Creutzfeldt-Jakob disease: heat shock protein 70 mRNA levels in mononuclear blood cells and clinical study

Prion diseases such as Creutzfeldt-Jakob disease (CJD) are associated in mo st cases with the accumulation of an unusual isoform of prion protein (PrPS C). PrPSC is derived from the abnormal folding of the cellular isoform of p rion protein (PrPC). On the other hand, heat shock protein is known to ensu re proper protein assembly and folding and to facilitate proteolytic digest ion of abnormal or denatured proteins. Many studies have therefore hypothes ized that heat shock protein is linked to prion disease. We examined the re lationship between heal shock protein HSP70 and prion disease in CJD patien ts. HSP70 mRNA levels in mononuclear blood cells (MBCs) were compared in 14 CJD patients (10 confirmed by histo-pathological study), 12 vascular demen tia (VD) patients, 16 patients with Parkinson's disease and dementia (PD) a nd 14 nondemented control subjects. The possible correlation between HSP70 mRNA expression levels and clinical findings was also evaluated. HSP70 mRNA expression levels in MBCs were measured by northern blotting, HSP70 mRNA l evels in MBCs from patients with CJD were significantly higher than those f rom patients with VD or PD and in nondemented controls. Age at symptom onse t, dementia severity, disease duration and neuroimaging grade of CJD patien ts were not correlated with relative HSP70 mRNA levels. No significant rela tionship between HSP70 mRNA levels and ageing was found. These results sugg est that measurement of HSP70 mRNA in MBCs might provide an auxiliary tool for the diagnosis of CJD.