Detection by PCR of TTV DNA in serum from 24 previously untreated patients (PUPs) with hemophilia.

The baseline samples were obtained just before the first infusion with recombinant concentrates. Serum samples after the first and the last treatments were obtained 3 to 6 months after the corresponding infusion. A plus sign indicates positive results on PCR assay; a negative sign, negative results; and an asterisk, sample not available.