology Department, Centro Hospitalar de São João, EPE, 4200-319 Porto, Portugal.
authors.forename: Patrícia Caetano
authors.initials: PC
authors.lastname: Mota
authors.forename: António
authors.initials: A
authors.lastname: Morais
authors.forename: Carmo
authors.initials: C
authors.lastname: Palmares
authors.forename: Marília
authors.initials: M
authors.lastname: Beltrão
authors.forename: Natália
authors.initials: N
authors.lastname: Melo
authors.forename: Ana Cristina
authors.initials: AC
authors.lastname: Santos
authors.forename: Luís
authors.initials: L
authors.lastname: Delgado
mesh_terms: D000328:Adult; D015703:Antigens, CD / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry / Q000166:cytology; D016516:CD4-CD8 Ratio; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism*; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D039001:Integrin alpha Chains / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D017565:Sarcoidosis, Pulmonary / Q000175:diagnosis*; D012680:Sensitivity and Specificity
chemical_list: D015703:Antigens, CD; D015415:Biomarkers; D039001:Integrin alpha Chains; C091367:alpha E integrins