title: Cathelicidin as a link between sarcoidosis and tuberculosis.
abstract: METHODS
  Sarcoidosis and tuberculosis share notable clinical, radiological, histological, and immunological similarities. The importance of vitamin D has long been investigated in these two granulomatous lung diseases. Cathelicidin is an antimicrobial peptide of the innate immune system, directly induced by vitD3.
  
  
  OBJECTIVE
  To evaluate the role of cathelicidin in sarcoidosis and tuberculosis development.
  
  
  METHODS
  The study included 30 consecutive patients with active lung tuberculosis, 30 patients with sarcoidosis, and 20 healthy controls. 25-hydroxyvitamin D [25(OH)D] and cathelicidin levels were measured in blood samples.
  
  
  RESULTS
  Vitamin D levels were significantly higher (p<0.001) in tuberculosis patients (22.5 ± 9.96 ng/ml) than in sarcoidosis patients (11.75 ± 8.92 ng/ml). Severe vitamin D deficiency was as frequent as 47% in sarcoidosis patients compared to only 3% in tuberculosis patients. Cathelicidin levels were significantly higher in the control group (120.37 ± 41.03 pg/ml) than in sarcoidosis (67.68 ± 38.03 pg/ml) and tuberculosis (68.74 ± 39.44 pg/ml) patients (p<0.001). However, no significant difference in cathelicidin levels was observed between tuberculosis and sarcoidosis patients (p=0.966). The optimum cathelicidin cut-off value to distinguish sarcoidosis patients from healthy controls was 107.14 pg/ml (sensitivity 81.5%, specificity 71.2%).
  
  
  CONCLUSIONS
  Cathelicidin appears to play different roles in the development of granulomatous lung disease.
authors.affiliation: Yedikule Chest Diseases and Surgery Education and Research Hospital, Istanbul. korucuercan@hotmail.com.
authors.forename: Ercan
authors.initials: E
authors.lastname: Korucu
authors.forename: Leyla
authors.initials: L
authors.lastname: Pur Ozyigit
authors.forename: Mediha Gonenc
authors.initials: MG
authors.lastname: Ortakoylu
authors.forename: Ayse
authors.initials: A
authors.lastname: Bahadir
authors.forename: Esma Seda
authors.initials: ES
authors.lastname: Akalin
authors.forename: Asuman
authors.initials: A
authors.lastname: Kara
authors.forename: Hafize
authors.initials: H
authors.lastname: Uzun
authors.forename: Burak
authors.initials: B
authors.lastname: Onal
authors.forename: Emel
authors.initials: E
authors.lastname: Caglar
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D023181:Antimicrobial Cationic Peptides / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D003937:Diagnosis, Differential; D015536:Down-Regulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D017565:Sarcoidosis, Pulmonary / Q000097:blood* / Q000175:diagnosis; D014397:Tuberculosis, Pulmonary / Q000097:blood* / Q000175:diagnosis; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000175:diagnosis; D055815:Young Adult; D054804:Cathelicidins
chemical_list: D023181:Antimicrobial Cationic Peptides; D015415:Biomarkers; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D054804:Cathelicidins