Transfusion-transmitted cytomegalovirus: the part-time pathogen

Viral infection is a well-known risk of blood product transfusion and much work has been devoted to the detection of such well-known pathogens as human immunodeficiency virus and hepatitis viruses in blood donors. Cytomegalovirus (CMV) is found in a much larger percentage of donor units than these other viruses but will cause disease in only a minority of recipients. Many pediatric patients (especially premature infants) are at risk for transfusion-transmitted CMV. This review describes work delineating the populations of patients most at risk for transfusion-transmitted CMV, describes methods for detecting CMV in blood donors, evaluates current methods for leuko-depletion of blood products, and provides recommendations for patients most likely to benefit from blood products with low risk of CMV transmission.