title: Polymorphism of the TT virus and its frequency in Polish blood donors.
abstract: OBJECTIVE
  To determine, in Polish blood donors, the frequency of TT virus (TTV) using different primers and the sequence diversity of TTV genotypes.
  
  
  METHODS
  Two-hundred blood donors were studied. TTV DNA was detected by the polymerase chain reaction (PCR) using primers for the coding (ORF1) and non-coding (NC) regions. Twenty isolates were genotyped by sequencing the ORF1 fragment.
  
  
  RESULTS
  TTV DNA was detected in 78% of donors using NC primers and in 10% using ORF1 primers. The frequency of TTV DNA detection by NC primers was observed to increase with donor age, whereas the frequency of detection by ORF primers did not differ between various age-groups. The nucleotide sequence homology of Polish TTV isolates ranged from 59 to 99%. Three genotypes (1b, 2b and 2c) were identified.
  
  
  CONCLUSIONS
  The frequency of TTV detection depends on the primers used for the PCR. Using the NC primers the virus is detected in the majority of donors, whereas the ORF1 primers strongly underestimate the prevalence of TTV. The frequency of TTV DNA increases with age. Polish TTV isolates are highly polymorphic and are classified as 1b, 2b and 2c.
authors.affiliation: Institute of Haematology and Blood Transfusion, Warsaw, Poland. pit@init.waw.pl
authors.forename: P
authors.initials: P
authors.lastname: Grabarczyk
authors.forename: E
authors.initials: E
authors.lastname: Brojer
mesh_terms: D000328:Adult; D000367:Age Factors; D001782:Blood Donors; D017931:DNA Primers; D004266:DNA Virus Infections / Q000453:epidemiology* / Q000235:genetics; D005188:False Negative Reactions; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D011044:Poland; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D015995:Prevalence; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA; D022783:Torque teno virus / Q000235:genetics*
chemical_list: D017931:DNA Primers