Assessment of removal of human cytomegalovirus from blood components by leukocyte depletion filters using real-time quantitative PCR.

To assess removal of cytomegalovirus (CMV) by leukocyte depletion (LD) filters, we developed a spiking model of latent virus using peripheral blood mononuclear cells (PBMCs) infected by coculture with CMV-infected human fibroblasts. Infected PBMCs were purified by dual magnetic column selection and then spiked into whole blood units or buffy coat pools prior to LD by filtration. CMV load and fibroblast contamination were assessed using quantitative CMV DNA real-time PCR and quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) of mRNA encoding the fibroblast-specific splice variant of prolyl-4-hydroxylase, respectively. After correcting for fibroblast-associated CMV, the mean CMV load was reduced in whole blood by LD from 7.42 x 10(2) to 1.13 copies per microliter (2.81(10)log reduction) and from 3.8 x 10(2) to 4.77 copies per microliter (1.9(10)log reduction) in platelets. These results suggest that LD by filtration reduces viral burden but does not completely remove CMV from blood components.