A firm diagnosis of variant Creutzfeldt Jakob disease (vCJD) is difficult to make because it is based on distinguishing misfolded prion proteins (PrP^Sc) from normally folded prion proteins in human brain biopsies. In 20 July issue of the Lancet, Wadsworth and colleagues from Imperial College School of Medicine, London, UK, describe a new technique based on a highly sensitive immunoblotting assay that can accurately detect PrP^Sc in peripheral tissue in patients suspected of vCJD.

Wadsworth et al. applied a selective precipitation technique combined with high-sensitivity western blotting and enhanced chemiluminescence to identify PrP^Sc in post-mortem tissues from four patients with confirmed vCJD and from individuals without neurological disease. With this method they could detect PrP^Sc in peripheral tissue at concentrations 104-105-fold lower than those reported in the brain. Concentrations of PrP^Sc were consistently higher in tonsils and spleen while all other tissues tested...