Once the most feared infectious pathogen threatening patients after hematopoietic cell transplantation, cytomegalovirus (CMV) today is merely a shadow of its former self. We have come a long way in the past two decades. As with suppression of early infection and disease caused by other herpes viruses, forced patience in CMV allows resurgence later in patients whose immunity remains weakened. There is yet work to be done.
Tremendous strides have been made in minimizing the adverse effects of infection after hematopoietic stem cell transplantation (HSCT) over the past several decades. Sequentially, risk factors for various infectious complications have been identified; the nature of deficits in host defenses and their change over time have been characterized; new antimicrobial agents have supplanted older, more toxic, or less efficacious ones; and clinical trials to define the most effective ways to quell morbidity have been conducted.
What can be done about chronic graft-versus-host disease (GVHD)? Strategies that completely eradicate it rob much of the curative powers of allogeneic hematopoietic cell transplantation (HCT). Left uncontrolled, it is a source of considerable morbidity and represents the major cause of death in HCT survivors.