Viral infections in leukemia and bone marrow transplant patients

Infections by herpesviruses are common phenomena in patients being treated for acute leukemia and those undergoing bone marrow transplantation. Reactivation of endogenous latent virus caused by the immunosuppressive and cytotoxic effects of cytoreductive therapies is a common mechanism of infection. With cytomegalovirus (CMV), acquisition of exogenous virus by transfusion of blood products containing virus and from the bone marrow graft in the case of bone marrow transplantation can occur. Serious morbidity can result and occasional mortality. CMV infections in allogeneic BMT recipients have high case fatality rates. Treatment and preventive strategies for herpes simplex virus (HSV), CMV, and varicella zoster virus (VZV) have been developed to reduce morbidity. Acyclovir, either given prophylactically or as treatment of active infection, has been highly successful in reducing illness from HSV and VZV infection. For CMV, provision of CMV-seronegative blood products is the mainstay of prevention of morbidity in seronegative patients and is especially important in the care of patients undergoing allogeneic BMT. Ganciclovir given either prophylactically or as early therapy for patients detected to be shedding CMV appears to be a promising strategy. Bolstering host immunity through augmentation of anti-CMV cytotoxic T-cell responses appears to be an exciting candidate therapy under development.