Viral diagnostics and antiviral therapy in hematopoietic stem cell transplantation.

Viral infections are important causes of morbidity and mortality in hematopoietic stem cell transplant (HSCT) recipients. Some viruses, such as the respiratory and gastrointestinal viruses, are acquired from the healthcare or community in the midst of or after HSCT. Other viruses, such as the herpes-virus family, establish latency after resolution of primary infection but then may reactivate during the immunosuppression that occurs with HSCT. Due to the improved sensitivity and turn-around time with PCR-based molecular diagnostic methods, traditional viral diagnostic methods such as viral culture and rapid shell vial are rapidly being replaced or supplemented. Prophylactic and preemptive strategies are increasingly used to limit reactivation of viruses that have established latency. Improvements in diagnostics result in earlier viral detection and antiviral initiation which may improve outcomes. Newly identified viruses such as human metapneumovirus are being increasingly recognized as pathogens in HSCT recipients. Treatment strategies for viral pathogens continue to change as our understanding of these viral diseases improves.