Inactivation of infectious pathogens in labile blood components: meeting the challenge

Substantial improvement in the safety of blood transfusion has been achieved through the addition of new tests, such as nucleic acid tests, yet residual risk associated with transfusion of blood components persists. Transfusion of blood components has been implicated in the transmission of viruses, bacteria, and protozoa. While it is commonly recognized that hepatitis B virus (HBV), hepatitis C virus (HCV), cytomegalovirus (CMV), and the retroviruses, such as human immunodeficiency virus (HIV) and the human lymphotrophic viruses (HTLV) can be transmitted through cellular components, other pathogens are emerging as potentially significant transfusion-associated infectious agents. For example, transmission of protozoan infections due to trypanosomes and babesia have been reported. In addition to viral and protozoal infectious agents, bacterial contamination of platelet and red cell concentrates continues to be reported; and may be an under-reported transfusion complication. More importantly, new infectious agents may periodically enter the donor population before they can be definitively identified and tested for to maintain consistent safety of the blood supply. The paradigm for this possibility is the HIV pandemic, which erupted in 1979. During the past decade a number of methods to inactivate infectious pathogens in labile blood components have been developed and have entered the advanced clinical trial phase.