title: Tobacco mosaic virus in cigarettes and saliva of smokers.
abstract: BACKGROUND
  Tobacco mosaic virus (TMV) has been described as viable in cigarettes or cigar tobacco. It has been cultured about 50 years ago from sputa and thoracentesis fluids of cigarette smokers with a history of pulmonary disease and from lung cancerous matter. In addition, TMV RNA has been recovered recently from human stools while tobacco DNA was recovered from smokers' bronchoalveolar lavages.
  
  
  OBJECTIVE
  We assessed the prevalence, titers, and infectivity of TMV in tobacco cigarettes and in the saliva of smokers and non smokers.
  
  
  METHODS
  Tobacco cigarettes from 10 packs of different brands were purchased. Saliva was collected from 12 smokers and 15 non-smokers. Cigarettes and saliva samples were tested for the presence of TMV RNA using a home-made quantitative real-time RT-PCR assay. TMV RNA quantification was enabled by using dilutions of purified TMV. TMV viability was tested by inoculating leaves of Nicotiana tabacum Xanthi (NtX).
  
  
  RESULTS
  All 47 smoking cigarettes of six brands were TMV RNA-positive (mean titer, 9.5 log(10)copies/cigarette); TMV was found viable in 53% of them. In addition, 20/44 (45%) saliva from 12 smokers compared to 0/16 saliva from 15 non-smokers tested positive for TMV RNA (mean titer, 3.8 log(10)copies/ml) (p=0.001).
  
  
  CONCLUSIONS
  Our results indicate that the TMV genome may get access to the human body by direct exposure through smoking. Although plant viruses are considered not pathogenic for animals, these data prompt to study if TMV RNA is present and induces a modification of the transcriptional program in lung cells of cigarette smokers.
authors.affiliation: Aix-Marseille University, URMITE UM63 CNRS 7278 IRD 198 INSERM U1095, IHU Méditerranée Infection, 27 Boulevard Jean Moulin, 13385 Marseille Cedex 05, France.
authors.forename: Fanny
authors.initials: F
authors.lastname: Balique
authors.forename: Philippe
authors.initials: P
authors.lastname: Colson
authors.forename: Didier
authors.initials: D
authors.lastname: Raoult
mesh_terms: D006801:Humans; D015995:Prevalence; D060888:Real-Time Polymerase Chain Reaction; D012463:Saliva / Q000821:virology*; D012907:Smoking; D014027:Tobacco Mosaic Virus / Q000302:isolation & purification*; D062789:Tobacco Products / Q000821:virology*; D019562:Viral Load; D014776:Virus Cultivation