THE DISTRIBUTION OF INFECTIVITY IN BLOOD COMPONENTS AND PLASMA DERIVATIVES IN EXPERIMENTAL-MODELS OF TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHY

BACKGROUND: The administration of blood components from donors who sub sequently develop Creutzfeldt-Jakob disease has raised the issue of bl ood as a possible vehicle for iatrogenic disease. STUDY DESIGN AND MET HODS: We examined infectivity in blood components and Cohn plasma frac tions in normal human blood that had been ''spiked'' with trypsinized cells from a scrapie-infected hamster brain, and in blood of clinicall y ill mice that had been inoculated with a mouse-adapted strain of hum an transmissible spongiform encephalopathy. Infectivity was assayed by intracerebral inoculation of the blood specimens into healthy animals . RESULTS: Most of the infectivity in spiked human blood was associate d with cellular blood components; the smaller amount present in plasma , when fractionated, was found mainly in cryoprecipitate (the source o f factor VIII) and fraction I+II+III (the source of fibrinogen and imm unoglobulin); almost none was recovered in fraction IV (the source of vitamin-K-dependent proteins) and fraction V (the source of albumin). Mice infected with the human strain of spongiform encephalopathy had v ery low levels of endogenous infectivity in buffy coat, plasma, cryopr ecipitate, and fraction I+II+III, and no detectable infectivity in fra ctions IV or V. CONCLUSION: Convergent results from exogenous spiking and endogenous infectivity experiments, in which decreasing levels of infectivity occurred in cellular blood components, plasma, and plasma fractions, suggest a potential but, minimal risk of acquiring Creutzfe ldt-Jakob disease from the administration of human plasma protein conc entrates.