Transmission of HTLV-II via blood transfusion.

Transmission of HTLV-I by transfusion is well documented in Japan, where HTLV-I is endemic. In non endemic regions such as the United States, HTLV-I/II infection has been transmitted by transfusion as well, but no effort to distinguish HTLV-I from HTLV-II infection was made in these studies. There is a growing body of evidence that a substantial proportion of HTLV-I/II seropositivity in the US is due to infection with HTLV-II. We report 2 cases of apparent transfusion-transmitted HTLV-II infection and discuss the importance of distinguishing between the two viruses in blood donors and recipients.