title: Diagnostic Value of the CD103+CD4+/CD4+ Ratio to Differentiate Sarcoidosis from Other Causes of Lymphocytic Alveolitis.
abstract: BACKGROUND
  The CD103 integrin is present on CD4+ lymphocytes of the bronchial mucosa, but not on peripheral blood CD4+ lymphocytes. It has been hypothesized that CD4+ lymphocytes in pulmonary sarcoidosis originate from redistribution from the peripheral blood to the lung, and therefore do not bear the CD103 integrin. Some data suggest that a low CD103+ percentage among bronchoalveolar lavage fluid (BALF) CD4+ lymphocytes discriminates between sarcoidosis and other diagnoses.
  
  
  OBJECTIVE
  To determine the diagnostic value of BALF CD103+ to identify sarcoidosis among other causes of alveolar lymphocytosis in a large retrospective case series.
  
  
  METHODS
  Among 391 consecutive bronchoalveolar lavages performed at our institution and analyzed by flow cytometry, we identified 207 cases, which were grouped into nine diagnostic categories: sarcoidosis, tuberculosis, non-tuberculous infections, hypersensitivity pneumonitis, non-specific interstitial pneumonia, organizing pneumonia, drug-induced lung diseases, other interstitial lung diseases (ILDs), and other diagnoses. To assess the discriminative value of the CD103+CD4+/CD4+ ratio to distinguish sarcoidosis from other entities, areas under ROC curves (AUC) were calculated.
  
  
  RESULTS
  Sarcoidosis patients (n = 53) had significantly lower CD103+CD4+/CD4+ ratios than patients in other diagnostic categories. The AUC was 62% for sarcoidosis compared to all other diagnoses, and 69% for sarcoidosis compared to other ILDs. When combining CD103+CD4+/CD4+ and CD4+/CD8+ ratios, the AUC increased to 76 and 78%, respectively. When applying previously published cut-offs to our population, the AUC varied between 54 and 73%.
  
  
  CONCLUSIONS
  The CD103+CD4+/CD4+ ratio does not accurately discriminate between sarcoidosis and other causes of lymphocytic alveolitis, neither alone nor in combination with the CD4+/CD8+ ratio, and is not a powerful marker for the diagnosis of sarcoidosis.
authors.affiliation: Lausanne University School of Medicine, Lausanne, Switzerland.
authors.forename: Lisa
authors.initials: L
authors.lastname: Bretagne
authors.forename: Ibrahima-Dina
authors.initials: ID
authors.lastname: Diatta
authors.forename: Mohamed
authors.initials: M
authors.lastname: Faouzi
authors.forename: Antoine
authors.initials: A
authors.lastname: Nobile
authors.forename: Massimo
authors.initials: M
authors.lastname: Bongiovanni
authors.forename: Laurent P
authors.initials: LP
authors.lastname: Nicod
authors.forename: Romain
authors.initials: R
authors.lastname: Lazor
mesh_terms: D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000378:metabolism*; D016516:CD4-CD8 Ratio; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D039001:Integrin alpha Chains / Q000378:metabolism*; D008214:Lymphocytes / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D017565:Sarcoidosis, Pulmonary / Q000175:diagnosis* / Q000276:immunology
chemical_list: D015703:Antigens, CD; D039001:Integrin alpha Chains; C091367:alpha E integrins