CMV: when bad viruses turn good

Abstract
Cytomegalovirus (CMV) has had a reputation for causing morbidity and mortality after allogeneic stem cell transplantation (SCT). In this issue of Blood, Elmaagacli et al find an unexpected favorable association of a low rate of leukemic relapse in acute myeloid leukemia patients who reactivate CMV in the first few weeks of SCT.1