Our previous bioassay studies in lambs and a transgenic mouse line (Tg338) expressing the ovine VRQ PRNP allele revealed that scrapie prions were associated with different peripheral blood components such as buffy coat, peripheral blood mononuclear cells (PBMC), B lymphocytes and platelet-rich plasma from preclinically and clinically affected sheep naturally infected with classical scrapie [8, 9]. This evidence concerns the gene PRNP and scrapie.