[Application of a test of cellular fusion in Creutzfeldt-Jakob and Alzheimer diseases (author's transl)].

We have tested the in vitro cellular fusing activity of brain suspensions from the following categories of patients: CJD (53 cases), Alzheimer (23 cases), and non-neurological controls (25 cases). CSF specimens were also available for 26 of the CJD patients. Our results show that 65-75 per cent of CJD brain specimens induce cell fusion but that this activity is only rarely reflected in matched CSF specimens. Among other types of degenerative neurological diseases, a sharp distinction appeared between familial Alzheimer disease, which caused fusion at nearly the same frequency as CJD, and sporadic Alzheimer disease, which was not significantly different from the non-neurological control specimens. The biological and clinical significance of these results are discussed.