title: Serum torque teno virus DNA titer in idiopathic pulmonary fibrosis patients with acute respiratory worsening.
abstract: OBJECTIVE
  Acute respiratory worsening is defined as the unexpected rapid deterioration of idiopathic pulmonary fibrosis (IPF), and idiopathic acute respiratory worsening is known as an acute exacerbation of IPF. Torque teno virus (TTV) is a circular single-stranded DNA virus whose pathological significance remains unclear. The aim of the present study was to investigate the prevalence and titer of TTV DNA in IPF patients with acute respiratory worsening.
  
  
  METHODS
  The serum TTV DNA titer was measured using real-time PCR in nine IPF patients (two treated with steroids and immunosuppressants; seven treated without steroids or immunosuppressants) who developed acute worsening, including five patients with acute exacerbation. The serum TTV DNA titer was also measured in eight stable IPF cases and four IPF cases of lung cancer. In addition, in order to examine time course changes in the TTV DNA titer, the titer was measured more than once, with an interval of four weeks or longer, in eight patients.
  
  
  RESULTS
  Among the nine IPF patients with acute worsening, the TTV DNA titer was above 1×10(6) copies/mL in two subjects without acute exacerbation who had been continuously treated with steroids and immunosuppressants. Meanwhile, the mean TTV DNA titer was 2.4±2.6 (×10(4) copies/mL) in the five patients with acute exacerbation and 3.1±3.4 (×10(4) copies/mL) in the eight patients with stable IPF. Moreover, the TTV DNA titers were increased in all three IPF patients who started treatment with steroids and immunosuppressants.
  
  
  CONCLUSIONS
  Our results suggest that it is unlikely that TTV is directly involved in the onset of acute exacerbation of IPF and that the serum TTV DNA titer potentially reflects the immunosuppressive state of the host due to treatment.
authors.affiliation: Division of Pulmonary Medicine, Department of Medicine, Jichi Medical University, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Bando
authors.forename: Masayuki
authors.initials: M
authors.lastname: Nakayama
authors.forename: Masaharu
authors.initials: M
authors.lastname: Takahashi
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Hosono
authors.forename: Naoko
authors.initials: N
authors.lastname: Mato
authors.forename: Hideaki
authors.initials: H
authors.lastname: Yamasawa
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Okamoto
authors.forename: Yukihiko
authors.initials: Y
authors.lastname: Sugiyama
mesh_terms: D000368:Aged; D001992:Bronchoalveolar Lavage Fluid / Q000821:virology; D004266:DNA Virus Infections / Q000503:physiopathology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000503:physiopathology* / Q000821:virology; D008297:Male; D015995:Prevalence; D060888:Real-Time Polymerase Chain Reaction; D012141:Respiratory Tract Infections / Q000503:physiopathology* / Q000821:virology; D017422:Sequence Analysis, DNA; D022783:Torque teno virus / Q000235:genetics*