3. Be presenting with recurrent CMV infection (defined as a new detection of CMV infection in a subject who had at least one previously documented episode of CMV infection posttransplant, and who has had at least 2 weeks of undetectable CMV DNA between the episodes (during active surveillance, based on same local laboratory and same sample type). The subject must also have been off any anti-CMV treatment between the current and prior infection. Otherwise, the current infection may be considered continuation of the prior infection.