Epidemiological and quantitative study of GBV-C infection in french polytransfused children

From 1999 to 2002, 246 serum samples taken from polytransfused children were tested for the presence of GB virus C (GBV-C) RNA using a real-time reverse transcription-polymerase chain reaction (RT-PCR) assay. This assay was based on the TaqMan technology and allowed viral load determination in infected children with a dynamic range from 10(3) to 10(7) genome equivalent (gEq) copies/ml. The limit of detection was estimated to 619 gEq copies/ml with a > or = 95% probability of a positive result. Thirty five sera were found to be GBV-C RNA positive, corresponding to a prevalence of GBV-C of 14.2%. The mean viral load was high, i.e., 6 +/- 1.4 log (range 3.22-7.42) gEq copies/ml, but low viral loads were also detected. Sequencing of the 5'-untranslated region (UTR) identified a majority of genotype 2 strains (82%) distributed into two subtypes, 88.5% genotype 2a and 11.5% genotype 2b. In conclusion, GBV-C active infection is very frequent in exposed populations such as polytransfused children. GBV-C RNA quantitation using real-time assay may be useful for diagnosis and follow-up of the natural history of GBV-C infection.