title: Presence and significance of TT virus in Danish patients on maintenance hemodialysis.
abstract: OBJECTIVE
  To determine the prevalence of TT virus (TTV) in a population of Danish hemodialysis patients and evaluate possible relations between TTV infection and elevated levels of C-reactive protein (CRP) and hypo-response to treatment with erythropoietin (EPO).
  
  
  METHODS
  Patients on maintenance hemodialysis at a single center were invited to participate. Demographic and clinical data were registered. Blood samples for virological and routine biochemical tests were drawn simultaneously. TTV DNA was detected using polymerase chain reaction (PCR). TTV viral load was estimated by means of semi-quantitative PCR. All patients were tested for hepatitis B, hepatitis C and GB virus C.
  
  
  RESULTS
  Of 252 patients, 204 (80.9%) gave their written informed consent to participate in the study. The prevalence of TTV was 68% and 50% of TTV-positive patients had a high TTV viral load. TTV-positive patients were significantly older than TTV-negative patients (p = 0.011). No relations were found between TTV infection and elevated levels of alanine aminotransferase (ALT) or CRP or hypo-response to EPO treatment. The mean hemoglobin concentration was 11.24 +/- 1.48 g/dl. Patients with a high TTV viral load had a lower level of hemoglobin (10.86 +/- 1.47 g/dl) than the others (p = 0.01). This trend suggested a positive relation between TTV infection and the number of blood transfusions. A restriction fragment length polymorphism assay suggested that patients were infected with different TTV strains.
  
  
  CONCLUSIONS
  TTV is common in patients on maintenance hemodialysis. The presence of TTV is associated with increasing age. Patients with a high TTV viral load had lower levels of hemoglobin than the others. TTV infection is not related to elevated levels of ALT or CRP or to hypo-response to EPO treatment.
authors.affiliation: Clinical Research Unit, Hvidovre University Hospital, Denmark.
authors.forename: Trine
authors.initials: T
authors.lastname: Boysen
authors.forename: Jens K
authors.initials: JK
authors.lastname: Christensen
authors.forename: Chris D
authors.initials: CD
authors.lastname: Madsen
authors.forename: Jesper
authors.initials: J
authors.lastname: Eugen-Olsen
authors.forename: Laurids S
authors.initials: LS
authors.lastname: Christensen
authors.forename: Helle
authors.initials: H
authors.lastname: Møller-Sørensen
authors.forename: Annika
authors.initials: A
authors.lastname: Weber
authors.forename: Søren D
authors.initials: SD
authors.lastname: Ladefoged
authors.forename: Kim
authors.initials: K
authors.lastname: Krogsgaard
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D001483:Base Sequence; D015331:Cohort Studies; D004266:DNA Virus Infections / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology* / Q000209:etiology; D003718:Denmark / Q000453:epidemiology; D004921:Erythropoietin / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D015994:Incidence; D007676:Kidney Failure, Chronic / Q000628:therapy; D008134:Long-Term Care; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D011336:Probability; D011379:Prognosis; D011994:Recombinant Proteins; D006435:Renal Dialysis / Q000009:adverse effects* / Q000379:methods; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D012307:Risk Factors; D017678:Sex Distribution; D018709:Statistics, Nonparametric; D022783:Torque teno virus / Q000302:isolation & purification*; D019562:Viral Load
chemical_list: D011994:Recombinant Proteins; D004921:Erythropoietin