Role of Donor Leukocytes and Leukodepletion in Transfusion-Associated Viral Infections

Research over the past decade has led to increasing appreciation of the importance of donor leukocytes in the transmission of blood-borne viruses. Donor leukocytes are directly involved in transmission of herpes viruses and retroviruses, agents which exist primarily as latent infections in lymphocytes of asymptomatic carriers. Controlled clinical studies have now established that filter-leukodepletion can prevent transmission of cytomegalovirus, and in vitro data suggests possible reduction in transmission of several retroviruses. Recent evidence also suggests that the immunological activation events that occur following transfusion of allogeneic donor leukocytes may both facilitate transmission of donor viral infections to recipients and precipitate reactivation of preexisting recipient viral infections.