LETTERS TO THE EDITOR Volume 39, September 1999 TRANSFUSION 1035 L E T T E R S T O T H E E D I T O R Absence of intrauterine transmission of TT virus TT virus is a DNA agent that has recently been identified in the serum of a patient with transfusion-associated hepatitis of unknown etiology. 1 Thus far, TT virus has not been associ- ated with clinical disease. It may be transmitted by blood transfusion, 1-3 but its presence in persons at low risk for blood-borne infections, 3 including infants less than 2 years old, 4 suggests that nonparenteral transmission may occur. In light of the structural similarities between TT virus and parvoviruses 1 (whose role in inducing serious intrauterine infections in newborns is well known 5 ), we considered it par- ticularly important to determine whether congenital trans- mission of TT virus occurs. We studied 101 pregnant women who enrolled consecu- tively in the Milano Cord Blood Bank program between Janu- ary 1997 and February 1998. Blood samples were collected from the women and from the umbilical vein of their live- born infants following full-term deliveries. The median age of the women was 32 years (range, 23-44 years). Ninety-four women (93.1%) had a vaginal delivery, and 7 (6.9%) had cae- sarean delivery. All 101 women tested negative for hepatitis B surface antigen (Wellcozyme HBsAg, Abbott Laboratories, Chicago, IL), antibodies to HIV(HIV-1/ HIV-2, Ortho Diagnos- tic Systems, Raritan, NJ), and antibodies to hepatitis C virus (HCV 3.0, Ortho). Serum TT virus DNA, detected by a semi- nested polymerase chain reaction, 3 was found in 9 (8.9%) of 101 women. However, 0 of 9 newborns of TT virus-infected women were viremic, as determined by the absence of TT virus DNA in their sera. The 5-minute Apgar score distribu- tion was not different for newborns of TT virus DNA-positive mothers and newborns of TT virus DNA-negative mothers (8.78 ± 0.67 vs. 9.21 ± 0.85; p>0.05 by t test). Six months after delivery, follow-up interviews were con- ducted by a blood bank physician. At that time, all 101 infants were alive and well, except for 1 infant of a TT virus DNA- negative mother; this infant had developed renal thrombo- sis at 1 month of age. Our findings suggest that, despite a rela- tively high frequency of TT virus infection among women of reproductive age, intrauterine transmission of TT virus is an uncommon event. Because we studied only women who delivered live-born infants, we cannot exclude the possibil- ity that TT virus is associated with fetal damage at earlier stages of pregnancy. Furthermore, we cannot exclude peri- natal transmission during delivery, as our samples were ob- tained from cord blood. Daniele Prati, MD e-m ail: dprati@yahoo.com Claudia De Mattei, DSc Elena Farma, DSc Lucilla Lecchi, DSc Girolamo Sirchia, MD, FRCP (Edin) Centro Trasfusionale e di Im m unologia dei Trapianti IRCCS Ospedale Maggiore Milan, Italy Benjamin Chen, PhD Sentinel Biosciences, Inc. Palo Alto, CA REFERENCES 1. Okamoto H, Nishizawa T, Kato N, et al. Molecular cloning and characterization of a novel DNA virus (TTV) associated with posttransfusion hepatitis of unknown etiology. Hepatol Res 1998;10:1-16. 2. Simmonds P, Davidson F, Lycett C, et al. Detection of a novel DNA virus (TTV) in blood donors and blood products. Lan- cet 1998;352:191-5. 3. Prati D, Lin YH, De Mattei C, et al. A prospective study on TT virus (TTV) infection in transfusion-dependent patients with β-thalassemia. Blood 1999; 93:1502-5. 4. Yamada-Osaki M, Sumazaki R, Noguchi E, et al. Transfusion- transmitted virus. Lancet 1998;352:1309-10. 5. Brown KE, Green SW, Antunez de Mayolo J, et al. Congenital anaemia after transplacental B19 parvovirus infection. Lan- cet 1994; 343:895-6.