Prophylaxis of cytomegalovirus infection.

Effective prophylaxis of cytomegalovirus (CMV) infection following bone marrow transplantation is based on the epidemiology of infection. In seronegative recipients, primary infection is acquired from blood products or bone marrow derived from seropositive donors. The principal source of infection in seropositive recipients appears to be reactivation of latent endogenous CMV. Transfusion-associated infection can be eliminated by using only seronegative donors for transfusion support. The putative source of virus is the leukocyte, and leukocyte depletion has been shown to be an effective alternative to the use of seronegative blood products. Passive immunoprophylaxis with different immunoglobulin preparations to prevent primary infection or to modify the manifestations of infection has been extensively explored with conflicting results. Whether these differing results are attributable to differences in the regimen or the dose of immunoglobulin remains unclear. Although the most common source of CMV infection in seropositive patients is reactivation, reinfection may also occur. Passive immunoprophylaxis has been studied less in seropositive bone marrow recipients, but no protection was observed in two trials. Suppression of CMV with antiviral agents may be the most effective means of preventing disease due to viral reactivation. In one study, intravenous acyclovir was shown to reduce the incidence of CMV disease by 50%, although this result warrants confirmation. Ganciclovir and foscarnet are also under investigation as prophylactic agents for the prevention of CMV disease in seropositive patients.