title: Vitamin D status and antimicrobial peptide cathelicidin (LL-37) concentrations in patients with active pulmonary tuberculosis.
abstract: BACKGROUND
  Vitamin D insufficiency is common in industrialized and developing nations. Recent studies have shown that vitamin D insufficiency is associated with a higher risk of active tuberculosis. Laboratory studies provided a mechanism for this link on the basis of findings that vitamin D metabolites regulate the expression of cathelicidin (LL-37), which is an endogenous antimicrobial peptide with activity against Mycobacterium tuberculosis. Little information is available on the clinical relation between vitamin D, LL-37 concentrations, and disease severity in patients with tuberculosis.
  
  
  OBJECTIVE
  The primary objective of the study was to evaluate the relation between vitamin D nutriture, serum LL-37 concentrations, and tuberculosis by using samples stored in the Tuberculosis Trials Consortium serum repository.
  
  
  METHODS
  We measured 25-hydroxyvitamin D [25(OH)D] and LL-37 concentrations in 95 serum specimens from patients with culture-confirmed pulmonary tuberculosis and correlated these concentrations to clinical and demographic variables.
  
  
  RESULTS
  The prevalence of vitamin D insufficiency [serum 25(OH)D concentration lt 30 ng/mL] in patients with active tuberculosis was 86% (n = 95) with a mean baseline serum 25(OH)D concentration of 20.4 ng/mL. Factors associated with vitamin D insufficiency were black race and indoor lifestyle. The mean ( plusmn SD) baseline LL-37 concentration was 49.5 plusmn 23.8 ng/mL. Higher LL-37 concentrations correlated with acid fast bacilli sputum smear positivity and weight gt 10% below ideal body weight. Serum vitamin D status of the study subjects did not correlate with serum LL-37 concentrations.
  
  
  CONCLUSIONS
  More prospectively designed studies are needed to evaluate the clinical implications of vitamin D insufficiency in patients with tuberculosis and the utility of circulating LL-37 as a potential biomarker in patients with active tuberculosis disease. The parent trial was registered at clinicaltrials.gov as NCT00023335.
authors.affiliation: Department of Medicine, Emory University, Atlanta, GA, USA. ayamshchikov@gmail.com
authors.forename: Alexandra V
authors.initials: AV
authors.lastname: Yamshchikov
authors.forename: Ekaterina V
authors.initials: EV
authors.lastname: Kurbatova
authors.forename: Meena
authors.initials: M
authors.lastname: Kumari
authors.forename: Henry M
authors.initials: HM
authors.lastname: Blumberg
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Ziegler
authors.forename: Susan M
authors.initials: SM
authors.lastname: Ray
authors.forename: Vin
authors.initials: V
authors.lastname: Tangpricha
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D023181:Antimicrobial Cationic Peptides; D044383:Black People; D054804:Cathelicidins / Q000097:blood*; D005260:Female; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification; D015995:Prevalence; D012307:Risk Factors; D012720:Severity of Illness Index; D013183:Sputum / Q000382:microbiology; D013472:Sunlight; D013851:Thinness; D014397:Tuberculosis, Pulmonary / Q000097:blood* / Q000150:complications / Q000188:drug therapy; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000150:complications* / Q000208:ethnology
chemical_list: D023181:Antimicrobial Cationic Peptides; D054804:Cathelicidins; D014807:Vitamin D; C104450:25-hydroxyvitamin D