Expanding role of cytomegalovirus as a human pathogen.

Cytomegalovirus (CMV) continues to be a leading cause of morbidity and mortality in transplant recipients, despite major advancements in preventative strategies. Antiviral prophylaxis and pre-emptive antiviral therapeutic regimens are associated with a high incidence of late-onset end-organ disease and cause drug-related toxicity when overused. Therefore, the identification of risk factors for CMV replication is required. Genetic and immunological factors that predispose individuals to CMV-related clinical complications have been identified and may be instrumental for optimizing CMV treatment in the future. Evidence suggests a causal pathogenetic link between CMV-related complications and inflammatory diseases in non-canonically immunosuppressed individuals such as patients with lung injury and critically ill and cancer patients. However, a randomized clinical trial is required to determine if a causal relationship exists.