Histocompatibility antigens in Alzheimer's disease. A preliminary study.

A preliminary study of Alzheimer's disease showed an apparent excess of the antigen A2 in patients who presented the disease before the age of 60, whereas those with onset after 64 showed different frequencies of the antigens A1 and A3 when compared with the local population. There was no abnormality in the distribution of B locus antigens. The findings are briefly discussed.