Viremia and excretion of TT virus in immunosuppressed heart transplant recipients and in immunocompetent individuals

Background. The TT virus (TTV) was discovered in patients with symptomatic posttransfusion hepatitis, but many viremic individuals are asymptomatic. I nadvertent transfusion-associated transmission must therefore be anticipate d. We screened blood donors and heart transplant recipients for TTV infecti ons. Methods. Nested polymerase chain reaction was used to detect TTV DNA in pla sma, serum, urine, and fecal samples from 600 blood donors, from 100 health y individuals, and from 495 heart transplant recipients. Results. A total of 3.2% of the blood donors, but 25% of the heart transpla nt recipients were viremic, TTV subtypes G1a/b and G2a/b were observed in b oth groups, but the subtype distributions were discrepant. A severe, acute infection with TTV subtype 3 was observed in one blood donor. The prevalenc e of TTV infections in heart transplant recipients was not correlated to tr ansfusion frequency. Nine viremic heart transplant recipients and their 75 blood donors were studied in detail. Seven blood donors were viremic, but o nly two "pairs" of viremic blood donors and transfusion recipients had iden tical TTV isolates. TTV DNA was detected in the feces of 5% (5/100) of immu nocompetent individuals (staff), in 46% (52/112) of viremic heart transplan t recipients, and in the urine of 55% (20/36), TTV DNA was detected in six of six batches of pooled "virus-inactivated" plasma (solvent/detergent trea ted), and in none of eight batches of commercial immunoglobulins. Conclusion. Although TTV is transfusion-transmissible, the parenteral trans mission rate may have been overestimated. Many TTV infections are apparentl y acquired by nonparenteral routes. Immunoglobulins are safe but pooled pla sma is not safe regarding TTV transmission.