Laboratory diagnosis of variant Creutzfeldt-Jakob disease

The neuropathological and biochemical features of 33 cases of variant Creut zfeldt-Jakob disease (vCJD) diagnosed up to the end of 1998 are analysed in relation to the 646 cases of suspected CJD referred to the CJD Surveillanc e Unit laboratory from 1990 to 1998. Morphological studies of the central n ervous system, lymphoid tissues and other organs were accompanied by immuno cytochemistry;. Western blot analysis of PrPRES was performed on frozen bra in tissue. The findings were analysed in relation to clinical and genetic d ata. The pathology of vCJD showed morphological and immunocytochemical char acteristics distinct from other cases of CJD. PrP accumulation was widespre ad in lymphoid tissues in vCJD, but was not identified in other non-neural tissues. PrPRES accumulation in vCJD brain tissue showed a uniform glycotyp e pattern distinct from sporadic CJD All analysed cases of vCJD were methio nine homozygotes at codon 129 of the PrP gene. No evidence currently exists to suggest that cases of CJD diagnosed in indi viduals who are MV or VV at codon 129 of the PrP gene represent 'human bovi ne spongiform encaphalopathy (BSE)'. Continued surveillance is required to further investigate this possibility, with the need to investigate autopsy tissues from suspected cases by histological and biochemical techniques.