Clinical virology of cytomegalovirus infection following hematopoietic transplantation

Abstract

Cytomegalovirus (CMV) causes significant morbidity and mortality in allogeneic stem cell transplant recipients. The incidence of early CMV disease has been dramatically reduced by use of preemptive therapeutic strategies. Nevertheless, a trend toward a later appearance of CMV disease is being increasingly recognized. Currently, quantitative real-time PCR assays are the first-line choice for monitoring active CMV infection. However, no threshold DNAemia levels for triggering the initiation of preemptive therapy have been clinically validated in large studies. Although more time limited than universal prophylaxis, preemptive therapy strategies may also result in over treatment. Combined virological and immunological monitoring may lead to a more targeted use of antiviral therapy. The emergence of CMV strains resistant to antivirals is unfrequent, and must be suspected when rising viral DNAemia levels are observed after several weeks of treatment in the context of a severe immunosuppressive state. Genotypic assays are the first-line choice for detecting CMV resistance.