Study of the diagnosis and treatment of prion diseases

Introduction: With the discovery of the prion protein (PrP), immunodiagnostic procedures were applied to diagnose Creutzfeldt–Jakobdisease (CJD). Materials and methods: Before the development of the conformation-dependent immunoassay (CDI), all immunoassays for the disease-causing PrP isoform (PrPSc) used limited proteolysis to digest the precursorcellular PrP (PrPC). A subset of 18 regions of patients brain with sporadic CJD (sCJD) was examined by histology, immunohistochemistry (IHC), and the CDI. Results: Three out of 18 regions showed consistently positive by histology and 4 out of 18 by IHC for the sCJD patients. In contrast, the CDI was positive in all 18 regions for all sCJD patients. In both gray and white matter, 90% of the total PrPSc was protease-sensitive and thus, it would have been degraded by procedures using proteases to eliminate PrPC. Findings argue that the CDI should be used to establish rule out the diagnosis of prion disease when a small number of samples is available as it is the case with brain biopsy. Conclusion: IHC should not be used as the standard against which all other immunodiagnostic techniques are compared because, an immunoassay such as the CDI, is substantially more sensitive

Keywords:

CJD , Prion disease , Immunohistochemistry (IHC) , Treatment , Diagnosis