Alteration of protein kinase C conformation in red blood cells: a potential marker for Alzheimer's disease but not for Parkinson's disease.

There is a growing evidence of early changes of blood cells in Alzheimer's disease (AD). We have developed an original novel method for quantifying the alteration of protein kinase C (PKC) by its fluorescence spectrum: by using Fim-1, a specific fluorescent probe made for protein kinase C that detects the conformational changes of this. We show that the PKC conformation is altered in red blood cells (RBC) from AD patients as compared to RBC from healthy controls. This alteration is independent of the patient's age and of the stage of the disease. It is not observed in the RBC of non-demented patients suffering from Parkinson's disease (PD). If PKC alteration is proven to be specific to AD as compared with other dementia, this method could be for a simple, low cost screening test among patients suspected of having AD and may have a strong predictive value.